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

[Marek Szyprowski <m.szyprowski@samsung.com>]

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