Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932772Ab2JZMt5 (ORCPT ); Fri, 26 Oct 2012 08:49:57 -0400 Received: from kiruna.synopsys.com ([198.182.44.80]:54796 "EHLO kiruna.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932708Ab2JZMtx (ORCPT ); Fri, 26 Oct 2012 08:49:53 -0400 Message-ID: <508A865E.6030903@synopsys.com> Date: Fri, 26 Oct 2012 18:17:26 +0530 From: Vineet Gupta User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: CC: , , , , Subject: Re: [PATCH v5] serial/arc-uart: Add new driver References: <1351252996-28484-1-git-send-email-vgupta@synopsys.com> <1351252996-28484-2-git-send-email-vgupta@synopsys.com> <20121026121032.GD26342@arwen.pp.htv.fi> In-Reply-To: <20121026121032.GD26342@arwen.pp.htv.fi> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.12.197.56] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 26494 Lines: 839 On Friday 26 October 2012 05:40 PM, Felipe Balbi wrote: > On Fri, Oct 26, 2012 at 05:33:16PM +0530, Vineet.Gupta1@synopsys.com wrote: >> From: Vineet Gupta >> >> Driver for non-standard on-chip UART, instantiated in the ARC (Synopsys) >> FPGA Boards such as ARCAngel4/ML50x >> >> Signed-off-by: Vineet Gupta >> --- >> drivers/tty/serial/Kconfig | 23 ++ >> drivers/tty/serial/Makefile | 1 + >> drivers/tty/serial/arc_uart.c | 754 ++++++++++++++++++++++++++++++++++++++ >> include/uapi/linux/serial_core.h | 2 + >> 4 files changed, 780 insertions(+), 0 deletions(-) >> create mode 100644 drivers/tty/serial/arc_uart.c >> >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig >> index 2a53be5..b176801 100644 >> --- a/drivers/tty/serial/Kconfig >> +++ b/drivers/tty/serial/Kconfig >> @@ -1423,4 +1423,27 @@ config SERIAL_EFM32_UART_CONSOLE >> depends on SERIAL_EFM32_UART=y >> select SERIAL_CORE_CONSOLE >> >> +config SERIAL_ARC >> + tristate "ARC UART driver support" >> + select SERIAL_CORE >> + help >> + Driver for on-chip UART for ARC(Synopsys) for the legacy >> + FPGA Boards (ML50x/ARCAngel4) >> + >> +config SERIAL_ARC_CONSOLE >> + bool "Console on ARC UART" >> + depends on SERIAL_ARC=y >> + select SERIAL_CORE_CONSOLE >> + help >> + Enable system Console on ARC UART >> + >> +config SERIAL_ARC_NR_PORTS >> + int "Number of ARC UART ports" >> + depends on SERIAL_ARC >> + range 1 3 >> + default "1" >> + help >> + Set this to the number of serial ports you want the driver >> + to support. >> + >> endmenu >> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile >> index 4f694da..df1b998 100644 >> --- a/drivers/tty/serial/Makefile >> +++ b/drivers/tty/serial/Makefile >> @@ -82,3 +82,4 @@ obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o >> obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o >> obj-$(CONFIG_SERIAL_AR933X) += ar933x_uart.o >> obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o >> +obj-$(CONFIG_SERIAL_ARC) += arc_uart.o >> diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c >> new file mode 100644 >> index 0000000..c12efae >> --- /dev/null >> +++ b/drivers/tty/serial/arc_uart.c >> @@ -0,0 +1,754 @@ >> +/* >> + * ARC On-Chip(fpga) UART Driver >> + * >> + * Copyright (C) 2010-2012 Synopsys, Inc. (www.synopsys.com) >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + * vineetg: July 10th 2012 >> + * -Decoupled the driver from arch/arc >> + * +Using platform_get_resource() for irq/membase (thx to bfin_uart.c) >> + * +Using early_platform_xxx() for early console (thx to mach-shmobile/xxx) >> + * >> + * Vineetg: Aug 21st 2010 >> + * -Is uart_tx_stopped() not done in tty write path as it has already been >> + * taken care of, in serial core >> + * >> + * Vineetg: Aug 18th 2010 >> + * -New Serial Core based ARC UART driver >> + * -Derived largely from blackfin driver albiet with some major