diff options
| author | Paul Burton <paul.burton@imgtec.com> | 2016-10-05 19:18:16 +0200 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2016-10-06 18:02:01 +0200 |
| commit | 20d330645cfb8cfecfb82b369e4d3084e429e68a (patch) | |
| tree | c2e0661dbbb76ad83b2645db4291954bbd19c69d /arch/mips/include/asm/dma-coherence.h | |
| parent | MIPS: dma-default: Don't check hw_coherentio if device is non-coherent (diff) | |
| download | linux-20d330645cfb8cfecfb82b369e4d3084e429e68a.tar.xz linux-20d330645cfb8cfecfb82b369e4d3084e429e68a.zip | |
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/include/asm/dma-coherence.h')
| -rw-r--r-- | arch/mips/include/asm/dma-coherence.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/mips/include/asm/dma-coherence.h b/arch/mips/include/asm/dma-coherence.h index 4fbce79fb57f..72d0eab02afc 100644 --- a/arch/mips/include/asm/dma-coherence.h +++ b/arch/mips/include/asm/dma-coherence.h @@ -15,7 +15,9 @@ enum coherent_io_user_state { IO_COHERENCE_DISABLED, }; -#ifdef CONFIG_DMA_MAYBE_COHERENT +#if defined(CONFIG_DMA_PERDEV_COHERENT) +/* Don't provide (hw_)coherentio to avoid misuse */ +#elif defined(CONFIG_DMA_MAYBE_COHERENT) extern enum coherent_io_user_state coherentio; extern int hw_coherentio; #else |