commit ab6494f0c96f ("nommu: Add noMMU support to the DMA API") have
add CONFIG_MMU compilation flag but that prohibit to use dma_mmap_wc()
when the platform doesn't have MMU.
This patch call vm_iomap_memory() in noMMU case to test if addresses
are correct and set wma->vm_flags rather than all return an error.
Signed-off-by: Benjamin Gaignard <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: [email protected]
---
arch/arm/mm/dma-mapping.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index ab4f745..230875e 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -868,6 +868,9 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
vma->vm_end - vma->vm_start,
vma->vm_page_prot);
}
+#else
+ ret = vm_iomap_memory(vma, vma->vm_start,
+ (vma->vm_end - vma->vm_start));
#endif /* CONFIG_MMU */
return ret;
--
1.9.1
+ Vladimir
2016-12-01 14:48 GMT+01:00 Benjamin Gaignard <[email protected]>:
> commit ab6494f0c96f ("nommu: Add noMMU support to the DMA API") have
> add CONFIG_MMU compilation flag but that prohibit to use dma_mmap_wc()
> when the platform doesn't have MMU.
>
> This patch call vm_iomap_memory() in noMMU case to test if addresses
> are correct and set wma->vm_flags rather than all return an error.
>
> Signed-off-by: Benjamin Gaignard <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: [email protected]
> ---
> arch/arm/mm/dma-mapping.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index ab4f745..230875e 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -868,6 +868,9 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> vma->vm_end - vma->vm_start,
> vma->vm_page_prot);
> }
> +#else
> + ret = vm_iomap_memory(vma, vma->vm_start,
> + (vma->vm_end - vma->vm_start));
> #endif /* CONFIG_MMU */
>
> return ret;
> --
> 1.9.1
>
On 09/12/16 15:27, Benjamin Gaignard wrote:
> + Vladimir
I'm not in DMA, but I can see that with your patch it deviates from
dma_common_mmap(), can you give more context, please?
Cheers
Vladimir
>
> 2016-12-01 14:48 GMT+01:00 Benjamin Gaignard <[email protected]>:
>> commit ab6494f0c96f ("nommu: Add noMMU support to the DMA API") have
>> add CONFIG_MMU compilation flag but that prohibit to use dma_mmap_wc()
>> when the platform doesn't have MMU.
>>
>> This patch call vm_iomap_memory() in noMMU case to test if addresses
>> are correct and set wma->vm_flags rather than all return an error.
>>
>> Signed-off-by: Benjamin Gaignard <[email protected]>
>> Cc: Catalin Marinas <[email protected]>
>> Cc: [email protected]
>> ---
>> arch/arm/mm/dma-mapping.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>> index ab4f745..230875e 100644
>> --- a/arch/arm/mm/dma-mapping.c
>> +++ b/arch/arm/mm/dma-mapping.c
>> @@ -868,6 +868,9 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
>> vma->vm_end - vma->vm_start,
>> vma->vm_page_prot);
>> }
>> +#else
>> + ret = vm_iomap_memory(vma, vma->vm_start,
>> + (vma->vm_end - vma->vm_start));
>> #endif /* CONFIG_MMU */
>>
>> return ret;
>> --
>> 1.9.1
>>
>
2016-12-09 16:36 GMT+01:00 Vladimir Murzin <[email protected]>:
> On 09/12/16 15:27, Benjamin Gaignard wrote:
>> + Vladimir
>
> I'm not in DMA, but I can see that with your patch it deviates from
> dma_common_mmap(), can you give more context, please?
I'm working on ARM platform with MMU (stm32f4) to enable display driver.
Framebuffer is allocated with dma_alloc_wc() and when userland try to mmap
drm/kms fraemwork calls dma_mmap_wc().
All this is in drivers/gpu/drm/drm_gem_cma_helper.c
dma_mmap_wc() call failed because __arm_dma_mmap() always return an
error if CONFIG_MMU
isn't defined.
That what I try to solve with this patch.
> Cheers
> Vladimir
>
>>
>> 2016-12-01 14:48 GMT+01:00 Benjamin Gaignard <[email protected]>:
>>> commit ab6494f0c96f ("nommu: Add noMMU support to the DMA API") have
>>> add CONFIG_MMU compilation flag but that prohibit to use dma_mmap_wc()
>>> when the platform doesn't have MMU.
>>>
>>> This patch call vm_iomap_memory() in noMMU case to test if addresses
>>> are correct and set wma->vm_flags rather than all return an error.
>>>
>>> Signed-off-by: Benjamin Gaignard <[email protected]>
>>> Cc: Catalin Marinas <[email protected]>
>>> Cc: [email protected]
>>> ---
>>> arch/arm/mm/dma-mapping.c | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>>> index ab4f745..230875e 100644
>>> --- a/arch/arm/mm/dma-mapping.c
>>> +++ b/arch/arm/mm/dma-mapping.c
>>> @@ -868,6 +868,9 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
>>> vma->vm_end - vma->vm_start,
>>> vma->vm_page_prot);
>>> }
>>> +#else
>>> + ret = vm_iomap_memory(vma, vma->vm_start,
>>> + (vma->vm_end - vma->vm_start));
>>> #endif /* CONFIG_MMU */
>>>
>>> return ret;
>>> --
>>> 1.9.1
>>>
>>
>
--
Benjamin Gaignard
Graphic Study Group
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
On Thu, Dec 01, 2016 at 02:48:00PM +0100, Benjamin Gaignard wrote:
> commit ab6494f0c96f ("nommu: Add noMMU support to the DMA API") have
> add CONFIG_MMU compilation flag but that prohibit to use dma_mmap_wc()
> when the platform doesn't have MMU.
>
> This patch call vm_iomap_memory() in noMMU case to test if addresses
> are correct and set wma->vm_flags rather than all return an error.
ITYM vma.
I think this is fine, but I've no way to know as I don't run nommu here...
I've been hoping that others working on nommu would at least give an
ack or something, but I guess not.
So, please put it in the patch system, thanks.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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