tweaks >> + * >> + * TODO: >> + * -check if sysreq works >> + */ >> + >> +#if defined(CONFIG_SERIAL_ARC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) >> +#define SUPPORT_SYSRQ >> +#endif >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +/************************************* >> + * ARC UART Hardware Specs >> + ************************************/ >> +#define ARC_UART_TX_FIFO_SIZE 1 >> + >> +/* >> + * UART Register set (this is not a Standards Compliant IP) >> + * Also each reg is Word aligned, but only 8 bits wide >> + */ >> +#define R_ID0 0 >> +#define R_ID1 4 >> +#define R_ID2 8 >> +#define R_ID3 12 >> +#define R_DATA 16 >> +#define R_STS 20 >> +#define R_BAUDL 24 >> +#define R_BAUDH 28 >> + >> +/* Bits for UART Status Reg (R/W) */ >> +#define RXIENB 0x04 /* Receive Interrupt Enable */ >> +#define TXIENB 0x40 /* Transmit Interrupt Enable */ >> + >> +#define RXEMPTY 0x20 /* Receive FIFO Empty: No char receivede */ >> +#define TXEMPTY 0x80 /* Transmit FIFO Empty, thus char can be written into */ >> + >> +#define RXFULL 0x08 /* Receive FIFO full */ >> +#define RXFULL1 0x10 /* Receive FIFO has space for 1 char (tot space=4) */ >> + >> +#define RXFERR 0x01 /* Frame Error: Stop Bit not detected */ >> +#define RXOERR 0x02 /* OverFlow Err: Char recv but RXFULL still set */ >> + >> +/* Uart bit fiddling helpers: lowest level */ >> +#define RBASE(uart, reg) (uart->port.membase + reg) >> +#define UART_REG_SET(u, r, v) writeb((v), RBASE(u, r)) >> +#define UART_REG_GET(u, r) readb(RBASE(u, r)) >> + >> +#define UART_REG_OR(u, r, v) UART_REG_SET(u, r, UART_REG_GET(u, r) | (v)) >> +#define UART_REG_CLR(u, r, v) UART_REG_SET(u, r, UART_REG_GET(u, r) & ~(v)) >> + >> +/* Uart bit fiddling helpers: API level */ >> +#define UART_SET_DATA(uart, val) UART_REG_SET(uart, R_DATA, val) >> +#define UART_GET_DATA(uart) UART_REG_GET(uart, R_DATA) >> + >> +#define UART_SET_BAUDH(uart, val) UART_REG_SET(uart, R_BAUDH, val) >> +#define UART_SET_BAUDL(uart, val) UART_REG_SET(uart, R_BAUDL, val) >> + >> +#define UART_CLR_STATUS(uart, val) UART_REG_CLR(uart, R_STS, val) >> +#define UART_GET_STATUS(uart) UART_REG_GET(uart, R_STS) >> + >> +#define UART_ALL_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, RXIENB|TXIENB) >> +#define UART_RX_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, RXIENB) >> +#define UART_TX_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, TXIENB) >> + >> +#define UART_ALL_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, RXIENB|TXIENB) >> +#define UART_RX_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, RXIENB) >> +#define UART_TX_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, TXIENB) >> + >> +#define ARC_SERIAL_DEV_NAME "ttyARC" >> + >> +struct arc_uart_port { >> + struct uart_port port; >> + unsigned long baud; >> + int is_emulated; /* H/w vs. Instruction Set Simulator */ >> +}; >> + >> +static struct arc_uart_port arc_uart_ports[CONFIG_SERIAL_ARC_NR_PORTS]; >> + >> +#ifdef CONFIG_SERIAL_ARC_CONSOLE >> +static struct console arc_console; >> +#endif >> + >> +#define DRIVER_NAME "arc-uart" >> + >> +static struct uart_driver arc_uart_driver = { >> + .owner = THIS_MODULE, >> + .driver_name = DRIVER_NAME, >> + .dev_name = ARC_SERIAL_DEV_NAME, >> + .major = 0, >> + .minor = 0, >> + .nr = CONFIG_SERIAL_ARC_NR_PORTS, >> +#ifdef CONFIG_SERIAL_ARC_CONSOLE >> + .cons = &arc_console, >> +#else >> + .cons = NULL, > else branch isn't necessary. The structure is declared static and > everything is initialized to zero unless overwritten by code. Correct - Fixed in next ver ! >> +#endif >> +}; >> + >> +static void arc_serial_stop_rx(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; > I would suggest using container_of() here. It's very unlikely to happen, > but if another field is added before struct uart_port member in your > structure, this will break. I agree that container_of() would make it future safe - but I don't foresee any significant changes to driver specially the arc_uart_port structure. >> + UART_RX_IRQ_DISABLE(uart); >> +} >> + >> +static void arc_serial_stop_tx(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + while (!