Hi Javier
On Wed, 22 Feb 2012, Javier Martin wrote:
> If the attached video sensor cannot provide the
> requested image size, try to use resizing engine
> included in the eMMa-PrP IP.
>
> This patch supports both averaging and bilinear
> algorithms.
>
> Signed-off-by: Javier Martin <javier.martin@xxxxxxxxxxxxxxxxx>
> ---
> Changes since v1:
> - Fix several cosmetic issues.
> - Don't return -EINVAL if resizing is not possible.
> - Only allow resizing for YUYV format at the moment.
> - Simplify some lines of code.
>
> ---
> drivers/media/video/mx2_camera.c | 256 +++++++++++++++++++++++++++++++++++++-
> 1 files changed, 252 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/video/mx2_camera.c b/drivers/media/video/mx2_camera.c
> index fcb6b3f..453ad4c 100644
> --- a/drivers/media/video/mx2_camera.c
> +++ b/drivers/media/video/mx2_camera.c
[snip]
> @@ -1059,6 +1154,119 @@ static int mx2_camera_get_formats(struct soc_camera_device *icd,
> return formats;
> }
>
> +static int mx2_emmaprp_resize(struct mx2_camera_dev *pcdev,
> + struct v4l2_mbus_framefmt *mf_in,
> + struct v4l2_pix_format *pix_out)
> +{
> + int num, den;
> + unsigned long m;
> + int i, dir;
> +
> + for (dir = RESIZE_DIR_H; dir <= RESIZE_DIR_V; dir++) {
> + unsigned char *s = pcdev->resizing[dir].s;
> + int len = 0;
> + int in, out;
> +
> + if (dir == RESIZE_DIR_H) {
> + in = mf_in->width;
> + out = pix_out->width;
> + } else {
> + in = mf_in->height;
> + out = pix_out->height;
> + }
> +
> + if (in < out)
> + return -EINVAL;
> + else if (in == out)
> + continue;
> +
> + /* Calculate ratio */
> + m = gcd(in, out);
> + num = in / m;
> + den = out / m;
> + if (num > RESIZE_NUM_MAX)
> + return -EINVAL;
> +
> + if ((num >= 2 * den) && (den == 1) &&
> + (num < 9) && (!(num & 0x01))) {
> + int sum = 0;
> + int j;
> +
> + /* Average scaling for >= 2:1 ratios */
> + /* Support can be added for num >=9 and odd values */
> +
In this function you modify your controller private data:
> + pcdev->resizing[dir].algo = RESIZE_ALGO_AVERAGING;
> + len = num;
> +
> + for (i = 0; i < (len / 2); i++)
> + s[i] = 8;
> +
> + do {
> + for (i = 0; i < (len / 2); i++) {
> + s[i] = s[i] >> 1;
> + sum = 0;
> + for (j = 0; j < (len / 2); j++)
> + sum += s[j];
> + if (sum == 4)
> + break;
> + }
> + } while (sum != 4);
> +
> + for (i = (len / 2); i < len; i++)
> + s[i] = s[len - i - 1];
> +
> + s[len - 1] |= SZ_COEF;
> + } else {
> + /* bilinear scaling for < 2:1 ratios */
> + int v; /* overflow counter */
> + int coeff, nxt; /* table output */
> + int in_pos_inc = 2 * den;
> + int out_pos = num;
> + int out_pos_inc = 2 * num;
> + int init_carry = num - den;
> + int carry = init_carry;
> +
Here too:
> + pcdev->resizing[dir].algo = RESIZE_ALGO_BILINEAR;
> + v = den + in_pos_inc;
> + do {
> + coeff = v - out_pos;
> + out_pos += out_pos_inc;
> + carry += out_pos_inc;
> + for (nxt = 0; v < out_pos; nxt++) {
> + v += in_pos_inc;
> + carry -= in_pos_inc;
> + }
> +
> + if (len > RESIZE_NUM_MAX)
> + return -EINVAL;
> +
> + coeff = ((coeff << BC_COEF) +
> + (in_pos_inc >> 1)) / in_pos_inc;
> +
> + if (coeff >= (SZ_COEF - 1))
> + coeff--;
> +
> + coeff |= SZ_COEF;
> + s[len] = (unsigned char)coeff;
> + len++;
> +
> + for (i = 1; i < nxt; i++) {
> + if (len >= RESIZE_NUM_MAX)
> + return -EINVAL;
> + s[len] = 0;
> + len++;
> + }
> + } while (carry != init_carry);
> + }
And here again:
> + pcdev->resizing[dir].len = len;
> + if (dir == RESIZE_DIR_H)
> + mf_in->width = pix_out->width;
> + else
> + mf_in->height = pix_out->height;
> + }
> + return 0;
> +}
> +
> static int mx2_camera_set_fmt(struct soc_camera_device *icd,
> struct v4l2_format *f)
> {
[snip]
> @@ -1163,6 +1394,20 @@ static int mx2_camera_try_fmt(struct soc_camera_device *icd,
> if (ret < 0)
> return ret;
>
> + dev_dbg(icd->parent, "%s: sensor params: width = %d, height = %d\n",
> + __func__, pcdev->s_width, pcdev->s_height);
> +
> + /* If the sensor does not support image size try PrP resizing */
And this is what actually triggered me this time:
> + pcdev->emma_prp = mx27_emma_prp_get_format(xlate->code,
> + xlate->host_fmt->fourcc);
> +
> + memset(pcdev->resizing, 0, sizeof(pcdev->resizing));
> + if ((mf.width != pix->width || mf.height != pix->height) &&
> + pcdev->emma_prp->cfg.in_fmt == PRP_CNTL_DATA_IN_YUV422) {
And here too you cann the function, that modifies your persistent data.
So, I, probably, didn't explain it well: .try_fmt() should not modify any
your persistent data (used for real tasks, at least). Let's say, a program
does S_FMT, you decide to use and configure EMMA resizing. For which you
set .algo and .len resizer configuration members. Then the user does a
TRY_FMT, you change those values. But the user decided to not use the
result of that TRY_FMT and continues to STREAMON, hoping to get, what they
last configured with S_FMT. But your .algo, .len, and now also ->emma_prp,
have changed. So, your mx2_start_streaming() willconfuse things
completely.
> + if (mx2_emmaprp_resize(pcdev, &mf, pix) < 0)
> + dev_dbg(icd->parent, "%s: can't resize\n", __func__);
> + }
> +
> if (mf.field == V4L2_FIELD_ANY)
> mf.field = V4L2_FIELD_NONE;
> /*
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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