linux/drivers/serial/mrst_max3110.c
Alan Cox 91efa75ce1 serial: mrst_max3110: Make the IRQ option runtime
And while we are at it allow it to fail to find one. Without this the IRQ
option will cause the 3110 driver to fail on 0.7 SFI firmware.

Acked-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22 10:20:03 -07:00

920 lines
20 KiB
C

/*
* mrst_max3110.c - spi uart protocol driver for Maxim 3110
*
* Copyright (c) 2008-2010, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* Note:
* 1. From Max3110 spec, the Rx FIFO has 8 words, while the Tx FIFO only has
* 1 word. If SPI master controller doesn't support sclk frequency change,
* then the char need be sent out one by one with some delay
*
* 2. Currently only RX availabe interrrupt is used, no need for waiting TXE
* interrupt for a low speed UART device
*/
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/kthread.h>
#include <linux/spi/spi.h>
#include "mrst_max3110.h"
#define PR_FMT "mrst_max3110: "
#define UART_TX_NEEDED 1
#define CON_TX_NEEDED 2
#define BIT_IRQ_PENDING 3
struct uart_max3110 {
struct uart_port port;
struct spi_device *spi;
char name[24];
wait_queue_head_t wq;
struct task_struct *main_thread;
struct task_struct *read_thread;
struct mutex thread_mutex;;
u32 baud;
u16 cur_conf;
u8 clock;
u8 parity, word_7bits;
u16 irq;
unsigned long uart_flags;
/* console related */
struct circ_buf con_xmit;
};
/* global data structure, may need be removed */
static struct uart_max3110 *pmax;
static void receive_chars(struct uart_max3110 *max,
unsigned char *str, int len);
static int max3110_read_multi(struct uart_max3110 *max, u8 *buf);
static void max3110_con_receive(struct uart_max3110 *max);
static int max3110_write_then_read(struct uart_max3110 *max,
const void *txbuf, void *rxbuf, unsigned len, int always_fast)
{
struct spi_device *spi = max->spi;
struct spi_message message;
struct spi_transfer x;
int ret;
spi_message_init(&message);
memset(&x, 0, sizeof x);
x.len = len;
x.tx_buf = txbuf;
x.rx_buf = rxbuf;
spi_message_add_tail(&x, &message);
if (always_fast)
x.speed_hz = spi->max_speed_hz;
else if (max->baud)
x.speed_hz = max->baud;
/* Do the i/o */
ret = spi_sync(spi, &message);
return ret;
}
/* Write a 16b word to the device */
static int max3110_out(struct uart_max3110 *max, const u16 out)
{
void *buf;
u16 *obuf, *ibuf;
u8 ch;
int ret;
buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
if (!buf)
return -ENOMEM;
obuf = buf;
ibuf = buf + 4;
*obuf = out;
ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
if (ret) {
pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
__func__, ret, out);
goto exit;
}
/* If some valid data is read back */
if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
ch = *ibuf & 0xff;
receive_chars(max, &ch, 1);
}
exit:
kfree(buf);
return ret;
}
/*
* This is usually used to read data from SPIC RX FIFO, which doesn't
* need any delay like flushing character out.
*
* Return how many valide bytes are read back
*/
static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
{
void *buf;
u16 *obuf, *ibuf;
u8 *pbuf, valid_str[M3110_RX_FIFO_DEPTH];
int i, j, blen;
blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
if (!buf) {
pr_warning(PR_FMT "%s(): fail to alloc dma buffer\n", __func__);
return 0;
}
/* tx/rx always have the same length */
obuf = buf;
ibuf = buf + blen;
if (max3110_write_then_read(max, obuf, ibuf, blen, 1)) {
kfree(buf);
return 0;
}
/* If caller doesn't provide a buffer, then handle received char */
pbuf = rxbuf ? rxbuf : valid_str;
for (i = 0, j = 0; i < M3110_RX_FIFO_DEPTH; i++) {
if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
pbuf[j++] = ibuf[i] & 0xff;
}
if (j && (pbuf == valid_str))
receive_chars(max, valid_str, j);
kfree(buf);
return j;
}
static void serial_m3110_con_putchar(struct uart_port *port, int ch)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
struct circ_buf *xmit = &max->con_xmit;
if (uart_circ_chars_free(xmit)) {
xmit->buf[xmit->head] = (char)ch;
xmit->head = (xmit->head + 1) & (PAGE_SIZE - 1);
}
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*
* The console_lock must be held when we get here.
