2013-08-01 20:51:43

by Andreas Herrmann

Subject: [PATCH] ARM: dma-mapping: highbank: Restrict DMA to 32-bit addresses

Some devices on Calxeda ECX-2000 are restricted to 32-bit DMA. Thus
the platform needs to set dma_zone_size, otherwise dma-mapping code is
complaining, e.g.

calxedaxgmac fff50000.ethernet: coherent DMA mask 0xffffffff is smaller than system
GFP_DMA mask 0xffffffffffffffff

Same is true for sata_highbank. For the latter dma_coherent_mask could
be increased but due to the lack of DMA32 zone we need to adapt
arm_dma_limit in general.

Signed-off-by: Andreas Herrmann <[email protected]>
---
arch/arm/mach-highbank/Kconfig | 1 +
arch/arm/mach-highbank/highbank.c | 3 +++
arch/arm/mm/dma-mapping.c | 4 ++++
3 files changed, 8 insertions(+)

diff --git a/arch/arm/mach-highbank/Kconfig b/arch/arm/mach-highbank/Kconfig
index cd9fcb1..efe4961 100644
--- a/arch/arm/mach-highbank/Kconfig
+++ b/arch/arm/mach-highbank/Kconfig
@@ -18,3 +18,4 @@ config ARCH_HIGHBANK
select PL320_MBOX
select SPARSE_IRQ
select USE_OF
+ select ZONE_DMA if ARM_LPAE
diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index 8881579..31b26de 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -176,6 +176,9 @@ static const char *highbank_match[] __initconst = {
};

DT_MACHINE_START(HIGHBANK, "Highbank")
+#ifdef CONFIG_ZONE_DMA
+ .dma_zone_size = DMA_BIT_MASK(32),
+#endif
.smp = smp_ops(highbank_smp_ops),
.init_irq = highbank_init_irq,
.init_time = highbank_timer_init,
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 7f9b179..f404dfc 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -651,7 +651,11 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (!mask)
return NULL;

+#ifdef CONFIG_ARM_LPAE
+ if (mask <= 0xffffffffULL)
+#else
if (mask < 0xffffffffULL)
+#endif
gfp |= GFP_DMA;

/*
--
1.7.9.5

2013-08-01 20:46:44

by Russell King - ARM Linux

Subject: Re: [PATCH] ARM: dma-mapping: highbank: Restrict DMA to 32-bit addresses

On Thu, Aug 01, 2013 at 10:40:47PM +0200, Andreas Herrmann wrote:
>
> Some devices on Calxeda ECX-2000 are restricted to 32-bit DMA. Thus
> the platform needs to set dma_zone_size, otherwise dma-mapping code is
> complaining, e.g.
>
> calxedaxgmac fff50000.ethernet: coherent DMA mask 0xffffffff is smaller than system
> GFP_DMA mask 0xffffffffffffffff
>
> Same is true for sata_highbank. For the latter dma_coherent_mask could
> be increased but due to the lack of DMA32 zone we need to adapt
> arm_dma_limit in general.

Please wait until I post my dma mask patches. Thanks.