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