(UART_GET_STATUS(uart) & TXEMPTY)) >> + cpu_relax(); >> + >> + UART_TX_IRQ_DISABLE(uart); >> +} >> + >> +/* >> + * Return TIOCSER_TEMT when transmitter is not busy. >> + */ >> +static unsigned int arc_serial_tx_empty(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + unsigned int stat; >> + >> + stat = UART_GET_STATUS(uart); >> + if (stat & TXEMPTY) >> + return TIOCSER_TEMT; >> + else >> + return 0; > else is unnecessary you can convert this into: > > if (stat & TXEMPTY) > return TIOCSER_TEMT; > > return 0; OK ! > >> +} >> + >> +/* >> + * Driver internal routine, used by both tty(serial core) as well as tx-isr >> + * -Called under spinlock in either cases >> + * -also tty->stopped / tty->hw_stopped has already been checked >> + * = by uart_start( ) before calling us >> + * = tx_ist checks that too before calling >> + */ >> +static void arc_serial_tx_chars(struct arc_uart_port *uart) >> +{ >> + struct circ_buf *xmit = &uart->port.state->xmit; >> + int sent = 0; >> + unsigned char ch; >> + >> + if (unlikely(uart->port.x_char)) { >> + UART_SET_DATA(uart, uart->port.x_char); >> + uart->port.icount.tx++; >> + uart->port.x_char = 0; >> + sent = 1; >> + } else if (xmit->tail != xmit->head) { /* TODO: uart_circ_empty */ >> + ch = xmit->buf[xmit->tail]; >> + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); >> + uart->port.icount.tx++; >> + while (!(UART_GET_STATUS(uart) & TXEMPTY)) >> + cpu_relax(); >> + UART_SET_DATA(uart, ch); >> + sent = 1; >> + } >> + >> + /* >> + * If num chars in xmit buffer are too few, ask tty layer for more. >> + * By Hard ISR to schedule processing in software interrupt part >> + */ >> + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) >> + uart_write_wakeup(&uart->port); >> + >> + if (sent) >> + UART_TX_IRQ_ENABLE(uart); >> +} >> + >> +/* >> + * port is locked and interrupts are disabled >> + * uart_start( ) calls us under the port spinlock irqsave >> + */ >> +static void arc_serial_start_tx(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + arc_serial_tx_chars(uart); >> +} >> + >> +static void arc_serial_rx_chars(struct arc_uart_port *uart) >> +{ >> + struct tty_struct *tty = tty_port_tty_get(&uart->port.state->port); >> + unsigned int status, ch, flg = 0; >> + >> + if (!tty) >> + return; > can this really happen ? why would you receive characters while tty is > NULL ? Since we are getting a ref to tty - it makes sense to check if the pointer is not NULL. Alan had pointed to a possible hangup race which could yield a NULL tty. But I'm not really an expert in serial core to be sure if at all this will happen - so added the check. >> + /* >> + * UART has 4 deep RX-FIFO. Driver's recongnition of this fact >> + * is very subtle. Here's how ... >> + * Upon getting a RX-Intr, such that RX-EMPTY=0, meaning data available, >> + * driver reads the DATA Reg and keeps doing that in a loop, until >> + * RX-EMPTY=1. Multiple chars being avail, with a single Interrupt, >> + * before RX-EMPTY=0, implies some sort of buffering going on in the >> + * controller, which is indeed the Rx-FIFO. >> + */ >> + while (!