From 12b827758f51d4b614a677dd453b0e854e46aa65 Mon Sep 17 00:00:00 2001 From: Heiko Stuebner Date: Thu, 7 Jul 2022 01:15:33 +0200 Subject: 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 Reviewed-by: Rob Herring Reviewed-by: Guo Ren Signed-off-by: Heiko Stuebner Link: https://lore.kernel.org/r/20220706231536.2041855-2-heiko@sntech.de Signed-off-by: Palmer Dabbelt --- drivers/of/address.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'drivers/of') 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); -- cgit v1.2.3