[SPARC64]: Add hypervisor API negotiation and fix console bugs.
Hypervisor interfaces need to be negotiated in order to use
some API calls reliably. So add a small set of interfaces
to request API versions and query current settings.
This allows us to fix some bugs in the hypervisor console:
1) If we can negotiate API group CORE of at least major 1
minor 1 we can use con_read and con_write which can improve
console performance quite a bit.
2) When we do a console write request, we should hold the
spinlock around the whole request, not a byte at a time.
What would happen is that it's easy for output from
different cpus to get mixed with each other.
3) Use consistent udelay() based polling, udelay(1) each
loop with a limit of 1000 polls to handle stuck hypervisor
console.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/serial/sunhv.c b/drivers/serial/sunhv.c
index c3a6bd2..96557e6 100644
--- a/drivers/serial/sunhv.c
+++ b/drivers/serial/sunhv.c
@@ -1,6 +1,6 @@
/* sunhv.c: Serial driver for SUN4V hypervisor console.
*
- * Copyright (C) 2006 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
*/
#include <linux/module.h>
@@ -35,57 +35,51 @@
#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 char *con_write_page;
+static char *con_read_page;
+
static int hung_up = 0;
-static struct tty_struct *receive_chars(struct uart_port *port)
+static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
{
- struct tty_struct *tty = NULL;
+ while (!uart_circ_empty(xmit)) {
+ long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
+
+ if (status != HV_EOK)
+ break;
+
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ }
+}
+
+static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
+{
+ while (!uart_circ_empty(xmit)) {
+ unsigned long ra = __pa(xmit->buf + xmit->tail);
+ unsigned long len, status, sent;
+
+ len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
+ UART_XMIT_SIZE);
+ status = sun4v_con_write(ra, len, &sent);
+ if (status != HV_EOK)
+ break;
+ xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
+ port->icount.tx += sent;
+ }
+}
+
+static int receive_chars_getchar(struct uart_port *port, struct tty_struct *tty)
+{
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;
+ long c = sun4v_con_getchar(&status);
if (status == HV_EWOULDBLOCK)
break;
@@ -110,27 +104,90 @@
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))
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);
+ tty_insert_flip_char(tty, c, TTY_NORMAL);
}
- if (saw_console_brk)
+ return saw_console_brk;
+}
+
+static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
+{
+ int saw_console_brk = 0;
+ int limit = 10000;
+
+ while (limit-- > 0) {
+ unsigned long ra = __pa(con_read_page);
+ unsigned long bytes_read, i;
+ long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
+
+ if (stat != HV_EOK) {
+ bytes_read = 0;
+
+ if (stat == CON_BREAK) {
+ if (uart_handle_break(port))
+ continue;
+ saw_console_brk = 1;
+ *con_read_page = 0;
+ bytes_read = 1;
+ } else if (stat == CON_HUP) {
+ hung_up = 1;
+ uart_handle_dcd_change(port, 0);
+ continue;
+ } else {
+ /* HV_EWOULDBLOCK, etc. */
+ break;
+ }
+ }
+
+ if (hung_up) {
+ hung_up = 0;
+ uart_handle_dcd_change(port, 1);
+ }
+
+ for (i = 0; i < bytes_read; i++)
+ uart_handle_sysrq_char(port, con_read_page[i]);
+
+ if (tty == NULL)
+ continue;
+
+ port->icount.rx += bytes_read;
+
+ tty_insert_flip_string(tty, con_read_page, bytes_read);
+ }
+
+ return saw_console_brk;
+}
+
+struct sunhv_ops {
+ void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
+ int (*receive_chars)(struct uart_port *port, struct tty_struct *tty);
+};
+
+static struct sunhv_ops bychar_ops = {
+ .transmit_chars = transmit_chars_putchar,
+ .receive_chars = receive_chars_getchar,
+};
+
+static struct sunhv_ops bywrite_ops = {
+ .transmit_chars = transmit_chars_write,
+ .receive_chars = receive_chars_read,
+};
+
+static struct sunhv_ops *sunhv_ops = &bychar_ops;
+
+static struct tty_struct *receive_chars(struct uart_port *port)
+{
+ struct tty_struct *tty = NULL;
+
+ if (port->info != NULL) /* Unopened serial console */
+ tty = port->info->tty;
+
+ if (sunhv_ops->receive_chars(port, tty))
sun_do_break();
return tty;
@@ -147,15 +204,7 @@
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++;
- }
+ sunhv_ops->transmit_chars(port, xmit);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
@@ -212,7 +261,7 @@
struct circ_buf *xmit = &port->info->xmit;
while (!uart_circ_empty(xmit)) {
- long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
+ long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
if (status != HV_EOK)
break;
@@ -231,9 +280,10 @@
spin_lock_irqsave(&port->lock, flags);
while (limit-- > 0) {
- long status = hypervisor_con_putchar(ch);
+ long status = sun4v_con_putchar(ch);
if (status == HV_EOK)
break;
+ udelay(1);
}
spin_unlock_irqrestore(&port->lock, flags);
@@ -254,15 +304,15 @@
{
if (break_state) {
unsigned long flags;
- int limit = 1000000;
+ int limit = 10000;
spin_lock_irqsave(&port->lock, flags);
while (limit-- > 0) {
- long status = hypervisor_con_putchar(CON_BREAK);
+ long status = sun4v_con_putchar(CON_BREAK);
if (status == HV_EOK)
break;
- udelay(2);
+ udelay(1);
}
spin_unlock_irqrestore(&port->lock, flags);
@@ -359,38 +409,99 @@
static struct uart_port *sunhv_port;
-static inline void sunhv_console_putchar(struct uart_port *port, char c)
+/* Copy 's' into the con_write_page, decoding "\n" into
+ * "\r\n" along the way. We have to return two lengths
+ * because the caller needs to know how much to advance
+ * 's' and also how many bytes to output via con_write_page.
