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authorPaul Burton <paul.burton@imgtec.com>2016-10-05 18:18:16 +0100
committerRalf Baechle <ralf@linux-mips.org>2016-10-06 18:02:01 +0200
commit20d330645cfb8cfecfb82b369e4d3084e429e68a (patch)
treec2e0661dbbb76ad83b2645db4291954bbd19c69d /arch/mips/mm
parentcfa93fb9c2eae805f2c16d72bad04ca49b6e16d2 (diff)
MIPS: Support per-device DMA coherence
On some MIPS systems, a subset of devices may have DMA coherent with CPU caches. For example in systems including a MIPS I/O Coherence Unit (IOCU), some devices may be connected to that IOCU whilst others are not. Prior to this patch, we have a plat_device_is_coherent() function but no implementation which does anything besides return a global true or false, optionally chosen at runtime. For devices such as those described above this is insufficient. Fix this by tracking DMA coherence on a per-device basis with a dma_coherent field in struct dev_archdata. Setting this from arch_setup_dma_ops() takes care of devices which set the dma-coherent property via device tree, and any PCI devices beneath a bridge described in DT, automatically. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14349/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/mm')
-rw-r--r--arch/mips/mm/c-r4k.c4
-rw-r--r--arch/mips/mm/dma-default.c2
2 files changed, 5 insertions, 1 deletions
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 78ac033a0f07..88cfaf81c958 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1935,8 +1935,12 @@ void r4k_cache_init(void)
__local_flush_icache_user_range = local_r4k_flush_icache_user_range;
#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
+# if defined(CONFIG_DMA_PERDEV_COHERENT)
+ if (0) {
+# else
if ((coherentio == IO_COHERENCE_ENABLED) ||
((coherentio == IO_COHERENCE_DEFAULT) && hw_coherentio)) {
+# endif
_dma_cache_wback_inv = (void *)cache_noop;
_dma_cache_wback = (void *)cache_noop;
_dma_cache_inv = (void *)cache_noop;
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 7ae4c55c935a..46d5696c4f27 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -24,7 +24,7 @@
#include <dma-coherence.h>
-#ifdef CONFIG_DMA_MAYBE_COHERENT
+#if defined(CONFIG_DMA_MAYBE_COHERENT) && !defined(CONFIG_DMA_PERDEV_COHERENT)
/* User defined DMA coherency from command line. */
enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT;
EXPORT_SYMBOL_GPL(coherentio);