[PATCH 0/7] Refactor reserved memory regions handling code

[PATCH 0/7] Refactor reserved memory regions handling code

[Marek Szyprowski]

Hello,

The reserved memory regions handling code was reworked to handle
unlimited so called "static" memory nodes in commit 00c9a452a235 ("of:
reserved_mem: Add code to dynamically allocate reserved_mem array").

The side effect of this rework was a set of bugs fixed later by commits
0fd17e598333 ("of: reserved_mem: Allow reserved_mem framework detect
"cma=" kernel param") and 2c223f7239f3 ("of: reserved_mem: Restructure
call site for dma_contiguous_early_fixup()"). As a result, the code in
drivers/of/of_reserved_mem.c became a mix of generic code and CMA
specific fixups.

In this patchset I try to untangle this spaghetti and perform some code
cleanup. I hope nothing breaks this time.

Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Patch summary:

Marek Szyprowski (7):
  of: reserved_mem: remove fdt node from the structure
  of: reserved_mem: use -ENODEV instead of -ENOENT
  of: reserved_mem: switch to ops based OF_DECLARE()
  of: reserved_mem: replace CMA quirks by generic methods
  of: reserved_mem: rearrange code a bit
  of: reserved_mem: clarify fdt_scan_reserved_mem*() functions
  of: reserved_mem: rework fdt_init_reserved_mem_node()

 drivers/memory/tegra/tegra210-emc-table.c |  17 +-
 drivers/of/fdt.c                          |   2 +-
 drivers/of/of_private.h                   |   2 +-
 drivers/of/of_reserved_mem.c              | 289 ++++++++++++----------
 include/linux/cma.h                       |  10 -
 include/linux/dma-map-ops.h               |   3 -
 include/linux/of_reserved_mem.h           |  18 +-
 kernel/dma/coherent.c                     |  19 +-
 kernel/dma/contiguous.c                   |  86 +++++--
 kernel/dma/swiotlb.c                      |  18 +-
 10 files changed, 256 insertions(+), 208 deletions(-)

-- 
2.34.1

[PATCH 1/7] of: reserved_mem: remove fdt node from the structure

[Marek Szyprowski]

FDT node is not needed for anything besides the initialization, so it can
be simply passed as an argument to the reserved memory region init
function.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/memory/tegra/tegra210-emc-table.c |  3 ++-
 drivers/of/of_reserved_mem.c              | 25 ++++++++++-------------
 include/linux/of_reserved_mem.h           |  4 ++--
 kernel/dma/coherent.c                     |  4 +---
 kernel/dma/contiguous.c                   |  3 +--
 kernel/dma/swiotlb.c                      |  5 ++---
 6 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/memory/tegra/tegra210-emc-table.c b/drivers/memory/tegra/tegra210-emc-table.c
index 34a8785d2861..ac1d1e13482a 100644
--- a/drivers/memory/tegra/tegra210-emc-table.c
+++ b/drivers/memory/tegra/tegra210-emc-table.c
@@ -75,7 +75,8 @@ static const struct reserved_mem_ops tegra210_emc_table_ops = {
 	.device_release = tegra210_emc_table_device_release,
 };
 
-static int tegra210_emc_table_init(struct reserved_mem *rmem)
+static int tegra210_emc_table_init(unsigned long node,
+				   struct reserved_mem *rmem)
 {
 	pr_debug("Tegra210 EMC table at %pa, size %lu bytes\n", &rmem->base,
 		 (unsigned long)rmem->size);
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 1fd28f805610..6705b7afebf0 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -104,7 +104,8 @@ static void __init alloc_reserved_mem_array(void)
 	reserved_mem = new_array;
 }
 
-static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem);
+static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
+					      unsigned long node);
 /*
  * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
  */
@@ -118,13 +119,12 @@ static void __init fdt_reserved_mem_save_node(unsigned long node, const char *un
 		return;
 	}
 
-	rmem->fdt_node = node;
 	rmem->name = uname;
 	rmem->base = base;
 	rmem->size = size;
 
 	/* Call the region specific initialization function */
-	fdt_init_reserved_mem_node(rmem);
+	fdt_init_reserved_mem_node(rmem, node);
 
 	reserved_mem_count++;
 }
@@ -483,7 +483,8 @@ static const struct of_device_id __rmem_of_table_sentinel
 /*
  * __reserved_mem_init_node() - call region specific reserved memory init code
  */
-static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
+static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
+					   unsigned long node)
 {
 	extern const struct of_device_id __reservedmem_of_table[];
 	const struct of_device_id *i;
@@ -493,10 +494,10 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
 		reservedmem_of_init_fn initfn = i->data;
 		const char *compat = i->compatible;
 
-		if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
+		if (!of_flat_dt_is_compatible(node, compat))
 			continue;
 
-		ret = initfn(rmem);
+		ret = initfn(node, rmem);
 		if (ret == 0) {
 			pr_info("initialized node %s, compatible id %s\n",
 				rmem->name, compat);
@@ -526,11 +527,6 @@ static int __init __rmem_cmp(const void *a, const void *b)
 	if (ra->size > rb->size)
 		return 1;
 
-	if (ra->fdt_node < rb->fdt_node)
-		return -1;
-	if (ra->fdt_node > rb->fdt_node)
-		return 1;
-
 	return 0;
 }
 
@@ -564,19 +560,20 @@ static void __init __rmem_check_for_overlap(void)
 /**
  * fdt_init_reserved_mem_node() - Initialize a reserved memory region
  * @rmem: reserved_mem struct of the memory region to be initialized.
+ * @node: fdt node of the initialized region
  *
  * This function is used to call the region specific initialization
  * function for a reserved memory region.
  */
-static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem)
+static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
+					      unsigned long node)
 {
-	unsigned long node = rmem->fdt_node;
 	int err = 0;
 	bool nomap;
 
 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 
-	err = __reserved_mem_init_node(rmem);
+	err = __reserved_mem_init_node(rmem, node);
 	if (err != 0 && err != -ENOENT) {
 		pr_info("node %s compatible matching fail\n", rmem->name);
 		if (nomap)
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index f573423359f4..5159938bfe03 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -11,7 +11,6 @@ struct resource;
 
 struct reserved_mem {
 	const char			*name;
-	unsigned long			fdt_node;
 	const struct reserved_mem_ops	*ops;
 	phys_addr_t			base;
 	phys_addr_t			size;
@@ -25,7 +24,8 @@ struct reserved_mem_ops {
 				  struct device *dev);
 };
 
-typedef int (*reservedmem_of_init_fn)(struct reserved_mem *rmem);
+typedef int (*reservedmem_of_init_fn)(unsigned long node,
+				      struct reserved_mem *rmem);
 
