From: Laurentiu Mihalcea <[email protected]>

The driver currently derives the memory region type from the referenced
memory node name, creating a hidden DT ABI. Since memory node names are
not constrained by the binding, incorrect names can silently pass DT
validation, as seen in examples using "vdevbuffer" instead of
"vdev0buffer" ([1] and [2]).

Parse memory-region-names to identify the expected memory regions and avoid
relying on memory node names as ABI.

Link: 
https://lore.kernel.org/imx/[email protected]/ 
[1]
Link: 
https://lore.kernel.org/imx/alexXTYQHUs76J7v@SMW015318/T/#mb9dc709ff3adc24d9db6d30c973f37b580f6f1f9
 [2]

Signed-off-by: Laurentiu Mihalcea <[email protected]>
Signed-off-by: Frank Li <[email protected]>
---
 drivers/remoteproc/imx_rproc.c | 13 +++++++++++--
 drivers/remoteproc/imx_rproc.h | 21 +++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 745ce52cd8226..ce9bdfc1fa985 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -643,7 +643,7 @@ static int imx_rproc_prepare(struct rproc *rproc)
                int err;
                struct resource res;
 
-               err = of_reserved_mem_region_to_resource(np, i++, &res);
+               err = imx_rproc_rmem_to_resource(np, i++, &res);
                if (err)
                        break;
 
@@ -818,11 +818,20 @@ static int imx_rproc_addr_init(struct imx_rproc *priv,
        if (nph <= 0)
                return 0;
 
+       if (!of_property_present(np, "memory-region-names")) {
+               dev_warn(dev, "using node names for carveouts should be 
avoided\n");
+       } else {
+               if (nph != of_property_count_strings(np, 
"memory-region-names")) {
+                       dev_err(dev, "invalid reserved memory name count\n");
+                       return -EINVAL;
+               }
+       }
+
        /* remap optional addresses */
        for (a = 0; a < nph; a++) {
                struct resource res;
 
-               err = of_reserved_mem_region_to_resource(np, a, &res);
+               err = imx_rproc_rmem_to_resource(np, a, &res);
                if (err) {
                        dev_err(dev, "unable to resolve memory region\n");
                        return err;
diff --git a/drivers/remoteproc/imx_rproc.h b/drivers/remoteproc/imx_rproc.h
index 0d7d48352a109..3632bc375c711 100644
--- a/drivers/remoteproc/imx_rproc.h
+++ b/drivers/remoteproc/imx_rproc.h
@@ -7,6 +7,8 @@
 #ifndef _IMX_RPROC_H
 #define _IMX_RPROC_H
 
+#include <linux/of_reserved_mem.h>
+
 /* address translation table */
 struct imx_rproc_att {
        u32 da; /* device address (From Cortex M4 view)*/
@@ -45,4 +47,23 @@ struct imx_rproc_dcfg {
        u32                             reset_vector_mask;
 };
 
+static inline int imx_rproc_rmem_to_resource(struct device_node *np,
+                                            int index,
+                                            struct resource *res)
+{
+       int ret;
+
+       ret = of_reserved_mem_region_to_resource(np, index, res);
+       if (ret)
+               return ret;
+
+       /* "memory-region-names" is optional */
+       ret = of_property_read_string_index(np, "memory-region-names",
+                                           index, &res->name);
+       if (ret == -EINVAL)
+               return 0;
+
+       return ret;
+}
+
 #endif /* _IMX_RPROC_H */

-- 
2.43.0


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