Hello,
this series adds drivers for the UART and ACM controllers found in the
Espressif ESP32 and ESP32S3 SoCs.
Changes v3->v4:
- address review comments, listed in each patch
- add reviewed-by tags
Changes v2->v3:
- address review comments, listed in each patch
Changes v1->v2:
- address review comments, listed in each patch
- add cleanup for the uart_get_baud_rate function
Max Filippov (5):
serial: core: tidy invalid baudrate handling in uart_get_baud_rate
dt-bindings: serial: document esp32-uart
drivers/tty/serial: add driver for the ESP32 UART
dt-bindings: serial: document esp32s3-acm
drivers/tty/serial: add ESP32S3 ACM device driver
.../bindings/serial/esp,esp32-acm.yaml | 42 +
.../bindings/serial/esp,esp32-uart.yaml | 51 ++
drivers/tty/serial/Kconfig | 27 +
drivers/tty/serial/Makefile | 2 +
drivers/tty/serial/esp32_acm.c | 459 +++++++++++
drivers/tty/serial/esp32_uart.c | 741 ++++++++++++++++++
drivers/tty/serial/serial_core.c | 4 +-
include/uapi/linux/serial_core.h | 6 +
8 files changed, 1329 insertions(+), 3 deletions(-)
create mode 100644 Documentation/devicetree/bindings/serial/esp,esp32-acm.yaml
create mode 100644 Documentation/devicetree/bindings/serial/esp,esp32-uart.yaml
create mode 100644 drivers/tty/serial/esp32_acm.c
create mode 100644 drivers/tty/serial/esp32_uart.c
--
2.30.2
Add driver for the UART controllers of the Espressif ESP32 and ESP32S3
SoCs. Hardware specification is available at the following URLs:
https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf
(Chapter 13 UART Controller)
https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
(Chapter 26 UART Controller)
Signed-off-by: Max Filippov <[email protected]>
---
Changes v2->v3:
- rework brk handling in esp32_uart_rxint
- only increment port->icount.rx in case insert_flip_char() is called
- use HZ instead of msecs_to_jiffies(1000) in esp32_uart_put_char_sync
- add early return to esp32_uart_transmit_buffer
- use request_irq/free_irq instead of devm_* versions
- add blank lines before certain return statements
Changes v1->v2:
- redefine register fields using BIT and GENMASK
- drop _MASK suffix from register field definitions
- drop *_SHIFT definitions where possible
- drop unused rxfifo_full_thrhd_mask and txfifo_empty_thrhd_mask
- split register reads/writes and bitwise operations into multiple lines
- use u8 instead of unsigned char in internal functions
- add timeout to esp32_uart_put_char_sync
- use uart_port_tx_limited in esp32_uart_transmit_buffer
- use IRQ_RETVAL in esp32_uart_int
- disable clock in esp32_uart_startup in case devm_request_irq fails
- rearrange devm_request_irq with enabling IRQs in the UART registers
- drop empty esp32_uart_release_port and esp32_uart_request_port
- simplify esp32_uart_tx_empty
- mask out unsupported CMSPAR flag in termios->c_cflag in
esp32_uart_set_termios
- invoke uart_update_timeout in esp32_uart_set_termios
- drop MODULE_DESCRIPTION
- rearrange esp32_uart_set_baud: return bool indicating whether baud
rate was set or not, use it in the esp32_uart_set_termios to set the
default 115200
- turn 'locked' into bool in esp32_uart_console_write
- turn num_read into unsigned int in esp32_uart_earlycon_read
drivers/tty/serial/Kconfig | 13 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/esp32_uart.c | 741 +++++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
4 files changed, 758 insertions(+)
create mode 100644 drivers/tty/serial/esp32_uart.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index bdc568a4ab66..d9ca6b268f01 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1578,6 +1578,19 @@ config SERIAL_NUVOTON_MA35D1_CONSOLE
but you can alter that using a kernel command line option such as
"console=ttyNVTx".
+config SERIAL_ESP32
+ tristate "Espressif ESP32 UART support"
+ depends on XTENSA_PLATFORM_ESP32 || (COMPILE_TEST && OF)
+ select SERIAL_CORE
+ select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
+ help
+ Driver for the UART controllers of the Espressif ESP32xx SoCs.
+ When earlycon option is enabled the following kernel command line
+ snippets may be used:
+ earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000
+ earlycon=esp32uart,mmio32,0x3ff40000,115200n8
+
endmenu
config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 138abbc89738..7b73137df7f3 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o
+obj-$(CONFIG_SERIAL_ESP32) += esp32_uart.o
# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/esp32_uart.c b/drivers/tty/serial/esp32_uart.c
new file mode 100644
index 000000000000..bb5471e8b6b6
--- /dev/null
+++ b/drivers/tty/serial/esp32_uart.c
@@ -0,0 +1,741 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+#include <asm/serial.h>
+
+#define DRIVER_NAME "esp32-uart"
+#define DEV_NAME "ttyS"
+#define UART_NR 3
+
+#define ESP32_UART_TX_FIFO_SIZE 127
+#define ESP32_UART_RX_FIFO_SIZE 127
+
+#define UART_FIFO_REG 0x00
+#define UART_INT_RAW_REG 0x04
+#define UART_INT_ST_REG 0x08
+#define UART_INT_ENA_REG 0x0c
+#define UART_INT_CLR_REG 0x10
+#define UART_RXFIFO_FULL_INT BIT(0)
+#define UART_TXFIFO_EMPTY_INT BIT(1)
+#define UART_BRK_DET_INT BIT(7)
+#define UART_CLKDIV_REG 0x14
+#define ESP32_UART_CLKDIV GENMASK(19, 0)
+#define ESP32S3_UART_CLKDIV GENMASK(11, 0)
+#define UART_CLKDIV_SHIFT 0
+#define UART_CLKDIV_FRAG GENMASK(23, 20)
+#define UART_STATUS_REG 0x1c
+#define ESP32_UART_RXFIFO_CNT GENMASK(7, 0)
+#define ESP32S3_UART_RXFIFO_CNT GENMASK(9, 0)
+#define UART_RXFIFO_CNT_SHIFT 0
+#define UART_DSRN BIT(13)
+#define UART_CTSN BIT(14)
+#define ESP32_UART_TXFIFO_CNT GENMASK(23, 16)
+#define ESP32S3_UART_TXFIFO_CNT GENMASK(25, 16)
+#define UART_TXFIFO_CNT_SHIFT 16
+#define UART_CONF0_REG 0x20
+#define UART_PARITY BIT(0)
+#define UART_PARITY_EN BIT(1)
+#define UART_BIT_NUM GENMASK(3, 2)
+#define UART_BIT_NUM_5 0
+#define UART_BIT_NUM_6 1
+#define UART_BIT_NUM_7 2
+#define UART_BIT_NUM_8 3
+#define UART_STOP_BIT_NUM GENMASK(5, 4)
+#define UART_STOP_BIT_NUM_1 1
+#define UART_STOP_BIT_NUM_2 3
+#define UART_SW_RTS BIT(6)
+#define UART_SW_DTR BIT(7)
+#define UART_LOOPBACK BIT(14)
+#define UART_TX_FLOW_EN BIT(15)
+#define UART_RTS_INV BIT(23)
+#define UART_DTR_INV BIT(24)
+#define UART_CONF1_REG 0x24
+#define UART_RXFIFO_FULL_THRHD_SHIFT 0
+#define ESP32_UART_TXFIFO_EMPTY_THRHD_SHIFT 8
+#define ESP32S3_UART_TXFIFO_EMPTY_THRHD_SHIFT 10
+#define ESP32_UART_RX_FLOW_EN BIT(23)
+#define ESP32S3_UART_RX_FLOW_EN BIT(22)
+
+struct esp32_port {
+ struct uart_port port;
+ struct clk *clk;
+};
+
+struct esp32_uart_variant {
+ u32 clkdiv_mask;
+ u32 rxfifo_cnt_mask;
+ u32 txfifo_cnt_mask;
+ u32 txfifo_empty_thrhd_shift;
+ u32 rx_flow_en;
+ const char *type;
+};
+
+static const struct esp32_uart_variant esp32_variant = {
+ .clkdiv_mask = ESP32_UART_CLKDIV,
+ .rxfifo_cnt_mask = ESP32_UART_RXFIFO_CNT,
+ .txfifo_cnt_mask = ESP32_UART_TXFIFO_CNT,
+ .txfifo_empty_thrhd_shift = ESP32_UART_TXFIFO_EMPTY_THRHD_SHIFT,
+ .rx_flow_en = ESP32_UART_RX_FLOW_EN,
+ .type = "ESP32 UART",
+};
+
+static const struct esp32_uart_variant esp32s3_variant = {
+ .clkdiv_mask = ESP32S3_UART_CLKDIV,
+ .rxfifo_cnt_mask = ESP32S3_UART_RXFIFO_CNT,
+ .txfifo_cnt_mask = ESP32S3_UART_TXFIFO_CNT,
+ .txfifo_empty_thrhd_shift = ESP32S3_UART_TXFIFO_EMPTY_THRHD_SHIFT,
+ .rx_flow_en = ESP32S3_UART_RX_FLOW_EN,
+ .type = "ESP32S3 UART",
+};
+
+static const struct of_device_id esp32_uart_dt_ids[] = {
+ {
+ .compatible = "esp,esp32-uart",
+ .data = &esp32_variant,
+ }, {
+ .compatible = "esp,esp32s3-uart",
+ .data = &esp32s3_variant,
+ }, { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, esp32_uart_dt_ids);
+
+static struct esp32_port *esp32_uart_ports[UART_NR];
+
+static const struct esp32_uart_variant *port_variant(struct uart_port *port)
+{
+ return port->private_data;
+}
+