 #ifdef CONFIG_OF_RESERVED_MEM
 
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 1147497bc512..34621acbd3c5 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -367,10 +367,8 @@ static const struct reserved_mem_ops rmem_dma_ops = {
 	.device_release	= rmem_dma_device_release,
 };
 
-static int __init rmem_dma_setup(struct reserved_mem *rmem)
+static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
-
 	if (of_get_flat_dt_prop(node, "reusable", NULL))
 		return -EINVAL;
 
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index c56004d314dc..81a2fa4971ee 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -475,9 +475,8 @@ static const struct reserved_mem_ops rmem_cma_ops = {
 	.device_release = rmem_cma_device_release,
 };
 
-static int __init rmem_cma_setup(struct reserved_mem *rmem)
+static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
 	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
 	struct cma *cma;
 	int err;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d8e6f1d889d5..f3a12e15a951 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1860,10 +1860,9 @@ static const struct reserved_mem_ops rmem_swiotlb_ops = {
 	.device_release = rmem_swiotlb_device_release,
 };
 
-static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
+static int __init rmem_swiotlb_setup(unsigned long node,
+				     struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
-
 	if (of_get_flat_dt_prop(node, "reusable", NULL) ||
 	    of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
 	    of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
-- 
2.34.1

[PATCH 2/7] of: reserved_mem: use -ENODEV instead of -ENOENT

[Marek Szyprowski]

When given reserved memory region doesn't really support given node,
return -ENODEV instead of -ENOENT. Then fix __reserved_mem_init_node()
function to properly propagate error code different from -ENODEV instead
of silently ignoring it.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/of/of_reserved_mem.c | 7 ++++---
 kernel/dma/coherent.c        | 2 +-
 kernel/dma/contiguous.c      | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 6705b7afebf0..9aff460a0420 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -488,9 +488,10 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 {
 	extern const struct of_device_id __reservedmem_of_table[];
 	const struct of_device_id *i;
-	int ret = -ENOENT;
+	int ret = -ENODEV;
 
-	for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
+	for (i = __reservedmem_of_table; ret == -ENODEV &&
+	     i < &__rmem_of_table_sentinel; i++) {
 		reservedmem_of_init_fn initfn = i->data;
 		const char *compat = i->compatible;
 
@@ -574,7 +575,7 @@ static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 
 	err = __reserved_mem_init_node(rmem, node);
-	if (err != 0 && err != -ENOENT) {
+	if (err != 0 && err != -ENODEV) {
 		pr_info("node %s compatible matching fail\n", rmem->name);
 		if (nomap)
 			memblock_clear_nomap(rmem->base, rmem->size);
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 34621acbd3c5..64f9ba618e19 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -370,7 +370,7 @@ static const struct reserved_mem_ops rmem_dma_ops = {
 static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
 {
 	if (of_get_flat_dt_prop(node, "reusable", NULL))
-		return -EINVAL;
+		return -ENODEV;
 
 #ifdef CONFIG_ARM
 	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 81a2fa4971ee..e6fc6906b5c0 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -483,7 +483,7 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 
 	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
 	    of_get_flat_dt_prop(node, "no-map", NULL))
-		return -EINVAL;
+		return -ENODEV;
 
 	if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
 		pr_err("Reserved memory: incorrect alignment of CMA region\n");
-- 
2.34.1

[PATCH 3/7] of: reserved_mem: switch to ops based OF_DECLARE()

[Marek Szyprowski]

Move init function from OF_DECLARE() argument to the given reserved
memory region ops structure and then pass that structure to the
OF_DECLARE() initializer. This makes it possible in the future to add
more functions called by the generic code before given memory region is
initialized and rmem object created.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/memory/tegra/tegra210-emc-table.c | 14 ++++++++------
 drivers/of/of_reserved_mem.c              |  5 +++--
 include/linux/of_reserved_mem.h           | 15 ++++++++-------
 kernel/dma/coherent.c                     | 13 +++++++------
 kernel/dma/contiguous.c                   | 15 ++++++++-------
 kernel/dma/swiotlb.c                      | 13 +++++++------
 6 files changed, 41 insertions(+), 34 deletions(-)

diff --git a/drivers/memory/tegra/tegra210-emc-table.c b/drivers/memory/tegra/tegra210-emc-table.c
index ac1d1e13482a..f6395bc9dbc8 100644
--- a/drivers/memory/tegra/tegra210-emc-table.c
+++ b/drivers/memory/tegra/tegra210-emc-table.c
@@ -70,11 +70,6 @@ static void tegra210_emc_table_device_release(struct reserved_mem *rmem,
 	memunmap(timings);
 }
 
-static const struct reserved_mem_ops tegra210_emc_table_ops = {
-	.device_init = tegra210_emc_table_device_init,
-	.device_release = tegra210_emc_table_device_release,
-};
-
 static int tegra210_emc_table_init(unsigned long node,
 				   struct reserved_mem *rmem)
 {
@@ -85,5 +80,12 @@ static int tegra210_emc_table_init(unsigned long node,
 
 	return 0;
 }
+
+static const struct reserved_mem_ops tegra210_emc_table_ops = {
+	.node_init = tegra210_emc_table_init,
+	.device_init = tegra210_emc_table_device_init,
+	.device_release = tegra210_emc_table_device_release,
+};
+
 RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
-		       tegra210_emc_table_init);
+		       &tegra210_emc_table_ops);
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 9aff460a0420..675f1c1c6627 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -492,14 +492,15 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 
 	for (i = __reservedmem_of_table; ret == -ENODEV &&
 	     i < &__rmem_of_table_sentinel; i++) {
-		reservedmem_of_init_fn initfn = i->data;
+		const struct reserved_mem_ops *ops = i->data;
 		const char *compat = i->compatible;
 
 		if (!of_flat_dt_is_compatible(node, compat))
 			continue;
 
-		ret = initfn(node, rmem);
+		ret = ops->node_init(node, rmem);
 		if (ret == 0) {
+			rmem->ops = ops;
 			pr_info("initialized node %s, compatible id %s\n",
 				rmem->name, compat);
 			break;
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index 5159938bfe03..dc00502a6b69 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -18,19 +18,20 @@ struct reserved_mem {
 };
 
 struct reserved_mem_ops {
+	int	(*node_init)(unsigned long fdt_node, struct reserved_mem *rmem);
 	int	(*device_init)(struct reserved_mem *rmem,
 			       struct device *dev);
 	void	(*device_release)(struct reserved_mem *rmem,
 				  struct device *dev);
 };
 
-typedef int (*reservedmem_of_init_fn)(unsigned long node,
-				      struct reserved_mem *rmem);
-
 #ifdef CONFIG_OF_RESERVED_MEM
 
