[PATCH 2/2] drm: mali-dp: Check for sufficient address space

[Mihail Atanassov]

If the device-tree 'reg' node doesn't reserve enough
space for the DP, fail to bind.

Reviewed-by: Brian Starkey <brian.starkey@xxxxxxx>
Signed-off-by: Mihail Atanassov <mihail.atanassov@xxxxxxx>
---
 drivers/gpu/drm/arm/malidp_drv.c  | 20 ++++++++++++++++++++
 drivers/gpu/drm/arm/malidp_regs.h |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index 43238f4..66622a5 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -296,6 +296,20 @@ static bool malidp_is_compatible_hw_id(struct malidp_hw_device *hwdev,
 	return true;
 }
 
+static bool malidp_is_sufficient_address_space(const struct resource *res,
+					       const struct of_device_id *dev_id)
+{
+	resource_size_t res_size = resource_size(res);
+	const char *compatstr_dp500 = "arm,mali-dp500";
+
+	if (!strnstr(dev_id->compatible, compatstr_dp500,
+		     sizeof(dev_id->compatible)))
+		return res_size >= MALIDP550_ADDR_SPACE_SIZE;
+	else if (res_size < MALIDP500_ADDR_SPACE_SIZE)
+		return false;
+	return true;
+}
+
 #define MAX_OUTPUT_CHANNELS	3
 
 static int malidp_bind(struct device *dev)
@@ -376,6 +390,12 @@ static int malidp_bind(struct device *dev)
 		goto query_hw_fail;
 	}
 
+	if (!malidp_is_sufficient_address_space(res, dev_id)) {
+		DRM_ERROR("Insufficient address space in device-tree.\n");
+		ret = -EINVAL;
+		goto query_hw_fail;
+	}
+
 	if (!malidp_is_compatible_hw_id(hwdev, dev_id)) {
 		ret = -EINVAL;
 		goto query_hw_fail;
diff --git a/drivers/gpu/drm/arm/malidp_regs.h b/drivers/gpu/drm/arm/malidp_regs.h
index 7a89997..e0651d2 100644
--- a/drivers/gpu/drm/arm/malidp_regs.h
+++ b/drivers/gpu/drm/arm/malidp_regs.h
@@ -95,6 +95,7 @@
 #define MALIDP_PRODUCT_ID(__core_id) ((u32)(__core_id) >> 16)
 
 /* register offsets and bits specific to DP500 */
+#define MALIDP500_ADDR_SPACE_SIZE	0x01000
 #define MALIDP500_DC_BASE		0x00000
 #define MALIDP500_DC_CONTROL		0x0000c
 #define   MALIDP500_DC_CONFIG_REQ	(1 << 17)
@@ -127,6 +128,7 @@
 #define MALIDP500_CONFIG_ID		0x00fd4
 
 /* register offsets and bits specific to DP550/DP650 */
+#define MALIDP550_ADDR_SPACE_SIZE	0x10000
 #define MALIDP550_DE_CONTROL		0x00010
 #define MALIDP550_DE_LINE_COUNTER	0x00014
 #define MALIDP550_DE_AXI_CONTROL	0x00018
-- 
1.8.3