On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar <santosh.shilimkar@xxxxxx> wrote: > 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 | 43 +++++++++++++++++++++++++++++++++++++++++++ > include/linux/dma-mapping.h | 7 +++++++ > 2 files changed, 50 insertions(+) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 573db15..7e4a43b 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -187,6 +187,47 @@ 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) > +{ > + dma_addr_t dma_addr; > + phys_addr_t paddr, size; A problem with using dma_addr_t and phys_addr_t is that they normally depend on CONFIG_LPAE, but the address cell sizes are independent of that. That is why all the memory related functions stick with u64. I think you would have issues here if you have a platform with sizes of 4GB or more. You need to properly cap the sizes and addresses. > + int ret; > + > + /* > + * 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 < 0) { Perhaps an error is not the right return for the default case. The default should probably be dma_addr and paddr equal to 0 and size 4GB. > + dev_dbg(dev, "no dma range information to setup\n"); > + return; > + } else { You don't need the else here. > + /* 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 > @@ -217,6 +258,8 @@ static struct platform_device *of_platform_device_create_pdata( > dev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > if (!dev->dev.dma_mask) > dev->dev.dma_mask = &dev->dev.coherent_dma_mask; You should move all DMA related setup into of_dma_configure. > + > + 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