+static void esp32_uart_write(struct uart_port *port, unsigned long reg, u32 v)
+{
+ writel(v, port->membase + reg);
+}
+
+static u32 esp32_uart_read(struct uart_port *port, unsigned long reg)
+{
+ return readl(port->membase + reg);
+}
+
+static u32 esp32_uart_tx_fifo_cnt(struct uart_port *port)
+{
+ u32 status = esp32_uart_read(port, UART_STATUS_REG);
+
+ return (status & port_variant(port)->txfifo_cnt_mask) >> UART_TXFIFO_CNT_SHIFT;
+}
+
+static u32 esp32_uart_rx_fifo_cnt(struct uart_port *port)
+{
+ u32 status = esp32_uart_read(port, UART_STATUS_REG);
+
+ return (status & port_variant(port)->rxfifo_cnt_mask) >> UART_RXFIFO_CNT_SHIFT;
+}
+
+/* return TIOCSER_TEMT when transmitter is not busy */
+static unsigned int esp32_uart_tx_empty(struct uart_port *port)
+{
+ return esp32_uart_tx_fifo_cnt(port) ? 0 : TIOCSER_TEMT;
+}
+
+static void esp32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ u32 conf0 = esp32_uart_read(port, UART_CONF0_REG);
+
+ conf0 &= ~(UART_LOOPBACK |
+ UART_SW_RTS | UART_RTS_INV |
+ UART_SW_DTR | UART_DTR_INV);
+
+ if (mctrl & TIOCM_RTS)
+ conf0 |= UART_SW_RTS;
+ if (mctrl & TIOCM_DTR)
+ conf0 |= UART_SW_DTR;
+ if (mctrl & TIOCM_LOOP)
+ conf0 |= UART_LOOPBACK;
+
+ esp32_uart_write(port, UART_CONF0_REG, conf0);
+}
+
+static unsigned int esp32_uart_get_mctrl(struct uart_port *port)
+{
+ u32 status = esp32_uart_read(port, UART_STATUS_REG);
+ unsigned int ret = TIOCM_CAR;
+
+ if (status & UART_DSRN)
+ ret |= TIOCM_DSR;
+ if (status & UART_CTSN)
+ ret |= TIOCM_CTS;
+
+ return ret;
+}
+
+static void esp32_uart_stop_tx(struct uart_port *port)
+{
+ u32 int_ena;
+
+ int_ena = esp32_uart_read(port, UART_INT_ENA_REG);
+ int_ena &= ~UART_TXFIFO_EMPTY_INT;
+ esp32_uart_write(port, UART_INT_ENA_REG, int_ena);
+}
+
+static void esp32_uart_rxint(struct uart_port *port)
+{
+ struct tty_port *tty_port = &port->state->port;
+ u32 rx_fifo_cnt = esp32_uart_rx_fifo_cnt(port);
+ unsigned long flags;
+ u32 i;
+
+ if (!rx_fifo_cnt)
+ return;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ for (i = 0; i < rx_fifo_cnt; ++i) {
+ u32 rx = esp32_uart_read(port, UART_FIFO_REG);
+
+ if (!rx &&
+ (esp32_uart_read(port, UART_INT_ST_REG) & UART_BRK_DET_INT)) {
+ esp32_uart_write(port, UART_INT_CLR_REG, UART_BRK_DET_INT);
+ ++port->icount.brk;
+ uart_handle_break(port);
+ } else {
+ if (uart_handle_sysrq_char(port, (unsigned char)rx))
+ continue;
+ tty_insert_flip_char(tty_port, rx, TTY_NORMAL);
+ ++port->icount.rx;
+ }
+ }
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ tty_flip_buffer_push(tty_port);
+}
+
+static void esp32_uart_put_char(struct uart_port *port, u8 c)
+{
+ esp32_uart_write(port, UART_FIFO_REG, c);
+}
+
+static void esp32_uart_put_char_sync(struct uart_port *port, u8 c)
+{
+ unsigned long timeout = jiffies + HZ;
+
+ while (esp32_uart_tx_fifo_cnt(port) >= ESP32_UART_TX_FIFO_SIZE) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(port->dev, "timeout waiting for TX FIFO\n");
+ return;
+ }
+ cpu_relax();
+ }
+ esp32_uart_put_char(port, c);
+}
+
+static void esp32_uart_transmit_buffer(struct uart_port *port)
+{
+ u32 tx_fifo_used = esp32_uart_tx_fifo_cnt(port);
+ unsigned int pending;
+ u8 ch;
+
+ if (tx_fifo_used >= ESP32_UART_TX_FIFO_SIZE)
+ return;
+
+ pending = uart_port_tx_limited(port, ch,
+ ESP32_UART_TX_FIFO_SIZE - tx_fifo_used,
+ true, esp32_uart_put_char(port, ch),
+ ({}));
+ if (pending) {
+ u32 int_ena;
+
+ int_ena = esp32_uart_read(port, UART_INT_ENA_REG);
+ int_ena |= UART_TXFIFO_EMPTY_INT;
+ esp32_uart_write(port, UART_INT_ENA_REG, int_ena);
+ }
+}
+
+static void esp32_uart_txint(struct uart_port *port)
+{
+ esp32_uart_transmit_buffer(port);
+}
+
+static irqreturn_t esp32_uart_int(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ u32 status;
+
+ status = esp32_uart_read(port, UART_INT_ST_REG);
+
+ if (status & (UART_RXFIFO_FULL_INT | UART_BRK_DET_INT))
+ esp32_uart_rxint(port);
+ if (status & UART_TXFIFO_EMPTY_INT)
+ esp32_uart_txint(port);
+
+ esp32_uart_write(port, UART_INT_CLR_REG, status);
+
+ return IRQ_RETVAL(status);
+}
+
+static void esp32_uart_start_tx(struct uart_port *port)
+{
+ esp32_uart_transmit_buffer(port);
+}
+
+static void esp32_uart_stop_rx(struct uart_port *port)
+{
+ u32 int_ena;
+
+ int_ena = esp32_uart_read(port, UART_INT_ENA_REG);
+ int_ena &= ~UART_RXFIFO_FULL_INT;
+ esp32_uart_write(port, UART_INT_ENA_REG, int_ena);
+}
+
+static int esp32_uart_startup(struct uart_port *port)
+{
+ int ret = 0;
+ unsigned long flags;
+ struct esp32_port *sport = container_of(port, struct esp32_port, port);
+
+ ret = clk_prepare_enable(sport->clk);
+ if (ret)
+ return ret;
+
+ ret = request_irq(port->irq, esp32_uart_int, 0, DRIVER_NAME, port);
+ if (ret) {
+ clk_disable_unprepare(sport->clk);
+ return ret;
+ }
+
+ spin_lock_irqsave(&port->lock, flags);
+ esp32_uart_write(port, UART_CONF1_REG,
+ (1 << UART_RXFIFO_FULL_THRHD_SHIFT) |
+ (1 << port_variant(port)->txfifo_empty_thrhd_shift));
+ esp32_uart_write(port, UART_INT_CLR_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT);
+ esp32_uart_write(port, UART_INT_ENA_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return ret;
+}
+
+static void esp32_uart_shutdown(struct uart_port *port)
+{
+ struct esp32_port *sport = container_of(port, struct esp32_port, port);
+
+ esp32_uart_write(port, UART_INT_ENA_REG, 0);
+ free_irq(port->irq, port);
+ clk_disable_unprepare(sport->clk);
+}
+
+static bool esp32_uart_set_baud(struct uart_port *port, u32 baud)
+{
+ u32 div = port->uartclk / baud;
+ u32 frag = (port->uartclk * 16) / baud - div * 16;
+
+ if (div <= port_variant(port)->clkdiv_mask) {
+ esp32_uart_write(port, UART_CLKDIV_REG,
+ div | FIELD_PREP(UART_CLKDIV_FRAG, frag));
+ return true;
+ }
+
+ return false;
+}
+
+static void esp32_uart_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ const struct ktermios *old)
+{
+ unsigned long flags;
+ u32 conf0, conf1;
+ u32 baud;
+ const u32 rx_flow_en = port_variant(port)->rx_flow_en;
+
+ termios->c_cflag &= ~CMSPAR;
+
+ baud = uart_get_baud_rate(port, termios, old,
+ port->uartclk / port_variant(port)->clkdiv_mask,
+ port->uartclk / 16);
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ conf0 = esp32_uart_read(port, UART_CONF0_REG);
+ conf0 &= ~(UART_PARITY_EN | UART_PARITY | UART_BIT_NUM | UART_STOP_BIT_NUM);
+
+ conf1 = esp32_uart_read(port, UART_CONF1_REG);
+ conf1 &= ~rx_flow_en;
+
+ if (termios->c_cflag & PARENB) {
+ conf0 |= UART_PARITY_EN;
+ if (termios->c_cflag & PARODD)
+ conf0 |= UART_PARITY;
+ }
+
+ switch (termios->c_cflag & CSIZE) {
+ case CS5:
+ conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_5);
+ break;
+ case CS6:
+ conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_6);
+ break;
+ case CS7:
+ conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_7);
+ break;
+ case CS8:
+ conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_8);
+ break;
+ }
+
+ if (termios->c_cflag & CSTOPB)
+ conf0 |= FIELD_PREP(UART_STOP_BIT_NUM, UART_STOP_BIT_NUM_2);
+ else
+ conf0 |= FIELD_PREP(UART_STOP_BIT_NUM, UART_STOP_BIT_NUM_1);
+
+ if (termios->c_cflag & CRTSCTS)
+ conf1 |= rx_flow_en;
+
+ esp32_uart_write(port, UART_CONF0_REG, conf0);
+ esp32_uart_write(port, UART_CONF1_REG, conf1);
+
+ if (baud) {
+ esp32_uart_set_baud(port, baud);
+ uart_update_timeout(port, termios->c_cflag, baud);
+ } else {
+ if (esp32_uart_set_baud(port, 115200)) {
+ baud = 115200;
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ uart_update_timeout(port, termios->c_cflag, baud);
+ } else {
+ dev_warn(port->dev,
+ "unable to set speed to %d baud or the default 115200\n",
+ baud);
+ }
+ }
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *esp32_uart_type(struct uart_port *port)
+{
+ return port_variant(port)->type;
+}
+
+/* configure/auto-configure the port */
