Refuse to bind if the device-tree compatible string
lists a different hardware version.
Reviewed-by: Brian Starkey <brian.starkey@xxxxxxx>
Signed-off-by: Mihail Atanassov <mihail.atanassov@xxxxxxx>
---
A couple of small improvements to driver-to-hardware binding.
drivers/gpu/drm/arm/malidp_drv.c | 52 +++++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/arm/malidp_regs.h | 2 ++
2 files changed, 54 insertions(+)
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index 32f746e..43238f4 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -256,6 +256,46 @@ static void malidp_lastclose(struct drm_device *drm)
};
MODULE_DEVICE_TABLE(of, malidp_drm_of_match);
+static bool malidp_is_compatible_hw_id(struct malidp_hw_device *hwdev,
+ const struct of_device_id *dev_id)
+{
+ u32 core_id;
+ const char *compatstr_dp500 = "arm,mali-dp500";
+ bool is_dp500;
+ bool dt_is_dp500;
+
+ /*
+ * The DP500 CORE_ID register is in a different location, so check it
+ * first. If the product id field matches, then this is DP500, otherwise
+ * check the DP550/650 CORE_ID register.
+ */
+ core_id = malidp_hw_read(hwdev, MALIDP500_DC_BASE + MALIDP_DE_CORE_ID);
+ /* Offset 0x18 will never read 0x500 on products other than DP500. */
+ is_dp500 = (MALIDP_PRODUCT_ID(core_id) == 0x500);
+ dt_is_dp500 = strnstr(dev_id->compatible, compatstr_dp500,
+ sizeof(dev_id->compatible)) != NULL;
+ if (is_dp500 != dt_is_dp500) {
+ DRM_ERROR("Device-tree expects %s, but hardware %s DP500.\n",
+ dev_id->compatible, is_dp500 ? "is" : "is not");
+ return false;
+ } else if (!dt_is_dp500) {
+ u16 product_id;
+ char buf[32];
+
+ core_id = malidp_hw_read(hwdev,
+ MALIDP550_DC_BASE + MALIDP_DE_CORE_ID);
+ product_id = MALIDP_PRODUCT_ID(core_id);
+ snprintf(buf, sizeof(buf), "arm,mali-dp%X", product_id);
+ if (!strnstr(dev_id->compatible, buf,
+ sizeof(dev_id->compatible))) {
+ DRM_ERROR("Device-tree expects %s, but hardware is DP%03X.\n",
+ dev_id->compatible, product_id);
+ return false;
+ }
+ }
+ return true;
+}
+
#define MAX_OUTPUT_CHANNELS 3
static int malidp_bind(struct device *dev)
@@ -266,6 +306,7 @@ static int malidp_bind(struct device *dev)
struct malidp_drm *malidp;
struct malidp_hw_device *hwdev;
struct platform_device *pdev = to_platform_device(dev);
+ struct of_device_id const *dev_id;
/* number of lines for the R, G and B output */
u8 output_width[MAX_OUTPUT_CHANNELS];
int ret = 0, i;
@@ -329,6 +370,17 @@ static int malidp_bind(struct device *dev)
clk_prepare_enable(hwdev->aclk);
clk_prepare_enable(hwdev->mclk);
+ dev_id = of_match_device(malidp_drm_of_match, dev);
+ if (!dev_id) {
+ ret = -EINVAL;
+ goto query_hw_fail;
+ }
+
+ if (!malidp_is_compatible_hw_id(hwdev, dev_id)) {
+ ret = -EINVAL;
+ goto query_hw_fail;
+ }
+
ret = hwdev->query_hw(hwdev);
if (ret) {
DRM_ERROR("Invalid HW configuration\n");
diff --git a/drivers/gpu/drm/arm/malidp_regs.h b/drivers/gpu/drm/arm/malidp_regs.h
index 73fecb3..7a89997 100644
--- a/drivers/gpu/drm/arm/malidp_regs.h
+++ b/drivers/gpu/drm/arm/malidp_regs.h
@@ -92,6 +92,8 @@
#define MALIDP_DE_H_ACTIVE(x) (((x) & 0x1fff) << 0)
#define MALIDP_DE_V_ACTIVE(x) (((x) & 0x1fff) << 16)
+#define MALIDP_PRODUCT_ID(__core_id) ((u32)(__core_id) >> 16)
+
/* register offsets and bits specific to DP500 */
#define MALIDP500_DC_BASE 0x00000
#define MALIDP500_DC_CONTROL 0x0000c
--
1.8.3
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