cpm_uart_core.c

linux 内核源代码

/*
 *  linux/drivers/serial/cpm_uart.c
 *
 *  Driver for CPM (SCC/SMC) serial ports; core driver
 *
 *  Based on arch/ppc/cpm2_io/uart.c by Dan Malek
 *  Based on ppc8xx.c by Thomas Gleixner
 *  Based on drivers/serial/amba.c by Russell King
 *
 *  Maintainer: Kumar Gala ([e-mail]) (CPM2)
 *              Pantelis Antoniou ([e-mail]) (CPM1)
 *
 *  Copyright (C) 2004, 2007 Freescale Semiconductor, Inc.
 *            (C) 2004 Intracom, S.A.
 *            (C) 2005-2006 MontaVista Software, Inc.
 * 		Vitaly Bordug <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <linux/fs_uart_pd.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/fs_pd.h>
#include <asm/udbg.h>

#ifdef CONFIG_PPC_CPM_NEW_BINDING
#include <linux/of_platform.h>
#endif

#if defined(CONFIG_SERIAL_CPM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>
#include <linux/kernel.h>

#include "cpm_uart.h"


/**************************************************************/

static int  cpm_uart_tx_pump(struct uart_port *port);
static void cpm_uart_init_smc(struct uart_cpm_port *pinfo);
static void cpm_uart_init_scc(struct uart_cpm_port *pinfo);
static void cpm_uart_initbd(struct uart_cpm_port *pinfo);

/**************************************************************/

#ifndef CONFIG_PPC_CPM_NEW_BINDING
/* Track which ports are configured as uarts */
int cpm_uart_port_map[UART_NR];
/* How many ports did we config as uarts */
int cpm_uart_nr;

/* Place-holder for board-specific stuff */
struct platform_device* __attribute__ ((weak)) __init
early_uart_get_pdev(int index)
{
	return NULL;
}


static void cpm_uart_count(void)
{
	cpm_uart_nr = 0;
#ifdef CONFIG_SERIAL_CPM_SMC1
	cpm_uart_port_map[cpm_uart_nr++] = UART_SMC1;
#endif
#ifdef CONFIG_SERIAL_CPM_SMC2
	cpm_uart_port_map[cpm_uart_nr++] = UART_SMC2;
#endif
#ifdef CONFIG_SERIAL_CPM_SCC1
	cpm_uart_port_map[cpm_uart_nr++] = UART_SCC1;
#endif
#ifdef CONFIG_SERIAL_CPM_SCC2
	cpm_uart_port_map[cpm_uart_nr++] = UART_SCC2;
#endif
#ifdef CONFIG_SERIAL_CPM_SCC3
	cpm_uart_port_map[cpm_uart_nr++] = UART_SCC3;
#endif
#ifdef CONFIG_SERIAL_CPM_SCC4
	cpm_uart_port_map[cpm_uart_nr++] = UART_SCC4;
#endif
}

/* Get UART number by its id */
static int cpm_uart_id2nr(int id)
{
	int i;
	if (id < UART_NR) {
		for (i=0; i<UART_NR; i++) {
			if (cpm_uart_port_map[i] == id)
				return i;
		}
	}

	/* not found or invalid argument */
	return -1;
}
#endif

/*
 * Check, if transmit buffers are processed
*/
static unsigned int cpm_uart_tx_empty(struct uart_port *port)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	cbd_t __iomem *bdp = pinfo->tx_bd_base;
	int ret = 0;

	while (1) {
		if (in_be16(&bdp->cbd_sc) & BD_SC_READY)
			break;

		if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP) {
			ret = TIOCSER_TEMT;
			break;
		}
		bdp++;
	}

	pr_debug("CPM uart[%d]:tx_empty: %d\n", port->line, ret);

	return ret;
}

static void cpm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	/* Whee. Do nothing. */
}

static unsigned int cpm_uart_get_mctrl(struct uart_port *port)
{
	/* Whee. Do nothing. */
	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}

/*
 * Stop transmitter
 */
static void cpm_uart_stop_tx(struct uart_port *port)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	smc_t __iomem *smcp = pinfo->smcp;
	scc_t __iomem *sccp = pinfo->sccp;

	pr_debug("CPM uart[%d]:stop tx\n", port->line);

	if (IS_SMC(pinfo))
		clrbits8(&smcp->smc_smcm, SMCM_TX);
	else
		clrbits16(&sccp->scc_sccm, UART_SCCM_TX);
}

/*
 * Start transmitter
 */
static void cpm_uart_start_tx(struct uart_port *port)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	smc_t __iomem *smcp = pinfo->smcp;
	scc_t __iomem *sccp = pinfo->sccp;

	pr_debug("CPM uart[%d]:start tx\n", port->line);

	if (IS_SMC(pinfo)) {
		if (in_8(&smcp->smc_smcm) & SMCM_TX)
			return;
	} else {
		if (in_be16(&sccp->scc_sccm) & UART_SCCM_TX)
			return;
	}

	if (cpm_uart_tx_pump(port) != 0) {
		if (IS_SMC(pinfo)) {
			setbits8(&smcp->smc_smcm, SMCM_TX);
		} else {
			setbits16(&sccp->scc_sccm, UART_SCCM_TX);
		}
	}
}