+static void esp32_uart_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE)
+ port->type = PORT_ESP32UART;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int esp32_uart_poll_init(struct uart_port *port)
+{
+ struct esp32_port *sport = container_of(port, struct esp32_port, port);
+
+ return clk_prepare_enable(sport->clk);
+}
+
+static void esp32_uart_poll_put_char(struct uart_port *port, unsigned char c)
+{
+ esp32_uart_put_char_sync(port, c);
+}
+
+static int esp32_uart_poll_get_char(struct uart_port *port)
+{
+ if (esp32_uart_rx_fifo_cnt(port))
+ return esp32_uart_read(port, UART_FIFO_REG);
+ else
+ return NO_POLL_CHAR;
+
+}
+#endif
+
+static const struct uart_ops esp32_uart_pops = {
+ .tx_empty = esp32_uart_tx_empty,
+ .set_mctrl = esp32_uart_set_mctrl,
+ .get_mctrl = esp32_uart_get_mctrl,
+ .stop_tx = esp32_uart_stop_tx,
+ .start_tx = esp32_uart_start_tx,
+ .stop_rx = esp32_uart_stop_rx,
+ .startup = esp32_uart_startup,
+ .shutdown = esp32_uart_shutdown,
+ .set_termios = esp32_uart_set_termios,
+ .type = esp32_uart_type,
+ .config_port = esp32_uart_config_port,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_init = esp32_uart_poll_init,
+ .poll_put_char = esp32_uart_poll_put_char,
+ .poll_get_char = esp32_uart_poll_get_char,
+#endif
+};
+
+static void esp32_uart_console_putchar(struct uart_port *port, u8 c)
+{
+ esp32_uart_put_char_sync(port, c);
+}
+
+static void esp32_uart_string_write(struct uart_port *port, const char *s,
+ unsigned int count)
+{
+ uart_console_write(port, s, count, esp32_uart_console_putchar);
+}
+
+static void
+esp32_uart_console_write(struct console *co, const char *s, unsigned int count)
+{
+ struct esp32_port *sport = esp32_uart_ports[co->index];
+ struct uart_port *port = &sport->port;
+ unsigned long flags;
+ bool locked = true;
+
+ if (port->sysrq)
+ locked = false;
+ else if (oops_in_progress)
+ locked = spin_trylock_irqsave(&port->lock, flags);
+ else
+ spin_lock_irqsave(&port->lock, flags);
+
+ esp32_uart_string_write(port, s, count);
+
+ if (locked)
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static int __init esp32_uart_console_setup(struct console *co, char *options)
+{
+ struct esp32_port *sport;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+ int ret;
+
+ /*
+ * check whether an invalid uart number has been specified, and
+ * if so, search for the first available port that does have
+ * console support.
+ */
+ if (co->index == -1 || co->index >= ARRAY_SIZE(esp32_uart_ports))
+ co->index = 0;
+
+ sport = esp32_uart_ports[co->index];
+ if (!sport)
+ return -ENODEV;
+
+ ret = clk_prepare_enable(sport->clk);
+ if (ret)
+ return ret;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(&sport->port, co, baud, parity, bits, flow);
+}
+
+static int esp32_uart_console_exit(struct console *co)
+{
+ struct esp32_port *sport = esp32_uart_ports[co->index];
+
+ clk_disable_unprepare(sport->clk);
+ return 0;
+}
+
+static struct uart_driver esp32_uart_reg;
+static struct console esp32_uart_console = {
+ .name = DEV_NAME,
+ .write = esp32_uart_console_write,
+ .device = uart_console_device,
+ .setup = esp32_uart_console_setup,
+ .exit = esp32_uart_console_exit,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &esp32_uart_reg,
+};
+
+static void esp32_uart_earlycon_putchar(struct uart_port *port, u8 c)
+{
+ esp32_uart_put_char_sync(port, c);
+}
+
+static void esp32_uart_earlycon_write(struct console *con, const char *s,
+ unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, esp32_uart_earlycon_putchar);
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int esp32_uart_earlycon_read(struct console *con, char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ unsigned int num_read = 0;
+
+ while (num_read < n) {
+ int c = esp32_uart_poll_get_char(&dev->port);
+
+ if (c == NO_POLL_CHAR)
+ break;
+ s[num_read++] = c;
+ }
+ return num_read;
+}
+#endif
+
+static int __init esp32xx_uart_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = esp32_uart_earlycon_write;
+#ifdef CONFIG_CONSOLE_POLL
+ device->con->read = esp32_uart_earlycon_read;
+#endif
+ if (device->port.uartclk != BASE_BAUD * 16)
+ esp32_uart_set_baud(&device->port, device->baud);
+
+ return 0;
+}
+
+static int __init esp32_uart_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ device->port.private_data = (void *)&esp32_variant;
+
+ return esp32xx_uart_early_console_setup(device, options);
+}
+
+OF_EARLYCON_DECLARE(esp32uart, "esp,esp32-uart",
+ esp32_uart_early_console_setup);
+
+static int __init esp32s3_uart_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ device->port.private_data = (void *)&esp32s3_variant;
+
+ return esp32xx_uart_early_console_setup(device, options);
+}
+
+OF_EARLYCON_DECLARE(esp32s3uart, "esp,esp32s3-uart",
+ esp32s3_uart_early_console_setup);
+
+static struct uart_driver esp32_uart_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = DRIVER_NAME,
+ .dev_name = DEV_NAME,
+ .nr = ARRAY_SIZE(esp32_uart_ports),
+ .cons = &esp32_uart_console,
+};
+
+static int esp32_uart_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ static const struct of_device_id *match;
+ struct uart_port *port;
+ struct esp32_port *sport;
+ struct resource *res;
+ int ret;
+
+ match = of_match_device(esp32_uart_dt_ids, &pdev->dev);
+ if (!match)
+ return -ENODEV;
+
+ sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
+ if (!sport)
+ return -ENOMEM;
+
+ port = &sport->port;
+
+ ret = of_alias_get_id(np, "serial");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+ return ret;
+ }
+ if (ret >= UART_NR) {
+ dev_err(&pdev->dev, "driver limited to %d serial ports\n", UART_NR);
+ return -ENOMEM;
+ }
+
+ port->line = ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ port->mapbase = res->start;
+ port->membase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(port->membase))
+ return PTR_ERR(port->membase);
+
+ sport->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(sport->clk))
+ return PTR_ERR(sport->clk);
+
+ port->uartclk = clk_get_rate(sport->clk);
+ port->dev = &pdev->dev;
+ port->type = PORT_ESP32UART;
+ port->iotype = UPIO_MEM;
+ port->irq = platform_get_irq(pdev, 0);
+ port->ops = &esp32_uart_pops;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->has_sysrq = 1;
+ port->fifosize = ESP32_UART_TX_FIFO_SIZE;
+ port->private_data = (void *)match->data;
+
+ esp32_uart_ports[port->line] = sport;
+
+ platform_set_drvdata(pdev, port);
+
+ return uart_add_one_port(&esp32_uart_reg, port);
+}
+
+static int esp32_uart_remove(struct platform_device *pdev)
+{
+ struct uart_port *port = platform_get_drvdata(pdev);
+
+ uart_remove_one_port(&esp32_uart_reg, port);
+
+ return 0;
+}
+
+
+static struct platform_driver esp32_uart_driver = {
+ .probe = esp32_uart_probe,
+ .remove = esp32_uart_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = esp32_uart_dt_ids,
+ },
+};
+
+static int __init esp32_uart_init(void)
+{
+ int ret;
+
+ ret = uart_register_driver(&esp32_uart_reg);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&esp32_uart_driver);
+ if (ret)
+ uart_unregister_driver(&esp32_uart_reg);
+
+ return ret;
+}
+
+static void __exit esp32_uart_exit(void)
+{
+ platform_driver_unregister(&esp32_uart_driver);
+ uart_unregister_driver(&esp32_uart_reg);
+}
+
+module_init(esp32_uart_init);
+module_exit(esp32_uart_exit);
+
+MODULE_AUTHOR("Max Filippov <[email protected]>");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index add349889d0a..ff076d6be159 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -245,4 +245,7 @@
/* Sunplus UART */
#define PORT_SUNPLUS 123
+/* Espressif ESP32 UART */
+#define PORT_ESP32UART 124
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
2.30.2
Add documentation for the ESP32xx UART controllers.
