PCI: Implement devm_pci_remap_cfgspace()

The introduction of the pci_remap_cfgspace() interface allows PCI host
controller drivers to map PCI config space through a dedicated kernel
interface. Current PCI host controller drivers use the devm_ioremap_*()
devres interfaces to map PCI configuration space regions so in order to
update them to the new pci_remap_cfgspace() mapping interface a new set of
devres interfaces should be implemented so that PCI host controller drivers
can make use of them.

Introduce two new functions in the PCI kernel layer and Devres
documentation:

- devm_pci_remap_cfgspace()
- devm_pci_remap_cfg_resource()

so that PCI host controller drivers can make use of them to map PCI
configuration space regions.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index bf34d5b3a7330e5c26f9c6eebe977ed853804959..e72587fe477d5f1ad958e9810f1e5c46cbccc786 100644 (file)
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -342,8 +342,10 @@ PER-CPU MEM
   devm_free_percpu()
 
 PCI
-  pcim_enable_device() : after success, all PCI ops become managed
-  pcim_pin_device()    : keep PCI device enabled after release
+  devm_pci_remap_cfgspace()    : ioremap PCI configuration space
+  devm_pci_remap_cfg_resource()        : ioremap PCI configuration space resource
+  pcim_enable_device()         : after success, all PCI ops become managed
+  pcim_pin_device()            : keep PCI device enabled after release
 
 PHY
   devm_usb_get_phy()

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bd98674a0419205423322736240c0924932359f5..4129f94538619b1c46372c017e518b80bfdc3c9d 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3401,6 +3401,88 @@ void pci_unmap_iospace(struct resource *res)
 #endif
 }
 
+/**
+ * devm_pci_remap_cfgspace - Managed pci_remap_cfgspace()
+ * @dev: Generic device to remap IO address for
+ * @offset: Resource address to map
+ * @size: Size of map
+ *
+ * Managed pci_remap_cfgspace().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *devm_pci_remap_cfgspace(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 = pci_remap_cfgspace(offset, size);
+       if (addr) {
+               *ptr = addr;
+               devres_add(dev, ptr);
+       } else
+               devres_free(ptr);
+
+       return addr;
+}
+EXPORT_SYMBOL(devm_pci_remap_cfgspace);
+
+/**
+ * devm_pci_remap_cfg_resource - check, request region and ioremap cfg resource
+ * @dev: generic device to handle the resource for
+ * @res: configuration space resource to be handled
+ *
+ * Checks that a resource is a valid memory region, requests the memory
+ * region and ioremaps with pci_remap_cfgspace() API that ensures the
+ * proper PCI configuration space memory attributes are guaranteed.
+ *
+ * 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_pci_remap_cfg_resource(&pdev->dev, res);
+ *     if (IS_ERR(base))
+ *             return PTR_ERR(base);
+ */
+void __iomem *devm_pci_remap_cfg_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_pci_remap_cfgspace(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_pci_remap_cfg_resource);
+
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
        u16 old_cmd, cmd;

diff --git a/include/linux/pci.h b/include/linux/pci.h
index eb3da1a04e6cdc7d3f4efab5532f53abcdf3a28f..70534d66d18a3a66179dee9c6a18c4f949e2c0a8 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1199,6 +1199,11 @@ unsigned long pci_address_to_pio(phys_addr_t addr);
 phys_addr_t pci_pio_to_address(unsigned long pio);
 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
 void pci_unmap_iospace(struct resource *res);
+void __iomem *devm_pci_remap_cfgspace(struct device *dev,
+                                     resource_size_t offset,
+                                     resource_size_t size);
+void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
+                                         struct resource *res);
 
 static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
 {