Hi Linus, this patch adds support for when the service processor (the
other end of the console) resets due to a critical error; we can resume
the connection when it comes back. Please apply.
Signed-off-by: Hollis Blanchard <[email protected]>
--
Hollis Blanchard
IBM Linux Technology Center
===== drivers/char/hvsi.c 1.2 vs edited =====
--- 1.2/drivers/char/hvsi.c Mon Sep 13 19:23:15 2004
+++ edited/drivers/char/hvsi.c Wed Oct 20 17:10:34 2004
@@ -29,11 +29,6 @@
* the OS cannot change the speed of the port through this protocol.
*/
-/* TODO:
- * test FSP reset
- * add udbg support for xmon/kdb
- */
-
#undef DEBUG
#include <linux/console.h>
@@ -54,6 +49,7 @@
#include <asm/prom.h>
#include <asm/uaccess.h>
#include <asm/vio.h>
+#include <asm/param.h>
#define HVSI_MAJOR 229
#define HVSI_MINOR 128
@@ -74,6 +70,7 @@
struct hvsi_struct {
struct work_struct writer;
+ struct work_struct handshaker;
wait_queue_head_t emptyq; /* woken when outbuf is emptied */
wait_queue_head_t stateq; /* woken when HVSI state changes */
spinlock_t lock;
@@ -109,6 +106,7 @@
HVSI_WAIT_FOR_VER_QUERY,
HVSI_OPEN,
HVSI_WAIT_FOR_MCTRL_RESPONSE,
+ HVSI_FSP_DIED,
};
#define HVSI_CONSOLE 0x1
@@ -172,6 +170,13 @@
} u;
} __attribute__((packed));
+
+
+static inline int is_console(struct hvsi_struct *hp)
+{
+ return hp->flags & HVSI_CONSOLE;
+}
+
static inline int is_open(struct hvsi_struct *hp)
{
/* if we're waiting for an mctrl then we're already open */
@@ -188,6 +193,7 @@
"HVSI_WAIT_FOR_VER_QUERY",
"HVSI_OPEN",
"HVSI_WAIT_FOR_MCTRL_RESPONSE",
+ "HVSI_FSP_DIED",
};
const char *name = state_names[hp->state];
@@ -296,14 +302,9 @@
return 0;
}
-/*
- * we can't call tty_hangup() directly here because we need to call that
- * outside of our lock
- */
-static struct tty_struct *hvsi_recv_control(struct hvsi_struct *hp,
- uint8_t *packet)
+static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
+ struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
{
- struct tty_struct *to_hangup = NULL;
struct hvsi_control *header = (struct hvsi_control *)packet;
switch (header->verb) {
@@ -313,15 +314,14 @@
pr_debug("hvsi%i: CD dropped\n", hp->index);
hp->mctrl &= TIOCM_CD;
if (!(hp->tty->flags & CLOCAL))
- to_hangup = hp->tty;
+ *to_hangup = hp->tty;
}
break;
case VSV_CLOSE_PROTOCOL:
- printk(KERN_DEBUG
- "hvsi%i: service processor closed connection!\n", hp->index);
- __set_state(hp, HVSI_CLOSED);
- to_hangup = hp->tty;
- hp->tty = NULL;
+ pr_debug("hvsi%i: service processor came back\n", hp->index);
+ if (hp->state != HVSI_CLOSED) {
+ *to_handshake = hp;
+ }
break;
default:
printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
@@ -329,8 +329,6 @@
dump_packet(packet);
break;
}
-
- return to_hangup;
}
static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
@@ -388,8 +386,8 @@
switch (hp->state) {
case HVSI_WAIT_FOR_VER_QUERY:
- __set_state(hp, HVSI_OPEN);
hvsi_version_respond(hp, query->seqno);
+ __set_state(hp, HVSI_OPEN);
break;
default:
printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
@@ -467,17 +465,20 @@
* incoming data).
*/
static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
- struct tty_struct **hangup)
+ struct tty_struct **hangup, struct hvsi_struct **handshake)
{
uint8_t *packet = hp->inbuf;
int chunklen;
*flip = NULL;
*hangup = NULL;
+ *handshake = NULL;
chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
- if (chunklen == 0)
+ if (chunklen == 0) {
+ pr_debug("%s: 0-length read\n", __FUNCTION__);
return 0;
+ }
pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
dbg_dump_hex(hp->inbuf_end, chunklen);
@@ -509,7 +510,7 @@
*flip = hvsi_recv_data(hp, packet);
break;
case VS_CONTROL_PACKET_HEADER:
- *hangup = hvsi_recv_control(hp, packet);
+ hvsi_recv_control(hp, packet, hangup, handshake);
break;
case VS_QUERY_RESPONSE_PACKET_HEADER:
hvsi_recv_response(hp, packet);
@@ -526,8 +527,8 @@
packet += len_packet(packet);
- if (*hangup) {
- pr_debug("%s: hangup\n", __FUNCTION__);
+ if (*hangup || *handshake) {
+ pr_debug("%s: hangup or handshake\n", __FUNCTION__);
/*
* we need to send the hangup now before receiving any more data.