Signed-off-by: Max Filippov <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
---
Changes v2->v3:
- add a reference to serial.yaml
Changes v1->v2:
- drop '|' from description
- change 'compatible' property type to enum
- drop label from the example node
- fix example indentation
.../bindings/serial/esp,esp32-uart.yaml | 51 +++++++++++++++++++
1 file changed, 51 insertions(+)
create mode 100644 Documentation/devicetree/bindings/serial/esp,esp32-uart.yaml
diff --git a/Documentation/devicetree/bindings/serial/esp,esp32-uart.yaml b/Documentation/devicetree/bindings/serial/esp,esp32-uart.yaml
new file mode 100644
index 000000000000..2a80ca997a0c
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/esp,esp32-uart.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/esp,esp32-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ESP32xx UART controllers
+
+maintainers:
+ - Max Filippov <[email protected]>
+
+description:
+ ESP32 UART controller is a part of the ESP32 SoC.
+ ESP32S3 UART controller is a part of the ESP32S3 SoC.
+ Both SoCs are produced by Espressif Systems Co. Ltd.
+
+allOf:
+ - $ref: serial.yaml#
+
+properties:
+ compatible:
+ enum:
+ - esp,esp32-uart
+ - esp,esp32s3-uart
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - clocks
+
+additionalProperties: false
+
+examples:
+ - |
+ serial@60000000 {
+ compatible = "esp,esp32s3-uart";
+ reg = <0x60000000 0x80>;
+ interrupts = <27 1 0>;
+ clocks = <&serial_clk>;
+ };
--
2.30.2
Add driver for the ACM controller of the Espressif ESP32S3 Soc.
Hardware specification is available at the following URL:
https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
(Chapter 33 USB Serial/JTAG Controller)
Signed-off-by: Max Filippov <[email protected]>
---
Changes v2->v3:
- use HZ instead of msecs_to_jiffies(1000) in esp32_acm_put_char_sync
- add early return to esp32_acm_transmit_buffer
- use request_irq/free_irq instead of devm_* versions
Changes v1->v2:
- redefine register fields using BIT and GENMASK
- drop _MASK suffix from register field definitions
- drop *_SHIFT definitions where possible
- split register reads/writes and bitwise operations into multiple lines
- use u8 instead of unsigned char in internal functions
- add timeout to esp32_acm_put_char_sync
- use uart_port_tx_limited in esp32_acm_transmit_buffer
- use IRQ_RETVAL in esp32_acm_int
- drop esp32s3_acm_console_putchar and esp32s3_acm_earlycon_putchar
- turn num_read into unsigned int in esp32_acm_earlycon_read
- drop MODULE_DESCRIPTION
drivers/tty/serial/Kconfig | 14 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/esp32_acm.c | 459 +++++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
4 files changed, 477 insertions(+)
create mode 100644 drivers/tty/serial/esp32_acm.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index d9ca6b268f01..85807db8f7ce 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1591,6 +1591,20 @@ config SERIAL_ESP32
earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000
earlycon=esp32uart,mmio32,0x3ff40000,115200n8
+config SERIAL_ESP32_ACM
+ tristate "Espressif ESP32 USB ACM support"
+ depends on XTENSA_PLATFORM_ESP32 || (COMPILE_TEST && OF)
+ select SERIAL_CORE
+ select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
+ help
+ Driver for the CDC ACM controllers of the Espressif ESP32S3 SoCs
+ that share separate USB controller with the JTAG adapter.
+ The device name used for this controller is ttyACM.
+ When earlycon option is enabled the following kernel command line
+ snippet may be used:
+ earlycon=esp32s3acm,mmio32,0x60038000
+
endmenu
config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 7b73137df7f3..970a292ca418 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o
obj-$(CONFIG_SERIAL_ESP32) += esp32_uart.o
+obj-$(CONFIG_SERIAL_ESP32_ACM) += esp32_acm.o
# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
new file mode 100644
index 000000000000..f02abd2ac65e
--- /dev/null
+++ b/drivers/tty/serial/esp32_acm.c
@@ -0,0 +1,459 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+#include <asm/serial.h>
+
+#define DRIVER_NAME "esp32s3-acm"
+#define DEV_NAME "ttyACM"
+#define UART_NR 4
+
+#define ESP32S3_ACM_TX_FIFO_SIZE 64
+
+#define USB_SERIAL_JTAG_EP1_REG 0x00
+#define USB_SERIAL_JTAG_EP1_CONF_REG 0x04
+#define USB_SERIAL_JTAG_WR_DONE BIT(0)
+#define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE BIT(1)
+#define USB_SERIAL_JTAG_INT_ST_REG 0x0c
+#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST BIT(2)
+#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST BIT(3)
+#define USB_SERIAL_JTAG_INT_ENA_REG 0x10
+#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA BIT(2)
+#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA BIT(3)
+#define USB_SERIAL_JTAG_INT_CLR_REG 0x14
+#define USB_SERIAL_JTAG_IN_EP1_ST_REG 0x2c
+#define USB_SERIAL_JTAG_IN_EP1_WR_ADDR GENMASK(8, 2)
+#define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c
+#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT GENMASK(22, 16)
+
+static const struct of_device_id esp32s3_acm_dt_ids[] = {
+ {
+ .compatible = "esp,esp32s3-acm",
+ }, { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, esp32s3_acm_dt_ids);
+
+static struct uart_port *esp32s3_acm_ports[UART_NR];
+
+static void esp32s3_acm_write(struct uart_port *port, unsigned long reg, u32 v)
+{
+ writel(v, port->membase + reg);
+}
+
+static u32 esp32s3_acm_read(struct uart_port *port, unsigned long reg)
+{
+ return readl(port->membase + reg);
+}
+
+static u32 esp32s3_acm_tx_fifo_free(struct uart_port *port)
+{
+ u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG);
+
+ return status & USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE;
+}
+
+static u32 esp32s3_acm_tx_fifo_cnt(struct uart_port *port)
+{
+ u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_IN_EP1_ST_REG);
+
+ return FIELD_GET(USB_SERIAL_JTAG_IN_EP1_WR_ADDR, status);
+}
+
+static u32 esp32s3_acm_rx_fifo_cnt(struct uart_port *port)
+{
+ u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_OUT_EP1_ST_REG);
+
+ return FIELD_GET(USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT, status);
+}
+
+/* return TIOCSER_TEMT when transmitter is not busy */
+static unsigned int esp32s3_acm_tx_empty(struct uart_port *port)
+{
+ return esp32s3_acm_tx_fifo_cnt(port) == 0 ? TIOCSER_TEMT : 0;
+}
+
+static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static unsigned int esp32s3_acm_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_CAR;
+}
+
+static void esp32s3_acm_stop_tx(struct uart_port *port)
+{
+ u32 int_ena;
+
+ int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);
+ int_ena &= ~USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA;
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);
+}
+
+static void esp32s3_acm_rxint(struct uart_port *port)
+{
+ struct tty_port *tty_port = &port->state->port;
+ u32 rx_fifo_cnt = esp32s3_acm_rx_fifo_cnt(port);
+ unsigned long flags;
+ u32 i;
+
+ if (!rx_fifo_cnt)
+ return;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ for (i = 0; i < rx_fifo_cnt; ++i) {
+ u32 rx = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG);
+
+ ++port->icount.rx;
+ tty_insert_flip_char(tty_port, rx, TTY_NORMAL);
+ }
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ tty_flip_buffer_push(tty_port);
+}
+
+static void esp32s3_acm_push(struct uart_port *port)
+{
+ if (esp32s3_acm_tx_fifo_free(port))
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG,
+ USB_SERIAL_JTAG_WR_DONE);
+}
+
+static void esp32s3_acm_put_char(struct uart_port *port, u8 c)
+{
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_REG, c);
+}
+
+static void esp32s3_acm_put_char_sync(struct uart_port *port, u8 c)
+{
+ unsigned long timeout = jiffies + HZ;
+