-#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
-	_OF_DECLARE(reservedmem, name, compat, init, reservedmem_of_init_fn)
+#define RESERVEDMEM_OF_DECLARE(name, compat, ops)			\
+	static const struct of_device_id __of_table_##name		\
+		__used __section("__reservedmem_of_table")		\
+		__aligned(__alignof__(struct of_device_id))		\
+		 = { .compatible = compat, .data = ops }
 
 int of_reserved_mem_device_init_by_idx(struct device *dev,
 				       struct device_node *np, int idx);
@@ -48,8 +49,8 @@ int of_reserved_mem_region_count(const struct device_node *np);
 
 #else
 
-#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
-	_OF_DECLARE_STUB(reservedmem, name, compat, init, reservedmem_of_init_fn)
+#define RESERVEDMEM_OF_DECLARE(name, compat, ops)			\
+	_OF_DECLARE_STUB(reservedmem, name, compat, init, void *)
 
 static inline int of_reserved_mem_device_init_by_idx(struct device *dev,
 					struct device_node *np, int idx)
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 64f9ba618e19..bcdc0f76d2e8 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -362,10 +362,6 @@ static void rmem_dma_device_release(struct reserved_mem *rmem,
 		dev->dma_mem = NULL;
 }
 
-static const struct reserved_mem_ops rmem_dma_ops = {
-	.device_init	= rmem_dma_device_init,
-	.device_release	= rmem_dma_device_release,
-};
 
 static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
 {
@@ -388,7 +384,6 @@ static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
 	}
 #endif
 
-	rmem->ops = &rmem_dma_ops;
 	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
 		&rmem->base, (unsigned long)rmem->size / SZ_1M);
 	return 0;
@@ -405,5 +400,11 @@ static int __init dma_init_reserved_memory(void)
 core_initcall(dma_init_reserved_memory);
 #endif /* CONFIG_DMA_GLOBAL_POOL */
 
-RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
+static const struct reserved_mem_ops rmem_dma_ops = {
+	.node_init	= rmem_dma_setup,
+	.device_init	= rmem_dma_device_init,
+	.device_release	= rmem_dma_device_release,
+};
+
+RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", &rmem_dma_ops);
 #endif
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index e6fc6906b5c0..efeebda92537 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -470,11 +470,6 @@ static void rmem_cma_device_release(struct reserved_mem *rmem,
 	dev->cma_area = NULL;
 }
 
-static const struct reserved_mem_ops rmem_cma_ops = {
-	.device_init	= rmem_cma_device_init,
-	.device_release = rmem_cma_device_release,
-};
-
 static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 {
 	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
@@ -499,7 +494,6 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 	if (default_cma)
 		dma_contiguous_default_area = cma;
 
-	rmem->ops = &rmem_cma_ops;
 	rmem->priv = cma;
 
 	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
@@ -511,5 +505,12 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 
 	return 0;
 }
-RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
+
+static const struct reserved_mem_ops rmem_cma_ops = {
+	.node_init	= rmem_cma_setup,
+	.device_init	= rmem_cma_device_init,
+	.device_release = rmem_cma_device_release,
+};
+
+RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", &rmem_cma_ops);
 #endif
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index f3a12e15a951..327525181b8a 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1855,11 +1855,6 @@ static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
 	dev->dma_io_tlb_mem = &io_tlb_default_mem;
 }
 
-static const struct reserved_mem_ops rmem_swiotlb_ops = {
-	.device_init = rmem_swiotlb_device_init,
-	.device_release = rmem_swiotlb_device_release,
-};
-
 static int __init rmem_swiotlb_setup(unsigned long node,
 				     struct reserved_mem *rmem)
 {
@@ -1875,5 +1870,11 @@ static int __init rmem_swiotlb_setup(unsigned long node,
 	return 0;
 }
 
-RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
+static const struct reserved_mem_ops rmem_swiotlb_ops = {
+	.node_init = rmem_swiotlb_setup,
+	.device_init = rmem_swiotlb_device_init,
+	.device_release = rmem_swiotlb_device_release,
+};
+
+RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", &rmem_swiotlb_ops);
 #endif /* CONFIG_DMA_RESTRICTED_POOL */
-- 
2.34.1

Re: [PATCH 3/7] of: reserved_mem: switch to ops based OF_DECLARE()

[Marek Szyprowski]