((status = UART_GET_STATUS(uart)) & RXEMPTY)) { >> + >> + ch = UART_GET_DATA(uart); >> + uart->port.icount.rx++; >> + >> + if (unlikely(status & (RXOERR | RXFERR))) { >> + if (status & RXOERR) { >> + uart->port.icount.overrun++; >> + flg = TTY_OVERRUN; >> + UART_CLR_STATUS(uart, RXOERR); >> + } >> + >> + if (status & RXFERR) { >> + uart->port.icount.frame++; >> + flg = TTY_FRAME; >> + UART_CLR_STATUS(uart, RXFERR); >> + } >> + } else >> + flg = TTY_NORMAL; >> + >> + if (unlikely(uart_handle_sysrq_char(&uart->port, ch))) >> + goto done; >> + >> + uart_insert_char(&uart->port, status, RXOERR, ch, flg); >> + >> +done: >> + tty_flip_buffer_push(tty); >> + } >> + >> + tty_kref_put(tty); >> +} >> + >> +/* >> + * A note on the Interrupt handling state machine of this driver >> + * >> + * kernel printk writes funnel thru the console driver framework and in order >> + * to keep things simple as well as efficient, it writes to UART in polled >> + * mode, in one shot, and exits. >> + * >> + * OTOH, Userland output (via tty layer), uses interrupt based writes as there >> + * can be undeterministic delay between char writes. >> + * >> + * Thus Rx-interrupts are always enabled, while tx-interrupts are by default >> + * disabled. >> + * >> + * When tty has some data to send out, serial core calls driver's start_tx >> + * which >> + * -checks-if-tty-buffer-has-char-to-send >> + * -writes-data-to-uart >> + * -enable-tx-intr >> + * >> + * Once data bits are pushed out, controller raises the Tx-room-avail-Interrupt. >> + * The first thing Tx ISR does is disable further Tx interrupts (as this could >> + * be the last char to send, before settling down into the quiet polled mode). >> + * It then calls the exact routine used by tty layer write to send out any >> + * more char in tty buffer. In case of sending, it re-enables Tx-intr. In case >> + * of no data, it remains disabled. >> + * This is how the transmit state machine is dynamically switched on/off >> + */ >> + >> +static irqreturn_t arc_serial_isr(int irq, void *dev_id) >> +{ >> + struct arc_uart_port *uart = dev_id; >> + unsigned int status; >> + >> + status = UART_GET_STATUS(uart); >> + >> + /* >> + * Single IRQ for both Rx (data available) Tx (room available) Interrupt >> + * notifications from the UART Controller. >> + * To demultiplex between the two, we check the relevant bits >> + */ >> + if ((status & RXIENB) && !(status & RXEMPTY)) { >> + >> + /* already in ISR, no need of xx_irqsave */ >> + spin_lock(&uart->port.lock); >> + arc_serial_rx_chars(uart); >> + spin_unlock(&uart->port.lock); >> + } >> + >> + if ((status & TXIENB) && (status & TXEMPTY)) { >> + >> + /* Unconditionally disable further Tx-Interrupts. >> + * will be enabled by tx_chars() if needed. >> + */ >> + UART_TX_IRQ_DISABLE(uart); >> + >> + spin_lock(&uart->port.lock); >> + >> + if (!uart_tx_stopped(&uart->port)) >> + arc_serial_tx_chars(uart); >> + >> + spin_unlock(&uart->port.lock); >> + } >> + >> + return IRQ_HANDLED; >> +} >> + >> +static unsigned int arc_serial_get_mctrl(struct uart_port *port) >> +{ >> + /* >> + * Pretend we have a Modem status reg and following bits are >> + * always set, to satify the serial core state machine >> + * (DSR) Data Set Ready >> + * (CTS) Clear To Send >> + * (CAR) Carrier Detect >> + */ >> + return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; >> +} >> + >> +static void arc_serial_set_mctrl(struct uart_port *port, unsigned int mctrl) >> +{ >> + /* MCR not present */ >> +} >> + >> +/* Enable Modem Status Interrupts */ >> + >> +static void arc_serial_enable_ms(struct uart_port *port) >> +{ >> + /* MSR not present */ >> +} >> + >> +static void arc_serial_break_ctl(struct uart_port *port, int break_state) >> +{ >> + /* ARC UART doesn't support sending Break signal */ >> +} >> + >> +static int arc_serial_startup(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + /* Before we hook up the ISR, Disable all UART Interrupts */ >> + UART_ALL_IRQ_DISABLE(uart); >> + >> + if (request_irq(uart->port.irq, arc_serial_isr, 0, "arc uart rx-tx", >> + uart)) { >> + pr_warn("Unable to attach ARC UART interrupt\n"); >> + return -EBUSY; >> + } >> + >> + UART_RX_IRQ_ENABLE(uart); /* Only Rx IRQ enabled to begin with */ >> + >> + return 0; >> +} >> + >> +/* This is not really needed */ >> +static void arc_serial_shutdown(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + free_irq(uart->port.irq, uart); >> +} >> + >> +static void >> +arc_serial_set_termios(struct uart_port *port, struct ktermios *new, >> + struct ktermios *old) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + unsigned int baud, uartl, uarth, hw_val; >> + unsigned long flags; >> + >> + /* >> + * Use the generic handler so that any specially encoded baud rates >> + * such as SPD_xx flags or "%B0" can be handled >> + * Max Baud I suppose will not be more than current 115K * 4 >> + * Formula for ARC UART is: hw-val = ((CLK/(BAUD*4)) -1) >> + * spread over two 8-bit registers >> + */ >> + baud = uart_get_baud_rate(port, new, old, 0, 460800); >> + >> + hw_val = port->uartclk / (uart->baud * 4) - 1; >> + uartl = hw_val & 0xFF; >> + uarth = (hw_val >> 8) & 0xFF; >> + >> + /* >> + * UART ISS(Instruction Set simulator) emulation has a subtle bug: >> + * A existing value of Baudh = 0 is used as a indication to startup >> + * it's internal state machine. >> + * Thus if baudh is set to 0, 2 times, it chokes. >> + * This happens with BAUD=115200 and the formaula above >> + * Until that is fixed, when running on ISS, we will set baudh to !0 >> + */ >> + if (uart->is_emulated) >> + uarth = 1; >> + >> + spin_lock_irqsave(&port->lock, flags); >> + >> + UART_ALL_IRQ_DISABLE(uart); >> + >> + UART_SET_BAUDL(uart, uartl); >> + UART_SET_BAUDH(uart, uarth); >> + >> + UART_RX_IRQ_ENABLE(uart); >> + >> + /* >> + * UART doesn't support Parity/Hardware Flow Control; >> + * Only supports 8N1 character size >> + */ >> + new->c_cflag &= ~(CMSPAR|CRTSCTS|CSIZE); >> + new->c_cflag |= CS8; >> + >> + if (old) >> + tty_termios_copy_hw(new, old); >> + >> + /* Don't rewrite B0 */ >> + if (tty_termios_baud_rate(new)) >> + tty_termios_encode_baud_rate(new, baud, baud); >> + >> + uart_update_timeout(port, new->c_cflag, baud); >> + >> + spin_unlock_irqrestore(&port->lock, flags); >> +} >> + >> +static const char *arc_serial_type(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + return uart->port.type == PORT_ARC ? DRIVER_NAME : NULL; >> +} >> + >> +/* >> + * Release the memory region(s) being used by 'port'. >> + */ >> +static void arc_serial_release_port(struct uart_port *port) >> +{ >> +} >> + >> +/* >> + * Request the memory region(s) being used by 'port'. >> + */ >> +static int arc_serial_request_port(struct uart_port *port) >> +{ >> + return 0; >> +} >> + >> +/* >> + * Verify the new serial_struct (for TIOCSSERIAL). >> + */ >> +static int >> +arc_serial_verify_port(struct uart_port *port, struct serial_struct *ser) >> +{ >> + return 0; >> +} > why all these empty functions with wrong comments above them ?? Copy/paste cruft. Empty functions deleted in next ver ! Regarding verify_port, I'm not sure whether it needs to elaborately check for PORT_UNKNOWN -> PORT_ARC or can we simply continue to return 0. But IMHO the comment in there is right. No ? >> +/* >> + * Configure/autoconfigure the port. >> + */ >> +static void arc_serial_config_port(struct uart_port *port, int flags) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + if (flags & UART_CONFIG_TYPE && >> + arc_serial_request_port(&uart->port) == 0) >> + uart->port.type = PORT_ARC; >> +} >> + >> +#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_ARC_CONSOLE) >> + >> +static void arc_serial_poll_putchar(struct uart_port *port, unsigned char chr) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + >> + while (!