+ while (!esp32s3_acm_tx_fifo_free(port)) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(port->dev, "timeout waiting for TX FIFO\n");
+ return;
+ }
+ cpu_relax();
+ }
+ esp32s3_acm_put_char(port, c);
+ esp32s3_acm_push(port);
+}
+
+static void esp32s3_acm_transmit_buffer(struct uart_port *port)
+{
+ u32 tx_fifo_used;
+ unsigned int pending;
+ u8 ch;
+
+ if (!esp32s3_acm_tx_fifo_free(port))
+ return;
+
+ tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port);
+ pending = uart_port_tx_limited(port, ch,
+ ESP32S3_ACM_TX_FIFO_SIZE - tx_fifo_used,
+ true, esp32s3_acm_put_char(port, ch),
+ ({}));
+ if (pending) {
+ u32 int_ena;
+
+ int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);
+ int_ena |= USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA;
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);
+ }
+ esp32s3_acm_push(port);
+}
+
+static void esp32s3_acm_txint(struct uart_port *port)
+{
+ esp32s3_acm_transmit_buffer(port);
+}
+
+static irqreturn_t esp32s3_acm_int(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ u32 status;
+
+ status = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ST_REG);
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_CLR_REG, status);
+
+ if (status & USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST)
+ esp32s3_acm_rxint(port);
+ if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST)
+ esp32s3_acm_txint(port);
+
+ return IRQ_RETVAL(status);
+}
+
+static void esp32s3_acm_start_tx(struct uart_port *port)
+{
+ esp32s3_acm_transmit_buffer(port);
+}
+
+static void esp32s3_acm_stop_rx(struct uart_port *port)
+{
+ u32 int_ena;
+
+ int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);
+ int_ena &= ~USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA;
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);
+}
+
+static int esp32s3_acm_startup(struct uart_port *port)
+{
+ int ret;
+
+ ret = request_irq(port->irq, esp32s3_acm_int, 0, DRIVER_NAME, port);
+ if (ret)
+ return ret;
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG,
+ USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA);
+
+ return 0;
+}
+
+static void esp32s3_acm_shutdown(struct uart_port *port)
+{
+ esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, 0);
+ free_irq(port->irq, port);
+}
+
+static void esp32s3_acm_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ const struct ktermios *old)
+{
+}
+
+static const char *esp32s3_acm_type(struct uart_port *port)
+{
+ return "ESP32S3 ACM";
+}
+
+/* configure/auto-configure the port */
+static void esp32s3_acm_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE)
+ port->type = PORT_ESP32ACM;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static void esp32s3_acm_poll_put_char(struct uart_port *port, unsigned char c)
+{
+ esp32s3_acm_put_char_sync(port, c);
+}
+
+static int esp32s3_acm_poll_get_char(struct uart_port *port)
+{
+ if (esp32s3_acm_rx_fifo_cnt(port))
+ return esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG);
+ else
+ return NO_POLL_CHAR;
+}
+#endif
+
+static const struct uart_ops esp32s3_acm_pops = {
+ .tx_empty = esp32s3_acm_tx_empty,
+ .set_mctrl = esp32s3_acm_set_mctrl,
+ .get_mctrl = esp32s3_acm_get_mctrl,
+ .stop_tx = esp32s3_acm_stop_tx,
+ .start_tx = esp32s3_acm_start_tx,
+ .stop_rx = esp32s3_acm_stop_rx,
+ .startup = esp32s3_acm_startup,
+ .shutdown = esp32s3_acm_shutdown,
+ .set_termios = esp32s3_acm_set_termios,
+ .type = esp32s3_acm_type,
+ .config_port = esp32s3_acm_config_port,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_put_char = esp32s3_acm_poll_put_char,
+ .poll_get_char = esp32s3_acm_poll_get_char,
+#endif
+};
+
+static void esp32s3_acm_string_write(struct uart_port *port, const char *s,
+ unsigned int count)
+{
+ uart_console_write(port, s, count, esp32s3_acm_put_char_sync);
+}
+
+static void
+esp32s3_acm_console_write(struct console *co, const char *s, unsigned int count)
+{
+ struct uart_port *port = esp32s3_acm_ports[co->index];
+ unsigned long flags;
+ bool locked = true;
+
+ if (port->sysrq)
+ locked = false;
+ else if (oops_in_progress)
+ locked = spin_trylock_irqsave(&port->lock, flags);
+ else
+ spin_lock_irqsave(&port->lock, flags);
+
+ esp32s3_acm_string_write(port, s, count);
+
+ if (locked)
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static struct uart_driver esp32s3_acm_reg;
+static struct console esp32s3_acm_console = {
+ .name = DEV_NAME,
+ .write = esp32s3_acm_console_write,
+ .device = uart_console_device,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &esp32s3_acm_reg,
+};
+
+static void esp32s3_acm_earlycon_write(struct console *con, const char *s,
+ unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, esp32s3_acm_put_char_sync);
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ unsigned int num_read = 0;
+
+ while (num_read < n) {
+ int c = esp32s3_acm_poll_get_char(&dev->port);
+
+ if (c == NO_POLL_CHAR)
+ break;
+ s[num_read++] = c;
+ }
+ return num_read;
+}
+#endif
+
+static int __init esp32s3_acm_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = esp32s3_acm_earlycon_write;
+#ifdef CONFIG_CONSOLE_POLL
+ device->con->read = esp32s3_acm_earlycon_read;
+#endif
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(esp32s3acm, "esp,esp32s3-acm",
+ esp32s3_acm_early_console_setup);
+
+static struct uart_driver esp32s3_acm_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = DRIVER_NAME,
+ .dev_name = DEV_NAME,
+ .nr = ARRAY_SIZE(esp32s3_acm_ports),
+ .cons = &esp32s3_acm_console,
+};
+
+static int esp32s3_acm_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct uart_port *port;
+ struct resource *res;
+ int ret;
+
+ port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ ret = of_alias_get_id(np, "serial");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+ return ret;
+ }
+ if (ret >= UART_NR) {
+ dev_err(&pdev->dev, "driver limited to %d serial ports\n",
+ UART_NR);
+ return -ENOMEM;
+ }
+
+ port->line = ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ port->mapbase = res->start;
+ port->membase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(port->membase))
+ return PTR_ERR(port->membase);
+
+ port->dev = &pdev->dev;
+ port->type = PORT_ESP32ACM;
+ port->iotype = UPIO_MEM;
+ port->irq = platform_get_irq(pdev, 0);
+ port->ops = &esp32s3_acm_pops;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->has_sysrq = 1;
+ port->fifosize = ESP32S3_ACM_TX_FIFO_SIZE;
+
+ esp32s3_acm_ports[port->line] = port;
+
+ platform_set_drvdata(pdev, port);
+
+ return uart_add_one_port(&esp32s3_acm_reg, port);
+}
+
+static int esp32s3_acm_remove(struct platform_device *pdev)
+{
+ struct uart_port *port = platform_get_drvdata(pdev);
+
+ uart_remove_one_port(&esp32s3_acm_reg, port);
+ return 0;
+}
+
+
+static struct platform_driver esp32s3_acm_driver = {
+ .probe = esp32s3_acm_probe,
+ .remove = esp32s3_acm_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = esp32s3_acm_dt_ids,
+ },
+};
+
+static int __init esp32s3_acm_init(void)
+{
+ int ret;
+
+ ret = uart_register_driver(&esp32s3_acm_reg);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&esp32s3_acm_driver);
+ if (ret)
+ uart_unregister_driver(&esp32s3_acm_reg);
+
+ return ret;
+}
+
+static void __exit esp32s3_acm_exit(void)
+{
+ platform_driver_unregister(&esp32s3_acm_driver);
+ uart_unregister_driver(&esp32s3_acm_reg);
+}
+
+module_init(esp32s3_acm_init);
+module_exit(esp32s3_acm_exit);
+
+MODULE_AUTHOR("Max Filippov <[email protected]>");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index ff076d6be159..1045bf096837 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -248,4 +248,7 @@
/* Espressif ESP32 UART */
#define PORT_ESP32UART 124
+/* Espressif ESP32 ACM */
+#define PORT_ESP32ACM 125
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
2.30.2
Add documentation for the ESP32S3 USB CDC-ACM controller.