On 13.03.2026 16:07, Marek Szyprowski wrote:
> Move init function from OF_DECLARE() argument to the given reserved
> memory region ops structure and then pass that structure to the
> OF_DECLARE() initializer. This makes it possible in the future to add
> more functions called by the generic code before given memory region is
> initialized and rmem object created.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>   drivers/memory/tegra/tegra210-emc-table.c | 14 ++++++++------
>   drivers/of/of_reserved_mem.c              |  5 +++--
>   include/linux/of_reserved_mem.h           | 15 ++++++++-------
>   kernel/dma/coherent.c                     | 13 +++++++------
>   kernel/dma/contiguous.c                   | 15 ++++++++-------
>   kernel/dma/swiotlb.c                      | 13 +++++++------
>   6 files changed, 41 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/memory/tegra/tegra210-emc-table.c b/drivers/memory/tegra/tegra210-emc-table.c
> index ac1d1e13482a..f6395bc9dbc8 100644
> --- a/drivers/memory/tegra/tegra210-emc-table.c
> +++ b/drivers/memory/tegra/tegra210-emc-table.c
> @@ -70,11 +70,6 @@ static void tegra210_emc_table_device_release(struct reserved_mem *rmem,
>   	memunmap(timings);
>   }
>   
> -static const struct reserved_mem_ops tegra210_emc_table_ops = {
> -	.device_init = tegra210_emc_table_device_init,
> -	.device_release = tegra210_emc_table_device_release,
> -};
> -
>   static int tegra210_emc_table_init(unsigned long node,
>   				   struct reserved_mem *rmem)
>   {
> @@ -85,5 +80,12 @@ static int tegra210_emc_table_init(unsigned long node,
>   
>   	return 0;
>   }
> +
> +static const struct reserved_mem_ops tegra210_emc_table_ops = {
> +	.node_init = tegra210_emc_table_init,
> +	.device_init = tegra210_emc_table_device_init,
> +	.device_release = tegra210_emc_table_device_release,
> +};
> +
>   RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
> -		       tegra210_emc_table_init);
> +		       &tegra210_emc_table_ops);
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 9aff460a0420..675f1c1c6627 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -492,14 +492,15 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
>   
>   	for (i = __reservedmem_of_table; ret == -ENODEV &&
>   	     i < &__rmem_of_table_sentinel; i++) {
> -		reservedmem_of_init_fn initfn = i->data;
> +		const struct reserved_mem_ops *ops = i->data;
>   		const char *compat = i->compatible;
>   
>   		if (!of_flat_dt_is_compatible(node, compat))
>   			continue;
>   
> -		ret = initfn(node, rmem);
> +		ret = ops->node_init(node, rmem);
>   		if (ret == 0) {
> +			rmem->ops = ops;
>   			pr_info("initialized node %s, compatible id %s\n",
>   				rmem->name, compat);
>   			break;
> diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
> index 5159938bfe03..dc00502a6b69 100644
> --- a/include/linux/of_reserved_mem.h
> +++ b/include/linux/of_reserved_mem.h
> @@ -18,19 +18,20 @@ struct reserved_mem {
>   };
>   
>   struct reserved_mem_ops {
> +	int	(*node_init)(unsigned long fdt_node, struct reserved_mem *rmem);
>   	int	(*device_init)(struct reserved_mem *rmem,
>   			       struct device *dev);
>   	void	(*device_release)(struct reserved_mem *rmem,
>   				  struct device *dev);
>   };
>   
> -typedef int (*reservedmem_of_init_fn)(unsigned long node,
> -				      struct reserved_mem *rmem);
> -
>   #ifdef CONFIG_OF_RESERVED_MEM
>   
> -#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
> -	_OF_DECLARE(reservedmem, name, compat, init, reservedmem_of_init_fn)
> +#define RESERVEDMEM_OF_DECLARE(name, compat, ops)			\
> +	static const struct of_device_id __of_table_##name		\
> +		__used __section("__reservedmem_of_table")		\
> +		__aligned(__alignof__(struct of_device_id))		\
> +		 = { .compatible = compat, .data = ops }
>   
>   int of_reserved_mem_device_init_by_idx(struct device *dev,
>   				       struct device_node *np, int idx);
> @@ -48,8 +49,8 @@ int of_reserved_mem_region_count(const struct device_node *np);
>   
>   #else
>   
> -#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
> -	_OF_DECLARE_STUB(reservedmem, name, compat, init, reservedmem_of_init_fn)
> +#define RESERVEDMEM_OF_DECLARE(name, compat, ops)			\
> +	_OF_DECLARE_STUB(reservedmem, name, compat, init, void *)
>   
>   static inline int of_reserved_mem_device_init_by_idx(struct device *dev,
>   					struct device_node *np, int idx)
> diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
> index 64f9ba618e19..bcdc0f76d2e8 100644
> --- a/kernel/dma/coherent.c
> +++ b/kernel/dma/coherent.c
> @@ -362,10 +362,6 @@ static void rmem_dma_device_release(struct reserved_mem *rmem,
>   		dev->dma_mem = NULL;
>   }
>   
> -static const struct reserved_mem_ops rmem_dma_ops = {
> -	.device_init	= rmem_dma_device_init,
> -	.device_release	= rmem_dma_device_release,
> -};
>   
>   static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
>   {
> @@ -388,7 +384,6 @@ static int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem)
>   	}
>   #endif
>   
> -	rmem->ops = &rmem_dma_ops;
>   	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
>   		&rmem->base, (unsigned long)rmem->size / SZ_1M);
>   	return 0;
> @@ -405,5 +400,11 @@ static int __init dma_init_reserved_memory(void)
>   core_initcall(dma_init_reserved_memory);
>   #endif /* CONFIG_DMA_GLOBAL_POOL */
>   
> -RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
> +static const struct reserved_mem_ops rmem_dma_ops = {
> +	.node_init	= rmem_dma_setup,
> +	.device_init	= rmem_dma_device_init,
> +	.device_release	= rmem_dma_device_release,
> +};
> +
> +RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", &rmem_dma_ops);
>   #endif
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index e6fc6906b5c0..efeebda92537 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -470,11 +470,6 @@ static void rmem_cma_device_release(struct reserved_mem *rmem,
>   	dev->cma_area = NULL;
>   }
>   
> -static const struct reserved_mem_ops rmem_cma_ops = {
> -	.device_init	= rmem_cma_device_init,
> -	.device_release = rmem_cma_device_release,
> -};
> -
>   static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
>   {
>   	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
> @@ -499,7 +494,6 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
>   	if (default_cma)
>   		dma_contiguous_default_area = cma;
>   
> -	rmem->ops = &rmem_cma_ops;
>   	rmem->priv = cma;
>   
>   	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
> @@ -511,5 +505,12 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
>   
>   	return 0;
>   }
> -RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
> +
> +static const struct reserved_mem_ops rmem_cma_ops = {
> +	.node_init	= rmem_cma_setup,
> +	.device_init	= rmem_cma_device_init,
> +	.device_release = rmem_cma_device_release,
> +};
> +
> +RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", &rmem_cma_ops);
>   #endif
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index f3a12e15a951..327525181b8a 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -1855,11 +1855,6 @@ static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
>   	dev->dma_io_tlb_mem = &io_tlb_default_mem;
>   }
>   
> -static const struct reserved_mem_ops rmem_swiotlb_ops = {
> -	.device_init = rmem_swiotlb_device_init,
> -	.device_release = rmem_swiotlb_device_release,
> -};
> -
>   static int __init rmem_swiotlb_setup(unsigned long node,
>   				     struct reserved_mem *rmem)
>   {
> @@ -1875,5 +1870,11 @@ static int __init rmem_swiotlb_setup(unsigned long node,
>   	return 0;
>   }
>   
> -RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
> +static const struct reserved_mem_ops rmem_swiotlb_ops = {
> +	.node_init = rmem_swiotlb_setup,
> +	.device_init = rmem_swiotlb_device_init,
> +	.device_release = rmem_swiotlb_device_release,
> +};
> +
> +RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", &rmem_swiotlb_ops);
>   #endif /* CONFIG_DMA_RESTRICTED_POOL */

It looks that this chunk got lost during the rebase, sorry for the noise:

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 327525181b8a..44b566d20e04 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1864,7 +1864,6 @@ static int __init rmem_swiotlb_setup(unsigned long 
node,
             of_get_flat_dt_prop(node, "no-map", NULL))
                 return -EINVAL;

-       rmem->ops = &rmem_swiotlb_ops;
         pr_info("Reserved memory: created restricted DMA pool at %pa, 
size %ld MiB\n",
                 &rmem->base, (unsigned long)rmem->size / SZ_1M);
         return 0;


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH 3/7] of: reserved_mem: switch to ops based OF_DECLARE()

[kernel test robot]

Hi Marek,

kernel test robot noticed the following build errors:

[auto build test ERROR on robh/for-next]
[also build test ERROR on tegra/for-next akpm-mm/mm-everything linus/master v7.0-rc3 next-20260311]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Marek-Szyprowski/of-reserved_mem-remove-fdt-node-from-the-structure/20260314-023123
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20260313150802.1121442-4-m.szyprowski%40samsung.com
patch subject: [PATCH 3/7] of: reserved_mem: switch to ops based OF_DECLARE()
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20260314/202603142347.aops46Bf-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260314/202603142347.aops46Bf-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603142347.aops46Bf-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/memory/tegra/tegra210-emc-table.c: In function 'tegra210_emc_table_init':
>> drivers/memory/tegra/tegra210-emc-table.c:79:22: error: 'tegra210_emc_table_ops' undeclared (first use in this function); did you mean 'tegra210_emc_table_init'?
      79 |         rmem->ops = &tegra210_emc_table_ops;
         |                      ^~~~~~~~~~~~~~~~~~~~~~
         |                      tegra210_emc_table_init
   drivers/memory/tegra/tegra210-emc-table.c:79:22: note: each undeclared identifier is reported only once for each function it appears in


vim +79 drivers/memory/tegra/tegra210-emc-table.c

10de21148f7d28 Joseph Lo        2019-05-29  72  
6888259214366b Marek Szyprowski 2026-03-13  73  static int tegra210_emc_table_init(unsigned long node,
6888259214366b Marek Szyprowski 2026-03-13  74  				   struct reserved_mem *rmem)
10de21148f7d28 Joseph Lo        2019-05-29  75  {
10de21148f7d28 Joseph Lo        2019-05-29  76  	pr_debug("Tegra210 EMC table at %pa, size %lu bytes\n", &rmem->base,
10de21148f7d28 Joseph Lo        2019-05-29  77  		 (unsigned long)rmem->size);
10de21148f7d28 Joseph Lo        2019-05-29  78  
10de21148f7d28 Joseph Lo        2019-05-29 @79  	rmem->ops = &tegra210_emc_table_ops;
10de21148f7d28 Joseph Lo        2019-05-29  80  
10de21148f7d28 Joseph Lo        2019-05-29  81  	return 0;
10de21148f7d28 Joseph Lo        2019-05-29  82  }
f954eaa20bd915 Marek Szyprowski 2026-03-13  83  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 4/7] of: reserved_mem: replace CMA quirks by generic methods

[Marek Szyprowski]

Add optional reserved memory callbacks to perform region verification and
early fixup, then move all CMA related code in of_reserved_mem.c to them.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/of/of_reserved_mem.c    | 97 +++++++++++++++++++++------------
 include/linux/cma.h             | 10 ----
 include/linux/dma-map-ops.h     |  3 -
 include/linux/of_reserved_mem.h |  3 +
 kernel/dma/contiguous.c         | 70 +++++++++++++++++-------
 5 files changed, 116 insertions(+), 67 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 675f1c1c6627..399cdd11a9ca 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -24,8 +24,6 @@
 #include <linux/slab.h>
 #include <linux/memblock.h>
 #include <linux/kmemleak.h>
-#include <linux/cma.h>
-#include <linux/dma-map-ops.h>
 
 #include "of_private.h"
 
@@ -106,6 +104,11 @@ static void __init alloc_reserved_mem_array(void)
 
 static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
 					      unsigned long node);
+static int fdt_validate_reserved_mem_node(unsigned long node,
+					  phys_addr_t *align);
+static int fdt_fixup_reserved_mem_node(unsigned long node,
+				       phys_addr_t base, phys_addr_t size);
+
 /*
  * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
  */
@@ -154,21 +157,19 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 					     const char *uname)
 {
 	phys_addr_t base, size;
-	int i, len;
+	int i, len, err;
 	const __be32 *prop;
-	bool nomap, default_cma;
+	bool nomap;
 
 	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
 	if (!prop)
 		return -ENOENT;
 
 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
-	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
 
-	if (default_cma && cma_skip_dt_default_reserved_mem()) {
-		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");
-		return -EINVAL;
-	}
+	err = fdt_validate_reserved_mem_node(node, NULL);
+	if (err && err != -ENODEV)
+		return err;
 
 	for (i = 0; i < len; i++) {
 		u64 b, s;
@@ -179,10 +180,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 		size = s;
 
 		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
-			/* Architecture specific contiguous memory fixup. */
-			if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
-			    of_get_flat_dt_prop(node, "reusable", NULL))
-				dma_contiguous_early_fixup(base, size);
+			fdt_fixup_reserved_mem_node(node, base, size);
 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
 				uname, &base, (unsigned long)(size / SZ_1M));
 		} else {
@@ -253,17 +251,19 @@ void __init fdt_scan_reserved_mem_reg_nodes(void)
 
 	fdt_for_each_subnode(child, fdt, node) {
 		const char *uname;
-		bool default_cma = of_get_flat_dt_prop(child, "linux,cma-default", NULL);
 		u64 b, s;
+		int ret;
 
 		if (!of_fdt_device_is_available(fdt, child))
 			continue;
-		if (default_cma && cma_skip_dt_default_reserved_mem())
-			continue;
 
 		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))
 			continue;
 
+		ret = fdt_validate_reserved_mem_node(node, NULL);
+		if (ret && ret != -ENODEV)
+			continue;
+
 		base = b;
 		size = s;
 
@@ -397,7 +397,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 	phys_addr_t base = 0, align = 0, size;
 	int i, len;
 	const __be32 *prop;
-	bool nomap, default_cma;
+	bool nomap;
 	int ret;
 
 	prop = of_get_flat_dt_prop(node, "size", &len);
@@ -421,19 +421,10 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 	}
 
 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
-	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
 
-	if (default_cma && cma_skip_dt_default_reserved_mem()) {
-		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");
-		return -EINVAL;
-	}
-
-	/* Need adjust the alignment to satisfy the CMA requirement */
-	if (IS_ENABLED(CONFIG_CMA)
-	    && of_flat_dt_is_compatible(node, "shared-dma-pool")
-	    && of_get_flat_dt_prop(node, "reusable", NULL)
-	    && !nomap)
-		align = max_t(phys_addr_t, align, CMA_MIN_ALIGNMENT_BYTES);
+	ret = fdt_validate_reserved_mem_node(node, &align);
+	if (ret && ret != -ENODEV)
+		return ret;
 
 	prop = of_flat_dt_get_addr_size_prop(node, "alloc-ranges", &len);
 	if (prop) {
@@ -468,25 +459,61 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 		       uname, (unsigned long)(size / SZ_1M));
 		return -ENOMEM;
 	}
-	/* Architecture specific contiguous memory fixup. */
-	if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
-	    of_get_flat_dt_prop(node, "reusable", NULL))
-		dma_contiguous_early_fixup(base, size);
+
+	fdt_fixup_reserved_mem_node(node, base, size);
+
 	/* Save region in the reserved_mem array */
 	fdt_reserved_mem_save_node(node, uname, base, size);
 	return 0;
 }
 
