From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Mon, 27 Mar 2017 10:49:36 +0100 Subject: [PATCH v2 08/22] lib: implement Devres ioremap_nopost() interface In-Reply-To: <20170327094954.7162-1-lorenzo.pieralisi@arm.com> References: <20170327094954.7162-1-lorenzo.pieralisi@arm.com> Message-ID: <20170327094954.7162-9-lorenzo.pieralisi@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The introduction of the ioremap_nopost() interface allows kernel drivers to map memory through a dedicated kernel interface providing non-posted writes semantics. Introduce two new functions in the Devres kernel layer and Devres documentation: - devm_ioremap_nopost() - devm_ioremap_nopost_resource() so that drivers can make use of devm_* interface to map memory regions requiring non-posted writes memory attributes. Signed-off-by: Lorenzo Pieralisi Cc: Jonathan Corbet Cc: Bjorn Helgaas Cc: Tejun Heo --- Documentation/driver-model/devres.txt | 3 ++ include/linux/device.h | 2 + include/linux/io.h | 2 + lib/devres.c | 78 +++++++++++++++++++++++++++++++++++ 4 files changed, 85 insertions(+) diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index bf34d5b..9991a66 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -294,7 +294,10 @@ IOMAP devm_ioremap() devm_ioremap_nocache() devm_ioremap_wc() + devm_ioremap_nopost() devm_ioremap_resource() : checks resource, requests memory region, ioremaps + devm_ioremap_nopost_resource() : do devm_ioremap_resource() with nopost + memory attributes devm_iounmap() pcim_iomap() pcim_iomap_regions() : do request_region() and iomap() on multiple BARs diff --git a/include/linux/device.h b/include/linux/device.h index 9ef518a..1dce865 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -689,6 +689,8 @@ extern unsigned long devm_get_free_pages(struct device *dev, 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_ioremap_nopost_resource(struct device *dev, + struct resource *res); /* allows to add/remove a custom action to devres stack */ int devm_add_action(struct device *dev, void (*action)(void *), void *data); diff --git a/include/linux/io.h b/include/linux/io.h index 82ef36e..e34d799 100644 --- a/include/linux/io.h +++ b/include/linux/io.h @@ -79,6 +79,8 @@ void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset, resource_size_t size); void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset, resource_size_t size); +void __iomem *devm_ioremap_nopost(struct device *dev, resource_size_t offset, + resource_size_t size); void devm_iounmap(struct device *dev, void __iomem *addr); int check_signature(const volatile void __iomem *io_addr, const unsigned char *signature, int length); diff --git a/lib/devres.c b/lib/devres.c index cb1464c..4e05660 100644 --- a/lib/devres.c +++ b/lib/devres.c @@ -100,6 +100,34 @@ void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset, EXPORT_SYMBOL(devm_ioremap_wc); /** + * devm_ioremap_nopost - Managed ioremap_nopost() + * @dev: Generic device to remap IO address for + * @offset: BUS offset to map + * @size: Size of map + * + * Managed ioremap_nopost(). Map is automatically unmapped on driver detach. + */ +void __iomem *devm_ioremap_nopost(struct device *dev, resource_size_t offset, + resource_size_t size) +{ + void __iomem **ptr, *addr; + + ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return NULL; + + addr = ioremap_nopost(offset, size); + if (addr) { + *ptr = addr; + devres_add(dev, ptr); + } else + devres_free(ptr); + + return addr; +} +EXPORT_SYMBOL(devm_ioremap_nopost); + +/** * devm_iounmap - Managed iounmap() * @dev: Generic device to unmap for * @addr: Address to unmap @@ -163,6 +191,56 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res) } EXPORT_SYMBOL(devm_ioremap_resource); +/** + * devm_ioremap_nopost_resource() - devm_ioremap_resource() nopost version + * @dev: generic device to handle the resource for + * @res: resource to be handled + * + * Checks that a resource is a valid memory region, requests the memory + * region and ioremaps it with ioremap_nopost() interface. + * All operations are managed and will be undone on driver detach. + * + * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code + * on failure. Usage example: + * + * res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + * base = devm_ioremap_nopost_resource(&pdev->dev, res); + * if (IS_ERR(base)) + * return PTR_ERR(base); + */ +void __iomem *devm_ioremap_nopost_resource(struct device *dev, + struct resource *res) +{ + resource_size_t size; + const char *name; + void __iomem *dest_ptr; + + BUG_ON(!dev); + + if (!res || resource_type(res) != IORESOURCE_MEM) { + dev_err(dev, "invalid resource\n"); + return IOMEM_ERR_PTR(-EINVAL); + } + + size = resource_size(res); + name = res->name ?: dev_name(dev); + + if (!devm_request_mem_region(dev, res->start, size, name)) { + dev_err(dev, "can't request region for resource %pR\n", res); + return IOMEM_ERR_PTR(-EBUSY); + } + + dest_ptr = devm_ioremap_nopost(dev, res->start, size); + if (!dest_ptr) { + dev_err(dev, "ioremap failed for resource %pR\n", res); + devm_release_mem_region(dev, res->start, size); + dest_ptr = IOMEM_ERR_PTR(-ENOMEM); + } + + return dest_ptr; +} +EXPORT_SYMBOL(devm_ioremap_nopost_resource); + #ifdef CONFIG_HAS_IOPORT_MAP /* * Generic iomap devres -- 2.10.0