[SPARC64]: Add SUN4V Hypervisor Console driver.

Since it can do things like BREAK and HUP, we implement
this as a serial uart driver.

This still needs interrupt probing code, as I haven't figured
out how interrupts will work or be probed for on SUN4V yet.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 489 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b3c561abe3f6..89e5413cc2a3 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -582,6 +582,13 @@ config SERIAL_SUNSAB_CONSOLE
           on your Sparc system as the console, you can do so by answering
           Y to this option.
 
+config SERIAL_SUNHV
+        bool "Sun4v Hypervisor Console support"
+        depends on SPARC64
+        help
+          This driver supports the console device found on SUN4V Sparc
+          systems.  Say Y if you want to be able to use this device.
+
 config SERIAL_IP22_ZILOG
         tristate "IP22 Zilog8530 serial support"
         depends on SGI_IP22
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index eaf8e01db198..0f7f8d73d3ca 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SERIAL_SUNZILOG) += sunzilog.o
 obj-$(CONFIG_SERIAL_IP22_ZILOG) += ip22zilog.o
 obj-$(CONFIG_SERIAL_SUNSU) += sunsu.o
 obj-$(CONFIG_SERIAL_SUNSAB) += sunsab.o
+obj-$(CONFIG_SERIAL_SUNHV) += sunhv.o
 obj-$(CONFIG_SERIAL_MUX) += mux.o
 obj-$(CONFIG_SERIAL_68328) += 68328serial.o
 obj-$(CONFIG_SERIAL_68360) += 68360serial.o
diff --git a/drivers/serial/sunhv.c b/drivers/serial/sunhv.c
new file mode 100644
index 000000000000..2ba716eeb0bf
--- /dev/null
+++ b/drivers/serial/sunhv.c
@@ -0,0 +1,481 @@
+/* sunhv.c: Serial driver for SUN4V hypervisor console.
+ *
+ * Copyright (C) 2006 David S. Miller (davem@davemloft.net)
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/major.h>
+#include <linux/circ_buf.h>
+#include <linux/serial.h>
+#include <linux/sysrq.h>
+#include <linux/console.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+
+#include <asm/hypervisor.h>
+#include <asm/spitfire.h>
+
+#if defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial_core.h>
+
+#include "suncore.h"
+
+#define CON_BREAK       ((long)-1)
+#define CON_HUP         ((long)-2)
+
+static inline long hypervisor_con_getchar(long *status)
+{
+        register unsigned long func asm("%o5");
+        register unsigned long arg0 asm("%o0");
+        register unsigned long arg1 asm("%o1");
+
+        func = HV_FAST_CONS_GETCHAR;
+        arg0 = 0;
+        arg1 = 0;
+        __asm__ __volatile__("ta        %6"
+                             : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
+                             : "0" (func), "1" (arg0), "2" (arg1),
+                               "i" (HV_FAST_TRAP));
+
+        *status = arg0;
+
+        return (long) arg1;
+}
+
+static inline long hypervisor_con_putchar(long ch)
+{
+        register unsigned long func asm("%o5");
+        register unsigned long arg0 asm("%o0");
+
+        func = HV_FAST_CONS_PUTCHAR;
+        arg0 = ch;
+        __asm__ __volatile__("ta        %4"
+                             : "=&r" (func), "=&r" (arg0)
+                             : "0" (func), "1" (arg0), "i" (HV_FAST_TRAP));
+
+        return (long) arg0;
+}
+
+#define IGNORE_BREAK    0x1
+#define IGNORE_ALL      0x2
+
+static int hung_up = 0;
+
+static struct tty_struct *receive_chars(struct uart_port *port, struct pt_regs *regs)
+{
+        struct tty_struct *tty = NULL;
+        int saw_console_brk = 0;
+        int limit = 10000;
+
+        if (port->info != NULL)         /* Unopened serial console */
+                tty = port->info->tty;
+
+        while (limit-- > 0) {
+                long status;
+                long c = hypervisor_con_getchar(&status);
+                unsigned char flag;
+
+                if (status == HV_EWOULDBLOCK)
+                        break;
+
+                if (c == CON_BREAK) {
+                        saw_console_brk = 1;
+                        c = 0;
+                }
+
+                if (c == CON_HUP) {
+                        hung_up = 1;
+                        uart_handle_dcd_change(port, 0);
+                } else if (hung_up) {
+                        hung_up = 0;
+                        uart_handle_dcd_change(port, 1);
+                }
+
+                if (tty == NULL) {
+                        uart_handle_sysrq_char(port, c, regs);
+                        continue;
+                }
+
+                flag = TTY_NORMAL;
+                port->icount.rx++;
+                if (c == CON_BREAK) {
+                        port->icount.brk++;
+                        if (uart_handle_break(port))
+                                continue;
+                        flag = TTY_BREAK;
+                }
+
+                if (uart_handle_sysrq_char(port, c, regs))
