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- // 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>
- #if defined(CONFIG_SERIAL_MUX_CONSOLE) && defined(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;
- 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_nocache(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;
- /* 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);
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