*/
static void serial_m3110_con_write(struct console *co,
const char *s, unsigned int count)
{
if (!pmax)
return;
uart_console_write(&pmax->port, s, count, serial_m3110_con_putchar);
if (!test_and_set_bit(CON_TX_NEEDED, &pmax->uart_flags))
wake_up_process(pmax->main_thread);
}
static int __init
serial_m3110_con_setup(struct console *co, char *options)
{
struct uart_max3110 *max = pmax;
int baud = 115200;
int bits = 8;
int parity = 'n';
int flow = 'n';
pr_info(PR_FMT "setting up console\n");
if (co->index == -1)
co->index = 0;
if (!max) {
pr_err(PR_FMT "pmax is NULL, return");
return -ENODEV;
}
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(&max->port, co, baud, parity, bits, flow);
}
static struct tty_driver *serial_m3110_con_device(struct console *co,
int *index)
{
struct uart_driver *p = co->data;
*index = co->index;
return p->tty_driver;
}
static struct uart_driver serial_m3110_reg;
static struct console serial_m3110_console = {
.name = "ttyS",
.write = serial_m3110_con_write,
.device = serial_m3110_con_device,
.setup = serial_m3110_con_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &serial_m3110_reg,
};
static unsigned int serial_m3110_tx_empty(struct uart_port *port)
{
return 1;
}
static void serial_m3110_stop_tx(struct uart_port *port)
{
return;
}
/* stop_rx will be called in spin_lock env */
static void serial_m3110_stop_rx(struct uart_port *port)
{
return;
}
#define WORDS_PER_XFER 128
static void send_circ_buf(struct uart_max3110 *max,
struct circ_buf *xmit)
{
void *buf;
u16 *obuf, *ibuf;
u8 valid_str[WORDS_PER_XFER];
int i, j, len, blen, dma_size, left, ret = 0;
dma_size = WORDS_PER_XFER * sizeof(u16) * 2;
buf = kzalloc(dma_size, GFP_KERNEL | GFP_DMA);
if (!buf)
return;
obuf = buf;
ibuf = buf + dma_size/2;
while (!uart_circ_empty(xmit)) {
left = uart_circ_chars_pending(xmit);
while (left) {
len = min(left, WORDS_PER_XFER);
blen = len * sizeof(u16);
memset(ibuf, 0, blen);
for (i = 0; i < len; i++) {
obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG;
xmit->tail = (xmit->tail + 1) &
(UART_XMIT_SIZE - 1);
}
/* Fail to send msg to console is not very critical */
ret = max3110_write_then_read(max, obuf, ibuf, blen, 0);
if (ret)
pr_warning(PR_FMT "%s(): get err msg %d\n",
__func__, ret);
for (i = 0, j = 0; i < len; i++) {
if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
valid_str[j++] = ibuf[i] & 0xff;
}
if (j)
receive_chars(max, valid_str, j);
max->port.icount.tx += len;
left -= len;
}
}
kfree(buf);
}
static void transmit_char(struct uart_max3110 *max)
{
struct uart_port *port = &max->port;
struct circ_buf *xmit = &port->state->xmit;
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return;
send_circ_buf(max, xmit);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
serial_m3110_stop_tx(port);
}
/*
* This will be called by uart_write() and tty_write, can't
* go to sleep
*/
static void serial_m3110_start_tx(struct uart_port *port)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
if (!test_and_set_bit(UART_TX_NEEDED, &max->uart_flags))
wake_up_process(max->main_thread);
}
static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
{
struct uart_port *port = &max->port;
struct tty_struct *tty;
int usable;
/* If uart is not opened, just return */
if (!port->state)
return;
tty = port->state->port.tty;
if (!tty)
return;
while (len) {
usable = tty_buffer_request_room(tty, len);
if (usable) {
tty_insert_flip_string(tty, str, usable);
str += usable;
port->icount.rx += usable;
}
len -= usable;
}
tty_flip_buffer_push(tty);
}
/*
* This routine will be used in read_thread or RX IRQ handling,
* it will first do one round buffer read(8 words), if there is some
* valid RX data, will try to read 5 more rounds till all data
* is read out.
