The encoder needs to know the nominal framerate for the constant bitrate
control mechanism to work. Currently the only way to set the framerate is
by using VIDIOC_S_PARM on the output queue.
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
drivers/media/platform/coda/coda-common.c | 102 ++++++++++++++++++++++++++++++
drivers/media/platform/coda/coda_regs.h | 4 ++
2 files changed, 106 insertions(+)
diff --git a/drivers/media/platform/coda/coda-common.c b/drivers/media/platform/coda/coda-common.c
index 367b6ba..351b4124 100644
--- a/drivers/media/platform/coda/coda-common.c
+++ b/drivers/media/platform/coda/coda-common.c
@@ -15,6 +15,7 @@
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/firmware.h>
+#include <linux/gcd.h>
#include <linux/genalloc.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -770,6 +771,104 @@ static int coda_decoder_cmd(struct file *file, void *fh,
return 0;
}
+static int coda_g_parm(struct file *file, void *fh, struct v4l2_streamparm *a)
+{
+ struct coda_ctx *ctx = fh_to_ctx(fh);
+ struct v4l2_fract *tpf;
+
+ if (a->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
+ return -EINVAL,
+
+ a->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
+ tpf = &a->parm.output.timeperframe;
+ tpf->denominator = ctx->params.framerate & CODA_FRATE_RES_MASK;
+ tpf->numerator = 1 + (ctx->params.framerate >>
+ CODA_FRATE_DIV_OFFSET);
+
+ return 0;
+}
+
+/*
+ * Approximate timeperframe v4l2_fract with values that can be written
+ * into the 16-bit CODA_FRATE_DIV and CODA_FRATE_RES fields.
+ */
+static void coda_approximate_timeperframe(struct v4l2_fract *timeperframe)
+{
+ struct v4l2_fract s = *timeperframe;
+ struct v4l2_fract f0;
+ struct v4l2_fract f1 = { 1, 0 };
+ struct v4l2_fract f2 = { 0, 1 };
+ unsigned int i, div, s_denominator;
+
+ /* Lower bound is 1/65535 */
+ if (s.numerator == 0 || s.denominator / s.numerator > 65535) {
+ timeperframe->numerator = 1;
+ timeperframe->denominator = 65535;
+ return;
+ }
+
+ /* Upper bound is 65536/1, map everything above to infinity */
+ if (s.denominator == 0 || s.numerator / s.denominator > 65536) {
+ timeperframe->numerator = 1;
+ timeperframe->denominator = 0;
+ return;
+ }
+
+ /* Reduce fraction to lowest terms */
+ div = gcd(s.numerator, s.denominator);
+ if (div > 1) {
+ s.numerator /= div;
+ s.denominator /= div;
+ }
+
+ if (s.numerator <= 65536 && s.denominator < 65536) {
+ *timeperframe = s;
+ return;
+ }
+
+ /* Find successive convergents from continued fraction expansion */
+ while (f2.numerator <= 65536 && f2.denominator < 65536) {
+ f0 = f1;
+ f1 = f2;
+
+ /* Stop when f2 exactly equals timeperframe */
+ if (s.numerator == 0)
+ break;
+
+ i = s.denominator / s.numerator;
+
+ f2.numerator = f0.numerator + i * f1.numerator;
+ f2.denominator = f0.denominator + i * f2.denominator;
+
+ s_denominator = s.numerator;
+ s.numerator = s.denominator % s.numerator;
+ s.denominator = s_denominator;
+ }
+
+ *timeperframe = f1;
+}
+
+static uint32_t coda_timeperframe_to_frate(struct v4l2_fract *timeperframe)
+{
+ return ((timeperframe->numerator - 1) << CODA_FRATE_DIV_OFFSET) |
+ timeperframe->denominator;
+}
+
+static int coda_s_parm(struct file *file, void *fh, struct v4l2_streamparm *a)
+{
+ struct coda_ctx *ctx = fh_to_ctx(fh);
+ struct v4l2_fract *tpf;
+
+ if (a->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
+ return -EINVAL;
+
+ tpf = &a->parm.output.timeperframe;
+ coda_approximate_timeperframe(tpf);
+ ctx->params.framerate = coda_timeperframe_to_frate(tpf);
+
+ return 0;
+}
+
static int coda_subscribe_event(struct v4l2_fh *fh,
const struct v4l2_event_subscription *sub)
{
@@ -810,6 +909,9 @@ static const struct v4l2_ioctl_ops coda_ioctl_ops = {
.vidioc_try_decoder_cmd = coda_try_decoder_cmd,
.vidioc_decoder_cmd = coda_decoder_cmd,
+ .vidioc_g_parm = coda_g_parm,
+ .vidioc_s_parm = coda_s_parm,
+
.vidioc_subscribe_event = coda_subscribe_event,
.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
};
diff --git a/drivers/media/platform/coda/coda_regs.h b/drivers/media/platform/coda/coda_regs.h
index 7d02624..00e4f51 100644
--- a/drivers/media/platform/coda/coda_regs.h
+++ b/drivers/media/platform/coda/coda_regs.h
@@ -263,6 +263,10 @@
#define CODADX6_PICHEIGHT_MASK 0x3ff
#define CODA7_PICHEIGHT_MASK 0xffff
#define CODA_CMD_ENC_SEQ_SRC_F_RATE 0x194
+#define CODA_FRATE_RES_OFFSET 0
+#define CODA_FRATE_RES_MASK 0xffff
+#define CODA_FRATE_DIV_OFFSET 16
+#define CODA_FRATE_DIV_MASK 0xffff
#define CODA_CMD_ENC_SEQ_MP4_PARA 0x198
#define CODA_MP4PARAM_VERID_OFFSET 6
#define CODA_MP4PARAM_VERID_MASK 0x01
--
2.1.4
--
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