The patch number 9595 was added via Andy Walls <[EMAIL PROTECTED]>
to http://linuxtv.org/hg/v4l-dvb master development tree.
Kernel patches in this development tree may be modified to be backward
compatible with older kernels. Compatibility modifications will be
removed before inclusion into the mainstream Kernel
If anyone has any objections, please let us know by sending a message to:
[EMAIL PROTECTED]
------
From: Andy Walls <[EMAIL PROTECTED]>
cx18: Improve handling of outgoing mailboxes detected to be busy
cx18: Improve handling of outgoing mailboxes detected to be busy. When
encountering a busy mailbox, sleep instead of polling, and wait for interrupt or
timeout. If the mailbox is still busy, force it free. When sending commands,
make sure we never create a situation where we mark the mailbox busy upon
sending, and ensure we always have a method to cleanly recover from a busy
mailbox.
Priority: high
Signed-off-by: Andy Walls <[EMAIL PROTECTED]>
---
linux/drivers/media/video/cx18/cx18-irq.c | 3
linux/drivers/media/video/cx18/cx18-mailbox.c | 140 ++++++++----------
2 files changed, 69 insertions(+), 74 deletions(-)
diff -r 9660fd745131 -r 928e80134880 linux/drivers/media/video/cx18/cx18-irq.c
--- a/linux/drivers/media/video/cx18/cx18-irq.c Wed Nov 05 23:33:27 2008 -0500
+++ b/linux/drivers/media/video/cx18/cx18-irq.c Fri Nov 07 21:57:46 2008 -0500
@@ -177,7 +177,8 @@ irqreturn_t cx18_irq_handler(int irq, vo
cx18_write_reg_expect(cx, hw2, HW2_INT_CLR_STATUS, ~hw2, hw2);
if (sw1 || sw2 || hw2)
- CX18_DEBUG_HI_IRQ("SW1: %x SW2: %x HW2: %x\n", sw1, sw2, hw2);
+ CX18_DEBUG_HI_IRQ("received interrupts "
+ "SW1: %x SW2: %x HW2: %x\n", sw1, sw2, hw2);
/* To do: interrupt-based I2C handling
if (hw2 & (HW2_I2C1_INT|HW2_I2C2_INT)) {
diff -r 9660fd745131 -r 928e80134880
linux/drivers/media/video/cx18/cx18-mailbox.c
--- a/linux/drivers/media/video/cx18/cx18-mailbox.c Wed Nov 05 23:33:27
2008 -0500
+++ b/linux/drivers/media/video/cx18/cx18-mailbox.c Fri Nov 07 21:57:46
2008 -0500
@@ -92,48 +92,6 @@ static const struct cx18_api_info *find_
return NULL;
}
-static struct cx18_mailbox __iomem *cx18_mb_is_complete(struct cx18 *cx, int
rpu,
- u32 *state, u32 *irq, u32 *req)
-{
- struct cx18_mailbox __iomem *mb = NULL;
- int wait_count = 0;
- u32 ack;
-
- switch (rpu) {
- case APU:
- mb = &cx->scb->epu2apu_mb;
- *state = cx18_readl(cx, &cx->scb->apu_state);
- *irq = cx18_readl(cx, &cx->scb->epu2apu_irq);
- break;
-
- case CPU:
- mb = &cx->scb->epu2cpu_mb;
- *state = cx18_readl(cx, &cx->scb->cpu_state);
- *irq = cx18_readl(cx, &cx->scb->epu2cpu_irq);
- break;
-
- default:
- break;
- }
-
- if (mb == NULL)
- return mb;
-
- do {
- *req = cx18_readl(cx, &mb->request);
- ack = cx18_readl(cx, &mb->ack);
- wait_count++;
- } while (*req != ack && wait_count < 600);
-
- if (*req == ack) {
- (*req)++;
- if (*req == 0 || *req == 0xffffffff)
- *req = 1;
- return mb;
- }
- return NULL;
-}
-
long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb, int rpu)
{
struct cx18_mailbox __iomem *ack_mb;
@@ -164,12 +122,13 @@ static int cx18_api_call(struct cx18 *cx
static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
{
const struct cx18_api_info *info = find_api_info(cmd);
- u32 state = 0, irq = 0, req, oldreq, err;
+ u32 state, irq, req, ack, err;
struct cx18_mailbox __iomem *mb;
+ u32 __iomem *xpu_state;
wait_queue_head_t *waitq;
struct mutex *mb_lock;
int timeout = 100;
- int sig = 0;
+ long unsigned int j, ret;
int i;
if (info == NULL) {
@@ -186,10 +145,16 @@ static int cx18_api_call(struct cx18 *cx
case APU:
waitq = &cx->mb_apu_waitq;
mb_lock = &cx->epu2apu_mb_lock;
+ irq = IRQ_EPU_TO_APU;
+ mb = &cx->scb->epu2apu_mb;
+ xpu_state = &cx->scb->apu_state;
break;
case CPU:
waitq = &cx->mb_cpu_waitq;
mb_lock = &cx->epu2cpu_mb_lock;
+ irq = IRQ_EPU_TO_CPU;
+ mb = &cx->scb->epu2cpu_mb;
+ xpu_state = &cx->scb->cpu_state;
break;
default:
CX18_WARN("Unknown RPU (%d) for API call\n", info->rpu);
@@ -198,51 +163,85 @@ static int cx18_api_call(struct cx18 *cx
mutex_lock(mb_lock);
cx18_setup_page(cx, SCB_OFFSET);
- mb = cx18_mb_is_complete(cx, info->rpu, &state, &irq, &req);
-
- if (mb == NULL) {
- mutex_unlock(mb_lock);
- CX18_ERR("mb %s busy\n", info->name);
- return -EBUSY;
- }
-
- oldreq = req - 1;
+
+ /*
+ * Wait for an in-use mailbox to complete
+ *
+ * If the XPU is responding with Ack's, the mailbox shouldn't be in
+ * a busy state, since we serialize access to it on our end.
