e fallback
        when `a5xx_zap_shader_init()` returns `-ENODEV`.
  - Previously, if `of_address_to_resource()` failed, the code returned
    an error without setting `zap_available = false`. That meant callers
    saw a generic error (not `-ENODEV`) and aborted bring-up instead of
    taking the designed fallback. This is precisely the oversight the
    commit fixes.

- Impact and risk assessment
  - Scope is small and contained to one function in a single driver
    file. No architectural changes.
  - Behavior change is specifically in error handling: failures to
    resolve “memory-region” now reliably signal “zap not available,”
    aligning with the existing, intentional `-ENODEV` fallback path in
    the Adreno bring-up sequence.
  - Using `of_reserved_mem_region_to_resource()` ensures the driver only
    uses regions actually initialized by the reserved-memory core
    (drivers/of/of_reserved_mem.c) and returns `-ENODEV` if the memory-
    region is missing or unavailable. This is safer than reading “reg”
    directly from the node and avoids mapping memory that wasn’t
    properly reserved.
  - Note: the function no longer calls `of_node_put(np)` after
    `of_get_child_by_name()`. There was already at least one leak path
    for `np` (the early `!of_device_is_available(np)` return). This
    commit removes the `of_node_put(np)` that existed on the success
    path. The leak is a single DT node ref during probe/init and
    practically negligible. It does not outweigh the bugfix in error
    handling. If desired, a follow-up to put `np` after use is trivial
    and independent of this fix.

- Stable backport considerations
  - This is a clear bugfix with a targeted change in error handling and
    a move to the correct reserved-memory API.
  - If a given stable series already has
    `of_reserved_mem_region_to_resource()`, this applies cleanly and is
    low risk.
  - If not, the minimal backport can keep the existing
    `of_address_to_resource()` path but still add the key fix (set
    `zap_available = false` when it fails), preserving the functional
    improvement with minimal churn.

- Conclusion
  - The change fixes a real user-visible issue (unnecessary bring-up
    failure instead of the intended fallback), is small and localized,
    and reduces misuse of DT reserved-memory. It satisfies stable
    criteria as a low-risk bugfix suitable for backport.

 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index f1230465bf0d0..8c6336b007dc0 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -10,7 +10,7 @@
 #include <linux/interconnect.h>
 #include <linux/firmware/qcom/qcom_scm.h>
 #include <linux/kernel.h>
-#include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/pm_opp.h>
 #include <linux/slab.h>
 #include <linux/soc/qcom/mdt_loader.h>
@@ -33,7 +33,7 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname,
 	struct device *dev = &gpu->pdev->dev;
 	const struct firmware *fw;
 	const char *signed_fwname = NULL;
-	struct device_node *np, *mem_np;
+	struct device_node *np;
 	struct resource r;
 	phys_addr_t mem_phys;
 	ssize_t mem_size;
@@ -51,18 +51,11 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname,
 		return -ENODEV;
 	}
 
-	mem_np = of_parse_phandle(np, "memory-region", 0);
-	of_node_put(np);
-	if (!mem_np) {
+	ret = of_reserved_mem_region_to_resource(np, 0, &r);
+	if (ret) {
 		zap_available = false;
-		return -EINVAL;
-	}
-
-	ret = of_address_to_resource(mem_np, 0, &r);
-	of_node_put(mem_np);
-	if (ret)
 		return ret;
-
+	}
 	mem_phys = r.start;
 
 	/*
-- 
2.51.0[PATCH AUTOSEL 6.17] drm/msm: Use of_reserved_mem_region_to_resource() for "memory-region"Sasha Levin <sashal@kernel.org> undefinedpatches@lists.linux.dev, stable@vger.kernel.org undefined undefined undefined undefined undefined undefined undefined undefined