diff options
Diffstat (limited to 'drivers/serial/mrst_max3110.c')
| -rw-r--r-- | drivers/serial/mrst_max3110.c | 844 |
1 files changed, 844 insertions, 0 deletions
diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c new file mode 100644 index 0000000..f6ad1ec --- /dev/null +++ b/drivers/serial/mrst_max3110.c @@ -0,0 +1,844 @@ +/* + * max3110.c - spi uart protocol driver for Maxim 3110 on Moorestown + * + * Copyright (C) Intel 2008 Feng Tang <feng.tang@intel.com> + * + * 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/init.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/platform_device.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/delay.h> +#include <asm/atomic.h> +#include <linux/spi/spi.h> +#include <linux/spi/dw_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; + + 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; + + unsigned long uart_flags; + + /* console related */ + struct circ_buf con_xmit; + + /* irq related */ + u16 irq; +}; + +/* global data structure, may need be removed */ +struct uart_max3110 *pmax; +static inline void receive_char(struct uart_max3110 *max, u8 ch); +static void receive_chars(struct uart_max3110 *max, + unsigned char *str, int len); +static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf); +static void max3110_console_receive(struct uart_max3110 *max); + +int max3110_write_then_read(struct uart_max3110 *max, + const u8 *txbuf, u8 *rxbuf, unsigned len, int always_fast) +{ + struct spi_device *spi = max->spi; + struct spi_message message; + struct spi_transfer x; + int ret; + + if (!txbuf || !rxbuf) + return -EINVAL; + + 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 = 3125000; + else if (max->baud) + x.speed_hz = max->baud; + + /* Do the i/o */ + ret = spi_sync(spi, &message); + return ret; +} + +/* Write a u16 to the device, and return one u16 read back */ +int max3110_out(struct uart_max3110 *max, const u16 out) +{ + u16 tmp; + int ret; + + ret = max3110_write_then_read(max, (u8 *)&out, (u8 *)&tmp, 2, 1); + if (ret) + return ret; + + /* If some valid data is read back */ + if (tmp & MAX3110_READ_DATA_AVAILABLE) + receive_char(max, (tmp & 0xff)); + + return ret; +} + +#define MAX_READ_LEN 20 +/* + * This is usually used to read data from SPIC RX FIFO, which doesn't + * need any delay like flushing character out. It returns how many + * valide bytes are read back + */ +static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf) +{ + u16 out[MAX_READ_LEN], in[MAX_READ_LEN]; + u8 *pbuf, valid_str[MAX_READ_LEN]; + int i, j, bytelen; + + if (len > MAX_READ_LEN) { + pr_err(PR_FMT "read len %d is too large\n", len); + return 0; + } + + bytelen = len * 2; + memset(out, 0, bytelen); + memset(in, 0, bytelen); + + if (max3110_write_then_read(max, (u8 *)out, (u8 *)in, bytelen, 1)) + return 0; + + /* If caller don't provide a buffer, then handle received char */ + pbuf = buf ? buf : valid_str; + + for (i = 0, j = 0; i < len; i++) { + if (in[i] & MAX3110_READ_DATA_AVAILABLE) + pbuf[j++] = (u8)(in[i] & 0xff); + } + + if (j && (pbuf == valid_str)) + receive_chars(max, valid_str, j); + + 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); + } + + + if (!test_and_set_bit(CON_TX_NEEDED, &max->uart_flags)) + wake_up_process(max->main_thread); +} + +/* + * 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); +} + +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 (!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, +}; + +#define MRST_CONSOLE (&serial_m3110_console) + +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 inline void send_circ_buf(struct uart_max3110 *max, + struct circ_buf *xmit) +{ + int len, left = 0; + u16 obuf[WORDS_PER_XFER], ibuf[WORDS_PER_XFER]; + u8 valid_str[WORDS_PER_XFER]; + int i, j; + + while (!uart_circ_empty(xmit)) { + left = uart_circ_chars_pending(xmit); + while (left) { + len = (left >= WORDS_PER_XFER) ? WORDS_PER_XFER : left; + + memset(obuf, 0, len * 2); + memset(ibuf, 0, len * 2); + for (i = 0; i < len; i++) { + obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG; + xmit->tail = (xmit->tail + 1) & + (UART_XMIT_SIZE - 1); + } + max3110_write_then_read(max, (u8 *)obuf, + (u8 *)ibuf, len * 2, 0); + + for (i = 0, j = 0; i < len; i++) { + if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE) + valid_str[j++] = (u8)(ibuf[i] & 