Retrieve DMA configuration from DT and setup platform device's DMA parameters. The DMA configuration in DT has to be specified using "dma-ranges" and "dma-coherent" properties if supported. We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops using "dma-coherent" device tree properties. The set_arch_dma_coherent_ops macro has to be defined by arch if it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is declared as nop. Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Olof Johansson <olof@xxxxxxxxx> Cc: Grant Likely <grant.likely@xxxxxxxxxx> Cc: Rob Herring <robh+dt@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> --- drivers/of/platform.c | 48 ++++++++++++++++++++++++++++++++++++++++--- include/linux/dma-mapping.h | 7 +++++++ 2 files changed, 52 insertions(+), 3 deletions(-) diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 48de98f..270c0b9 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -187,6 +187,50 @@ struct platform_device *of_device_alloc(struct device_node *np, EXPORT_SYMBOL(of_device_alloc); /** + * of_dma_configure - Setup DMA configuration + * @dev: Device to apply DMA configuration + * + * Try to get devices's DMA configuration from DT and update it + * accordingly. + * + * In case if platform code need to use own special DMA configuration,it + * can use Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event + * to fix up DMA configuration. + */ +static void of_dma_configure(struct device *dev) +{ + u64 dma_addr, paddr, size; + int ret; + + dev->coherent_dma_mask = DMA_BIT_MASK(32); + if (!dev->dma_mask) + dev->dma_mask = &dev->coherent_dma_mask; + + /* + * if dma-coherent property exist, call arch hook to setup + * dma coherent operations. + */ + if (of_dma_is_coherent(dev->of_node)) { + set_arch_dma_coherent_ops(dev); + dev_dbg(dev, "device is dma coherent\n"); + } + + /* + * if dma-ranges property doesn't exist - just return else + * setup the dma offset + */ + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size); + if ((ret == -ENODEV) || (ret < 0)) { + dev_dbg(dev, "no dma range information to setup\n"); + return; + } + + /* DMA ranges found. Calculate and set dma_pfn_offset */ + dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr); + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset); +} + +/** * of_platform_device_create_pdata - Alloc, initialize and register an of_device * @np: pointer to node to create device for * @bus_id: name to assign device @@ -214,9 +258,7 @@ static struct platform_device *of_platform_device_create_pdata( #if defined(CONFIG_MICROBLAZE) dev->archdata.dma_mask = 0xffffffffUL; #endif - dev->dev.coherent_dma_mask = DMA_BIT_MASK(32); - if (!dev->dev.dma_mask) - dev->dev.dma_mask = &dev->dev.coherent_dma_mask; + of_dma_configure(&dev->dev); dev->dev.bus = &platform_bus_type; dev->dev.platform_data = platform_data; diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index fd4aee2..c7d9b1b 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -123,6 +123,13 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask) extern u64 dma_get_required_mask(struct device *dev); +#ifndef set_arch_dma_coherent_ops +static inline int set_arch_dma_coherent_ops(struct device *dev) +{ + return 0; +} +#endif + static inline unsigned int dma_get_max_seg_size(struct device *dev) { return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html