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authorMichael Ellerman <mpe@ellerman.id.au>2020-01-26 22:52:47 +1100
committerRob Herring <robh@kernel.org>2020-01-28 08:26:20 -0600
commitdabf6b36b83a18d57e3d4b9d50544ed040d86255 (patch)
treebe02aaf9a02b27d300c787643a913c1a4ae0270d
parent9243f296916794d86dfcabd802b4dac1ac1448a9 (diff)
of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
There's an OF helper called of_dma_is_coherent(), which checks if a device has a "dma-coherent" property to see if the device is coherent for DMA. But on some platforms devices are coherent by default, and on some platforms it's not possible to update existing device trees to add the "dma-coherent" property. So add a Kconfig symbol to allow arch code to tell of_dma_is_coherent() that devices are coherent by default, regardless of the presence of the property. Select that symbol on powerpc when NOT_COHERENT_CACHE is not set, ie. when the system has a coherent cache. Fixes: 92ea637edea3 ("of: introduce of_dma_is_coherent() helper") Cc: stable@vger.kernel.org # v3.16+ Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de> Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rob Herring <robh@kernel.org>
-rw-r--r--arch/powerpc/Kconfig1
-rw-r--r--drivers/of/Kconfig4
-rw-r--r--drivers/of/address.c6
3 files changed, 10 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1ec34e16ed65..19f5aa8ac9a3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -238,6 +238,7 @@ config PPC
select NEED_DMA_MAP_STATE if PPC64 || NOT_COHERENT_CACHE
select NEED_SG_DMA_LENGTH
select OF
+ select OF_DMA_DEFAULT_COHERENT if !NOT_COHERENT_CACHE
select OF_EARLY_FLATTREE
select OLD_SIGACTION if PPC32
select OLD_SIGSUSPEND
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 37c2ccbefecd..d91618641be6 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -103,4 +103,8 @@ config OF_OVERLAY
config OF_NUMA
bool
+config OF_DMA_DEFAULT_COHERENT
+ # arches should select this if DMA is coherent by default for OF devices
+ bool
+
endif # OF
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 99c1b8058559..e8a39c3ec4d4 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -995,12 +995,16 @@ out:
* @np: device node
*
* It returns true if "dma-coherent" property was found
- * for this device in DT.
+ * for this device in the DT, or if DMA is coherent by
+ * default for OF devices on the current platform.
*/
bool of_dma_is_coherent(struct device_node *np)
{
struct device_node *node = of_node_get(np);
+ if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
+ return true;
+
while (node) {
if (of_property_read_bool(node, "dma-coherent")) {
of_node_put(node);