(UART_GET_STATUS(uart) & TXEMPTY)) >> + cpu_relax(); >> + >> + UART_SET_DATA(uart, chr); >> +} >> +#endif >> + >> +#ifdef CONFIG_CONSOLE_POLL >> +static int arc_serial_poll_getchar(struct uart_port *port) >> +{ >> + struct arc_uart_port *uart = (struct arc_uart_port *)port; >> + unsigned char chr; >> + >> + while (!(UART_GET_STATUS(uart) & RXEMPTY)) >> + cpu_relax(); >> + >> + chr = UART_GET_DATA(uart); >> + return chr; >> +} >> +#endif >> + >> +static struct uart_ops arc_serial_pops = { >> + .tx_empty = arc_serial_tx_empty, >> + .set_mctrl = arc_serial_set_mctrl, >> + .get_mctrl = arc_serial_get_mctrl, >> + .stop_tx = arc_serial_stop_tx, >> + .start_tx = arc_serial_start_tx, >> + .stop_rx = arc_serial_stop_rx, >> + .enable_ms = arc_serial_enable_ms, >> + .break_ctl = arc_serial_break_ctl, >> + .startup = arc_serial_startup, >> + .shutdown = arc_serial_shutdown, >> + .set_termios = arc_serial_set_termios, >> + .type = arc_serial_type, >> + .release_port = arc_serial_release_port, >> + .request_port = arc_serial_request_port, >> + .config_port = arc_serial_config_port, >> + .verify_port = arc_serial_verify_port, >> +#ifdef CONFIG_CONSOLE_POLL >> + .poll_put_char = arc_serial_poll_putchar, >> + .poll_get_char = arc_serial_poll_getchar, >> +#endif >> +}; >> + >> +static int __devinit >> +arc_uart_init_one(struct platform_device *pdev, struct arc_uart_port *uart) >> +{ >> + struct resource *res, *res2; >> + unsigned long *plat_data; >> + >> + if (pdev->id < 0 || pdev->id >= CONFIG_SERIAL_ARC_NR_PORTS) { >> + dev_err(&pdev->dev, "Wrong uart platform device id.\n"); >> + return -ENOENT; >> + } >> + >> + plat_data = ((unsigned long *)(pdev->dev.platform_data)); >> + uart->baud = plat_data[0]; >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + if (!res) >> + return -ENODEV; >> + >> + res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0); >> + if (!res2) >> + return -ENODEV; >> + >> + uart->port.mapbase = res->start; >> + uart->port.membase = ioremap_nocache(res->start, resource_size(res)); >> + if (!uart->port.membase) >> + /* No point of pr_err since UART itself is hosed here */ >> + return -ENXIO; >> + >> + uart->port.irq = res2->start; >> + uart->port.dev = &pdev->dev; >> + uart->port.iotype = UPIO_MEM; >> + uart->port.flags = UPF_BOOT_AUTOCONF; >> + uart->port.line = pdev->id; >> + uart->port.ops = &arc_serial_pops; >> + >> + uart->port.uartclk = plat_data[1]; >> + uart->port.fifosize = ARC_UART_TX_FIFO_SIZE; >> + >> + /* >> + * uart_insert_char( ) uses it in decideding whether to ignore a >> + * char or not. Explicitly setting it here, removes the subtelty >> + */ >> + uart->port.ignore_status_mask = 0; >> + >> + /* Real Hardware vs. emulated to work around a bug */ >> + uart->is_emulated = !!plat_data[2]; >> + >> + return 0; >> +} >> + >> +#ifdef CONFIG_SERIAL_ARC_CONSOLE >> + >> +static int __devinit arc_serial_console_setup(struct console *co, char *options) >> +{ >> + struct uart_port *port; >> + int baud = 115200; >> + int bits = 8; >> + int parity = 'n'; >> + int flow = 'n'; >> + >> + if (co->index < 0 || co->index >= CONFIG_SERIAL_ARC_NR_PORTS) >> + return -ENODEV; >> + >> + /* >> + * The uart port backing the console (e.g. ttyARC1) might not have been >> + * init yet. If so, defer the console setup to after the port. >> + */ >> + port = &arc_uart_ports[co->index].port; >> + if (!port->membase) >> + return -ENODEV; >> + >> + if (options) >> + uart_parse_options(options, &baud, &parity, &bits, &flow); >> + >> + /* >> + * Serial core will call port->ops->set_termios( ) >> + * which will set the baud reg >> + */ >> + return