| Message ID | 20171005033258.12825-3-bjorn.andersson@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Oct 4, 2017 at 10:32 PM, Bjorn Andersson <bjorn.andersson@linaro.org> 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. > > A complicating factor for the implementation is that the reserved_mem > objects are created from the flattened DeviceTree, as such we can't > use the device_node address for comparison. Fortunately the name of the > node will be used as "name" of the reserved_mem and will be used when > building the full_name, so we can compare the "name" with the basename > of the full_name to find the match. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > > Changes since v2: > - None > > Changes since v1: > - Previous patch provided interface to resolve memory-region reference, instead > of direct lookup by device_node > > drivers/of/of_reserved_mem.c | 26 ++++++++++++++++++++++++++ > include/linux/of_reserved_mem.h | 5 +++++ > 2 files changed, 31 insertions(+) > > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c > index d507c3569a88..b40cfce68fd4 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_reserved_mem_get() - acquire reserved_mem from a device node *_get() generally implies reference counting. Maybe "lookup" instead. Otherwise, Reviewed-by: Rob Herring <robh@kernel.org> > + * @np: node pointer of the desired reserved-memory region > + * > + * This function allows drivers to acquire a reference to the reserved_mem > + * struct based on a device node handle. > + * > + * Returns a reserved_mem reference, or NULL on error. > + */ > +struct reserved_mem *of_reserved_mem_get(struct device_node *np) > +{ > + const char *name; > + int i; > + > + if (!np->full_name) > + return NULL; > + > + name = kbasename(np->full_name); > + for (i = 0; i < reserved_mem_count; i++) > + if (!strcmp(reserved_mem[i].name, name)) > + return &reserved_mem[i]; > + > + return NULL; > +} > +EXPORT_SYMBOL_GPL(of_reserved_mem_get); > diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h > index f8e1992d6423..91b1eb5076e4 100644 > --- a/include/linux/of_reserved_mem.h > +++ b/include/linux/of_reserved_mem.h > @@ -44,6 +44,7 @@ int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, > void fdt_init_reserved_mem(void); > void fdt_reserved_mem_save_node(unsigned long node, const char *uname, > phys_addr_t base, phys_addr_t size); > +struct reserved_mem *of_reserved_mem_get(struct device_node *np); > #else > static inline int of_reserved_mem_device_init_by_idx(struct device *dev, > struct device_node *np, int idx) > @@ -55,6 +56,10 @@ static inline void of_reserved_mem_device_release(struct device *pdev) { } > 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) { } > +static inline struct reserved_mem *of_reserved_mem_get(struct device_node *np) > +{ > + return NULL; > +} > #endif > > /** > -- > 2.12.0 >
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index d507c3569a88..b40cfce68fd4 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_reserved_mem_get() - acquire reserved_mem from a device node + * @np: node pointer of the desired reserved-memory region + * + * This function allows drivers to acquire a reference to the reserved_mem + * struct based on a device node handle. + * + * Returns a reserved_mem reference, or NULL on error. + */ +struct reserved_mem *of_reserved_mem_get(struct device_node *np) +{ + const char *name; + int i; + + if (!np->full_name) + return NULL; + + name = kbasename(np->full_name); + for (i = 0; i < reserved_mem_count; i++) + if (!strcmp(reserved_mem[i].name, name)) + return &reserved_mem[i]; + + return NULL; +} +EXPORT_SYMBOL_GPL(of_reserved_mem_get); diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h index f8e1992d6423..91b1eb5076e4 100644 --- a/include/linux/of_reserved_mem.h +++ b/include/linux/of_reserved_mem.h @@ -44,6 +44,7 @@ int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, void fdt_init_reserved_mem(void); void fdt_reserved_mem_save_node(unsigned long node, const char *uname, phys_addr_t base, phys_addr_t size); +struct reserved_mem *of_reserved_mem_get(struct device_node *np); #else static inline int of_reserved_mem_device_init_by_idx(struct device *dev, struct device_node *np, int idx) @@ -55,6 +56,10 @@ static inline void of_reserved_mem_device_release(struct device *pdev) { } 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) { } +static inline struct reserved_mem *of_reserved_mem_get(struct device_node *np) +{ + return NULL; +} #endif /**
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. A complicating factor for the implementation is that the reserved_mem objects are created from the flattened DeviceTree, as such we can't use the device_node address for comparison. Fortunately the name of the node will be used as "name" of the reserved_mem and will be used when building the full_name, so we can compare the "name" with the basename of the full_name to find the match. Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> --- Changes since v2: - None Changes since v1: - Previous patch provided interface to resolve memory-region reference, instead of direct lookup by device_node drivers/of/of_reserved_mem.c | 26 ++++++++++++++++++++++++++ include/linux/of_reserved_mem.h | 5 +++++ 2 files changed, 31 insertions(+)