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ARM: asm: types: Introduce DMA_ADDR_T_64BIT

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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>
This commit is contained in:
Lokesh Vutla 2016-03-24 16:02:00 +05:30 committed by Tom Rini
parent 1cd29f0abd
commit 37217f0e0a
2 changed files with 19 additions and 2 deletions
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4
arch/arm/Kconfig
View File

@ -7,6 +7,10 @@ config SYS_ARCH
config ARM64
bool
config DMA_ADDR_T_64BIT
bool
default y if ARM64
config HAS_VBAR
bool

17
arch/arm/include/asm/types.h
View File

@ -46,16 +46,29 @@ typedef unsigned long long u64;
#endif /* CONFIG_ARM64 */
#ifdef CONFIG_PHYS_64BIT
typedef unsigned long long dma_addr_t;
typedef unsigned long long phys_addr_t;
typedef unsigned long long phys_size_t;
#else
/* DMA addresses are 32-bits wide */
typedef u32 dma_addr_t;
typedef unsigned long phys_addr_t;
typedef unsigned long phys_size_t;
#endif
/*
* A dma_addr_t can hold any valid DMA address, i.e., any address returned
* by the DMA API.
*
* 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.
*/
#ifdef CONFIG_DMA_ADDR_T_64BIT
typedef unsigned long long dma_addr_t;
#else
typedef u32 dma_addr_t;
#endif
#endif /* __KERNEL__ */
typedef unsigned long resource_size_t;