On Thu, Feb 27, 2014 at 3:17 PM, Santosh Shilimkar
<santosh.shilimkar@xxxxxx> wrote:
> From: Grygorii Strashko <grygorii.strashko@xxxxxx>
>
> This patch introduces ARM specific function arm_dt_dma_configure()
> which intended to 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 "dam-coherent" properties if supported. The DMA configuration applied
s/dam/dma/
> by arm_dt_dma_configure() as following:
> - call of_get_dma_range() and get supported DMA range info
> (dma_addr, cpu_addr, dma_size);
> - if "not found" then fill dma_mask as DMA_BIT_MASK(32)
> (this is default behaviour);
> - if "failed" then clean up dma_mask (DMA not supported)
> - if ok then update devices DMA configuration:
> set dma_mask to (dma_addr + dma_size - 1)
> set dma_pfn_offset to PFN_DOWN(cpu_addr - dma_addr)
>
> 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>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> ---
> arch/arm/include/asm/prom.h | 3 +++
> arch/arm/kernel/devtree.c | 61 +++++++++++++++++++++++++++++++++++++++++++
> drivers/of/platform.c | 5 +++-
> include/linux/of.h | 2 +-
> 4 files changed, 69 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
> index b681575..1acb732 100644
> --- a/arch/arm/include/asm/prom.h
> +++ b/arch/arm/include/asm/prom.h
> @@ -11,11 +11,13 @@
> #ifndef __ASMARM_PROM_H
> #define __ASMARM_PROM_H
>
> +struct device;
> #ifdef CONFIG_OF
>
> extern const struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
> extern void arm_dt_memblock_reserve(void);
> extern void __init arm_dt_init_cpu_maps(void);
> +extern void arm_dt_dma_configure(struct device *dev);
>
> #else /* CONFIG_OF */
>
> @@ -26,6 +28,7 @@ static inline const struct machine_desc *setup_machine_fdt(unsigned int dt_phys)
>
> static inline void arm_dt_memblock_reserve(void) { }
> static inline void arm_dt_init_cpu_maps(void) { }
> +static inline void arm_dt_dma_configure(struct device *dev) { }
>
> #endif /* CONFIG_OF */
> #endif /* ASMARM_PROM_H */
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index f751714..926b5dd 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -18,6 +18,9 @@
> #include <linux/of_fdt.h>
> #include <linux/of_irq.h>
> #include <linux/of_platform.h>
> +#include <linux/of_dma.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
>
> #include <asm/cputype.h>
> #include <asm/setup.h>
> @@ -235,3 +238,61 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
>
> return mdesc;
> }
> +
> +void arm_dt_dma_configure(struct device *dev)
The implementation may be ARM specific, but the need for the function
should not be.
> +{
> + dma_addr_t dma_addr;
> + phys_addr_t paddr, size;
> + dma_addr_t dma_mask;
> + int ret;
> +
> + /*
> + * if dma-ranges property doesn't exist - use 32 bits DMA mask
> + * by default and don't set skip archdata.dma_pfn_offset
> + */
> + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
> + if (ret == -ENODEV) {
> + dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + if (!dev->dma_mask)
> + dev->dma_mask = &dev->coherent_dma_mask;
> + return;
> + }
> +
> + /* if failed - disable DMA for device */
> + if (ret < 0) {
> + dev_err(dev, "failed to configure DMA\n");
> + return;
> + }
> +
> + /* DMA ranges found. Calculate and set dma_pfn_offset */
> + dev->archdata.dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
> +
> + /* Configure DMA mask */
> + dev->dma_mask = kmalloc(sizeof(*dev->dma_mask), GFP_KERNEL);
I don't believe that any ARM platform needs dma_mask to be different
from coherent_dma_mask. I traced the history to when 2 masks were
defined and this was my conclusion. Russell has also recently stated
the same:
https://lkml.org/lkml/2013/8/9/205
> + if (!dev->dma_mask)
> + return;
> +
> + dma_mask = dma_addr + size - 1;
> +
> + ret = arm_dma_set_mask(dev, dma_mask);
> + if (ret < 0) {
> + dev_err(dev, "failed to set DMA mask %#08x\n", dma_mask);
> + kfree(dev->dma_mask);
> + dev->dma_mask = NULL;
> + return;
> + }
> +
> + dev_dbg(dev, "dma_pfn_offset(%#08lx) dma_mask(%#016llx)\n",
> + dev->archdata.dma_pfn_offset, *dev->dma_mask);
> +
> + if (of_dma_is_coherent(dev->of_node)) {
> + set_dma_ops(dev, &arm_coherent_dma_ops);
All but this line could be in a common function. So make an arm
version of the function that calls the common function and then does
this. Or perhaps a per arch "get dma ops" function is all that is
needed.
> + dev_dbg(dev, "device is dma coherent\n");
> + }
> +
> + ret = dma_set_coherent_mask(dev, dma_mask);
> + if (ret < 0) {
> + dev_err(dev, "failed to set coherent DMA mask %#08x\n",
> + dma_mask);
> + }
> +}
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 404d1da..97d5533 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -213,10 +213,13 @@ static struct platform_device *of_platform_device_create_pdata(
>
> #if defined(CONFIG_MICROBLAZE)
> dev->archdata.dma_mask = 0xffffffffUL;
This should be moved into a microblaze specific version of the function.
> -#endif
> +#elif defined(CONFIG_ARM_LPAE)
> + arm_dt_dma_configure(&dev->dev);
> +#else
> dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> if (!dev->dev.dma_mask)
> dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
> +#endif
> dev->dev.bus = &platform_bus_type;
> dev->dev.platform_data = platform_data;
>
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 70c64ba..a321058 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -136,7 +136,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
> return of_read_number(cell, size);
> }
>
> -#if defined(CONFIG_SPARC)
> +#if defined(CONFIG_SPARC) || defined(CONFIG_ARM_LPAE)
> #include <asm/prom.h>
No. The idea here is to get rid of including prom.h.
Rob
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