From 9289db6c60bc9caa285fc6459db9236d92ba94f6 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Thu, 19 Nov 2015 20:26:59 -0700 Subject: dm: pci: Add functions to emulate 8- and 16-bit access Provide a few functions to support using 32-bit access to emulate 8- and 16-bit access. Signed-off-by: Simon Glass Reviewed-by: Stephen Warren Tested-by: Stephen Warren --- include/pci.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'include/pci.h') diff --git a/include/pci.h b/include/pci.h index ed135a5..ec2d104 100644 --- a/include/pci.h +++ b/include/pci.h @@ -1092,6 +1092,37 @@ static inline int pci_read_config_byte(pci_dev_t pcidev, int offset, } /** + * pci_conv_32_to_size() - convert a 32-bit read value to the given size + * + * Some PCI buses must always perform 32-bit reads. The data must then be + * shifted and masked to reflect the required access size and offset. This + * function performs this transformation. + * + * @value: Value to transform (32-bit value read from @offset & ~3) + * @offset: Register offset that was read + * @size: Required size of the result + * @return the value that would have been obtained if the read had been + * performed at the given offset with the correct size + */ +ulong pci_conv_32_to_size(ulong value, uint offset, enum pci_size_t size); + +/** + * pci_conv_size_to_32() - update a 32-bit value to prepare for a write + * + * Some PCI buses must always perform 32-bit writes. To emulate a smaller + * write the old 32-bit data must be read, updated with the required new data + * and written back as a 32-bit value. This function performs the + * transformation from the old value to the new value. + * + * @value: Value to transform (32-bit value read from @offset & ~3) + * @offset: Register offset that should be written + * @size: Required size of the write + * @return the value that should be written as a 32-bit access to @offset & ~3. + */ +ulong pci_conv_size_to_32(ulong old, ulong value, uint offset, + enum pci_size_t size); + +/** * struct dm_pci_emul_ops - PCI device emulator operations */ struct dm_pci_emul_ops { -- cgit v1.1