+                        continue;
+
+                if ((port->ignore_status_mask & IGNORE_ALL) ||
+                    ((port->ignore_status_mask & IGNORE_BREAK) &&
+                     (c == CON_BREAK)))
+                        continue;
+
+                tty_insert_flip_char(tty, c, flag);
+        }
+
+        if (saw_console_brk)
+                sun_do_break();
+
+        return tty;
+}
+
+static void transmit_chars(struct uart_port *port)
+{
+        struct circ_buf *xmit = &port->info->xmit;
+
+        if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+                return;
+
+        while (!uart_circ_empty(xmit)) {
+                long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
+
+                if (status != HV_EOK)
+                        break;
+
+                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+                port->icount.tx++;
+        }
+
+        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+                uart_write_wakeup(port);
+}
+
+static irqreturn_t sunhv_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+        struct uart_port *port = dev_id;
+        struct tty_struct *tty;
+        unsigned long flags;
+
+        spin_lock_irqsave(&port->lock, flags);
+        tty = receive_chars(port, regs);
+        transmit_chars(port);
+        spin_unlock_irqrestore(&port->lock, flags);
+
+        if (tty)
+                tty_flip_buffer_push(tty);
+
+        return IRQ_HANDLED;
+}
+
+/* port->lock is not held.  */
+static unsigned int sunhv_tx_empty(struct uart_port *port)
+{
+        /* Transmitter is always empty for us.  If the circ buffer
+         * is non-empty or there is an x_char pending, our caller
+         * will do the right thing and ignore what we return here.
+         */
+        return TIOCSER_TEMT;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+        return;
+}
+
+/* port->lock is held by caller and interrupts are disabled.  */
+static unsigned int sunhv_get_mctrl(struct uart_port *port)
+{
+        return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_stop_tx(struct uart_port *port)
+{
+        return;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_start_tx(struct uart_port *port)
+{
+        struct circ_buf *xmit = &port->info->xmit;
+        unsigned long flags;
+
+        spin_lock_irqsave(&port->lock, flags);
+
+        while (!uart_circ_empty(xmit)) {
+                long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
+
+                if (status != HV_EOK)
+                        break;
+
+                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+                port->icount.tx++;
+        }
+
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* port->lock is not held.  */
+static void sunhv_send_xchar(struct uart_port *port, char ch)
+{
+        unsigned long flags;
+        int limit = 10000;
+
+        spin_lock_irqsave(&port->lock, flags);
+
+        while (limit-- > 0) {
+                long status = hypervisor_con_putchar(ch);
+                if (status == HV_EOK)
+                        break;
+        }
+
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* port->lock held by caller.  */
+static void sunhv_stop_rx(struct uart_port *port)
+{
+}
+
+/* port->lock held by caller.  */
+static void sunhv_enable_ms(struct uart_port *port)
+{
+}
+
+/* port->lock is not held.  */
+static void sunhv_break_ctl(struct uart_port *port, int break_state)
+{
+        if (break_state) {
+                unsigned long flags;
+                int limit = 10000;
+
+                spin_lock_irqsave(&port->lock, flags);
+
+                while (limit-- > 0) {
+                        long status = hypervisor_con_putchar(CON_BREAK);
+                        if (status == HV_EOK)
+                                break;
+                }
+
+                spin_unlock_irqrestore(&port->lock, flags);
+        }
+}
+
+/* port->lock is not held.  */
+static int sunhv_startup(struct uart_port *port)
+{
+        return 0;
+}
+
+/* port->lock is not held.  */
+static void sunhv_shutdown(struct uart_port *port)
+{
+}
+
+/* port->lock is not held.  */
+static void sunhv_set_termios(struct uart_port *port, struct termios *termios,
+                              struct termios *old)
+{
+        unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
+        unsigned int quot = uart_get_divisor(port, baud);
+        unsigned int iflag, cflag;
+        unsigned long flags;
+
+        spin_lock_irqsave(&port->lock, flags);
+
+        iflag = termios->c_iflag;
+        cflag = termios->c_cflag;
+
+        port->ignore_status_mask = 0;
+        if (iflag & IGNBRK)
+                port->ignore_status_mask |= IGNORE_BREAK;
+        if ((cflag & CREAD) == 0)
+                port->ignore_status_mask |= IGNORE_ALL;
