/* ** 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 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 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/tty.h> #include <linux/ioport.h> #include <linux/init.h> #include <linux/serial.h> #include <linux/console.h> #include <linux/slab.h> #include <linux/delay.h> /* for udelay */ #include <linux/device.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/parisc-device.h> #ifdef CONFIG_MAGIC_SYSRQ #include <linux/sysrq.h> #define SUPPORT_SYSRQ #endif #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; static struct uart_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) #define GET_MUX_PORTS(iodc_data) ((((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_enable_ms - Enable modum status interrupts. * @port: Ptr to the uart_port. * * The Serial Mux does not support this function. */ static void mux_enable_ms(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->info->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) { int data; struct tty_struct *tty = port->info->tty; __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(tty, data & 0xFF, TTY_NORMAL); } if (start_count != port->icount.rx) { tty_flip_buffer_push(tty); } } /** * 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) { mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY); 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_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 termios *termios, struct termios *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 functino 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(unsigned long unused) { int i; for(i = 0; i < port_cnt; ++i) { if(!mux_ports[i].info) continue; mux_read(&mux_ports[i]); mux_write(&mux_ports[i]); } 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) { while(count--) pdc_iodc_putc(*s++); } static int mux_console_setup(struct console *co, char *options) { return 0; } struct tty_driver *mux_console_device(struct console *co, int *index) { *index = co->index; return mux_driver.tty_driver; } static struct console mux_console = { .name = "ttyB", .write = mux_console_write, .device = mux_console_device, .setup = mux_console_setup, .flags = CON_ENABLED | CON_PRINTBUFFER, .index = 0, }; #define MUX_CONSOLE &mux_console #else #define MUX_CONSOLE NULL #endif static 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, .enable_ms = mux_enable_ms, .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, ports; u8 iodc_data[32]; unsigned long bytecnt; struct uart_port *port; status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32); if(status != PDC_OK) { printk(KERN_ERR "Serial mux: Unable to read IODC.\n"); return 1; } ports = GET_MUX_PORTS(iodc_data); printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.3\n", ports); 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; } init_timer(&mux_timer); mux_timer.function = mux_poll; } for(i = 0; i < ports; ++i, ++port_cnt) { port = &mux_ports[port_cnt]; port->iobase = 0; port->mapbase = dev->hpa.start + MUX_OFFSET + (i * MUX_LINE_OFFSET); port->membase = ioremap_nocache(port->mapbase, MUX_LINE_OFFSET); port->iotype = UPIO_MEM; port->type = PORT_MUX; port->irq = NO_IRQ; port->uartclk = 0; port->fifosize = MUX_FIFO_SIZE; port->ops = &mux_pops; port->flags = UPF_BOOT_AUTOCONF; port->line = port_cnt; /* 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); } #ifdef CONFIG_SERIAL_MUX_CONSOLE register_console(&mux_console); #endif return 0; } static struct parisc_device_id mux_tbl[] = { { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0000D }, { 0, } }; MODULE_DEVICE_TABLE(parisc, mux_tbl); static struct parisc_driver serial_mux_driver = { .name = "serial_mux", .id_table = mux_tbl, .probe = mux_probe, }; /** * mux_init - Serial MUX initalization procedure. * * Register the Serial MUX driver. */ static int __init mux_init(void) { return register_parisc_driver(&serial_mux_driver); } /** * mux_exit - Serial MUX cleanup procedure. * * Unregister the Serial MUX driver from the tty layer. */ static void __exit mux_exit(void) { int i; for (i = 0; i < port_cnt; i++) { uart_remove_one_port(&mux_driver, &mux_ports[i]); if (mux_ports[i].membase) iounmap(mux_ports[i].membase); } 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);