[RFC,2/3] of: reserved_mem: Accessor for acquiring reserved_mem

Message ID 20170422173519.5782-2-bjorn.andersson@linaro.org
State New
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Series
  • [RFC,1/3] dt-binding: soc: qcom: Add binding for RFSA
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Commit Message

Bjorn Andersson April 22, 2017, 5:35 p.m.
In some cases drivers referencing a reserved-memory region might want to
remap the entire region, but when defining the reserved-memory by "size"
the client driver has no means to know the associated base address of
the reserved memory region.

This patch adds an accessor for such drivers to acquire a handle to
their associated reserved-memory for this purpose.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

---

I would have preferred if we could provide a mechanism for drivers to find the
reserved_mem of their own device_node, but without a phandle I have not been
able to figure out a sane way to make the match.

Suggestions are very welcome.

 drivers/of/of_reserved_mem.c    | 26 ++++++++++++++++++++++++++
 include/linux/of_reserved_mem.h |  8 ++++++++
 2 files changed, 34 insertions(+)

-- 
2.12.0

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Comments

Frank Rowand April 24, 2017, 5:27 p.m. | #1
On 04/22/17 10:35, Bjorn Andersson wrote:
> In some cases drivers referencing a reserved-memory region might want to

> remap the entire region, but when defining the reserved-memory by "size"

> the client driver has no means to know the associated base address of

> the reserved memory region.

> 

> This patch adds an accessor for such drivers to acquire a handle to

> their associated reserved-memory for this purpose.

> 

> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> ---

> 

> I would have preferred if we could provide a mechanism for drivers to find the

> reserved_mem of their own device_node, but without a phandle I have not been

> able to figure out a sane way to make the match.

> 

> Suggestions are very welcome.

> 

>  drivers/of/of_reserved_mem.c    | 26 ++++++++++++++++++++++++++

>  include/linux/of_reserved_mem.h |  8 ++++++++

>  2 files changed, 34 insertions(+)

> 

> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c

> index d507c3569a88..aa69c9590a5c 100644

> --- a/drivers/of/of_reserved_mem.c

> +++ b/drivers/of/of_reserved_mem.c

> @@ -397,3 +397,29 @@ void of_reserved_mem_device_release(struct device *dev)

>  	rmem->ops->device_release(rmem, dev);

>  }

>  EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);

> +

> +/**

> + * of_get_reserved_mem_by_idx() - acquire reserved_mem from memory-region

> + * @np:		node pointer containing the "memory-region"

> + * @idx:	index within memory-region

> + *

> + * This function allows drivers to acquire a reference to the reserved_mem

> + * struct which is referenced by their memory-region.

> + *

> + * Returns a reserved_mem reference, or NULL on error.

> + */

> +struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np, int idx)

> +{

> +	struct device_node *target;

> +	struct reserved_mem *rmem;

> +

> +	target = of_parse_phandle(np, "memory-region", idx);

> +	if (!target)

> +		return NULL;

> +

> +	rmem = __find_rmem(target);

> +	of_node_put(target);

> +

> +	return rmem;

> +}

> +EXPORT_SYMBOL_GPL(of_get_reserved_mem_by_idx);

> diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h

> index f8e1992d6423..a9abbe7dd3de 100644

> --- a/include/linux/of_reserved_mem.h

> +++ b/include/linux/of_reserved_mem.h

> @@ -34,6 +34,8 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,

>  				       struct device_node *np, int idx);

>  void of_reserved_mem_device_release(struct device *dev);

>  

> +struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np, int idx);

> +

>  int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,

>  					     phys_addr_t align,

>  					     phys_addr_t start,

> @@ -52,6 +54,12 @@ static inline int of_reserved_mem_device_init_by_idx(struct device *dev,

>  }

>  static inline void of_reserved_mem_device_release(struct device *pdev) { }

>  

> +static inline struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np,

> +							      int idx);

> +{

> +	return NULL;

> +}

> +

>  static inline void fdt_init_reserved_mem(void) { }

>  static inline void fdt_reserved_mem_save_node(unsigned long node,

>  		const char *uname, phys_addr_t base, phys_addr_t size) { }

> 


Reviewed-by: Frank Rowand <frank.rowand@sony.com>

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Patch hide | download patch | download mbox

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index d507c3569a88..aa69c9590a5c 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -397,3 +397,29 @@  void of_reserved_mem_device_release(struct device *dev)
 	rmem->ops->device_release(rmem, dev);
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
+
+/**
+ * of_get_reserved_mem_by_idx() - acquire reserved_mem from memory-region
+ * @np:		node pointer containing the "memory-region"
+ * @idx:	index within memory-region
+ *
+ * This function allows drivers to acquire a reference to the reserved_mem
+ * struct which is referenced by their memory-region.
+ *
+ * Returns a reserved_mem reference, or NULL on error.
+ */
+struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np, int idx)
+{
+	struct device_node *target;
+	struct reserved_mem *rmem;
+
+	target = of_parse_phandle(np, "memory-region", idx);
+	if (!target)
+		return NULL;
+
+	rmem = __find_rmem(target);
+	of_node_put(target);
+
+	return rmem;
+}
+EXPORT_SYMBOL_GPL(of_get_reserved_mem_by_idx);
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index f8e1992d6423..a9abbe7dd3de 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -34,6 +34,8 @@  int of_reserved_mem_device_init_by_idx(struct device *dev,
 				       struct device_node *np, int idx);
 void of_reserved_mem_device_release(struct device *dev);
 
+struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np, int idx);
+
 int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
 					     phys_addr_t align,
 					     phys_addr_t start,
@@ -52,6 +54,12 @@  static inline int of_reserved_mem_device_init_by_idx(struct device *dev,
 }
 static inline void of_reserved_mem_device_release(struct device *pdev) { }
 
+static inline struct reserved_mem *of_get_reserved_mem_by_idx(struct device_node *np,
+							      int idx);
+{
+	return NULL;
+}
+
 static inline void fdt_init_reserved_mem(void) { }
 static inline void fdt_reserved_mem_save_node(unsigned long node,
 		const char *uname, phys_addr_t base, phys_addr_t size) { }