diff options
Diffstat (limited to 'drivers/tty/serial/mux.c')
| -rw-r--r-- | drivers/tty/serial/mux.c | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c new file mode 100644 index 000000000..47ab280f5 --- /dev/null +++ b/drivers/tty/serial/mux.c @@ -0,0 +1,609 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* +** mux.c: +** serial driver for the Mux console found in some PA-RISC servers. +** +** (c) Copyright 2002 Ryan Bradetich +** (c) Copyright 2002 Hewlett-Packard Company +** +** This Driver currently only supports the console (port 0) on the MUX. +** Additional work will be needed on this driver to enable the full +** functionality of the MUX. +** +*/ + +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/serial.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/console.h> +#include <linux/delay.h> /* for udelay */ +#include <linux/device.h> +#include <asm/io.h> +#include <asm/irq.h> +#include <asm/parisc-device.h> + +#include <linux/sysrq.h> +#include <linux/serial_core.h> + +#define MUX_OFFSET 0x800 +#define MUX_LINE_OFFSET 0x80 + +#define MUX_FIFO_SIZE 255 +#define MUX_POLL_DELAY (30 * HZ / 1000) + +#define IO_DATA_REG_OFFSET 0x3c +#define IO_DCOUNT_REG_OFFSET 0x40 + +#define MUX_EOFIFO(status) ((status & 0xF000) == 0xF000) +#define MUX_STATUS(status) ((status & 0xF000) == 0x8000) +#define MUX_BREAK(status) ((status & 0xF000) == 0x2000) + +#define MUX_NR 256 +static unsigned int port_cnt __read_mostly; +struct mux_port { + struct uart_port port; + int enabled; +}; +static struct mux_port mux_ports[MUX_NR]; + +static struct uart_driver mux_driver = { + .owner = THIS_MODULE, + .driver_name = "ttyB", + .dev_name = "ttyB", + .major = MUX_MAJOR, + .minor = 0, + .nr = MUX_NR, +}; + +static struct timer_list mux_timer; + +#define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + IO_DATA_REG_OFFSET) +#define UART_GET_FIFO_CNT(p) __raw_readl((p)->membase + IO_DCOUNT_REG_OFFSET) + +/** + * get_mux_port_count - Get the number of available ports on the Mux. + * @dev: The parisc device. + * + * This function is used to determine the number of ports the Mux + * supports. The IODC data reports the number of ports the Mux + * can support, but there are cases where not all the Mux ports + * are connected. This function can override the IODC and + * return the true port count. + */ +static int __init get_mux_port_count(struct parisc_device *dev) +{ + int status; + u8 iodc_data[32]; + unsigned long bytecnt; + + /* If this is the built-in Mux for the K-Class (Eole CAP/MUX), + * we only need to allocate resources for 1 port since the + * other 7 ports are not connected. + */ + if(dev->id.hversion == 0x15) + return 1; + + status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32); + BUG_ON(status != PDC_OK); + + /* Return the number of ports specified in the iodc data. */ + return ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8; +} + +/** + * mux_tx_empty - Check if the transmitter fifo is empty. + * @port: Ptr to the uart_port. + * + * This function test if the transmitter fifo for the port + * described by 'port' is empty. If it is empty, this function + * should return TIOCSER_TEMT, otherwise return 0. + */ +static unsigned int mux_tx_empty(struct uart_port *port) +{ + return UART_GET_FIFO_CNT(port) ? 0 : TIOCSER_TEMT; +} + +/** + * mux_set_mctrl - Set the current state of the modem control inputs. + * @ports: Ptr to the uart_port. + * @mctrl: Modem control bits. + * + * The Serial MUX does not support CTS, DCD or DSR so this function + * is ignored. + */ +static void mux_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +/** + * mux_get_mctrl - Returns the current state of modem control inputs. + * @port: Ptr to the uart_port. + * + * The Serial MUX does not support CTS, DCD or DSR so these lines are + * treated as permanently active. + */ +static unsigned int mux_get_mctrl(struct uart_port *port) +{ + return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; +} + +/** + * mux_stop_tx - Stop transmitting characters. + * @port: Ptr to the uart_port. + * + * The Serial MUX does not support this function. + */ +static void mux_stop_tx(struct uart_port *port) +{ +} + +/** + * mux_start_tx - Start transmitting characters. + * @port: Ptr to the uart_port. + * + * The Serial Mux does not support this function. + */ +static void mux_start_tx(struct uart_port *port) +{ +} + +/** + * mux_stop_rx - Stop receiving characters. + * @port: Ptr to the uart_port. + * + * The Serial Mux does not support this function. + */ +static void mux_stop_rx(struct uart_port *port) +{ +} + +/** + * mux_break_ctl - Control the transmitssion of a break signal. + * @port: Ptr to the uart_port. + * @break_state: Raise/Lower the break signal. + * + * The Serial Mux does not support this function. + */ +static void mux_break_ctl(struct uart_port *port, int break_state) +{ +} + +/** + * mux_write - Write chars to the mux fifo. + * @port: Ptr to the uart_port. + * + * This function writes all the data from the uart buffer to + * the mux fifo. + */ +static void mux_write(struct uart_port *port) +{ + int count; + struct circ_buf *xmit = &port->state->xmit; + + if(port->x_char) { + UART_PUT_CHAR(port, port->x_char); + port->icount.tx++; + port->x_char = 0; + return; + } + + if(uart_circ_empty(xmit) || uart_tx_stopped(port)) { + mux_stop_tx(port); + return; + } + + count = (port->fifosize) - UART_GET_FIFO_CNT(port); + do { + UART_PUT_CHAR(port, xmit->buf[xmit->tail]); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + if(uart_circ_empty(xmit)) + break; + + } while(--count > 0); + + while(UART_GET_FIFO_CNT(port)) + udelay(1); + + if(uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + mux_stop_tx(port); +} + +/** + * mux_read - Read chars from the mux fifo. + * @port: Ptr to the uart_port. + * + * This reads all available data from the mux's fifo and pushes + * the data to the tty layer. + */ +static void mux_read(struct uart_port *port) +{ + struct tty_port *tport = &port->state->port; + int data; + __u32 start_count = port->icount.rx; + + while(1) { + data = __raw_readl(port->membase + IO_DATA_REG_OFFSET); + + if (MUX_STATUS(data)) + continue; + + if (MUX_EOFIFO(data)) + break; + + port->icount.rx++; + + if (MUX_BREAK(data)) { + port->icount.brk++; + if(uart_handle_break(port)) + continue; + } + + if (uart_handle_sysrq_char(port, data & 0xffu)) + continue; + + tty_insert_flip_char(tport, data & 0xFF, TTY_NORMAL); + } + + if (start_count != port->icount.rx) + tty_flip_buffer_push(tport); +} + +/** + * mux_startup - Initialize the port. + * @port: Ptr to the uart_port. + * + * Grab any resources needed for this port and start the + * mux timer. + */ +static int mux_startup(struct uart_port *port) +{ + mux_ports[port->line].enabled = 1; + return 0; +} + +/** + * mux_shutdown - Disable the port. + * @port: Ptr to the uart_port. + * + * Release any resources needed for the port. + */ +static void mux_shutdown(struct uart_port *port) +{ + mux_ports[port->line].enabled = 0; +} + +/** + * mux_set_termios - Chane port parameters. + * @port: Ptr to the uart_port. + * @termios: new termios settings. + * @old: old termios settings. + * + * The Serial Mux does not support this function. + */ +static void +mux_set_termios(struct uart_port *port, struct ktermios *termios, + struct ktermios *old) +{ +} + +/** + * mux_type - Describe the port. + * @port: Ptr to the uart_port. + * + * Return a pointer to a string constant describing the + * specified port. + */ +static const char *mux_type(struct uart_port *port) +{ + return "Mux"; +} + +/** + * mux_release_port - Release memory and IO regions. + * @port: Ptr to the uart_port. + * + * Release any memory and IO region resources currently in use by + * the port. + */ +static void mux_release_port(struct