+extern const struct of_device_id __reservedmem_of_table[];
 static const struct of_device_id __rmem_of_table_sentinel
 	__used __section("__reservedmem_of_table_end");
 
+static int __init fdt_fixup_reserved_mem_node(unsigned long node,
+					phys_addr_t base, phys_addr_t size)
+{
+	const struct of_device_id *i;
+	int ret = -ENODEV;
+
+	for (i = __reservedmem_of_table; ret == -ENODEV &&
+	     i < &__rmem_of_table_sentinel; i++) {
+		const struct reserved_mem_ops *ops = i->data;
+
+		if (!of_flat_dt_is_compatible(node, i->compatible))
+			continue;
+
+		if (ops->node_fixup)
+			ret = ops->node_fixup(node, base, size);
+	}
+	return ret;
+}
+
+static int __init fdt_validate_reserved_mem_node(unsigned long node, phys_addr_t *align)
+{
+	const struct of_device_id *i;
+	int ret = -ENODEV;
+
+	for (i = __reservedmem_of_table; ret == -ENODEV &&
+	     i < &__rmem_of_table_sentinel; i++) {
+		const struct reserved_mem_ops *ops = i->data;
+
+		if (!of_flat_dt_is_compatible(node, i->compatible))
+			continue;
+
+		if (ops->node_validate)
+			ret = ops->node_validate(node, align);
+	}
+	return ret;
+}
+
 /*
  * __reserved_mem_init_node() - call region specific reserved memory init code
  */
 static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 					   unsigned long node)
 {
-	extern const struct of_device_id __reservedmem_of_table[];
 	const struct of_device_id *i;
 	int ret = -ENODEV;
 
@@ -503,7 +530,7 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 			rmem->ops = ops;
 			pr_info("initialized node %s, compatible id %s\n",
 				rmem->name, compat);
-			break;
+			return ret;
 		}
 	}
 	return ret;
diff --git a/include/linux/cma.h b/include/linux/cma.h
index d0793eaaadaa..8555d38a97b1 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -61,14 +61,4 @@ extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
 extern bool cma_intersects(struct cma *cma, unsigned long start, unsigned long end);
 
 extern void cma_reserve_pages_on_error(struct cma *cma);
-
-#ifdef CONFIG_DMA_CMA
-extern bool cma_skip_dt_default_reserved_mem(void);
-#else
-static inline bool cma_skip_dt_default_reserved_mem(void)
-{
-	return false;
-}
-#endif
-
 #endif
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 60b63756df82..55ecd2934225 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -147,9 +147,6 @@ static inline void dma_free_contiguous(struct device *dev, struct page *page,
 {
 	__free_pages(page, get_order(size));
 }
-static inline void dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
-{
-}
 #endif /* CONFIG_DMA_CMA*/
 
 #ifdef CONFIG_DMA_DECLARE_COHERENT
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index dc00502a6b69..c240dfe45c9d 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -18,6 +18,9 @@ struct reserved_mem {
 };
 
 struct reserved_mem_ops {
+	int	(*node_validate)(unsigned long fdt_node, phys_addr_t *align);
+	int	(*node_fixup)(unsigned long fdt_node, phys_addr_t base,
+			      phys_addr_t size);
 	int	(*node_init)(unsigned long fdt_node, struct reserved_mem *rmem);
 	int	(*device_init)(struct reserved_mem *rmem,
 			       struct device *dev);
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index efeebda92537..65d216663e81 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -91,16 +91,6 @@ static int __init early_cma(char *p)
 }
 early_param("cma", early_cma);
 
-/*
- * cma_skip_dt_default_reserved_mem - This is called from the
- * reserved_mem framework to detect if the default cma region is being
- * set by the "cma=" kernel parameter.
- */
-bool __init cma_skip_dt_default_reserved_mem(void)
-{
-	return size_cmdline != -1;
-}
-
 #ifdef CONFIG_DMA_NUMA_CMA
 
 static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
@@ -470,25 +460,65 @@ static void rmem_cma_device_release(struct reserved_mem *rmem,
 	dev->cma_area = NULL;
 }
 
+static int __init __rmem_cma_verify_node(unsigned long node)
+{
+	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
+	    of_get_flat_dt_prop(node, "no-map", NULL))
+		return -ENODEV;
+
+	if (size_cmdline != -1 &&
+	    of_get_flat_dt_prop(node, "linux,cma-default", NULL)) {
+		pr_err("Skipping dt linux,cma-default node in favor for \"cma=\" kernel param.\n");
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int __init rmem_cma_validate(unsigned long node, phys_addr_t *align)
+{
+	int ret = __rmem_cma_verify_node(node);
+
+	if (ret)
+		return ret;
+
+	if (align)
+		*align = max_t(phys_addr_t, *align, CMA_MIN_ALIGNMENT_BYTES);
+
+	return 0;
+}
+
+static int __init rmem_cma_fixup(unsigned long node, phys_addr_t base,
+				    phys_addr_t size)
+{
+	int ret = __rmem_cma_verify_node(node);
+
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(base, size);
+	return 0;
+}
+
 static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 {
 	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
 	struct cma *cma;
-	int err;
+	int ret;
 
-	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
-	    of_get_flat_dt_prop(node, "no-map", NULL))
-		return -ENODEV;
+	ret = __rmem_cma_verify_node(node);
+	if (ret)
+		return ret;
 
 	if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
 		pr_err("Reserved memory: incorrect alignment of CMA region\n");
 		return -EINVAL;
 	}
 
-	err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
-	if (err) {
+	ret = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
+	if (ret) {
 		pr_err("Reserved memory: unable to setup CMA region\n");
-		return err;
+		return ret;
 	}
 
 	if (default_cma)
@@ -499,14 +529,16 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
 		&rmem->base, (unsigned long)rmem->size / SZ_1M);
 
-	err = dma_heap_cma_register_heap(cma);
-	if (err)
+	ret = dma_heap_cma_register_heap(cma);
+	if (ret)
 		pr_warn("Couldn't register CMA heap.");
 
 	return 0;
 }
 
 static const struct reserved_mem_ops rmem_cma_ops = {
+	.node_validate  = rmem_cma_validate,
+	.node_fixup	= rmem_cma_fixup,
 	.node_init	= rmem_cma_setup,
 	.device_init	= rmem_cma_device_init,
 	.device_release = rmem_cma_device_release,
-- 
2.34.1

[PATCH 5/7] of: reserved_mem: rearrange code a bit

[Marek Szyprowski]

