On Thu, 2018-06-14 at 13:31 +1000, Benjamin Herrenschmidt wrote:
> There are still quite a few cases where a device might want
> to get to a different node of the device-tree, obtain the
> resources and map them.
>
> This is generally open coded in drivers which is quite error prone
>
> We have of_iomap() and of_io_request_and_map() but they both
> have shortcomings, such as not returning the size of the
> resource found (which can be useful) and not being "managed".
>
> This adds a devm_of_iomap() that provides all of these and
> should probably replace uses of the above in most drivers.
>
> Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> ---
Greg, which tree should this go through ? Rob, ack pls ? :-)
I have dependencies on this coming up... I can put it in the FSI tree
if you want, it will be part of my next pull request.
Cheers,
Ben.
> include/linux/device.h | 4 ++++
> lib/devres.c | 36 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 40 insertions(+)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index beabdbc08420..1529775ecb36 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -686,6 +686,10 @@ extern void devm_free_pages(struct device *dev, unsigned
> long addr);
>
> void __iomem *devm_ioremap_resource(struct device *dev, struct resource
> *res);
>
> +void __iomem *devm_of_iomap(struct device *dev,
> + struct device_node *node, int index,
> + resource_size_t *size);
> +
> /* allows to add/remove a custom action to devres stack */
> int devm_add_action(struct device *dev, void (*action)(void *), void *data);
> void devm_remove_action(struct device *dev, void (*action)(void *), void
> *data);
> diff --git a/lib/devres.c b/lib/devres.c
> index 78eca713b1d9..e320f80c1c4e 100644
> --- a/lib/devres.c
> +++ b/lib/devres.c
> @@ -3,6 +3,7 @@
> #include <linux/io.h>
> #include <linux/gfp.h>
> #include <linux/export.h>
> +#include <linux/of_address.h>
>
> void devm_ioremap_release(struct device *dev, void *res)
> {
> @@ -163,6 +164,41 @@ void __iomem *devm_ioremap_resource(struct device *dev,
> struct resource *res)
> }
> EXPORT_SYMBOL(devm_ioremap_resource);
>
> +/*
> + * devm_of_iomap - Requests a resource and maps the memory mapped IO
> + * for a given device_node managed by a given device
> + *
> + * Checks that a resource is a valid memory region, requests the memory
> + * region and ioremaps it. All operations are managed and will be undone
> + * on driver detach of the device.
> + *
> + * This is to be used when a device requests/maps resources described
> + * by other device tree nodes (children or otherwise).
> + *
> + * @dev: The device "managing" the resource
> + * @node: The device-tree node where the resource resides
> + * @index: index of the MMIO range in the "reg" property
> + * @size: Returns the size of the resource (pass NULL if not needed)
> + * Returns a pointer to the requested and mapped memory or an ERR_PTR()
> encoded
> + * error code on failure. Usage example:
> + *
> + * base = devm_of_iomap(&pdev->dev, node, 0, NULL);
> + * if (IS_ERR(base))
> + * return PTR_ERR(base);
> + */
> +void __iomem *devm_of_iomap(struct device *dev, struct device_node *node,
> int index,
> + resource_size_t *size)
> +{
> + struct resource res;
> +
> + if (of_address_to_resource(node, index, &res))
> + return IOMEM_ERR_PTR(-EINVAL);
> + if (size)
> + *size = resource_size(&res);
> + return devm_ioremap_resource(dev, &res);
> +}
> +EXPORT_SYMBOL(devm_of_iomap);
> +
> #ifdef CONFIG_HAS_IOPORT_MAP
> /*
> * Generic iomap devres
