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authorHeiko Stuebner <heiko@sntech.de>2022-07-07 02:15:33 +0300
committerPalmer Dabbelt <palmer@rivosinc.com>2022-07-29 01:30:20 +0300
commit12b827758f51d4b614a677dd453b0e854e46aa65 (patch)
treeac1a5426c5da997208039af6bf9859f96fef889f /drivers/of
parent73448ae6204faa636292ae0d7ba8b2f6eb48179d (diff)
downloadlinux-12b827758f51d4b614a677dd453b0e854e46aa65.tar.xz
of: also handle dma-noncoherent in of_dma_is_coherent()
of_dma_is_coherent() currently expects the architecture to be non-coherent and some devices being coherent getting marked as such with the dma-coherent devicetree property. For PowerPC CONFIG_OF_DMA_DEFAULT_COHERENT was added which currently makes of_dma_is_coherent() always return true but doesn't handle the case of the architecture being coherent but some devices not. So modify the function to also check for dma-noncoherent and set a suitable default return value. If CONFIG_OF_DMA_DEFAULT_COHERENT is set the value starts with true and finding dma-noncoherent will set it to false and without CONFIG_OF_DMA_DEFAULT_COHERENT, the behaviour is reversed. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Rob Herring <robh@kernel.org> Reviewed-by: Guo Ren <guoren@kernel.org> Signed-off-by: Heiko Stuebner <heiko@sntech.de> Link: https://lore.kernel.org/r/20220706231536.2041855-2-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'drivers/of')
-rw-r--r--drivers/of/address.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 94f017d808c4..96f0a12e507c 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -1045,26 +1045,29 @@ phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
*
* It returns true if "dma-coherent" property was found
* for this device in the DT, or if DMA is coherent by
- * default for OF devices on the current platform.
+ * default for OF devices on the current platform and no
+ * "dma-noncoherent" property was found for this device.
*/
bool of_dma_is_coherent(struct device_node *np)
{
struct device_node *node;
-
- if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
- return true;
+ bool is_coherent = IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT);
node = of_node_get(np);
while (node) {
if (of_property_read_bool(node, "dma-coherent")) {
- of_node_put(node);
- return true;
+ is_coherent = true;
+ break;
+ }
+ if (of_property_read_bool(node, "dma-noncoherent")) {
+ is_coherent = false;
+ break;
}
node = of_get_next_dma_parent(node);
}
of_node_put(node);
- return false;
+ return is_coherent;
}
EXPORT_SYMBOL_GPL(of_dma_is_coherent);