Signed-off-by: Max Filippov <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
---
Changes v2->v3:
- add a reference to serial.yaml
Changes v1->v2:
- fix description
- rename node in the example
- fix example indentation
.../bindings/serial/esp,esp32-acm.yaml | 42 +++++++++++++++++++
1 file changed, 42 insertions(+)
create mode 100644 Documentation/devicetree/bindings/serial/esp,esp32-acm.yaml
diff --git a/Documentation/devicetree/bindings/serial/esp,esp32-acm.yaml b/Documentation/devicetree/bindings/serial/esp,esp32-acm.yaml
new file mode 100644
index 000000000000..e385ca9d9e2b
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/esp,esp32-acm.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/esp,esp32-acm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ESP32S3 ACM controller
+
+maintainers:
+ - Max Filippov <[email protected]>
+
+description:
+ Fixed function USB CDC-ACM device controller of the Espressif ESP32S3 SoC.
+
+allOf:
+ - $ref: serial.yaml#
+
+properties:
+ compatible:
+ const: esp,esp32s3-acm
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - interrupts
+
+additionalProperties: false
+
+examples:
+ - |
+ serial@60038000 {
+ compatible = "esp,esp32s3-acm";
+ reg = <0x60038000 0x1000>;
+ interrupts = <96 3 0>;
+ };
--
2.30.2
On Thu, Sep 28, 2023 at 08:16:31AM -0700, Max Filippov wrote:
> Add driver for the ACM controller of the Espressif ESP32S3 Soc.
Odd extra space :(
> Hardware specification is available at the following URL:
>
> https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> (Chapter 33 USB Serial/JTAG Controller)
I don't understand this driver, "ACM" is a USB host <-> gadget protocol,
why do you need a platform serial driver for this?
>
> Signed-off-by: Max Filippov <[email protected]>
> ---
> Changes v2->v3:
> - use HZ instead of msecs_to_jiffies(1000) in esp32_acm_put_char_sync
> - add early return to esp32_acm_transmit_buffer
> - use request_irq/free_irq instead of devm_* versions
>
> Changes v1->v2:
> - redefine register fields using BIT and GENMASK
> - drop _MASK suffix from register field definitions
> - drop *_SHIFT definitions where possible
> - split register reads/writes and bitwise operations into multiple lines
> - use u8 instead of unsigned char in internal functions
> - add timeout to esp32_acm_put_char_sync
> - use uart_port_tx_limited in esp32_acm_transmit_buffer
> - use IRQ_RETVAL in esp32_acm_int
> - drop esp32s3_acm_console_putchar and esp32s3_acm_earlycon_putchar
> - turn num_read into unsigned int in esp32_acm_earlycon_read
> - drop MODULE_DESCRIPTION
>
> drivers/tty/serial/Kconfig | 14 +
> drivers/tty/serial/Makefile | 1 +
> drivers/tty/serial/esp32_acm.c | 459 +++++++++++++++++++++++++++++++
> include/uapi/linux/serial_core.h | 3 +
> 4 files changed, 477 insertions(+)
> create mode 100644 drivers/tty/serial/esp32_acm.c
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index d9ca6b268f01..85807db8f7ce 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1591,6 +1591,20 @@ config SERIAL_ESP32
> earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000
> earlycon=esp32uart,mmio32,0x3ff40000,115200n8
>
> +config SERIAL_ESP32_ACM
> + tristate "Espressif ESP32 USB ACM support"
> + depends on XTENSA_PLATFORM_ESP32 || (COMPILE_TEST && OF)
> + select SERIAL_CORE
> + select SERIAL_CORE_CONSOLE
> + select SERIAL_EARLYCON
> + help
> + Driver for the CDC ACM controllers of the Espressif ESP32S3 SoCs
> + that share separate USB controller with the JTAG adapter.
> + The device name used for this controller is ttyACM.
> + When earlycon option is enabled the following kernel command line
> + snippet may be used:
> + earlycon=esp32s3acm,mmio32,0x60038000
> +
> endmenu
>
> config SERIAL_MCTRL_GPIO
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index 7b73137df7f3..970a292ca418 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
> obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
> obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o
> obj-$(CONFIG_SERIAL_ESP32) += esp32_uart.o
> +obj-$(CONFIG_SERIAL_ESP32_ACM) += esp32_acm.o
>
> # GPIOLIB helpers for modem control lines
> obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
> diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
> new file mode 100644
> index 000000000000..f02abd2ac65e
> --- /dev/null
> +++ b/drivers/tty/serial/esp32_acm.c
> @@ -0,0 +1,459 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
Why "or later"? I have to ask, sorry.
And no copyright information? That's fine, but be sure your company's
lawyers are ok with it...
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/console.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/serial_core.h>
> +#include <linux/slab.h>
> +#include <linux/tty_flip.h>
> +#include <asm/serial.h>
> +
> +#define DRIVER_NAME "esp32s3-acm"
> +#define DEV_NAME "ttyACM"
There is already a ttyACM driver in the kernel, will this conflict with
that one? And are you using the same major/minor numbers for it as
well? If so, how is this going to work?
> +#define UART_NR 4
> +
> +#define ESP32S3_ACM_TX_FIFO_SIZE 64
> +
> +#define USB_SERIAL_JTAG_EP1_REG 0x00
> +#define USB_SERIAL_JTAG_EP1_CONF_REG 0x04
> +#define USB_SERIAL_JTAG_WR_DONE BIT(0)
> +#define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE BIT(1)
> +#define USB_SERIAL_JTAG_INT_ST_REG 0x0c
> +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST BIT(2)
> +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST BIT(3)
> +#define USB_SERIAL_JTAG_INT_ENA_REG 0x10
> +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA BIT(2)
> +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA BIT(3)
> +#define USB_SERIAL_JTAG_INT_CLR_REG 0x14
> +#define USB_SERIAL_JTAG_IN_EP1_ST_REG 0x2c
> +#define USB_SERIAL_JTAG_IN_EP1_WR_ADDR GENMASK(8, 2)
> +#define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c
> +#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT GENMASK(22, 16)
> +
> +static const struct of_device_id esp32s3_acm_dt_ids[] = {
> + {
> + .compatible = "esp,esp32s3-acm",
> + }, { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, esp32s3_acm_dt_ids);
> +
> +static struct uart_port *esp32s3_acm_ports[UART_NR];
> +
> +static void esp32s3_acm_write(struct uart_port *port, unsigned long reg, u32 v)
> +{
> + writel(v, port->membase + reg);
> +}
> +
> +static u32 esp32s3_acm_read(struct uart_port *port, unsigned long reg)
> +{
> + return readl(port->membase + reg);
> +}
> +
> +static u32 esp32s3_acm_tx_fifo_free(struct uart_port *port)
> +{
> + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG);
> +
> + return status & USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE;
> +}
> +
> +static u32 esp32s3_acm_tx_fifo_cnt(struct uart_port *port)
> +{
> + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_IN_EP1_ST_REG);
> +
> + return FIELD_GET(USB_SERIAL_JTAG_IN_EP1_WR_ADDR, status);
> +}
> +
> +static u32 esp32s3_acm_rx_fifo_cnt(struct uart_port *port)
> +{
> + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_OUT_EP1_ST_REG);
> +
> + return FIELD_GET(USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT, status);
> +}
> +
> +/* return TIOCSER_TEMT when transmitter is not busy */
> +static unsigned int esp32s3_acm_tx_empty(struct uart_port *port)
> +{
> + return esp32s3_acm_tx_fifo_cnt(port) == 0 ? TIOCSER_TEMT : 0;
> +}
> +
> +static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl)
> +{
> +}
Do you have to have empty functions for callbacks that do nothing?
> --- a/include/uapi/linux/serial_core.h
> +++ b/include/uapi/linux/serial_core.h
> @@ -248,4 +248,7 @@
> /* Espressif ESP32 UART */
> #define PORT_ESP32UART 124
>
> +/* Espressif ESP32 ACM */
> +#define PORT_ESP32ACM 125
Why are these defines needed? What in userspace is going to require
them? If nothing, please do not add them.
