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lib: devres: add convenience function to remap a resource
Almost every platform_driver does the three steps get_resource, request_mem_region, ioremap. This does not only lead to a lot of code duplication, but also a huge number of similar error strings and inconsistent error codes on failure. So, introduce a helper function which simplifies remapping a resource and make it hard to do something wrong and add documentation for it. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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3 changed files with 55 additions and 0 deletions
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@ -262,6 +262,7 @@ IOMAP
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devm_ioremap()
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devm_ioremap_nocache()
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devm_iounmap()
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devm_request_and_ioremap() : checks resource, requests region, ioremaps
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pcim_iomap()
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pcim_iounmap()
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pcim_iomap_table() : array of mapped addresses indexed by BAR
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@ -490,6 +490,9 @@ extern int devres_release_group(struct device *dev, void *id);
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extern void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp);
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extern void devm_kfree(struct device *dev, void *p);
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void __iomem *devm_request_and_ioremap(struct device *dev,
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struct resource *res);
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struct device_dma_parameters {
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/*
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* a low level driver may set these to teach IOMMU code about
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51
lib/devres.c
51
lib/devres.c
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@ -85,6 +85,57 @@ void devm_iounmap(struct device *dev, void __iomem *addr)
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}
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EXPORT_SYMBOL(devm_iounmap);
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/**
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* devm_request_and_ioremap() - Check, request region, and ioremap resource
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* @dev: Generic device to handle the resource for
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* @res: resource to be handled
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*
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* Takes all necessary steps to ioremap a mem resource. Uses managed device, so
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* everything is undone on driver detach. Checks arguments, so you can feed
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* it the result from e.g. platform_get_resource() directly. Returns the
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* remapped pointer or NULL on error. Usage example:
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*
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* res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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* base = devm_request_and_ioremap(&pdev->dev, res);
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* if (!base)
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* return -EADDRNOTAVAIL;
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*/
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void __iomem *devm_request_and_ioremap(struct device *dev,
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struct resource *res)
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{
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resource_size_t size;
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const char *name;
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void __iomem *dest_ptr;
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BUG_ON(!dev);
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if (!res || resource_type(res) != IORESOURCE_MEM) {
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dev_err(dev, "invalid resource\n");
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return NULL;
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}
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size = resource_size(res);
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name = res->name ?: dev_name(dev);
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if (!devm_request_mem_region(dev, res->start, size, name)) {
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dev_err(dev, "can't request region for resource %pR\n", res);
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return NULL;
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}
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if (res->flags & IORESOURCE_CACHEABLE)
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dest_ptr = devm_ioremap(dev, res->start, size);
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else
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dest_ptr = devm_ioremap_nocache(dev, res->start, size);
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if (!dest_ptr) {
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dev_err(dev, "ioremap failed for resource %pR\n", res);
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devm_release_mem_region(dev, res->start, size);
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}
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return dest_ptr;
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}
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EXPORT_SYMBOL(devm_request_and_ioremap);
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#ifdef CONFIG_HAS_IOPORT
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/*
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* Generic iomap devres
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