uart_port *port) +{ +} + +/** + * mux_request_port - Request memory and IO regions. + * @port: Ptr to the uart_port. + * + * Request any memory and IO region resources required by the port. + * If any fail, no resources should be registered when this function + * returns, and it should return -EBUSY on failure. + */ +static int mux_request_port(struct uart_port *port) +{ + return 0; +} + +/** + * mux_config_port - Perform port autoconfiguration. + * @port: Ptr to the uart_port. + * @type: Bitmask of required configurations. + * + * Perform any autoconfiguration steps for the port. This function is + * called if the UPF_BOOT_AUTOCONF flag is specified for the port. + * [Note: This is required for now because of a bug in the Serial core. + * rmk has already submitted a patch to linus, should be available for + * 2.5.47.] + */ +static void mux_config_port(struct uart_port *port, int type) +{ + port->type = PORT_MUX; +} + +/** + * mux_verify_port - Verify the port information. + * @port: Ptr to the uart_port. + * @ser: Ptr to the serial information. + * + * Verify the new serial port information contained within serinfo is + * suitable for this port type. + */ +static int mux_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + if(port->membase == NULL) + return -EINVAL; + + return 0; +} + +/** + * mux_drv_poll - Mux poll function. + * @unused: Unused variable + * + * This function periodically polls the Serial MUX to check for new data. + */ +static void mux_poll(struct timer_list *unused) +{ + int i; + + for(i = 0; i < port_cnt; ++i) { + if(!mux_ports[i].enabled) + continue; + + mux_read(&mux_ports[i].port); + mux_write(&mux_ports[i].port); + } + + mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY); +} + + +#ifdef CONFIG_SERIAL_MUX_CONSOLE +static void mux_console_write(struct console *co, const char *s, unsigned count) +{ + /* Wait until the FIFO drains. */ + while(UART_GET_FIFO_CNT(&mux_ports[0].port)) + udelay(1); + + while(count--) { + if(*s == '\n') { + UART_PUT_CHAR(&mux_ports[0].port, '\r'); + } + UART_PUT_CHAR(&mux_ports[0].port, *s++); + } + +} + +static int mux_console_setup(struct console *co, char *options) +{ + return 0; +} + +static struct console mux_console = { + .name = "ttyB", + .write = mux_console_write, + .device = uart_console_device, + .setup = mux_console_setup, + .flags = CON_ENABLED | CON_PRINTBUFFER, + .index = 0, + .data = &mux_driver, +}; + +#define MUX_CONSOLE &mux_console +#else +#define MUX_CONSOLE NULL +#endif + +static const struct uart_ops mux_pops = { + .tx_empty = mux_tx_empty, + .set_mctrl = mux_set_mctrl, + .get_mctrl = mux_get_mctrl, + .stop_tx = mux_stop_tx, + .start_tx = mux_start_tx, + .stop_rx = mux_stop_rx, + .break_ctl = mux_break_ctl, + .startup = mux_startup, + .shutdown = mux_shutdown, + .set_termios = mux_set_termios, + .type = mux_type, + .release_port = mux_release_port, + .request_port = mux_request_port, + .config_port = mux_config_port, + .verify_port = mux_verify_port, +}; + +/** + * mux_probe - Determine if the Serial Mux should claim this device. + * @dev: The parisc device. + * + * Deterimine if the Serial Mux should claim this chip (return 0) + * or not (return 1). + */ +static int __init mux_probe(struct parisc_device *dev) +{ + int i, status; + + int port_count = get_mux_port_count(dev); + printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count); + + dev_set_drvdata(&dev->dev, (void *)(long)port_count); + request_mem_region(dev->hpa.start + MUX_OFFSET, + port_count * MUX_LINE_OFFSET, "Mux"); + + if(!port_cnt) { + mux_driver.cons = MUX_CONSOLE; + + status = uart_register_driver(&mux_driver); + if(status) { + printk(KERN_ERR "Serial mux: Unable to register driver.