Re: [PATCH v3 4/7] of: configure the platform device dma parameters

Rob Herring
2014-05-02T00:49:09Z

On Thu, Apr 24, 2014 at 10:30 AM, Santosh Shilimkar
<santosh.shilimkar@ti.com> 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.
>

[...]

> + /*
> + * 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)) {

The 1st condition is redundant.

> + 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

This is also dma related setup. Please move *all* dma setup into the function.

> - 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
>