/*
 * Stop receiver
 */
static void cpm_uart_stop_rx(struct uart_port *port)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	smc_t __iomem *smcp = pinfo->smcp;
	scc_t __iomem *sccp = pinfo->sccp;

	pr_debug("CPM uart[%d]:stop rx\n", port->line);

	if (IS_SMC(pinfo))
		clrbits8(&smcp->smc_smcm, SMCM_RX);
	else
		clrbits16(&sccp->scc_sccm, UART_SCCM_RX);
}

/*
 * Enable Modem status interrupts
 */
static void cpm_uart_enable_ms(struct uart_port *port)
{
	pr_debug("CPM uart[%d]:enable ms\n", port->line);
}

/*
 * Generate a break.
 */
static void cpm_uart_break_ctl(struct uart_port *port, int break_state)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

	pr_debug("CPM uart[%d]:break ctrl, break_state: %d\n", port->line,
		break_state);

	if (break_state)
		cpm_line_cr_cmd(pinfo, CPM_CR_STOP_TX);
	else
		cpm_line_cr_cmd(pinfo, CPM_CR_RESTART_TX);
}

/*
 * Transmit characters, refill buffer descriptor, if possible
 */
static void cpm_uart_int_tx(struct uart_port *port)
{
	pr_debug("CPM uart[%d]:TX INT\n", port->line);

	cpm_uart_tx_pump(port);
}

/*
 * Receive characters
 */
static void cpm_uart_int_rx(struct uart_port *port)
{
	int i;
	unsigned char ch;
	u8 *cp;
	struct tty_struct *tty = port->info->tty;
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	cbd_t __iomem *bdp;
	u16 status;
	unsigned int flg;

	pr_debug("CPM uart[%d]:RX INT\n", port->line);

	/* Just loop through the closed BDs and copy the characters into
	 * the buffer.
	 */
	bdp = pinfo->rx_cur;
	for (;;) {
		/* get status */
		status = in_be16(&bdp->cbd_sc);
		/* If this one is empty, return happy */
		if (status & BD_SC_EMPTY)
			break;

		/* get number of characters, and check spce in flip-buffer */
		i = in_be16(&bdp->cbd_datlen);

		/* If we have not enough room in tty flip buffer, then we try
		 * later, which will be the next rx-interrupt or a timeout
		 */
		if(tty_buffer_request_room(tty, i) < i) {
			printk(KERN_WARNING "No room in flip buffer\n");
			return;
		}

		/* get pointer */
		cp = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr), pinfo);

		/* loop through the buffer */
		while (i-- > 0) {
			ch = *cp++;
			port->icount.rx++;
			flg = TTY_NORMAL;

			if (status &
			    (BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV))
				goto handle_error;
			if (uart_handle_sysrq_char(port, ch))
				continue;

		      error_return:
			tty_insert_flip_char(tty, ch, flg);

		}		/* End while (i--) */

		/* This BD is ready to be used again. Clear status. get next */
		clrbits16(&bdp->cbd_sc, BD_SC_BR | BD_SC_FR | BD_SC_PR |
		                        BD_SC_OV | BD_SC_ID);
		setbits16(&bdp->cbd_sc, BD_SC_EMPTY);

		if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
			bdp = pinfo->rx_bd_base;
		else
			bdp++;

	} /* End for (;;) */

	/* Write back buffer pointer */
	pinfo->rx_cur = bdp;

	/* activate BH processing */
	tty_flip_buffer_push(tty);

	return;

	/* Error processing */

      handle_error:
	/* Statistics */
	if (status & BD_SC_BR)
		port->icount.brk++;
	if (status & BD_SC_PR)
		port->icount.parity++;
	if (status & BD_SC_FR)
		port->icount.frame++;
	if (status & BD_SC_OV)
		port->icount.overrun++;

	/* Mask out ignored conditions */
	status &= port->read_status_mask;

	/* Handle the remaining ones */
	if (status & BD_SC_BR)
		flg = TTY_BREAK;
	else if (status & BD_SC_PR)
		flg = TTY_PARITY;
	else if (status & BD_SC_FR)
		flg = TTY_FRAME;

	/* overrun does not affect the current character ! */
	if (status & BD_SC_OV) {
		ch = 0;
		flg = TTY_OVERRUN;
		/* We skip this buffer */
		/* CHECK: Is really nothing senseful there */
		/* ASSUMPTION: it contains nothing valid */
		i = 0;
	}
#ifdef SUPPORT_SYSRQ
	port->sysrq = 0;
#endif
	goto error_return;
}

