ARM: asm: types: Introduce DMA_ADDR_T_64BIT
authorLokesh Vutla <lokeshvutla@ti.com>
Thu, 24 Mar 2016 10:32:00 +0000 (16:02 +0530)
committerTom Rini <trini@konsulko.com>
Sun, 27 Mar 2016 13:13:03 +0000 (09:13 -0400)
commit37217f0e0ae92be4a9bba4291d669868d4a26544
tree9294de6ca596bc669c5634238672cdc47992b479
parent1cd29f0abd787eb881523452a77e12dab1cb32c5
ARM: asm: types: Introduce DMA_ADDR_T_64BIT

dma_addr_t holds any valid DMA address. If the DMA API only uses 32-bit
addresses, dma_addr_t need only be 32 bits wide.  Bus addresses, e.g., PCI BARs,
may be wider than 32 bits, but drivers do memory-mapped I/O to ioremapped
kernel virtual addresses, so they don't care about the size of the actual
bus addresses.
Also 32 bit ARM systems with LPAE enabled can use 64bit address space, but
DMA still use 32bit address like in case of DRA7 and Keystone platforms.

This is inspired from the Linux kernel types implementation[1]

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/linux/types.h#n142

Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
arch/arm/Kconfig
arch/arm/include/asm/types.h