*
* Use stack space as data buffer to save some system load, and chose
* 504 Btyes as a threadhold to do a bulk push to upper tty layer when
* receiving bulk data, a much bigger buffer may cause stack overflow
*/
static void max3110_con_receive(struct uart_max3110 *max)
{
int loop = 1, num, total = 0;
u8 recv_buf[512], *pbuf;
pbuf = recv_buf;
do {
num = max3110_read_multi(max, pbuf);
if (num) {
loop = 5;
pbuf += num;
total += num;
if (total >= 504) {
receive_chars(max, recv_buf, total);
pbuf = recv_buf;
total = 0;
}
}
} while (--loop);
if (total)
receive_chars(max, recv_buf, total);
}
static int max3110_main_thread(void *_max)
{
struct uart_max3110 *max = _max;
wait_queue_head_t *wq = &max->wq;
int ret = 0;
struct circ_buf *xmit = &max->con_xmit;
init_waitqueue_head(wq);
pr_info(PR_FMT "start main thread\n");
do {
wait_event_interruptible(*wq, max->uart_flags || kthread_should_stop());
mutex_lock(&max->thread_mutex);
if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
max3110_con_receive(max);
/* first handle console output */
if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
send_circ_buf(max, xmit);
/* handle uart output */
if (test_and_clear_bit(UART_TX_NEEDED, &max->uart_flags))
transmit_char(max);
mutex_unlock(&max->thread_mutex);
} while (!kthread_should_stop());
return ret;
}
static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
{
struct uart_max3110 *max = dev_id;
/* max3110's irq is a falling edge, not level triggered,
* so no need to disable the irq */
if (!test_and_set_bit(BIT_IRQ_PENDING, &max->uart_flags))
wake_up_process(max->main_thread);
return IRQ_HANDLED;
}
/* if don't use RX IRQ, then need a thread to polling read */
static int max3110_read_thread(void *_max)
{
struct uart_max3110 *max = _max;
pr_info(PR_FMT "start read thread\n");
do {
/*
* If can't acquire the mutex, it means the main thread
* is running which will also perform the rx job
*/
if (mutex_trylock(&max->thread_mutex)) {
max3110_con_receive(max);
mutex_unlock(&max->thread_mutex);
}
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ / 20);
} while (!kthread_should_stop());
return 0;
}
static int serial_m3110_startup(struct uart_port *port)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
u16 config = 0;
int ret = 0;
if (port->line != 0) {
pr_err(PR_FMT "uart port startup failed\n");
return -1;
}
/* Disable all IRQ and config it to 115200, 8n1 */
config = WC_TAG | WC_FIFO_ENABLE
| WC_1_STOPBITS
| WC_8BIT_WORD
| WC_BAUD_DR2;
/* as we use thread to handle tx/rx, need set low latency */
port->state->port.tty->low_latency = 1;
if (max->irq) {
max->read_thread = NULL;
ret = request_irq(max->irq, serial_m3110_irq,
IRQ_TYPE_EDGE_FALLING, "max3110", max);
if (ret) {
max->irq = 0;
pr_err(PR_FMT "unable to allocate IRQ, polling\n");
} else {
/* Enable RX IRQ only */
config |= WC_RXA_IRQ_ENABLE;
}
}
if (max->irq == 0) {
/* If IRQ is disabled, start a read thread for input data */
max->read_thread =
kthread_run(max3110_read_thread, max, "max3110_read");
if (IS_ERR(max->read_thread)) {
ret = PTR_ERR(max->read_thread);
max->read_thread = NULL;
pr_err(PR_FMT "Can't create read thread!\n");
return ret;
}
}
ret = max3110_out(max, config);
if (ret) {
if (max->irq)
free_irq(max->irq, max);
if (max->read_thread)
kthread_stop(max->read_thread);
max->read_thread = NULL;
return ret;
}
max->cur_conf = config;
return 0;
}
static void serial_m3110_shutdown(struct uart_port *port)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
u16 config;
if (max->read_thread) {
kthread_stop(max->read_thread);
max->read_thread = NULL;
}
if (max->irq)
free_irq(max->irq, max);
/* Disable interrupts from this port */
