The of_dma_is_coherent() helper parses the given DT device node to see if the "dma-coherent" property is supported and returns true or false accordingly.
If the arch is always coherent or always noncoherent, then the default DMA ops has to be specified accordingly. Cc: Greg Kroah-Hartman <[email protected]> Cc: Russell King <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Olof Johansson <[email protected]> Cc: Grant Likely <[email protected]> Cc: Rob Herring <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Linus Walleij <[email protected]> Signed-off-by: Santosh Shilimkar <[email protected]> Signed-off-by: Grygorii Strashko <[email protected]> --- drivers/of/platform.c | 23 +++++++++++++++++++++++ include/linux/of_platform.h | 7 +++++++ 2 files changed, 30 insertions(+) diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 2265a55..573db15 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -570,4 +570,27 @@ out: return ret; } EXPORT_SYMBOL_GPL(of_dma_get_range); + +/** + * of_dma_is_coherent - Check if device is coherent + * @np: device node + * + * It returns true if "dma-coherent" property was found + * for this device in DT. + */ +bool of_dma_is_coherent(struct device_node *np) +{ + struct device_node *node = of_node_get(np); + + while (node) { + if (of_property_read_bool(node, "dma-coherent")) { + of_node_put(node); + return true; + } + node = of_get_next_parent(node); + } + of_node_put(node); + return false; +} +EXPORT_SYMBOL_GPL(of_dma_is_coherent); #endif /* CONFIG_OF_ADDRESS */ diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h index ba7d3dc..dc52931 100644 --- a/include/linux/of_platform.h +++ b/include/linux/of_platform.h @@ -74,6 +74,8 @@ extern int of_platform_populate(struct device_node *root, struct device *parent); extern int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, phys_addr_t *paddr, phys_addr_t *size); +extern bool of_dma_is_coherent(struct device_node *np); + #else static inline int of_platform_populate(struct device_node *root, const struct of_device_id *matches, @@ -88,6 +90,11 @@ static inline int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, { return -ENODEV; } + +static inline bool of_dma_is_coherent(struct device_node *np) +{ + return false; +} #endif #endif /* _LINUX_OF_PLATFORM_H */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
