2 files changed, 54 insertions, 0 deletions

diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index 080f7631c672..6e59b3effb97 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -255,6 +255,46 @@ static const struct of_device_id  malidp_drm_of_match[] = {
 };
 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)
@@ -265,6 +305,7 @@ 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;
@@ -327,6 +368,17 @@ 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 73fecb38f955..7a89997dd134 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