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Commit 1f94a94f authored by Rob Herring's avatar Rob Herring Committed by Bjorn Helgaas
Browse files

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: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarThierry Reding <treding@nvidia.com>
parent 453c02c2

drivers/pci/access.c

+87 −0
Original line number Diff line number Diff line
@@ -67,6 +67,93 @@ EXPORT_SYMBOL(pci_bus_write_config_byte); 
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

include/linux/pci.h

+11 −0
Original line number Diff line number Diff line
@@ -560,6 +560,7 @@ static inline int pcibios_err_to_errno(int err) 
/* Low-level architecture-dependent routines */



struct pci_ops {

	void __iomem *(*map_bus)(struct pci_bus *bus, unsigned int devfn, int where);

	int (*read)(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val);

	int (*write)(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val);

};
@@ -857,6 +858,16 @@ int pci_bus_write_config_word(struct pci_bus *bus, unsigned int devfn, 
			      int where, u16 val);

int pci_bus_write_config_dword(struct pci_bus *bus, unsigned int devfn,

			       int where, u32 val);



int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn,

			    int where, int size, u32 *val);

int pci_generic_config_write(struct pci_bus *bus, unsigned int devfn,

			    int where, int size, u32 val);

int pci_generic_config_read32(struct pci_bus *bus, unsigned int devfn,

			      int where, int size, u32 *val);

int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn,

			       int where, int size, u32 val);



struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops);



static inline int pci_read_config_byte(const struct pci_dev *dev, int where, u8 *val)