+
+        /* XXX */
+        uart_update_timeout(port, cflag,
+                            (port->uartclk / (16 * quot)));
+
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *sunhv_type(struct uart_port *port)
+{
+        return "SUN4V HCONS";
+}
+
+static void sunhv_release_port(struct uart_port *port)
+{
+}
+
+static int sunhv_request_port(struct uart_port *port)
+{
+        return 0;
+}
+
+static void sunhv_config_port(struct uart_port *port, int flags)
+{
+}
+
+static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+        return -EINVAL;
+}
+
+static struct uart_ops sunhv_pops = {
+        .tx_empty       = sunhv_tx_empty,
+        .set_mctrl      = sunhv_set_mctrl,
+        .get_mctrl      = sunhv_get_mctrl,
+        .stop_tx        = sunhv_stop_tx,
+        .start_tx       = sunhv_start_tx,
+        .send_xchar     = sunhv_send_xchar,
+        .stop_rx        = sunhv_stop_rx,
+        .enable_ms      = sunhv_enable_ms,
+        .break_ctl      = sunhv_break_ctl,
+        .startup        = sunhv_startup,
+        .shutdown       = sunhv_shutdown,
+        .set_termios    = sunhv_set_termios,
+        .type           = sunhv_type,
+        .release_port   = sunhv_release_port,
+        .request_port   = sunhv_request_port,
+        .config_port    = sunhv_config_port,
+        .verify_port    = sunhv_verify_port,
+};
+
+static struct uart_driver sunhv_reg = {
+        .owner                  = THIS_MODULE,
+        .driver_name            = "serial",
+        .devfs_name             = "tts/",
+        .dev_name               = "ttyS",
+        .major                  = TTY_MAJOR,
+};
+
+static struct uart_port *sunhv_port;
+
+static inline void sunhv_console_putchar(struct uart_port *port, char c)
+{
+        unsigned long flags;
+        int limit = 10000;
+
+        spin_lock_irqsave(&port->lock, flags);
+
+        while (limit-- > 0) {
+                long status = hypervisor_con_putchar(c);
+                if (status == HV_EOK)
+                        break;
+        }
+
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void sunhv_console_write(struct console *con, const char *s, unsigned n)
+{
+        struct uart_port *port = sunhv_port;
+        int i;
+
+        for (i = 0; i < n; i++) {
+                if (*s == '\n')
+                        sunhv_console_putchar(port, '\r');
+                sunhv_console_putchar(port, *s++);
+        }
+}
+
+static int sunhv_console_setup(struct console *con, char *options)
+{
+        return 0;
+}
+
+static struct console sunhv_console = {
+        .name   =       "ttyS",
+        .write  =       sunhv_console_write,
+        .device =       uart_console_device,
+        .setup  =       sunhv_console_setup,
+        .flags  =       CON_PRINTBUFFER,
+        .index  =       -1,
+        .data   =       &sunhv_reg,
+};
+
+static void __init sunhv_console_init(void)
+{
+        if (con_is_present())
+                return;
+
+        sunhv_console.index = 0;
+        register_console(&sunhv_console);
+}
+
+static int __init sunhv_init(void)
+{
+        struct uart_port *port;
+        int ret;
+
+        if (tlb_type != hypervisor)
+                return -ENODEV;
+
+        port = kmalloc(sizeof(struct uart_port), GFP_KERNEL);
+        if (unlikely(!port))
+                return -ENOMEM;
+
+        port->line = 0;
+        port->ops = &sunhv_pops;
+        port->type = PORT_SUNHV;
+        port->uartclk = ( 29491200 / 16 ); /* arbitrary */
+
+        /* XXX Get interrupt. XXX */
+        if (request_irq(0 /* XXX */, sunhv_interrupt,
+                        SA_SHIRQ, "serial(sunhv)", port)) {
+                printk("sunhv: Cannot get IRQ %x\n",
+                       0 /* XXX */);
+                kfree(port);
+                return -ENODEV;
+        }
+
+        sunhv_reg.minor = sunserial_current_minor;
+        sunhv_reg.nr = 1;
+        sunhv_reg.cons = &sunhv_console;
+
+        ret = uart_register_driver(&sunhv_reg);
+        if (ret < 0) {
+                free_irq(0 /* XXX */, up);
+                kfree(port);
+
+                return ret;
+        }
+
+        sunhv_port = port;
+
+        sunserial_current_minor += 1;
+
+        sunhv_console_init();
+
+        uart_add_one_port(&sunhv_reg, port);
+
+        return 0;
+}
+
+static void __exit sunhv_exit(void)
+{
+        struct uart_port *port = sunhv_port;
+
+        BUG_ON(!port);
+
+        uart_remove_one_port(&sunhv_reg, port);
+        free_irq(0 /* XXX */, port);
+
+        sunserial_current_minor -= 1;
+
+        uart_unregister_driver(&sunhv_reg);
+
+        kfree(sunhv_port);
+        sunhv_port = NULL;
+}
+
+module_init(sunhv_init);
+module_exit(sunhv_exit);
+
+MODULE_AUTHOR("David S. Miller");
+MODULE_DESCRIPTION("SUN4V Hypervisor console driver")
+MODULE_LICENSE("GPL");