0xff); + } + + if (j) + receive_chars(max, valid_str, j); + + max->port.icount.tx += len; + left -= len; + } + } +} + +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; /* receive some char before the tty is opened */ + + while (len) { + usable = tty_buffer_request_room(tty, len); + if (usable) { + tty_insert_flip_string(tty, str, usable); + str += usable; + port->icount.rx += usable; + tty_flip_buffer_push(tty); + } + len -= usable; + } +} + +static inline void receive_char(struct uart_max3110 *max, u8 ch) +{ + receive_chars(max, &ch, 1); +} + +static void max3110_console_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, 8, pbuf); + + if (num) { + loop = 10; + pbuf += num; + total += num; + + if (total >= 500) { + 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_console_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; +} + +#ifdef CONFIG_MRST_MAX3110_IRQ +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; +} +#else +/* 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 { + mutex_lock(&max->thread_mutex); + max3110_console_receive(max); + mutex_unlock(&max->thread_mutex); + + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(HZ / 20); + } while (!kthread_should_stop()); + + return 0; +} +#endif + +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"); + + /* firstly disable all IRQ and config it to 115200, 8n1 */ + config = WC_TAG | WC_FIFO_ENABLE + | WC_1_STOPBITS + | WC_8BIT_WORD + | WC_BAUD_DR2; + ret = max3110_out(max, config); + + /* as we use thread to handle tx/rx, need set low latency */ + port->state->port.tty->low_latency = 1; + +#ifdef CONFIG_MRST_MAX3110_IRQ + ret = request_irq(max->irq, serial_m3110_irq, + IRQ_TYPE_EDGE_FALLING, "max3110", max); + if (ret) + return ret; + + /* enable RX IRQ only */ + config |= WC_RXA_IRQ_ENABLE; + max3110_out(max, config); +#else + /* if IRQ is disabled, start a read thread for input data */ + max->read_thread = + kthread_run(max3110_read_thread, max, "max3110_read"); +#endif + + 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; + } + +#ifdef CONFIG_MRST_MAX3110_IRQ + free_irq(max->irq, max); +#endif + + /* 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) +{ + /* give it fake type */ + port->type = PORT_PXA; +} + +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: + 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; + 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 (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) { + 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, /* must have */ + .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 = MRST_CONSOLE, +}; + +static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state) +{ + return 0; +} + +static int serial_m3110_resume(struct spi_device *spi) +{ + return 0; +} + +static struct dw_spi_chip spi0_uart = { + .poll_mode = 1, + .enable_dma = 0, + .type = SPI_FRF_SPI, +}; + +static int serial_m3110_probe(struct spi_device *spi) +{ + struct uart_max3110 *max; + int ret; + unsigned char *buffer; + u16 res; + max = kzalloc(sizeof(*max), GFP_KERNEL); + if (!max) + return -ENOMEM; + + /* set spi info */ + spi->mode = SPI_MODE_0; + spi->bits_per_word = 16; + max->clock = MAX3110_HIGH_CLK; + spi->controller_data = &spi0_uart; + + spi_setup(spi); + + max->port.type = PORT_PXA; /* need apply for a max3110 type */ + 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; + max->name = spi->modalias; /* use spi name as the name */ + 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 = (unsigned char *)__get_free_page(GFP_KERNEL); + if (!buffer) { + ret = -ENOMEM; + goto err_get_page; + } + max->con_xmit.buf = (unsigned char *)buffer; + max->con_xmit.head = 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; + } + + 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: + pmax = NULL; + kfree(max); + return ret; +} + +static int max3110_remove(struct spi_device *dev) +{ + struct uart_max3110 *max = pmax; + + if (!pmax) + return 0; + + pmax = NULL; + 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(max3110_remove), + .suspend = serial_m3110_suspend, + .resume = serial_m3110_resume, +}; + + +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; +} + +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"); +MODULE_ALIAS("max3110-uart"); |