Move __rmem_check_for_overlap() and __rmem_cmp() functions before
fdt_scan_reserved_mem_reg_nodes() to avoid forward declaration and keep
related code close together.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/of/of_reserved_mem.c | 99 ++++++++++++++++++------------------
 1 file changed, 49 insertions(+), 50 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 399cdd11a9ca..b8d4fbcde3b1 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -214,7 +214,55 @@ static int __init __reserved_mem_check_root(unsigned long node)
 	return 0;
 }
 
-static void __init __rmem_check_for_overlap(void);
+static int __init __rmem_cmp(const void *a, const void *b)
+{
+	const struct reserved_mem *ra = a, *rb = b;
+
+	if (ra->base < rb->base)
+		return -1;
+
+	if (ra->base > rb->base)
+		return 1;
+
+	/*
+	 * Put the dynamic allocations (address == 0, size == 0) before static
+	 * allocations at address 0x0 so that overlap detection works
+	 * correctly.
+	 */
+	if (ra->size < rb->size)
+		return -1;
+	if (ra->size > rb->size)
+		return 1;
+
+	return 0;
+}
+
+static void __init __rmem_check_for_overlap(void)
+{
+	int i;
+
+	if (reserved_mem_count < 2)
+		return;
+
+	sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
+	     __rmem_cmp, NULL);
+	for (i = 0; i < reserved_mem_count - 1; i++) {
+		struct reserved_mem *this, *next;
+
+		this = &reserved_mem[i];
+		next = &reserved_mem[i + 1];
+
+		if (this->base + this->size > next->base) {
+			phys_addr_t this_end, next_end;
+
+			this_end = this->base + this->size;
+			next_end = next->base + next->size;
+			pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
+			       this->name, &this->base, &this_end,
+			       next->name, &next->base, &next_end);
+		}
+	}
+}
 
 /**
  * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
@@ -536,55 +584,6 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 	return ret;
 }
 
-static int __init __rmem_cmp(const void *a, const void *b)
-{
-	const struct reserved_mem *ra = a, *rb = b;
-
-	if (ra->base < rb->base)
-		return -1;
-
-	if (ra->base > rb->base)
-		return 1;
-
-	/*
-	 * Put the dynamic allocations (address == 0, size == 0) before static
-	 * allocations at address 0x0 so that overlap detection works
-	 * correctly.
-	 */
-	if (ra->size < rb->size)
-		return -1;
-	if (ra->size > rb->size)
-		return 1;
-
-	return 0;
-}
-
-static void __init __rmem_check_for_overlap(void)
-{
-	int i;
-
-	if (reserved_mem_count < 2)
-		return;
-
-	sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
-	     __rmem_cmp, NULL);
-	for (i = 0; i < reserved_mem_count - 1; i++) {
-		struct reserved_mem *this, *next;
-
-		this = &reserved_mem[i];
-		next = &reserved_mem[i + 1];
-
-		if (this->base + this->size > next->base) {
-			phys_addr_t this_end, next_end;
-
-			this_end = this->base + this->size;
-			next_end = next->base + next->size;
-			pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
-			       this->name, &this->base, &this_end,
-			       next->name, &next->base, &next_end);
-		}
-	}
-}
 
 /**
  * fdt_init_reserved_mem_node() - Initialize a reserved memory region
-- 
2.34.1

[PATCH 6/7] of: reserved_mem: clarify fdt_scan_reserved_mem*() functions

[Marek Szyprowski]

Rename fdt_scan_reserved_mem_reg_nodes() to fdt_scan_reserved_mem_late()
to clearly show how it differs from fdt_scan_reserved_mem() and update
description of both functions.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/of/fdt.c             |  2 +-
 drivers/of/of_private.h      |  2 +-
 drivers/of/of_reserved_mem.c | 24 +++++++++++++++---------
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 331646d667b9..43a0944ca462 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1274,7 +1274,7 @@ void __init unflatten_device_tree(void)
 	void *fdt = initial_boot_params;
 
 	/* Save the statically-placed regions in the reserved_mem array */
-	fdt_scan_reserved_mem_reg_nodes();
+	fdt_scan_reserved_mem_late();
 
 	/* Populate an empty root node when bootloader doesn't provide one */
 	if (!fdt) {
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index df0bb00349e0..0ae16da066e2 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -186,7 +186,7 @@ static inline struct device_node *__of_get_dma_parent(const struct device_node *
 #endif
 
 int fdt_scan_reserved_mem(void);
-void __init fdt_scan_reserved_mem_reg_nodes(void);
+void __init fdt_scan_reserved_mem_late(void);
 
 bool of_fdt_device_is_available(const void *blob, unsigned long node);
 
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index b8d4fbcde3b1..229573d6dacb 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -265,16 +265,15 @@ static void __init __rmem_check_for_overlap(void)
 }
 
 /**
- * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
- * reserved memory regions.
+ * fdt_scan_reserved_mem_late() - Scan FDT and initialize remaining reserved
+ * memory regions.
  *
- * This function is used to scan through the DT and store the
- * information for the reserved memory regions that are defined using
- * the "reg" property. The region node number, name, base address, and
- * size are all stored in the reserved_mem array by calling the
- * fdt_reserved_mem_save_node() function.
+ * This function is used to scan again through the DT and initialize the
+ * the "static" reserved memory regions, that are defined using the "reg"
+ * property. Each such region is then initialized with its specific init
+ * function and stored in the global reserved_mem array.
  */
-void __init fdt_scan_reserved_mem_reg_nodes(void)
+void __init fdt_scan_reserved_mem_late(void)
 {
 	const void *fdt = initial_boot_params;
 	phys_addr_t base, size;
@@ -328,7 +327,14 @@ void __init fdt_scan_reserved_mem_reg_nodes(void)
 static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
 
 /*
- * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ * fdt_scan_reserved_mem() - reserve and allocate memory occupied by
+ * reserved memory regions.
+ *
+ * This function is used to scan through the FDT and mark memory occupied
+ * by all static (defined by the "reg" property) reserved memory regions.
+ * Then memory for all dynamic regions (defined by size & alignment) is
+ * allocated, a region specific init function is called and region information
+ * is stored in the reserved_mem array.
  */
 int __init fdt_scan_reserved_mem(void)
 {
-- 
2.34.1

[PATCH 7/7] of: reserved_mem: rework fdt_init_reserved_mem_node()

[Marek Szyprowski]

Move the content of fdt_reserved_mem_save_node() to
fdt_init_reserved_mem_node() function. Initialization is no longer
performed in two steps as it was initially, so
fdt_reserved_mem_save_node() name is a bit misleading and that function
actually perform full initialization of the reserved memory region.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/of/of_reserved_mem.c | 58 ++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 33 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 229573d6dacb..7146c1ba6ae1 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -102,36 +102,13 @@ static void __init alloc_reserved_mem_array(void)
 	reserved_mem = new_array;
 }
 