config = WC_TAG | WC_SW_SHDI;
max3110_out(max, config);
}
static void serial_m3110_release_port(struct uart_port *port)
{
}
static int serial_m3110_request_port(struct uart_port *port)
{
return 0;
}
static void serial_m3110_config_port(struct uart_port *port, int flags)
{
port->type = PORT_MAX3100;
}
static int
serial_m3110_verify_port(struct uart_port *port, struct serial_struct *ser)
{
/* we don't want the core code to modify any port params */
return -EINVAL;
}
static const char *serial_m3110_type(struct uart_port *port)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
return max->name;
}
static void
serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct uart_max3110 *max =
container_of(port, struct uart_max3110, port);
unsigned char cval;
unsigned int baud, parity = 0;
int clk_div = -1;
u16 new_conf = max->cur_conf;
switch (termios->c_cflag & CSIZE) {
case CS7:
cval = UART_LCR_WLEN7;
new_conf |= WC_7BIT_WORD;
break;
default:
/* We only support CS7 & CS8 */
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= CS8;
case CS8:
cval = UART_LCR_WLEN8;
new_conf |= WC_8BIT_WORD;
break;
}
baud = uart_get_baud_rate(port, termios, old, 0, 230400);
/* First calc the div for 1.8MHZ clock case */
switch (baud) {
case 300:
clk_div = WC_BAUD_DR384;
break;
case 600:
clk_div = WC_BAUD_DR192;
break;
case 1200:
clk_div = WC_BAUD_DR96;
break;
case 2400:
clk_div = WC_BAUD_DR48;
break;
case 4800:
clk_div = WC_BAUD_DR24;
break;
case 9600:
clk_div = WC_BAUD_DR12;
break;
case 19200:
clk_div = WC_BAUD_DR6;
break;
case 38400:
clk_div = WC_BAUD_DR3;
break;
case 57600:
clk_div = WC_BAUD_DR2;
break;
case 115200:
clk_div = WC_BAUD_DR1;
break;
case 230400:
if (max->clock & MAX3110_HIGH_CLK)
break;
default:
/* Pick the previous baud rate */
baud = max->baud;
clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
tty_termios_encode_baud_rate(termios, baud, baud);
}
if (max->clock & MAX3110_HIGH_CLK) {
clk_div += 1;
/* High clk version max3110 doesn't support B300 */
if (baud == 300) {
baud = 600;
clk_div = WC_BAUD_DR384;
}
if (baud == 230400)
clk_div = WC_BAUD_DR1;
tty_termios_encode_baud_rate(termios, baud, baud);
}
new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
if (unlikely(termios->c_cflag & CMSPAR))
termios->c_cflag &= ~CMSPAR;
if (termios->c_cflag & CSTOPB)
new_conf |= WC_2_STOPBITS;
else
new_conf &= ~WC_2_STOPBITS;
if (termios->c_cflag & PARENB) {
new_conf |= WC_PARITY_ENABLE;
parity |= UART_LCR_PARITY;
} else
new_conf &= ~WC_PARITY_ENABLE;
if (!(termios->c_cflag & PARODD))
parity |= UART_LCR_EPAR;
max->parity = parity;
uart_update_timeout(port, termios->c_cflag, baud);
new_conf |= WC_TAG;
if (new_conf != max->cur_conf) {
if (!max3110_out(max, new_conf)) {
max->cur_conf = new_conf;
max->baud = baud;
}
}
}
/* Don't handle hw handshaking */
static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
{
return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
}
static void serial_m3110_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}
static void serial_m3110_break_ctl(struct uart_port *port, int break_state)
{
}
static void serial_m3110_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
}
static void serial_m3110_enable_ms(struct uart_port *port)
{
}
struct uart_ops serial_m3110_ops = {
.tx_empty = serial_m3110_tx_empty,
.set_mctrl = serial_m3110_set_mctrl,
.get_mctrl = serial_m3110_get_mctrl,
.stop_tx = serial_m3110_stop_tx,
.start_tx = serial_m3110_start_tx,
.stop_rx = serial_m3110_stop_rx,
.enable_ms = serial_m3110_enable_ms,
.break_ctl = serial_m3110_break_ctl,
.startup = serial_m3110_startup,
.shutdown = serial_m3110_shutdown,
.set_termios = serial_m3110_set_termios,
