v4.19.13 snapshot.
diff --git a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c
new file mode 100644
index 0000000..00ce31e
--- /dev/null
+++ b/drivers/tty/serial/mux.c
@@ -0,0 +1,612 @@
+// 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);