\n"); + return 1; + } + } + + for(i = 0; i < port_count; ++i, ++port_cnt) { + struct uart_port *port = &mux_ports[port_cnt].port; + port->iobase = 0; + port->mapbase = dev->hpa.start + MUX_OFFSET + + (i * MUX_LINE_OFFSET); + port->membase = ioremap(port->mapbase, MUX_LINE_OFFSET); + port->iotype = UPIO_MEM; + port->type = PORT_MUX; + port->irq = 0; + port->uartclk = 0; + port->fifosize = MUX_FIFO_SIZE; + port->ops = &mux_pops; + port->flags = UPF_BOOT_AUTOCONF; + port->line = port_cnt; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MUX_CONSOLE); + + /* The port->timeout needs to match what is present in + * uart_wait_until_sent in serial_core.c. Otherwise + * the time spent in msleep_interruptable will be very + * long, causing the appearance of a console hang. + */ + port->timeout = HZ / 50; + spin_lock_init(&port->lock); + + status = uart_add_one_port(&mux_driver, port); + BUG_ON(status); + } + + return 0; +} + +static int __exit mux_remove(struct parisc_device *dev) +{ + int i, j; + int port_count = (long)dev_get_drvdata(&dev->dev); + + /* Find Port 0 for this card in the mux_ports list. */ + for(i = 0; i < port_cnt; ++i) { + if(mux_ports[i].port.mapbase == dev->hpa.start + MUX_OFFSET) + break; + } + BUG_ON(i + port_count > port_cnt); + + /* Release the resources associated with each port on the device. */ + for(j = 0; j < port_count; ++j, ++i) { + struct uart_port *port = &mux_ports[i].port; + + uart_remove_one_port(&mux_driver, port); + if(port->membase) + iounmap(port->membase); + } + + release_mem_region(dev->hpa.start + MUX_OFFSET, port_count * MUX_LINE_OFFSET); + return 0; +} + +/* Hack. This idea was taken from the 8250_gsc.c on how to properly order + * the serial port detection in the proper order. The idea is we always + * want the builtin mux to be detected before addin mux cards, so we + * specifically probe for the builtin mux cards first. + * + * This table only contains the parisc_device_id of known builtin mux + * devices. All other mux cards will be detected by the generic mux_tbl. + */ +static const struct parisc_device_id builtin_mux_tbl[] __initconst = { + { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x15, 0x0000D }, /* All K-class */ + { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x44, 0x0000D }, /* E35, E45, and E55 */ + { 0, } +}; + +static const struct parisc_device_id mux_tbl[] __initconst = { + { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0000D }, + { 0, } +}; + +MODULE_DEVICE_TABLE(parisc, builtin_mux_tbl); +MODULE_DEVICE_TABLE(parisc, mux_tbl); + +static struct parisc_driver builtin_serial_mux_driver __refdata = { + .name = "builtin_serial_mux", + .id_table = builtin_mux_tbl, + .probe = mux_probe, + .remove = __exit_p(mux_remove), +}; + +static struct parisc_driver serial_mux_driver __refdata = { + .name = "serial_mux", + .id_table = mux_tbl, + .probe = mux_probe, + .remove = __exit_p(mux_remove), +}; + +/** + * mux_init - Serial MUX initialization procedure. + * + * Register the Serial MUX driver. + */ +static int __init mux_init(void) +{ + register_parisc_driver(&builtin_serial_mux_driver); + register_parisc_driver(&serial_mux_driver); + + if(port_cnt > 0) { + /* Start the Mux timer */ + timer_setup(&mux_timer, mux_poll, 0); + mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY); + +#ifdef CONFIG_SERIAL_MUX_CONSOLE + register_console(&mux_console); +#endif + } + + return 0; +} + +/** + * mux_exit - Serial MUX cleanup procedure. + * + * Unregister the Serial MUX driver from the tty layer. + */ +static void __exit mux_exit(void) +{ + /* Delete the Mux timer. */ + if(port_cnt > 0) { + del_timer_sync(&mux_timer); +#ifdef CONFIG_SERIAL_MUX_CONSOLE + unregister_console(&mux_console); +#endif + } + + unregister_parisc_driver(&builtin_serial_mux_driver); + unregister_parisc_driver(&serial_mux_driver); + uart_unregister_driver(&mux_driver); +} + +module_init(mux_init); +module_exit(mux_exit); + +MODULE_AUTHOR("Ryan Bradetich"); +MODULE_DESCRIPTION("Serial MUX driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_CHARDEV_MAJOR(MUX_MAJOR); |