LoongArch maintains cache coherency in hardware, but its WUC attribute
(Weak-ordered UnCached, which is similar to WC) is out of the scope of
cache coherency machanism. This means WUC can only used for write-only
memory regions.
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Reviewed-by: WANG Xuerui <[email protected]>
Reviewed-by: Jiaxun Yang <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>
Rename struct dma_buf_map to struct iosys_map and corresponding APIs.
Over time dma-buf-map grew up to more functionality than the one used by
dma-buf: in fact it's just a shim layer to abstract system memory, that
can be accessed via regular load and store, from IO memory that needs to
be acessed via arch helpers.
The idea is to extend this API so it can fulfill other needs, internal
to a single driver. Example: in the i915 driver it's desired to share
the implementation for integrated graphics, which uses mostly system
memory, with discrete graphics, which may need to access IO memory.
The conversion was mostly done with the following semantic patch:
@r1@
@@
- struct dma_buf_map
+ struct iosys_map
@r2@
@@
(
- DMA_BUF_MAP_INIT_VADDR
+ IOSYS_MAP_INIT_VADDR
|
- dma_buf_map_set_vaddr
+ iosys_map_set_vaddr
|
- dma_buf_map_set_vaddr_iomem
+ iosys_map_set_vaddr_iomem
|
- dma_buf_map_is_equal
+ iosys_map_is_equal
|
- dma_buf_map_is_null
+ iosys_map_is_null
|
- dma_buf_map_is_set
+ iosys_map_is_set
|
- dma_buf_map_clear
+ iosys_map_clear
|
- dma_buf_map_memcpy_to
+ iosys_map_memcpy_to
|
- dma_buf_map_incr
+ iosys_map_incr
)
@@
@@
- #include <linux/dma-buf-map.h>
+ #include <linux/iosys-map.h>
Then some files had their includes adjusted and some comments were
update to remove mentions to dma-buf-map.
Since this is not specific to dma-buf anymore, move the documentation to
the "Bus-Independent Device Accesses" section.
v2:
- Squash patches
v3:
- Fix wrong removal of dma-buf.h from MAINTAINERS
- Move documentation from dma-buf.rst to device-io.rst
v4:
- Change documentation title and level
Signed-off-by: Lucas De Marchi <[email protected]>
Acked-by: Christian König <[email protected]>
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Thomas Zimmermann <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
CPU_LOONGSON2 -> CPU_LOONGSON2EF
CPU_LOONGSON3 -> CPU_LOONGSON64
As newer loongson-2 products (2G/2H/2K1000) can share kernel
implementation with loongson-3 while 2E/2F are less similar with
other LOONGSON64 products.
Signed-off-by: Jiaxun Yang <[email protected]>
Signed-off-by: Paul Burton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
The DRM driver stack is designed to work with cache coherent devices
only, but permits an optimization to be enabled in some cases, where
for some buffers, both the CPU and the GPU use uncached mappings,
removing the need for DMA snooping and allocation in the CPU caches.
The use of uncached GPU mappings relies on the correct implementation
of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU
will use cached mappings nonetheless. On x86 platforms, this does not
seem to matter, as uncached CPU mappings will snoop the caches in any
case. However, on ARM and arm64, enabling this optimization on a
platform where NoSnoop is ignored results in loss of coherency, which
breaks correct operation of the device. Since we have no way of
detecting whether NoSnoop works or not, just disable this
optimization entirely for ARM and arm64.
Cc: Christian Koenig <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: David Zhou <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Junwei Zhang <[email protected]>
Cc: Michel Daenzer <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Sean Paul <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: amd-gfx list <[email protected]>
Cc: dri-devel <[email protected]>
Reported-by: Carsten Haitzler <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Christian König <[email protected]>
Reviewed-by: Alex Deucher <[email protected]>
Link: https://patchwork.kernel.org/patch/10778815/
Signed-off-by: Christian König <[email protected]>
Huacai Chen