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| author | Paul Burton <paul.burton@imgtec.com> | 2016-10-05 18:18:16 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2016-10-06 18:02:01 +0200 |
| commit | 20d330645cfb8cfecfb82b369e4d3084e429e68a (patch) | |
| tree | c2e0661dbbb76ad83b2645db4291954bbd19c69d /arch/mips/mm | |
| parent | cfa93fb9c2eae805f2c16d72bad04ca49b6e16d2 (diff) | |
| download | linux-20d330645cfb8cfecfb82b369e4d3084e429e68a.tar.gz linux-20d330645cfb8cfecfb82b369e4d3084e429e68a.tar.xz | |
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.c | 4 | ||||
| -rw-r--r-- | arch/mips/mm/dma-default.c | 2 |
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); |