A recent change affecting the behaviour of phys_to_dma() to actually require the device tree ranges to work unmasked a bug in the Integrator DMA ranges.
The PL110 uses the CMA allocator to obtain coherent allocations from a dedicated 1MB video memory, leading to the following call chain:
drm_gem_cma_create() dma_alloc_attrs() dma_alloc_from_dev_coherent() __dma_alloc_from_coherent() dma_get_device_base() phys_to_dma() translate_phys_to_dma()
phys_to_dma() by way of translate_phys_to_dma() will nowadays not provide 1:1 mappings unless the ranges are properly defined in the device tree and reflected into the dev->dma_range_map.
There is a bug in the device trees because the DMA ranges are incorrectly specified, and the patch uncovers this bug.
Solution:
- Fix the LB (logic bus) ranges to be 1-to-1 like they should have always been. - Provide a 1:1 dma-ranges attribute to the PL110. - Mark the PL110 display controller as DMA coherent.
This makes the DMA ranges work right and makes the PL110 framebuffer work again.
Cc: Christoph Hellwig hch@lst.de Cc: Arnd Bergmann arnd@arndb.de Cc: stable@vger.kernel.org Fixes: af6f23b88e95 ("ARM/dma-mapping: use the generic versions of dma_to_phys/phys_to_dma by default") Signed-off-by: Linus Walleij linus.walleij@linaro.org --- ChangeLog v1->v2: - Drom dma-coherent, this device is not cache coherent whatsoever, just my misunderstanding. - Change Fixes: tag to a hopefully more appropriate one. - Update commit message.
SoC folks: please apply this directly for fixes if it seems to be the right thing to do. --- arch/arm/boot/dts/integratorap-im-pd1.dts | 1 + arch/arm/boot/dts/integratorap.dts | 8 ++++---- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm/boot/dts/integratorap-im-pd1.dts b/arch/arm/boot/dts/integratorap-im-pd1.dts index 31724753d3f3..14fab499f0fa 100644 --- a/arch/arm/boot/dts/integratorap-im-pd1.dts +++ b/arch/arm/boot/dts/integratorap-im-pd1.dts @@ -248,6 +248,7 @@ display@1000000 { /* 640x480 16bpp @ 25.175MHz is 36827428 bytes/s */ max-memory-bandwidth = <40000000>; memory-region = <&impd1_ram>; + dma-ranges;
port@0 { #address-cells = <1>; diff --git a/arch/arm/boot/dts/integratorap.dts b/arch/arm/boot/dts/integratorap.dts index c983435ed492..9148287fa0a9 100644 --- a/arch/arm/boot/dts/integratorap.dts +++ b/arch/arm/boot/dts/integratorap.dts @@ -262,7 +262,7 @@ bus@c0000000 { lm0: bus@c0000000 { compatible = "simple-bus"; ranges = <0x00000000 0xc0000000 0x10000000>; - dma-ranges = <0x00000000 0x80000000 0x10000000>; + dma-ranges = <0x00000000 0xc0000000 0x10000000>; reg = <0xc0000000 0x10000000>; #address-cells = <1>; #size-cells = <1>; @@ -270,7 +270,7 @@ lm0: bus@c0000000 { lm1: bus@d0000000 { compatible = "simple-bus"; ranges = <0x00000000 0xd0000000 0x10000000>; - dma-ranges = <0x00000000 0x80000000 0x10000000>; + dma-ranges = <0x00000000 0xd0000000 0x10000000>; reg = <0xd0000000 0x10000000>; #address-cells = <1>; #size-cells = <1>; @@ -278,7 +278,7 @@ lm1: bus@d0000000 { lm2: bus@e0000000 { compatible = "simple-bus"; ranges = <0x00000000 0xe0000000 0x10000000>; - dma-ranges = <0x00000000 0x80000000 0x10000000>; + dma-ranges = <0x00000000 0xe0000000 0x10000000>; reg = <0xe0000000 0x10000000>; #address-cells = <1>; #size-cells = <1>; @@ -286,7 +286,7 @@ lm2: bus@e0000000 { lm3: bus@f0000000 { compatible = "simple-bus"; ranges = <0x00000000 0xf0000000 0x10000000>; - dma-ranges = <0x00000000 0x80000000 0x10000000>; + dma-ranges = <0x00000000 0xf0000000 0x10000000>; reg = <0xf0000000 0x10000000>; #address-cells = <1>; #size-cells = <1>;