iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

staging: imx: use ktime_t for timestamps

Browse Source 
The imx media driver passes around monotonic timestamps in the deprecated
'timespec' format. This is not a problem for the driver, as they won't
overflow, but moving to either timespec64 or ktime_t is preferred.

I'm picking ktime_t for simplicity here. frame_interval_monitor() is
the main function that changes, as it tries to compare a time interval
in microseconds. The algorithm slightly changes here, to avoid 64-bit
division. The code previously assumed that the error was at most 32-bit
worth of microseconds here, so I'm making the same assumption but add
an explicit test for it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann 2017-11-27 14:20:00 +01:00 committed by Greg Kroah-Hartman
parent 6cf83f2a9e
commit ec8354b98b
3 changed files with 20 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/staging/media/imx/imx-media-csi.c
View File

@ -207,13 +207,9 @@ static irqreturn_t csi_idmac_eof_interrupt(int irq, void *dev_id)
goto unlock;
}
if (priv->fim) {
struct timespec cur_ts;
ktime_get_ts(&cur_ts);
if (priv->fim)
/* call frame interval monitor */
imx_media_fim_eof_monitor(priv->fim, &cur_ts);
}
imx_media_fim_eof_monitor(priv->fim, ktime_get());
csi_vb2_buf_done(priv);

30
drivers/staging/media/imx/imx-media-fim.c
View File

@ -66,7 +66,7 @@ struct imx_media_fim {
int icap_flags;
int counter;
struct timespec last_ts;
ktime_t last_ts;
unsigned long sum; /* usec */
unsigned long nominal; /* usec */
@ -147,22 +147,26 @@ static void send_fim_event(struct imx_media_fim *fim, unsigned long error)
* (presumably random) interrupt latency.
*/
static void frame_interval_monitor(struct imx_media_fim *fim,
struct timespec *ts)
ktime_t timestamp)
{
unsigned long interval, error, error_avg;
long long interval, error;
unsigned long error_avg;
bool send_event = false;
struct timespec diff;
if (!fim->enabled || ++fim->counter <= 0)
goto out_update_ts;
diff = timespec_sub(*ts, fim->last_ts);
interval = diff.tv_sec * 1000 * 1000 + diff.tv_nsec / 1000;
error = abs(interval - fim->nominal);
/* max error is less than l00µs, so use 32-bit division or fail */
interval = ktime_to_ns(ktime_sub(timestamp, fim->last_ts));
error = abs(interval - NSEC_PER_USEC * (u64)fim->nominal);
if (error > U32_MAX)
error = U32_MAX;
else
error = abs((u32)error / NSEC_PER_USEC);
if (fim->tolerance_max && error >= fim->tolerance_max) {
dev_dbg(fim->sd->dev,
"FIM: %lu ignored, out of tolerance bounds\n",
"FIM: %llu ignored, out of tolerance bounds\n",
error);
fim->counter--;
goto out_update_ts;
@ -184,7 +188,7 @@ static void frame_interval_monitor(struct imx_media_fim *fim,
}
out_update_ts:
fim->last_ts = *ts;
fim->last_ts = timestamp;
if (send_event)
send_fim_event(fim, error_avg);
}
@ -195,14 +199,14 @@ out_update_ts:
* to interrupt latency.
*/
static void fim_input_capture_handler(int channel, void *dev_id,
struct timespec *ts)
ktime_t timestamp)
{
struct imx_media_fim *fim = dev_id;
unsigned long flags;
spin_lock_irqsave(&fim->lock, flags);
frame_interval_monitor(fim, ts);
frame_interval_monitor(fim, timestamp);
if (!completion_done(&fim->icap_first_event))
complete(&fim->icap_first_event);
@ -405,14 +409,14 @@ err_free:
* the frame_interval_monitor() is called by the input capture event
* callback handler in that case.
*/
void imx_media_fim_eof_monitor(struct imx_media_fim *fim, struct timespec *ts)
void imx_media_fim_eof_monitor(struct imx_media_fim *fim, ktime_t timestamp)
{
unsigned long flags;
spin_lock_irqsave(&fim->lock, flags);
if (!icap_enabled(fim))
frame_interval_monitor(fim, ts);
frame_interval_monitor(fim, timestamp);
spin_unlock_irqrestore(&fim->lock, flags);
}

2
drivers/staging/media/imx/imx-media.h
View File

@ -280,7 +280,7 @@ int imx_media_pipeline_set_stream(struct imx_media_dev *imxmd,
/* imx-media-fim.c */
struct imx_media_fim;
void imx_media_fim_eof_monitor(struct imx_media_fim *fim, struct timespec *ts);
void imx_media_fim_eof_monitor(struct imx_media_fim *fim, ktime_t timestamp);
int imx_media_fim_set_stream(struct imx_media_fim *fim,
const struct v4l2_fract *frame_interval,
bool on);