V4L/DVB (9593): cx18: Add outgoing mailbox mutexes and check for ack via waitq vs poll

Add mutexes to ensure exclusive access for outgoing driver to CX23418 mailboxes.
Also wait on a waitq for mailbox acknowledgement from the CX23418 instead of
polling.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 41 insertions, 43 deletions

diff --git a/drivers/media/video/cx18/cx18-mailbox.c b/drivers/media/video/cx18/cx18-mailbox.c
index acff7dfb60df..d2975a2e6cb7 100644
--- a/drivers/media/video/cx18/cx18-mailbox.c
+++ b/drivers/media/video/cx18/cx18-mailbox.c
@@ -30,11 +30,6 @@
 #define API_FAST (1 << 2) /* Short timeout */
 #define API_SLOW (1 << 3) /* Additional 300ms timeout */
 
-#define APU 0
-#define CPU 1
-#define EPU 2
-#define HPU 3
-
 struct cx18_api_info {
         u32 cmd;
         u8 flags;               /* Flags, see above */
@@ -117,10 +112,7 @@ static struct cx18_mailbox __iomem *cx18_mb_is_complete(struct cx18 *cx, int rpu
                 *irq = cx18_readl(cx, &cx->scb->epu2cpu_irq);
                 break;
 
-        case HPU:
-                mb = &cx->scb->epu2hpu_mb;
-                *state = cx18_readl(cx, &cx->scb->hpu_state);
-                *irq = cx18_readl(cx, &cx->scb->epu2hpu_irq);
+        default:
                 break;
         }
 
@@ -142,25 +134,12 @@ static struct cx18_mailbox __iomem *cx18_mb_is_complete(struct cx18 *cx, int rpu
         return NULL;
 }
 
-long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb)
+long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb, int rpu)
 {
-        const struct cx18_api_info *info = find_api_info(mb->cmd);
         struct cx18_mailbox __iomem *ack_mb;
         u32 ack_irq;
-        u8 rpu = CPU;
-
-        if (info == NULL && mb->cmd) {
-                CX18_WARN("Cannot ack unknown command %x\n", mb->cmd);
-                return -EINVAL;
-        }
-        if (info)
-                rpu = info->rpu;
 
         switch (rpu) {
-        case HPU:
-                ack_irq = IRQ_EPU_TO_HPU_ACK;
-                ack_mb = &cx->scb->hpu2epu_mb;
-                break;
         case APU:
                 ack_irq = IRQ_EPU_TO_APU_ACK;
                 ack_mb = &cx->scb->apu2epu_mb;
@@ -170,7 +149,8 @@ long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb)
                 ack_mb = &cx->scb->cpu2epu_mb;
                 break;
         default:
-                CX18_WARN("Unknown RPU for command %x\n", mb->cmd);
+                CX18_WARN("Unhandled RPU (%d) for command %x ack\n",
+                          rpu, mb->cmd);
                 return -EINVAL;
         }
 
@@ -187,8 +167,8 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
         u32 state = 0, irq = 0, req, oldreq, err;
         struct cx18_mailbox __iomem *mb;
         wait_queue_head_t *waitq;
+        struct mutex *mb_lock;
         int timeout = 100;
-        int cnt = 0;
         int sig = 0;
         int i;
 
@@ -201,10 +181,27 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
                 CX18_DEBUG_HI_API("%s\n", info->name);
         else
                 CX18_DEBUG_API("%s\n", info->name);
+
+        switch (info->rpu) {
+        case APU:
+                waitq = &cx->mb_apu_waitq;
+                mb_lock = &cx->epu2apu_mb_lock;
+                break;
+        case CPU:
+                waitq = &cx->mb_cpu_waitq;
+                mb_lock = &cx->epu2cpu_mb_lock;
+                break;
+        default:
+                CX18_WARN("Unknown RPU (%d) for API call\n", info->rpu);
+                return -EINVAL;
+        }
+
+        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;
         }
@@ -216,34 +213,35 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
         cx18_writel(cx, 0, &mb->error);
         cx18_writel(cx, req, &mb->request);
 
-        switch (info->rpu) {
-        case APU: waitq = &cx->mb_apu_waitq; break;
-        case CPU: waitq = &cx->mb_cpu_waitq; break;
-        case EPU: waitq = &cx->mb_epu_waitq; break;
-        case HPU: waitq = &cx->mb_hpu_waitq; break;
-        default: return -EINVAL;
-        }
         if (info->flags & API_FAST)
                 timeout /= 2;
         cx18_write_reg_expect(cx, irq, SW1_INT_SET, irq, irq);
 
-        while (!sig && cx18_readl(cx, &mb->ack) != cx18_readl(cx, &mb->request)
-               && cnt < 660) {
-                if (cnt > 200 && !in_atomic())
-                        sig = cx18_msleep_timeout(10, 1);
-                cnt++;
-        }
-        if (sig)
-                return -EINTR;
-        if (cnt == 660) {
+        sig = wait_event_interruptible_timeout(
+                       *waitq,
+                       cx18_readl(cx, &mb->ack) == cx18_readl(cx, &mb->request),
+                       msecs_to_jiffies(timeout));
+        if (sig == 0) {
+                /* Timed out */
                 cx18_writel(cx, oldreq, &mb->request);
-                CX18_ERR("mb %s failed\n", info->name);
+                mutex_unlock(mb_lock);
+                CX18_ERR("sending %s timed out waiting for RPU to respond\n",
+                         info->name);
                 return -EINVAL;
+        } else if (sig < 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);
+                return -EINTR;
         }
+
         for (i = 0; i < MAX_MB_ARGUMENTS; i++)
                 data[i] = cx18_readl(cx, &mb->args[i]);
         err = cx18_readl(cx, &mb->error);
-        if (!in_atomic() && (info->flags & API_SLOW))
+        mutex_unlock(mb_lock);
+        if (info->flags & API_SLOW)
                 cx18_msleep_timeout(300, 0);
         if (err)
                 CX18_DEBUG_API("mailbox error %08x for command %s\n", err,