[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");