/*
 * Asynchron mode interrupt handler
 */
static irqreturn_t cpm_uart_int(int irq, void *data)
{
	u8 events;
	struct uart_port *port = (struct uart_port *)data;
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	smc_t __iomem *smcp = pinfo->smcp;
	scc_t __iomem *sccp = pinfo->sccp;

	pr_debug("CPM uart[%d]:IRQ\n", port->line);

	if (IS_SMC(pinfo)) {
		events = in_8(&smcp->smc_smce);
		out_8(&smcp->smc_smce, events);
		if (events & SMCM_BRKE)
			uart_handle_break(port);
		if (events & SMCM_RX)
			cpm_uart_int_rx(port);
		if (events & SMCM_TX)
			cpm_uart_int_tx(port);
	} else {
		events = in_be16(&sccp->scc_scce);
		out_be16(&sccp->scc_scce, events);
		if (events & UART_SCCM_BRKE)
			uart_handle_break(port);
		if (events & UART_SCCM_RX)
			cpm_uart_int_rx(port);
		if (events & UART_SCCM_TX)
			cpm_uart_int_tx(port);
	}
	return (events) ? IRQ_HANDLED : IRQ_NONE;
}

static int cpm_uart_startup(struct uart_port *port)
{
	int retval;
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

	pr_debug("CPM uart[%d]:startup\n", port->line);

	/* Install interrupt handler. */
	retval = request_irq(port->irq, cpm_uart_int, 0, "cpm_uart", port);
	if (retval)
		return retval;

	/* Startup rx-int */
	if (IS_SMC(pinfo)) {
		setbits8(&pinfo->smcp->smc_smcm, SMCM_RX);
		setbits16(&pinfo->smcp->smc_smcmr, (SMCMR_REN | SMCMR_TEN));
	} else {
		setbits16(&pinfo->sccp->scc_sccm, UART_SCCM_RX);
		setbits32(&pinfo->sccp->scc_gsmrl, (SCC_GSMRL_ENR | SCC_GSMRL_ENT));
	}

	if (!(pinfo->flags & FLAG_CONSOLE))
		cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);
	return 0;
}

inline void cpm_uart_wait_until_send(struct uart_cpm_port *pinfo)
{
	set_current_state(TASK_UNINTERRUPTIBLE);
	schedule_timeout(pinfo->wait_closing);
}

/*
 * Shutdown the uart
 */
static void cpm_uart_shutdown(struct uart_port *port)
{
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

	pr_debug("CPM uart[%d]:shutdown\n", port->line);

	/* free interrupt handler */
	free_irq(port->irq, port);

	/* If the port is not the console, disable Rx and Tx. */
	if (!(pinfo->flags & FLAG_CONSOLE)) {
		/* Wait for all the BDs marked sent */
		while(!cpm_uart_tx_empty(port)) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_timeout(2);
		}

		if (pinfo->wait_closing)
			cpm_uart_wait_until_send(pinfo);

		/* Stop uarts */
		if (IS_SMC(pinfo)) {
			smc_t __iomem *smcp = pinfo->smcp;
			clrbits16(&smcp->smc_smcmr, SMCMR_REN | SMCMR_TEN);
			clrbits8(&smcp->smc_smcm, SMCM_RX | SMCM_TX);
		} else {
			scc_t __iomem *sccp = pinfo->sccp;
			clrbits32(&sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT);
			clrbits16(&sccp->scc_sccm, UART_SCCM_TX | UART_SCCM_RX);
		}

		/* Shut them really down and reinit buffer descriptors */
		if (IS_SMC(pinfo))
			cpm_line_cr_cmd(pinfo, CPM_CR_STOP_TX);
		else
			cpm_line_cr_cmd(pinfo, CPM_CR_GRA_STOP_TX);

		cpm_uart_initbd(pinfo);
	}
}

static void cpm_uart_set_termios(struct uart_port *port,
                                 struct ktermios *termios,
                                 struct ktermios *old)
{
	int baud;
	unsigned long flags;
	u16 cval, scval, prev_mode;
	int bits, sbits;
	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
	smc_t __iomem *smcp = pinfo->smcp;
	scc_t __iomem *sccp = pinfo->sccp;

	pr_debug("CPM uart[%d]:set_termios\n", port->line);

	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);

	/* Character length programmed into the mode register is the
	 * sum of: 1 start bit, number of data bits, 0 or 1 parity bit,
	 * 1 or 2 stop bits, minus 1.
	 * The value 'bits' counts this for us.
	 */
	cval = 0;
	scval = 0;

	/* byte size */
	switch (termios->c_cflag & CSIZE) {
	case CS5:
		bits = 5;
		break;
	case CS6:
		bits = 6;
		break;
	case CS7:
		bits = 7;
		break;
	case CS8:
		bits = 8;
		break;
		/* Never happens, but GCC is too dumb to figure it out */
	default:
		bits = 8;
		break;
	}
	sbits = bits - 5;

	if (termios->c_cflag & CSTOPB) {