thanks,
greg k-h
On Thu, Sep 28, 2023 at 08:16:29AM -0700, Max Filippov wrote:
> Add driver for the UART controllers of the Espressif ESP32 and ESP32S3
> SoCs. Hardware specification is available at the following URLs:
>
> https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf
> (Chapter 13 UART Controller)
> https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> (Chapter 26 UART Controller)
>
> Signed-off-by: Max Filippov <[email protected]>
> ---
> Changes v2->v3:
> - rework brk handling in esp32_uart_rxint
> - only increment port->icount.rx in case insert_flip_char() is called
> - use HZ instead of msecs_to_jiffies(1000) in esp32_uart_put_char_sync
> - add early return to esp32_uart_transmit_buffer
> - use request_irq/free_irq instead of devm_* versions
> - add blank lines before certain return statements
>
> Changes v1->v2:
> - redefine register fields using BIT and GENMASK
> - drop _MASK suffix from register field definitions
> - drop *_SHIFT definitions where possible
> - drop unused rxfifo_full_thrhd_mask and txfifo_empty_thrhd_mask
> - split register reads/writes and bitwise operations into multiple lines
> - use u8 instead of unsigned char in internal functions
> - add timeout to esp32_uart_put_char_sync
> - use uart_port_tx_limited in esp32_uart_transmit_buffer
> - use IRQ_RETVAL in esp32_uart_int
> - disable clock in esp32_uart_startup in case devm_request_irq fails
> - rearrange devm_request_irq with enabling IRQs in the UART registers
> - drop empty esp32_uart_release_port and esp32_uart_request_port
> - simplify esp32_uart_tx_empty
> - mask out unsupported CMSPAR flag in termios->c_cflag in
> esp32_uart_set_termios
> - invoke uart_update_timeout in esp32_uart_set_termios
> - drop MODULE_DESCRIPTION
> - rearrange esp32_uart_set_baud: return bool indicating whether baud
> rate was set or not, use it in the esp32_uart_set_termios to set the
> default 115200
> - turn 'locked' into bool in esp32_uart_console_write
> - turn num_read into unsigned int in esp32_uart_earlycon_read
>
> drivers/tty/serial/Kconfig | 13 +
> drivers/tty/serial/Makefile | 1 +
> drivers/tty/serial/esp32_uart.c | 741 +++++++++++++++++++++++++++++++
> include/uapi/linux/serial_core.h | 3 +
> 4 files changed, 758 insertions(+)
> create mode 100644 drivers/tty/serial/esp32_uart.c
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index bdc568a4ab66..d9ca6b268f01 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1578,6 +1578,19 @@ config SERIAL_NUVOTON_MA35D1_CONSOLE
> but you can alter that using a kernel command line option such as
> "console=ttyNVTx".
>
> +config SERIAL_ESP32
> + tristate "Espressif ESP32 UART support"
> + depends on XTENSA_PLATFORM_ESP32 || (COMPILE_TEST && OF)
> + select SERIAL_CORE
> + select SERIAL_CORE_CONSOLE
> + select SERIAL_EARLYCON
> + help
> + Driver for the UART controllers of the Espressif ESP32xx SoCs.
> + When earlycon option is enabled the following kernel command line
> + snippets may be used:
> + earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000
> + earlycon=esp32uart,mmio32,0x3ff40000,115200n8
> +
> endmenu
>
> config SERIAL_MCTRL_GPIO
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index 138abbc89738..7b73137df7f3 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -88,6 +88,7 @@ obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
> obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
> obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
> obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o
> +obj-$(CONFIG_SERIAL_ESP32) += esp32_uart.o
>
> # GPIOLIB helpers for modem control lines
> obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
> diff --git a/drivers/tty/serial/esp32_uart.c b/drivers/tty/serial/esp32_uart.c
> new file mode 100644
> index 000000000000..bb5471e8b6b6
> --- /dev/null
> +++ b/drivers/tty/serial/esp32_uart.c
> @@ -0,0 +1,741 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
Same license and copyright question as I had on the ACM patch.
thanks,
greg k-h
On Tue, Oct 3, 2023 at 5:55 AM Greg Kroah-Hartman
<[email protected]> wrote:
>
> On Thu, Sep 28, 2023 at 08:16:31AM -0700, Max Filippov wrote:
> > Add driver for the ACM controller of the Espressif ESP32S3 Soc.
>
> Odd extra space :(
Ok.
> > Hardware specification is available at the following URL:
> >
> > https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> > (Chapter 33 USB Serial/JTAG Controller)
>
> I don't understand this driver, "ACM" is a USB host <-> gadget protocol,
> why do you need a platform serial driver for this?
The USB part of this piece of hardware is fixed and not controllable, so
all we have is a very limited UART interface. But to the outside world
it's a USB device with the CDC-ACM interface.
> > diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
> > new file mode 100644
> > index 000000000000..f02abd2ac65e
> > --- /dev/null
> > +++ b/drivers/tty/serial/esp32_acm.c
> > @@ -0,0 +1,459 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
>
> Why "or later"? I have to ask, sorry.
I don't really have a preference here. Is there a reason to choose
GPL-2.0 only for a new code?
> And no copyright information? That's fine, but be sure your company's
> lawyers are ok with it...
There's no company behind this, just myself.
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/bits.h>
> > +#include <linux/console.h>
> > +#include <linux/delay.h>
> > +#include <linux/io.h>
> > +#include <linux/irq.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/serial_core.h>
> > +#include <linux/slab.h>
> > +#include <linux/tty_flip.h>
> > +#include <asm/serial.h>
> > +
> > +#define DRIVER_NAME "esp32s3-acm"
> > +#define DEV_NAME "ttyACM"
>
> There is already a ttyACM driver in the kernel, will this conflict with
> that one? And are you using the same major/minor numbers for it as
> well? If so, how is this going to work?
I'll rename it to ttyS. I see that it coexists with the other driver that calls
its devices ttyS just fine.
> > +static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl)
> > +{
> > +}
>
> Do you have to have empty functions for callbacks that do nothing?
The serial core has unconditional calls to these callbacks.
> > --- a/include/uapi/linux/serial_core.h
> > +++ b/include/uapi/linux/serial_core.h
> > @@ -248,4 +248,7 @@
> > /* Espressif ESP32 UART */
> > #define PORT_ESP32UART 124
> >
> > +/* Espressif ESP32 ACM */
> > +#define PORT_ESP32ACM 125
>
> Why are these defines needed? What in userspace is going to require
> them? If nothing, please do not add them.
I don't understand what the alternatives are. The comment for the
uart_ops::config_port() callback says that port->type should be set
to the type of the port found, and I see that almost every serial driver
defines a unique PORT_* for that.
--
Thanks.
-- Max
On Tue, Oct 03, 2023 at 12:46:46PM -0700, Max Filippov wrote:
> > > Hardware specification is available at the following URL:
> > >
> > > https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> > > (Chapter 33 USB Serial/JTAG Controller)
> >
> > I don't understand this driver, "ACM" is a USB host <-> gadget protocol,
> > why do you need a platform serial driver for this?
>
> The USB part of this piece of hardware is fixed and not controllable, so
> all we have is a very limited UART interface. But to the outside world
> it's a USB device with the CDC-ACM interface.
Where is the "outside world" here? The other end of the tty connection?
So this is a "ACM gadget"? If so, please try to use that term as that's
what we use in the kernel to keep things straight.
> > > diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
> > > new file mode 100644
> > > index 000000000000..f02abd2ac65e
> > > --- /dev/null
> > > +++ b/drivers/tty/serial/esp32_acm.c
> > > @@ -0,0 +1,459 @@
> > > +// SPDX-License-Identifier: GPL-2.0-or-later
> >
> > Why "or later"? I have to ask, sorry.
>
> I don't really have a preference here. Is there a reason to choose
> GPL-2.0 only for a new code?
It's your call, you need to pick that, but I can provide recommendations
if you want :)
> > And no copyright information? That's fine, but be sure your company's
> > lawyers are ok with it...
>
> There's no company behind this, just myself.
Great, it's your copyright, be proud, put it on there!
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/bits.h>
> > > +#include <linux/console.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/io.h>
> > > +#include <linux/irq.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/serial_core.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/tty_flip.h>
> > > +#include <asm/serial.h>
> > > +
> > > +#define DRIVER_NAME "esp32s3-acm"
> > > +#define DEV_NAME "ttyACM"
> >
> > There is already a ttyACM driver in the kernel, will this conflict with
> > that one? And are you using the same major/minor numbers for it as
> > well? If so, how is this going to work?
>
> I'll rename it to ttyS. I see that it coexists with the other driver that calls
> its devices ttyS just fine.
Great. But if you are going to be like a ACM gadget, use ttyGS like
that driver does?
> > > +static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl)
> > > +{
> > > +}
> >
> > Do you have to have empty functions for callbacks that do nothing?
>
> The serial core has unconditional calls to these callbacks.
Ah, good catch, maybe we should fix up the serial core.
> > > --- a/include/uapi/linux/serial_core.h
> > > +++ b/include/uapi/linux/serial_core.h
> > > @@ -248,4 +248,7 @@
> > > /* Espressif ESP32 UART */
> > > #define PORT_ESP32UART 124
> > >
> > > +/* Espressif ESP32 ACM */
> > > +#define PORT_ESP32ACM 125
> >
> > Why are these defines needed? What in userspace is going to require
> > them? If nothing, please do not add them.
>
> I don't understand what the alternatives are. The comment for the
> uart_ops::config_port() callback says that port->type should be set
> to the type of the port found, and I see that almost every serial driver
> defines a unique PORT_* for that.
Yes, but not all do. If you don't need to do anything special, it can
just claim to be a normal device, we've had threads about this on the
list before. If you don't need to determine in userspace from the tty
connection what device it is, just use the default one instead.
thanks,
greg k-h
On Thu, Oct 5, 2023 at 11:57 AM Greg Kroah-Hartman
<[email protected]> wrote:
> On Tue, Oct 03, 2023 at 12:46:46PM -0700, Max Filippov wrote:
> > > > Hardware specification is available at the following URL:
> > > >
> > > > https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> > > > (Chapter 33 USB Serial/JTAG Controller)
> > >
> > > I don't understand this driver, "ACM" is a USB host <-> gadget protocol,
> > > why do you need a platform serial driver for this?
