[PATCH 2/4] powerpc/64: Honor swiotlb limit in coherent allocations
From: Scott Wood <hidden>
Date: 2014-08-08 23:41:11
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
FSL PCI cannot directly address the whole lower 4 GiB due to conflicts with PCICSRBAR and outbound windows, and thus max_direct_dma_addr is less than 4GiB. Honor that limit in dma_direct_alloc_coherent(). Note that setting the DMA mask to 31 bits is not an option, since many PCI drivers would fail if we reject 32-bit DMA in dma_supported(), and we have no control over the setting of coherent_dma_mask if dma_supported() returns true. Signed-off-by: Scott Wood <redacted> Cc: Shaohui Xie <redacted> --- arch/powerpc/kernel/dma.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index dfd99ef..a7b0156 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c@@ -15,6 +15,7 @@ #include <asm/vio.h> #include <asm/bug.h> #include <asm/machdep.h> +#include <asm/swiotlb.h> /* * Generic direct DMA implementation
@@ -25,6 +26,18 @@ * default the offset is PCI_DRAM_OFFSET. */ +static u64 __maybe_unused get_pfn_limit(struct device *dev) +{ + u64 pfn = (dev->coherent_dma_mask >> PAGE_SHIFT) + 1; + struct dev_archdata __maybe_unused *sd = &dev->archdata; + +#ifdef CONFIG_SWIOTLB + if (sd->max_direct_dma_addr && sd->dma_ops == &swiotlb_dma_ops) + pfn = min_t(u64, pfn, sd->max_direct_dma_addr >> PAGE_SHIFT); +#endif + + return pfn; +} void *dma_direct_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag,
@@ -40,7 +53,7 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size, #else struct page *page; int node = dev_to_node(dev); - u64 pfn = (dev->coherent_dma_mask >> PAGE_SHIFT) + 1; + u64 pfn = get_pfn_limit(dev); int zone; zone = dma_pfn_limit_to_zone(pfn);
--
1.9.1