[PATCH v3 2/4] media: mali-c55: Implement CCM block validation

[Jacopo Mondi]

From: Jacopo Mondi <jacopo.mondi+renesas@xxxxxxxxxxxxxxxx>

Implement validation of CCM block parameters.

CCM coefficients are expressed as 13 bits signed Q4.8 format and their
raw value cannot be higher than 8191 (BIT(13) - 1).

CCM gains are expressed as unsigned 12 bits Q4.8 format and their raw
value cannot be higher than 4095 (BIT(12) - 1).

CCM offsets are 12 bits unsigned integers and their value cannot be
higher than 4095 (BIT(12) - 1).

Validate the parameters provided by userspace using the .block_validate
callback of struct v4l2_isp_params_block_type_info.

Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@xxxxxxxxxxxxxxxx>

---
v3:
- new patch
---
 .../media/platform/arm/mali-c55/mali-c55-params.c  | 36 ++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-params.c b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
index 0da5215c52c3..333e66ee3923 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-params.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
@@ -477,6 +477,41 @@ static const mali_c55_params_handler mali_c55_params_handlers[] = {
 	[MALI_C55_PARAM_BLOCK_CCM] = &mali_c55_params_ccm,
 };
 
+static int mali_c55_ccm_validate(struct device *dev,
+				 const struct v4l2_isp_block_header *block)
+{
+	const struct mali_c55_params_ccm *ccm =
+		(const struct mali_c55_params_ccm *)(block);
+
+	for (unsigned int i = 0; i < 3; i++) {
+
+		for (unsigned int j = 0; j < 3; j++) {
+			/* Coefficients are 13 bits signed Q4.8. */
+			if (ccm->coeffs[i][j] > 8191) {
+				dev_dbg(dev, "Invalid ccm coefficient %u\n",
+					ccm->coeffs[i][j]);
+				return -EINVAL;
+			}
+		}
+
+		/* Gains are 12 bits unsigned Q4.8. */
+		if (ccm->gains[i] > 4095) {
+			dev_dbg(dev, "Invalid ccm gain %u\n",
+				ccm->gains[i]);
+			return -EINVAL;
+		}
+
+		/* Offsets are 12 bits unsigned integers. */
+		if (ccm->offs[i] > 4095) {
+			dev_dbg(dev, "Invalid ccm offset %u\n",
+				ccm->offs[i]);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static const struct v4l2_isp_params_block_type_info
 mali_c55_params_block_types_info[] = {
 	[MALI_C55_PARAM_BLOCK_SENSOR_OFFS] = {
@@ -514,6 +549,7 @@ mali_c55_params_block_types_info[] = {
 	},
 	[MALI_C55_PARAM_BLOCK_CCM] = {
 		.size = sizeof(struct mali_c55_params_ccm),
+		.block_validate = mali_c55_ccm_validate,
 	},
 };
 

-- 
2.54.0