| Message ID | 20170803025754.19101-1-bjorn.andersson@linaro.org |
|---|---|
| Headers | show |
| Series | Qualcomm remote filesystem shared memory driver | expand |
On Wed, Aug 2, 2017 at 9:57 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. Maybe we should add the device_node pointer when we unflatten? > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > > 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 > + * @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 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu 03 Aug 10:40 PDT 2017, Rob Herring wrote: > On Wed, Aug 2, 2017 at 9:57 PM, Bjorn Andersson > <bjorn.andersson@linaro.org> wrote: > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c [..] > > + rmem_nodes = of_find_node_by_path("/reserved-memory"); > > + for_each_available_child_of_node(rmem_nodes, node) { > > + ret = of_device_compatible_match(node, rmem_compats); > > + if (ret) > > I would just do: > > for_each_matching_node(node, ...) > of_platform_device_create(node, NULL, NULL); > > I don't think the kernel has to validate that ramoops and any others > we add are children of /reserved-memory. We should only have those > compatibles located there and any other location would be an error. > Okay, looks reasonable. Will update and resend once I know your decision on 2/5. Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri 04 Aug 07:50 PDT 2017, Rob Herring wrote: > On Thu, Aug 3, 2017 at 6:31 PM, Bjorn Andersson > <bjorn.andersson@linaro.org> wrote: > > On Thu 03 Aug 10:45 PDT 2017, Rob Herring wrote: > > > >> On Wed, Aug 2, 2017 at 9:57 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. > >> > >> Maybe we should add the device_node pointer when we unflatten? > >> > > > > It did try to figure something sane out in that direction. > > > > The solution I came up with was to amend populate_node() to in a !dryrun > > block check if the "dad" full_name is /reserved-memory and if so > > call call a new accessor in of_reserved_mem.c to add the "np" to the > > reserved_mem object with fdt_node equal offset. > > I was thinking doing it with the unflattened tree just after it has > been unflattened rather than during unflattening. > The problem is that the fdt_node of the reserved_mem is the offset in the flat tree, but we don't carry this information with us when we create the individual device_nodes. So, AFAICT, to fill out this information at any point after returning from the particular populate_node() call we will have to use some sort of heuristics in matching the two nodes. > > This code path is already cluttered due to the version differences when > > it comes to building full_name and we would end up checking for each > > node in the entire tree if the parent happens to be "/reserved-mem". > > > > So I went for the less intrusive and more straight forward comparison > > with basename(full_name) instead. > > That's good, because full_name is about to become just the basename. > I'll update patch 1/5 and resend the series. Thanks, Bjorn -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html