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>
diff --git a/arch/mips/include/asm/device.h b/arch/mips/include/asm/device.h
index c94fafb..21c2082 100644
--- a/arch/mips/include/asm/device.h
+++ b/arch/mips/include/asm/device.h
@@ -11,6 +11,11 @@
struct dev_archdata {
/* DMA operations on that device */
struct dma_map_ops *dma_ops;
+
+#ifdef CONFIG_DMA_PERDEV_COHERENT
+ /* Non-zero if DMA is coherent with CPU caches */
+ bool dma_coherent;
+#endif
};
struct pdev_archdata {