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

[Jacopo Mondi]

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

Implement validation of Gamma block parameters.

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

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

The Gamma LUT table is expected to have 0 as first member and 0xfff
as last member.

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  | 34 ++++++++++++++++++++++
 1 file changed, 34 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 5857e9c2daf7..e9ab0e2dee15 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-params.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
@@ -581,6 +581,38 @@ static int mali_c55_ccm_validate(struct device *dev,
 	return 0;
 }
 
+static int mali_c55_gamma_validate(struct device *dev,
+				   const struct v4l2_isp_block_header *block)
+{
+	const struct mali_c55_params_gamma *gamma =
+		(const struct mali_c55_params_gamma *)(block);
+
+	for (unsigned int i = 0; i < 3; i++) {
+		/* Gains are 12 bits unsigned Q4.8. */
+		if (gamma->gains[i] > 4095) {
+			dev_dbg(dev, "Invalid gain value %u\n",
+				gamma->gains[i]);
+			return -EINVAL;
+		}
+
+		/* Offsets are 12 bits unsigned integers. */
+		if (gamma->offs[i] > 4095) {
+			dev_dbg(dev, "Invalid offset value %u\n",
+				gamma->offs[i]);
+			return -EINVAL;
+		}
+	}
+
+	/* Check the first and last gamma lut entries match the expectations. */
+	if (gamma->lut[0] != 0 ||
+	    gamma->lut[MALI_C55_NUM_GAMMA_LUT_ELEMENTS - 1] != 0xfff) {
+		dev_dbg(dev, "Invalid Gamma LUT table\n");
+		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] = {
@@ -622,9 +654,11 @@ mali_c55_params_block_types_info[] = {
 	},
 	[MALI_C55_PARAM_BLOCK_GAMMA_FR] = {
 		.size = sizeof(struct mali_c55_params_gamma),
+		.block_validate = mali_c55_gamma_validate,
 	},
 	[MALI_C55_PARAM_BLOCK_GAMMA_DS] = {
 		.size = sizeof(struct mali_c55_params_gamma),
+		.block_validate = mali_c55_gamma_validate,
 	},
 };
 

-- 
2.54.0