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| author | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-26 22:52:47 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-14 16:29:56 -0500 |
| commit | 809f1863e83e31e3c3cc259fd2cc1470fc772aa5 (patch) | |
| tree | 5de106aa6ca06d91fb6b2c02aa5800b85c17f923 /drivers/of | |
| parent | 4c0e18da4a089a278b025637bfdbf0ff759a742f (diff) | |
| download | linux-stable-809f1863e83e31e3c3cc259fd2cc1470fc772aa5.tar.gz linux-stable-809f1863e83e31e3c3cc259fd2cc1470fc772aa5.tar.bz2 linux-stable-809f1863e83e31e3c3cc259fd2cc1470fc772aa5.zip | |
of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
commit dabf6b36b83a18d57e3d4b9d50544ed040d86255 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/of/address.c | 6 |
2 files changed, 9 insertions, 1 deletions
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index e2a48415d969..4ba54ffb3a4b 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -112,4 +112,8 @@ config OF_OVERLAY While this option is selected automatically when needed, you can enable it manually to improve device tree unit test coverage. +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 4fe5fe21cd49..b3bf8762f4e8 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -1009,12 +1009,16 @@ EXPORT_SYMBOL_GPL(of_dma_get_range); * @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); |