uart_set_options(port, co, baud, parity, bits, flow); >> +} >> + >> +static void arc_serial_console_putchar(struct uart_port *port, int ch) >> +{ >> + arc_serial_poll_putchar(port, (unsigned char)ch); >> +} >> + >> +/* >> + * Interrupts are disabled on entering >> + */ >> +static void arc_serial_console_write(struct console *co, const char *s, >> + unsigned int count) >> +{ >> + struct uart_port *port = &arc_uart_ports[co->index].port; >> + unsigned long flags; >> + >> + spin_lock_irqsave(&port->lock, flags); >> + uart_console_write(port, s, count, arc_serial_console_putchar); >> + spin_unlock_irqrestore(&port->lock, flags); >> +} >> + >> +static struct console arc_console = { >> + .name = ARC_SERIAL_DEV_NAME, >> + .write = arc_serial_console_write, >> + .device = uart_console_device, >> + .setup = arc_serial_console_setup, >> + .flags = CON_PRINTBUFFER, >> + .index = -1, >> + .data = &arc_uart_driver >> +}; >> + >> +static __init void early_serial_write(struct console *con, const char *s, >> + unsigned int n) >> +{ >> + struct uart_port *port = &arc_uart_ports[con->index].port; >> + unsigned int i; >> + >> + for (i = 0; i < n; i++, s++) { >> + if (*s == '\n') >> + arc_serial_poll_putchar(port, '\r'); >> + arc_serial_poll_putchar(port, *s); >> + } >> +} >> + >> +static struct __initdata console arc_early_serial_console = { >> + .name = "early_ARCuart", >> + .write = early_serial_write, >> + .flags = CON_PRINTBUFFER | CON_BOOT, >> + .index = -1 >> +}; >> + >> +static int __devinit arc_serial_probe_earlyprintk(struct platform_device *pdev) >> +{ >> + arc_early_serial_console.index = pdev->id; >> + >> + arc_uart_init_one(pdev, &arc_uart_ports[pdev->id]); >> + >> + arc_serial_console_setup(&arc_early_serial_console, NULL); >> + >> + register_console(&arc_early_serial_console); >> + return 0; >> +} >> +#else >> +static int __devinit arc_serial_probe_earlyprintk(struct platform_device *pdev) >> +{ >> + return -ENODEV; >> +} >> +#endif /* CONFIG_SERIAL_ARC_CONSOLE */ >> + >> +static int __devinit arc_serial_probe(struct platform_device *pdev) >> +{ >> + struct arc_uart_port *uart; >> + int rc; >> + >> + if (is_early_platform_device(pdev)) >> + return arc_serial_probe_earlyprintk(pdev); >> + >> + uart = &arc_uart_ports[pdev->id]; >> + rc = arc_uart_init_one(pdev, uart); >> + if (rc) >> + return rc; >> + >> + return uart_add_one_port(&arc_uart_driver, &uart->port); >> +} >> + >> +static int __devexit arc_serial_remove(struct platform_device *pdev) >> +{ >> + /* This will never be called */ >> + return 0; >> +} >> + >> +static struct platform_driver arc_platform_driver = { >> + .probe = arc_serial_probe, >> + .remove = __devexit_p(arc_serial_remove), >> + .driver = { >> + .name = DRIVER_NAME, >> + .owner = THIS_MODULE, >> + }, >> +}; >> + >> +#ifdef CONFIG_SERIAL_ARC_CONSOLE >> +/* >> + * Register an early platform driver of "earlyprintk" class. >> + * ARCH platform code installs the driver and probes the early devices >> + * The installation could rely on user specifying earlyprintk=xyx in cmd line >> + * or it could be done independently, for all "earlyprintk" class drivers. >> + * [see arch/arc/plat-arcfpga/platform.c] >> + */ >> +early_platform_init("earlyprintk", &arc_platform_driver); >> + >> +#endif /* CONFIG_SERIAL_ARC_CONSOLE */ >> + >> +static int __init arc_serial_init(void) >> +{ >> + int ret; >> + >> + pr_info("Serial: ARC serial driver: platform register\n"); > please remove this line, it's just useless IMHO. It has helped me enough in past when debugging the uncoupling of driver from ARC platform code. I'd rather keep it ! Many thanks for your review ! Once I see your reply I'll respin the next version. -Vineet -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/