> >
> > The USB part of this piece of hardware is fixed and not controllable, so
> > all we have is a very limited UART interface. But to the outside world
> > it's a USB device with the CDC-ACM interface.
>
> Where is the "outside world" here? The other end of the tty connection?
Yes.
> So this is a "ACM gadget"? If so, please try to use that term as that's
> what we use in the kernel to keep things straight.
Ok.
> > > > diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
> > > > new file mode 100644
> > > > index 000000000000..f02abd2ac65e
> > > > --- /dev/null
> > > > +++ b/drivers/tty/serial/esp32_acm.c
> > > > @@ -0,0 +1,459 @@
> > > > +// SPDX-License-Identifier: GPL-2.0-or-later
> > >
> > > Why "or later"? I have to ask, sorry.
> >
> > I don't really have a preference here. Is there a reason to choose
> > GPL-2.0 only for a new code?
>
> It's your call, you need to pick that, but I can provide recommendations
> if you want :)
Please do?
> > > And no copyright information? That's fine, but be sure your company's
> > > lawyers are ok with it...
> >
> > There's no company behind this, just myself.
>
> Great, it's your copyright, be proud, put it on there!
If I don't have to I'd rather not. This is just a piece of meaningless noise.
> > > > +#define DEV_NAME "ttyACM"
> > >
> > > There is already a ttyACM driver in the kernel, will this conflict with
> > > that one? And are you using the same major/minor numbers for it as
> > > well? If so, how is this going to work?
> >
> > I'll rename it to ttyS. I see that it coexists with the other driver that calls
> > its devices ttyS just fine.
>
> Great. But if you are going to be like a ACM gadget, use ttyGS like
> that driver does?
Ok.
> > > > --- a/include/uapi/linux/serial_core.h
> > > > +++ b/include/uapi/linux/serial_core.h
> > > > @@ -248,4 +248,7 @@
> > > > /* Espressif ESP32 UART */
> > > > #define PORT_ESP32UART 124
> > > >
> > > > +/* Espressif ESP32 ACM */
> > > > +#define PORT_ESP32ACM 125
> > >
> > > Why are these defines needed? What in userspace is going to require
> > > them? If nothing, please do not add them.
> >
> > I don't understand what the alternatives are. The comment for the
> > uart_ops::config_port() callback says that port->type should be set
> > to the type of the port found, and I see that almost every serial driver
> > defines a unique PORT_* for that.
>
> Yes, but not all do. If you don't need to do anything special, it can
> just claim to be a normal device, we've had threads about this on the
> list before. If you don't need to determine in userspace from the tty
> connection what device it is, just use the default one instead.
Ok, it looks like having
#define PORT_ESP32ACM (-1)
in the driver source should be ok? I've tested that it works.
--
Thanks.
-- Max
On Thu, Oct 05, 2023 at 02:21:55PM -0700, Max Filippov wrote:
> On Thu, Oct 5, 2023 at 11:57 AM Greg Kroah-Hartman
> > > > > --- /dev/null
> > > > > +++ b/drivers/tty/serial/esp32_acm.c
> > > > > @@ -0,0 +1,459 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0-or-later
> > > >
> > > > Why "or later"? I have to ask, sorry.
> > >
> > > I don't really have a preference here. Is there a reason to choose
> > > GPL-2.0 only for a new code?
> >
> > It's your call, you need to pick that, but I can provide recommendations
> > if you want :)
>
> Please do?
If you only want your code being used in Linux, then stick with
"GPL-2.0". If you want your code to be able to be copied into other
GPLv3 licensed code bodies (like Hurd and others), then license it as
"GPL-2.0-or-later". Your call.
> > > > And no copyright information? That's fine, but be sure your company's
> > > > lawyers are ok with it...
> > >
> > > There's no company behind this, just myself.
> >
> > Great, it's your copyright, be proud, put it on there!
>
> If I don't have to I'd rather not. This is just a piece of meaningless noise.
You already own the copyright by virtue of creating the code (you can't
give it away), so might as well put your mark on it to make it more
noticable. But it's not required, if you don't want to, no one can
force you, again, your call.
> > > > > --- a/include/uapi/linux/serial_core.h
> > > > > +++ b/include/uapi/linux/serial_core.h
> > > > > @@ -248,4 +248,7 @@
> > > > > /* Espressif ESP32 UART */
> > > > > #define PORT_ESP32UART 124
> > > > >
> > > > > +/* Espressif ESP32 ACM */
> > > > > +#define PORT_ESP32ACM 125
> > > >
> > > > Why are these defines needed? What in userspace is going to require
> > > > them? If nothing, please do not add them.
> > >
> > > I don't understand what the alternatives are. The comment for the
> > > uart_ops::config_port() callback says that port->type should be set
> > > to the type of the port found, and I see that almost every serial driver
> > > defines a unique PORT_* for that.
> >
> > Yes, but not all do. If you don't need to do anything special, it can
> > just claim to be a normal device, we've had threads about this on the
> > list before. If you don't need to determine in userspace from the tty
> > connection what device it is, just use the default one instead.
>
> Ok, it looks like having
>
> #define PORT_ESP32ACM (-1)
>
> in the driver source should be ok? I've tested that it works.
Hah, I like that hack. But why not just use PORT_UNKNOWN?
thanks,
greg k-h
On Fri, Oct 6, 2023 at 2:34 AM Greg Kroah-Hartman
<[email protected]> wrote:
> If you only want your code being used in Linux, then stick with
> "GPL-2.0". If you want your code to be able to be copied into other
> GPLv3 licensed code bodies (like Hurd and others), then license it as
> "GPL-2.0-or-later". Your call.
Thanks. From that point of view I prefer GPL-2.0-or-later.
> > > Yes, but not all do. If you don't need to do anything special, it can
> > > just claim to be a normal device, we've had threads about this on the
> > > list before. If you don't need to determine in userspace from the tty
> > > connection what device it is, just use the default one instead.
> >
> > Ok, it looks like having
> >
> > #define PORT_ESP32ACM (-1)
> >
> > in the driver source should be ok? I've tested that it works.
>
> Hah, I like that hack. But why not just use PORT_UNKNOWN?
A lot of functionality doesn't work with PORT_UNKNOWN, e.g.
console or modem control.
I've got the idea of using -1 from this email:
https://lore.kernel.org/linux-serial/[email protected]/
--
Thanks.
-- Max
On Fri, Oct 06, 2023 at 03:27:37AM -0700, Max Filippov wrote:
> On Fri, Oct 6, 2023 at 2:34 AM Greg Kroah-Hartman
> > > > Yes, but not all do. If you don't need to do anything special, it can
> > > > just claim to be a normal device, we've had threads about this on the
> > > > list before. If you don't need to determine in userspace from the tty
> > > > connection what device it is, just use the default one instead.
> > >
> > > Ok, it looks like having
> > >
> > > #define PORT_ESP32ACM (-1)
> > >
> > > in the driver source should be ok? I've tested that it works.
> >
> > Hah, I like that hack. But why not just use PORT_UNKNOWN?
>
> A lot of functionality doesn't work with PORT_UNKNOWN, e.g.
> console or modem control.
> I've got the idea of using -1 from this email:
> https://lore.kernel.org/linux-serial/[email protected]/
Ok, we should encode this as a "real" number, "PORT_ANY" and set it to
-1 and let all new devices use it.
thanks,
greg k-h
On Tue, Oct 3, 2023 at 2:47 PM Max Filippov <[email protected]> wrote:
>
> On Tue, Oct 3, 2023 at 5:55 AM Greg Kroah-Hartman
> <[email protected]> wrote:
> >
> > On Thu, Sep 28, 2023 at 08:16:31AM -0700, Max Filippov wrote:
> > > Add driver for the ACM controller of the Espressif ESP32S3 Soc.
> >
> > Odd extra space :(
>
> Ok.
>
> > > Hardware specification is available at the following URL:
> > >
> > > https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> > > (Chapter 33 USB Serial/JTAG Controller)
> >
> > I don't understand this driver, "ACM" is a USB host <-> gadget protocol,
> > why do you need a platform serial driver for this?
>
> The USB part of this piece of hardware is fixed and not controllable, so
> all we have is a very limited UART interface. But to the outside world
> it's a USB device with the CDC-ACM interface.
>
> > > diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c
> > > new file mode 100644
> > > index 000000000000..f02abd2ac65e
> > > --- /dev/null
> > > +++ b/drivers/tty/serial/esp32_acm.c
> > > @@ -0,0 +1,459 @@
> > > +// SPDX-License-Identifier: GPL-2.0-or-later
> >
> > Why "or later"? I have to ask, sorry.
>
> I don't really have a preference here. Is there a reason to choose
> GPL-2.0 only for a new code?
Yes, that's the default license for the kernel. So you should have a
reason for picking something else. Like maybe you copied all this from
somewhere else and that was the license.
Rob