+ */
+static int fill_con_write_page(const char *s, unsigned int n,
+ unsigned long *page_bytes)
{
+ const char *orig_s = s;
+ char *p = con_write_page;
+ int left = PAGE_SIZE;
+
+ while (n--) {
+ if (*s == '\n') {
+ if (left < 2)
+ break;
+ *p++ = '\r';
+ left--;
+ } else if (left < 1)
+ break;
+ *p++ = *s++;
+ left--;
+ }
+ *page_bytes = p - con_write_page;
+ return s - orig_s;
+}
+
+static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
+{
+ struct uart_port *port = sunhv_port;
unsigned long flags;
- int limit = 1000000;
spin_lock_irqsave(&port->lock, flags);
+ while (n > 0) {
+ unsigned long ra = __pa(con_write_page);
+ unsigned long page_bytes;
+ unsigned int cpy = fill_con_write_page(s, n,
+ &page_bytes);
- while (limit-- > 0) {
- long status = hypervisor_con_putchar(c);
- if (status == HV_EOK)
- break;
- udelay(2);
+ n -= cpy;
+ s += cpy;
+ while (page_bytes > 0) {
+ unsigned long written;
+ int limit = 1000000;
+
+ while (limit--) {
+ unsigned long stat;
+
+ stat = sun4v_con_write(ra, page_bytes,
+ &written);
+ if (stat == HV_EOK)
+ break;
+ udelay(1);
+ }
+ if (limit <= 0)
+ break;
+ page_bytes -= written;
+ ra += written;
+ }
}
-
spin_unlock_irqrestore(&port->lock, flags);
}
-static void sunhv_console_write(struct console *con, const char *s, unsigned n)
+static inline void sunhv_console_putchar(struct uart_port *port, char c)
+{
+ int limit = 1000000;
+
+ while (limit-- > 0) {
+ long status = sun4v_con_putchar(c);
+ if (status == HV_EOK)
+ break;
+ udelay(1);
+ }
+}
+
+static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
{
struct uart_port *port = sunhv_port;
+ unsigned long flags;
int i;
+ spin_lock_irqsave(&port->lock, flags);
for (i = 0; i < n; i++) {
if (*s == '\n')
sunhv_console_putchar(port, '\r');
sunhv_console_putchar(port, *s++);
}
+ spin_unlock_irqrestore(&port->lock, flags);
}
static struct console sunhv_console = {
.name = "ttyHV",
- .write = sunhv_console_write,
+ .write = sunhv_console_write_bychar,
.device = uart_console_device,
.flags = CON_PRINTBUFFER,
.index = -1,
@@ -410,6 +521,7 @@
static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
{
struct uart_port *port;
+ unsigned long minor;
int err;
if (op->irqs[0] == 0xffffffff)
@@ -419,6 +531,22 @@
if (unlikely(!port))
return -ENOMEM;
+ minor = 1;
+ if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
+ minor >= 1) {
+ err = -ENOMEM;
+ con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!con_write_page)
+ goto out_free_port;
+
+ con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!con_read_page)
+ goto out_free_con_write_page;
+
+ sunhv_console.write = sunhv_console_write_paged;
+ sunhv_ops = &bywrite_ops;
+ }
+
sunhv_port = port;
port->line = 0;
@@ -437,7 +565,7 @@
err = uart_register_driver(&sunhv_reg);
if (err)
- goto out_free_port;
+ goto out_free_con_read_page;
sunhv_reg.tty_driver->name_base = sunhv_reg.minor - 64;
sunserial_current_minor += 1;
@@ -463,6 +591,12 @@
sunserial_current_minor -= 1;
uart_unregister_driver(&sunhv_reg);
+out_free_con_read_page:
+ kfree(con_read_page);
+
+out_free_con_write_page:
+ kfree(con_write_page);
+
out_free_port:
kfree(port);
sunhv_port = NULL;