+ *
+ * If the wait for ack after sending a previous command was interrupted
+ * by a signal, we may get here and find a busy mailbox. After waiting,
+ * mark it "not busy" from our end, if the XPU hasn't ack'ed it still.
+ */
+ state = cx18_readl(cx, xpu_state);
+ req = cx18_readl(cx, &mb->request);
+ j = msecs_to_jiffies(timeout);
+ ret = wait_event_timeout(*waitq,
+ (ack = cx18_readl(cx, &mb->ack)) == req,
+ j);
+ if (req != ack) {
+ /* waited long enough, make the mbox "not busy" from our end */
+ cx18_writel(cx, req, &mb->ack);
+ CX18_ERR("mbox was found stuck busy when setting up for %s; "
+ "clearing busy and trying to proceed\n", info->name);
+ } else if (ret != j)
+ CX18_DEBUG_API("waited %u usecs for busy mbox to be acked\n",
+ jiffies_to_usecs(j-ret));
+
+ /* Build the outgoing mailbox */
+ req = ((req & 0xfffffffe) == 0xfffffffe) ? 1 : req + 1;
+
cx18_writel(cx, cmd, &mb->cmd);
for (i = 0; i < args; i++)
cx18_writel(cx, data[i], &mb->args[i]);
cx18_writel(cx, 0, &mb->error);
cx18_writel(cx, req, &mb->request);
-
+ cx18_writel(cx, req - 1, &mb->ack); /* ensure ack & req are distinct */
+
+ /* Notify the XPU and wait for it to send an Ack back */
if (info->flags & API_FAST)
timeout /= 2;
+ j = msecs_to_jiffies(timeout);
+
+ CX18_DEBUG_HI_IRQ("sending interrupt SW1: %x to send %s\n",
+ irq, info->name);
cx18_write_reg_expect(cx, irq, SW1_INT_SET, irq, irq);
- sig = wait_event_interruptible_timeout(
+ ret = wait_event_interruptible_timeout(
*waitq,
cx18_readl(cx, &mb->ack) == cx18_readl(cx, &mb->request),
- msecs_to_jiffies(timeout));
- if (sig == 0) {
+ j);
+ if (ret == 0) {
/* Timed out */
- cx18_writel(cx, oldreq, &mb->request);
mutex_unlock(mb_lock);
- CX18_ERR("sending %s timed out waiting for RPU to respond\n",
- info->name);
- return -EINVAL;
- } else if (sig < 0) {
+ CX18_ERR("sending %s timed out waiting for RPU "
+ "acknowledgement\n", info->name);
+ return -EINVAL;
+ } else if (ret < 0) {
/* Interrupted */
- cx18_writel(cx, oldreq, &mb->request);
mutex_unlock(mb_lock);
- CX18_WARN("sending %s interrupted waiting for RPU to respond\n",
- info->name);
+ CX18_WARN("sending %s was interrupted waiting for RPU"
+ "acknowledgement\n", info->name);
return -EINTR;
- }
-
+ } else if (ret != j)
+ CX18_DEBUG_HI_API("waited %u usecs for %s to be acked\n",
+ jiffies_to_usecs(j-ret), info->name);
+
+ /* Collect data returned by the XPU */
for (i = 0; i < MAX_MB_ARGUMENTS; i++)
data[i] = cx18_readl(cx, &mb->args[i]);
err = cx18_readl(cx, &mb->error);
mutex_unlock(mb_lock);
+
+ /*
+ * Wait for XPU to perform extra actions for the caller in some cases.
+ * e.g. CX18_CPU_DE_RELEASE_MDL will cause the CPU to send all buffers
+ * back in a burst shortly thereafter
+ */
if (info->flags & API_SLOW)
cx18_msleep_timeout(300, 0);
+
if (err)
CX18_DEBUG_API("mailbox error %08x for command %s\n", err,
info->name);
@@ -251,12 +250,7 @@ static int cx18_api_call(struct cx18 *cx
int cx18_api(struct cx18 *cx, u32 cmd, int args, u32 data[])
{
- int res = cx18_api_call(cx, cmd, args, data);
-
- /* Allow a single retry, probably already too late though.
- If there is no free mailbox then that is usually an indication
- of a more serious problem. */
- return (res == -EBUSY) ? cx18_api_call(cx, cmd, args, data) : res;
+ return cx18_api_call(cx, cmd, args, data);
}
static int cx18_set_filter_param(struct cx18_stream *s)
---
Patch is available at:
http://linuxtv.org/hg/v4l-dvb/rev/928e8013488054504d6a648e5c9356d1bed05b78
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