V4L/DVB (5917): ivtv: improve mailbox responsiveness.

First try polling for the result of a mailbox command, then
switch to a test/sleep loop. Also reduce the sleep time from 10 ms
to 1 ms. Improves the responsiveness of the mailbox handling.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

diff --git a/drivers/media/video/ivtv/ivtv-mailbox.c b/drivers/media/video/ivtv/ivtv-mailbox.c
index 814a673..5e3b679 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-mailbox.c
+++ b/drivers/media/video/ivtv/ivtv-mailbox.c
@@ -40,6 +40,7 @@
 #define API_HIGH_VOL    (1 << 5)       /* High volume command (i.e. called during encoding or decoding) */
 #define API_NO_WAIT_MB          (1 << 4)       /* Command may not wait for a free mailbox */
 #define API_NO_WAIT_RES         (1 << 5)       /* Command may not wait for the result */
+#define API_NO_POLL     (1 << 6)       /* Avoid pointless polling */
 
 struct ivtv_api_info {
        int flags;              /* Flags, see above */
@@ -51,7 +52,7 @@ struct ivtv_api_info {
 static const struct ivtv_api_info api_info[256] = {
        /* MPEG encoder API */
        API_ENTRY(CX2341X_ENC_PING_FW,                  API_FAST_RESULT),
-       API_ENTRY(CX2341X_ENC_START_CAPTURE,            API_RESULT),
+       API_ENTRY(CX2341X_ENC_START_CAPTURE,            API_RESULT | API_NO_POLL),
        API_ENTRY(CX2341X_ENC_STOP_CAPTURE,             API_RESULT),
        API_ENTRY(CX2341X_ENC_SET_AUDIO_ID,             API_CACHE),
        API_ENTRY(CX2341X_ENC_SET_VIDEO_ID,             API_CACHE),
@@ -96,7 +97,7 @@ static const struct ivtv_api_info api_info[256] = {
 
        /* MPEG decoder API */
        API_ENTRY(CX2341X_DEC_PING_FW,                  API_FAST_RESULT),
-       API_ENTRY(CX2341X_DEC_START_PLAYBACK,           API_RESULT),
+       API_ENTRY(CX2341X_DEC_START_PLAYBACK,           API_RESULT | API_NO_POLL),
        API_ENTRY(CX2341X_DEC_STOP_PLAYBACK,            API_RESULT),
        API_ENTRY(CX2341X_DEC_SET_PLAYBACK_SPEED,       API_RESULT),
        API_ENTRY(CX2341X_DEC_STEP_VIDEO,               API_RESULT),
@@ -290,6 +291,13 @@ static int ivtv_api_call(struct ivtv *itv, int cmd, int args, u32 data[])
        /* Get results */
        then = jiffies;
 
+       if (!(flags & API_NO_POLL)) {
+               /* First try to poll, then switch to delays */
+               for (i = 0; i < 100; i++) {
+                       if (readl(&mbox->flags) & IVTV_MBOX_FIRMWARE_DONE)
+                               break;
+               }
+       }
        while (!(readl(&mbox->flags) & IVTV_MBOX_FIRMWARE_DONE)) {
                if (jiffies - then > api_timeout) {
                        IVTV_DEBUG_WARN("Could not get result (%s)\n", api_info[cmd].name);
@@ -301,7 +309,7 @@ static int ivtv_api_call(struct ivtv *itv, int cmd, int args, u32 data[])
                if (flags & API_NO_WAIT_RES)
                        mdelay(1);
                else
-                       ivtv_msleep_timeout(10, 0);
+                       ivtv_msleep_timeout(1, 0);
        }
        if (jiffies - then > msecs_to_jiffies(100))
                IVTV_DEBUG_WARN("%s took %u jiffies\n",