-static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
-					      unsigned long node);
+static void fdt_init_reserved_mem_node(unsigned long node, const char *uname,
+				       phys_addr_t base, phys_addr_t size);
 static int fdt_validate_reserved_mem_node(unsigned long node,
 					  phys_addr_t *align);
 static int fdt_fixup_reserved_mem_node(unsigned long node,
 				       phys_addr_t base, phys_addr_t size);
 
-/*
- * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
- */
-static void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
-					      phys_addr_t base, phys_addr_t size)
-{
-	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
-
-	if (reserved_mem_count == total_reserved_mem_cnt) {
-		pr_err("not enough space for all defined regions.\n");
-		return;
-	}
-
-	rmem->name = uname;
-	rmem->base = base;
-	rmem->size = size;
-
-	/* Call the region specific initialization function */
-	fdt_init_reserved_mem_node(rmem, node);
-
-	reserved_mem_count++;
-}
-
 static int __init early_init_dt_reserve_memory(phys_addr_t base,
 					       phys_addr_t size, bool nomap)
 {
@@ -316,12 +293,14 @@ void __init fdt_scan_reserved_mem_late(void)
 
 		if (size) {
 			uname = fdt_get_name(fdt, child, NULL);
-			fdt_reserved_mem_save_node(child, uname, base, size);
+			fdt_init_reserved_mem_node(child, uname, base, size);
 		}
 	}
 
 	/* check for overlapping reserved regions */
 	__rmem_check_for_overlap();
+
+
 }
 
 static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
@@ -515,9 +494,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 	}
 
 	fdt_fixup_reserved_mem_node(node, base, size);
+	fdt_init_reserved_mem_node(node, uname, base, size);
 
-	/* Save region in the reserved_mem array */
-	fdt_reserved_mem_save_node(node, uname, base, size);
 	return 0;
 }
 
@@ -590,21 +568,31 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
 	return ret;
 }
 
-
 /**
  * fdt_init_reserved_mem_node() - Initialize a reserved memory region
- * @rmem: reserved_mem struct of the memory region to be initialized.
  * @node: fdt node of the initialized region
  *
  * This function is used to call the region specific initialization
- * function for a reserved memory region.
+ * function for a reserved memory region save all region specific data to
+ * reserved_mem array to let of_reserved_mem_lookup() function find it.
  */
-static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
-					      unsigned long node)
+static void __init fdt_init_reserved_mem_node(unsigned long node, const char *uname,
+					      phys_addr_t base, phys_addr_t size)
 {
 	int err = 0;
 	bool nomap;
 
+	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
+
+	if (reserved_mem_count == total_reserved_mem_cnt) {
+		pr_err("not enough space for all defined regions.\n");
+		return;
+	}
+
+	rmem->name = uname;
+	rmem->base = base;
+	rmem->size = size;
+
 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 
 	err = __reserved_mem_init_node(rmem, node);
@@ -614,6 +602,7 @@ static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
 			memblock_clear_nomap(rmem->base, rmem->size);
 		else
 			memblock_phys_free(rmem->base, rmem->size);
+		return;
 	} else {
 		phys_addr_t end = rmem->base + rmem->size - 1;
 		bool reusable =
@@ -624,7 +613,10 @@ static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem,
 			nomap ? "nomap" : "map",
 			reusable ? "reusable" : "non-reusable",
 			rmem->name ? rmem->name : "unknown");
+
 	}
+
+	reserved_mem_count++;
 }
 
 struct rmem_assigned_device {
-- 
2.34.1

Re: [PATCH 7/7] of: reserved_mem: rework fdt_init_reserved_mem_node()

[kernel test robot]

Hi Marek,

kernel test robot noticed the following build warnings:

[auto build test WARNING on robh/for-next]
[also build test WARNING on akpm-mm/mm-everything linus/master v7.0-rc3 next-20260311]
[cannot apply to tegra/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Marek-Szyprowski/of-reserved_mem-remove-fdt-node-from-the-structure/20260314-023123
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20260313150802.1121442-8-m.szyprowski%40samsung.com
patch subject: [PATCH 7/7] of: reserved_mem: rework fdt_init_reserved_mem_node()
config: arc-allnoconfig (https://download.01.org/0day-ci/archive/20260314/202603141108.XvqRlNaY-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260314/202603141108.XvqRlNaY-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603141108.XvqRlNaY-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'uname' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'base' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'size' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'uname' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'base' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'size' not described in 'fdt_init_reserved_mem_node'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 7/7] of: reserved_mem: rework fdt_init_reserved_mem_node()

[kernel test robot]

Hi Marek,

kernel test robot noticed the following build warnings:

[auto build test WARNING on robh/for-next]
[also build test WARNING on akpm-mm/mm-everything next-20260313]
[cannot apply to tegra/for-next linus/master v6.16-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Marek-Szyprowski/of-reserved_mem-remove-fdt-node-from-the-structure/20260314-023123
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20260313150802.1121442-8-m.szyprowski%40samsung.com
patch subject: [PATCH 7/7] of: reserved_mem: rework fdt_init_reserved_mem_node()
config: x86_64-rhel-9.4-kunit (https://download.01.org/0day-ci/archive/20260314/202603140843.vdpZ0bgs-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260314/202603140843.vdpZ0bgs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603140843.vdpZ0bgs-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'uname' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'base' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'size' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'uname' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'base' not described in 'fdt_init_reserved_mem_node'
>> Warning: drivers/of/of_reserved_mem.c:580 function parameter 'size' not described in 'fdt_init_reserved_mem_node'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 0/7] Refactor reserved memory regions handling code

[Rob Herring]

On Fri, Mar 13, 2026 at 04:07:55PM +0100, Marek Szyprowski wrote:
> Hello,
> 
> The reserved memory regions handling code was reworked to handle
> unlimited so called "static" memory nodes in commit 00c9a452a235 ("of:
> reserved_mem: Add code to dynamically allocate reserved_mem array").
> 
> The side effect of this rework was a set of bugs fixed later by commits
> 0fd17e598333 ("of: reserved_mem: Allow reserved_mem framework detect
> "cma=" kernel param") and 2c223f7239f3 ("of: reserved_mem: Restructure
> call site for dma_contiguous_early_fixup()"). As a result, the code in
> drivers/of/of_reserved_mem.c became a mix of generic code and CMA
> specific fixups.
> 
> In this patchset I try to untangle this spaghetti and perform some code
> cleanup. I hope nothing breaks this time.

This all looks good to me. Can you respin and fixup the issues.

Rob