.pm = serial_m3110_pm,
.type = serial_m3110_type,
.release_port = serial_m3110_release_port,
.request_port = serial_m3110_request_port,
.config_port = serial_m3110_config_port,
.verify_port = serial_m3110_verify_port,
};
static struct uart_driver serial_m3110_reg = {
.owner = THIS_MODULE,
.driver_name = "MRST serial",
.dev_name = "ttyS",
.major = TTY_MAJOR,
.minor = 64,
.nr = 1,
.cons = &serial_m3110_console,
};
#ifdef CONFIG_PM
static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
{
struct uart_max3110 *max = spi_get_drvdata(spi);
disable_irq(max->irq);
uart_suspend_port(&serial_m3110_reg, &max->port);
max3110_out(max, max->cur_conf | WC_SW_SHDI);
return 0;
}
static int serial_m3110_resume(struct spi_device *spi)
{
struct uart_max3110 *max = spi_get_drvdata(spi);
max3110_out(max, max->cur_conf);
uart_resume_port(&serial_m3110_reg, &max->port);
enable_irq(max->irq);
return 0;
}
#else
#define serial_m3110_suspend NULL
#define serial_m3110_resume NULL
#endif
static int __devinit serial_m3110_probe(struct spi_device *spi)
{
struct uart_max3110 *max;
void *buffer;
u16 res;
int ret = 0;
max = kzalloc(sizeof(*max), GFP_KERNEL);
if (!max)
return -ENOMEM;
/* Set spi info */
spi->bits_per_word = 16;
max->clock = MAX3110_HIGH_CLK;
spi_setup(spi);
max->port.type = PORT_MAX3100;
max->port.fifosize = 2; /* Only have 16b buffer */
max->port.ops = &serial_m3110_ops;
max->port.line = 0;
max->port.dev = &spi->dev;
max->port.uartclk = 115200;
max->spi = spi;
strcpy(max->name, spi->modalias);
max->irq = (u16)spi->irq;
mutex_init(&max->thread_mutex);
max->word_7bits = 0;
max->parity = 0;
max->baud = 0;
max->cur_conf = 0;
max->uart_flags = 0;
/* Check if reading configuration register returns something sane */
res = RC_TAG;
ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0);
if (ret < 0 || res == 0 || res == 0xffff) {
printk(KERN_ERR "MAX3111 deemed not present (conf reg %04x)",
res);
ret = -ENODEV;
goto err_get_page;
}
buffer = (void *)__get_free_page(GFP_KERNEL);
if (!buffer) {
ret = -ENOMEM;
goto err_get_page;
}
max->con_xmit.buf = buffer;
max->con_xmit.head = 0;
max->con_xmit.tail = 0;
max->main_thread = kthread_run(max3110_main_thread,
max, "max3110_main");
if (IS_ERR(max->main_thread)) {
ret = PTR_ERR(max->main_thread);
goto err_kthread;
}
spi_set_drvdata(spi, max);
pmax = max;
/* Give membase a psudo value to pass serial_core's check */
max->port.membase = (void *)0xff110000;
uart_add_one_port(&serial_m3110_reg, &max->port);
return 0;
err_kthread:
free_page((unsigned long)buffer);
err_get_page:
kfree(max);
return ret;
}
static int __devexit serial_m3110_remove(struct spi_device *dev)
{
struct uart_max3110 *max = spi_get_drvdata(dev);
if (!max)
return 0;
uart_remove_one_port(&serial_m3110_reg, &max->port);
free_page((unsigned long)max->con_xmit.buf);
if (max->main_thread)
kthread_stop(max->main_thread);
kfree(max);
return 0;
}
static struct spi_driver uart_max3110_driver = {
.driver = {
.name = "spi_max3111",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = serial_m3110_probe,
.remove = __devexit_p(serial_m3110_remove),
.suspend = serial_m3110_suspend,
.resume = serial_m3110_resume,
};
static int __init serial_m3110_init(void)
{
int ret = 0;
ret = uart_register_driver(&serial_m3110_reg);
if (ret)
return ret;
ret = spi_register_driver(&uart_max3110_driver);
if (ret)
uart_unregister_driver(&serial_m3110_reg);
return ret;
}
static void __exit serial_m3110_exit(void)
{
spi_unregister_driver(&uart_max3110_driver);
uart_unregister_driver(&serial_m3110_reg);
}
module_init(serial_m3110_init);
module_exit(serial_m3110_exit);
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("max3110-uart");