[media] coda: Use S_PARM to set nominal framerate for h.264 encoder

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@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/platform/coda/coda-common.c b/drivers/media/platform/coda/coda-common.c
index 24737f1a1a1bbc9dcd020c2e9e1d404046ad8ec0..a7cab14d10c969bd4a5a361bc0d0828a2fb48d41 100644 (file)
--- 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 7d026241171bc539aff9320c221c81365ca83b6d..00e4f5160c1f28698a846ac6c0798ee7f641b843 100644 (file)
--- 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