PCI: Add generic config accessors
Many PCI controllers' configuration space accesses are memory-mapped and
vary only in address calculation and access checks. There are 2 main
access methods: a decoded address space such as ECAM or a single address
and data register similar to x86. This implementation can support both
cases as well as be used in cases that need additional pre- or post-access
handling.
Add a new pci_ops member, map_bus, which can do access checks and any
necessary setup. It returns the address to use for the configuration space
access. The access types supported are 32-bit only accesses or correct
byte, word, or dword sized accesses.
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 49dd766..d9b64a1 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -67,6 +67,93 @@
EXPORT_SYMBOL(pci_bus_write_config_word);
EXPORT_SYMBOL(pci_bus_write_config_dword);
+int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 *val)
+{
+ void __iomem *addr;
+
+ addr = bus->ops->map_bus(bus, devfn, where);
+ if (!addr) {
+ *val = ~0;
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ }
+
+ if (size == 1)
+ *val = readb(addr);
+ else if (size == 2)
+ *val = readw(addr);
+ else
+ *val = readl(addr);
+
+ return PCIBIOS_SUCCESSFUL;
+}
+EXPORT_SYMBOL_GPL(pci_generic_config_read);
+
+int pci_generic_config_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ void __iomem *addr;
+
+ addr = bus->ops->map_bus(bus, devfn, where);
+ if (!addr)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ if (size == 1)
+ writeb(val, addr);
+ else if (size == 2)
+ writew(val, addr);
+ else
+ writel(val, addr);
+
+ return PCIBIOS_SUCCESSFUL;
+}
+EXPORT_SYMBOL_GPL(pci_generic_config_write);
+
+int pci_generic_config_read32(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 *val)
+{
+ void __iomem *addr;
+
+ addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
+ if (!addr) {
+ *val = ~0;
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ }
+
+ *val = readl(addr);
+
+ if (size <= 2)
+ *val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);
+
+ return PCIBIOS_SUCCESSFUL;
+}
+EXPORT_SYMBOL_GPL(pci_generic_config_read32);
+
+int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ void __iomem *addr;
+ u32 mask, tmp;
+
+ addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
+ if (!addr)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ if (size == 4) {
+ writel(val, addr);
+ return PCIBIOS_SUCCESSFUL;
+ } else {
+ mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8));
+ }
+
+ tmp = readl(addr) & mask;
+ tmp |= val << ((where & 0x3) * 8);
+ writel(tmp, addr);
+
+ return PCIBIOS_SUCCESSFUL;
+}
+EXPORT_SYMBOL_GPL(pci_generic_config_write32);
+
/**
* pci_bus_set_ops - Set raw operations of pci bus
* @bus: pci bus struct