* If we get "data, hangup, data", we can't deliver the second
@@ -560,16 +561,15 @@
struct hvsi_struct *hp = (struct hvsi_struct *)arg;
struct tty_struct *flip;
struct tty_struct *hangup;
+ struct hvsi_struct *handshake;
unsigned long flags;
- irqreturn_t handled = IRQ_NONE;
int again = 1;
pr_debug("%s\n", __FUNCTION__);
while (again) {
spin_lock_irqsave(&hp->lock, flags);
- again = hvsi_load_chunk(hp, &flip, &hangup);
- handled = IRQ_HANDLED;
+ again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
spin_unlock_irqrestore(&hp->lock, flags);
/*
@@ -587,6 +587,11 @@
if (hangup) {
tty_hangup(hangup);
}
+
+ if (handshake) {
+ pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
+ schedule_work(&handshake->handshaker);
+ }
}
spin_lock_irqsave(&hp->lock, flags);
@@ -603,7 +608,7 @@
tty_flip_buffer_push(flip);
}
- return handled;
+ return IRQ_HANDLED;
}
/* for boot console, before the irq handler is running */
@@ -757,6 +762,23 @@
return 0;
}
+static void hvsi_handshaker(void *arg)
+{
+ struct hvsi_struct *hp = (struct hvsi_struct *)arg;
+
+ if (hvsi_handshake(hp) >= 0)
+ return;
+
+ printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
+ if (is_console(hp)) {
+ /*
+ * ttys will re-attempt the handshake via hvsi_open, but
+ * the console will not.
+ */
+ printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
+ }
+}
+
static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
{
struct hvsi_data packet __ALIGNED__;
@@ -808,6 +830,10 @@
tty->driver_data = hp;
tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
+ mb();
+ if (hp->state == HVSI_FSP_DIED)
+ return -EIO;
+
spin_lock_irqsave(&hp->lock, flags);
hp->tty = tty;
hp->count++;
@@ -815,7 +841,7 @@
h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
spin_unlock_irqrestore(&hp->lock, flags);
- if (hp->flags & HVSI_CONSOLE)
+ if (is_console(hp))
return 0; /* this has already been handshaked as the console */
ret = hvsi_handshake(hp);
@@ -889,7 +915,7 @@
hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
/* only close down connection if it is not the console */
- if (!(hp->flags & HVSI_CONSOLE)) {
+ if (!is_console(hp)) {
h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
__set_state(hp, HVSI_CLOSED);
/*
@@ -943,12 +969,13 @@
return;
n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
- if (n != 0) {
- /*
- * either all data was sent or there was an error, and we throw away
- * data on error.
- */
+ if (n > 0) {
+ /* success */
+ pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
hp->n_outbuf = 0;
+ } else if (n == -EIO) {
+ __set_state(hp, HVSI_FSP_DIED);
+ printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
}
}
@@ -966,6 +993,19 @@
spin_lock_irqsave(&hp->lock, flags);
+ pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
+
+ if (!is_open(hp)) {
+ /*
+ * We could have a non-open connection if the service processor died
+ * while we were busily scheduling ourselves. In that case, it could
+ * be minutes before the service processor comes back, so only try
+ * again once a second.
+ */
+ schedule_delayed_work(&hp->writer, HZ);
+ goto out;
+ }
+
hvsi_push(hp);
if (hp->n_outbuf > 0)
schedule_delayed_work(&hp->writer, 10);
@@ -982,6 +1022,7 @@
wake_up_interruptible(&hp->tty->write_wait);
}
+out:
spin_unlock_irqrestore(&hp->lock, flags);
}
@@ -1022,6 +1063,8 @@
spin_lock_irqsave(&hp->lock, flags);
+ pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
+
if (!is_open(hp)) {
/* we're either closing or not yet open; don't accept data */
pr_debug("%s: not open\n", __FUNCTION__);
@@ -1294,6 +1337,7 @@
hp = &hvsi_ports[hvsi_count];
INIT_WORK(&hp->writer, hvsi_write_worker, hp);
+ INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
init_waitqueue_head(&hp->emptyq);
init_waitqueue_head(&hp->stateq);
hp->lock = SPIN_LOCK_UNLOCKED;
On Thu, 21 Oct 2004, Hollis Blanchard wrote:
>
> Hi Linus, this patch adds support for when the service processor (the
> other end of the console) resets due to a critical error; we can resume
> the connection when it comes back. Please apply.
Hmm.. Your revision numbers seem to imply that this is against something
that is from before my latest tty update that touched that file (which
removes the user/kernel pointer distractions).
Just to make me happier, mind checking this with current -BK first?
Linus
On Thursday 21 October 2004 22:01, Linus Torvalds wrote:
> On Thu, 21 Oct 2004, Hollis Blanchard wrote:
> > Hi Linus, this patch adds support for when the service processor (the
> > other end of the console) resets due to a critical error; we can resume
> > the connection when it comes back. Please apply.
>
> Hmm.. Your revision numbers seem to imply that this is against something
> that is from before my latest tty update that touched that file (which
> removes the user/kernel pointer distractions).
>
> Just to make me happier, mind checking this with current -BK first?
I've retested and things are still fine. Do you need me to resend the 3
patches? The originals should apply fine if you still have them.
--
Hollis Blanchard
IBM Linux Technology Center