Hi Lokesh, > > > On Thursday 24 March 2016 02:11 PM, Lukasz Majewski wrote: > > Hi Lokesh, > > > >> 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. > > > > I've already stumbled upon this issue... > > > >> > >> 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 > >> > >> Signed-off-by: Lokesh Vutla <[email protected]> > >> --- > >> arch/arm/include/asm/types.h | 17 +++++++++++++++-- > >> 1 file changed, 15 insertions(+), 2 deletions(-) > >> > >> diff --git a/arch/arm/include/asm/types.h > >> b/arch/arm/include/asm/types.h index 388058e..d108915 100644 > >> --- a/arch/arm/include/asm/types.h > >> +++ b/arch/arm/include/asm/types.h > >> @@ -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 > > > > Generally this approach is correct, but please pay attention to the > > CONFIG_PHYS_64BIT. > > > > The actual size of dma_addr_t (64 or 32 bits) is decided by > > defining or undefining CONFIG_PHYS_64BIT at > > arch/arm/include/asm/config.h. This is based on the status of > > CONFIG_ARM64. > > > > To avoid regression we need to take into account status of > > CONFIG_ARM64 to be sure that CONFIG_DMA_ADDR_T_64BIT is set on > > ARM64 systems. > > Good point. So we need to select DMA_ADDR_T_64BIT by default for all > ARM64 systems. I guess the below diff should be sufficient along with > the $subject patch? > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index e5f57ef..550ecde 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -7,6 +7,10 @@ config SYS_ARCH > config ARM64 > bool > > +config DMA_ADDR_T_64BIT > + bool > + default y if ARM64 > + > config HAS_VBAR > bool > > > Thanks and regards, > Lokesh >
Acked-by: Lukasz Majewski <[email protected]> > > > >> +typedef unsigned long long dma_addr_t; > >> +#else > >> +typedef u32 dma_addr_t; > >> +#endif > >> + > >> #endif /* __KERNEL__ */ > >> > >> typedef unsigned long resource_size_t; > > > > > > > -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
