diff mbox

drm/exynos: Add check for IOMMU while passing physically continous memory flag

Message ID CAD025yR9Xd0G81WdLDxKyu-RVZPPJAUOKZ+0b5oKUxYOe7q_pQ@mail.gmail.com
State New
Headers show

Commit Message

Vikas C Sajjan Aug. 2, 2013, 10:10 a.m. UTC 
Hi Inki Dae,

On 2 August 2013 12:58, Inki Dae <inki.dae@samsung.com> wrote:
>
>
> 2013/8/2 Vikas Sajjan <vikas.sajjan@linaro.org>
>>
>> Hi Rob,
>>
>> On 2 August 2013 06:03, Rob Clark <robdclark@gmail.com> wrote:
>> > On Thu, Aug 1, 2013 at 7:20 PM, Tomasz Figa <tomasz.figa@gmail.com>
>> > wrote:
>> >> Hi Vikas,
>> >>
>> >> On Thursday 01 of August 2013 16:49:32 Vikas Sajjan wrote:
>> >>> While trying to get boot-logo up on exynos5420 SMDK which has eDP
>> >>> panel
>> >>> connected with resolution 2560x1600, following error occured even with
>> >>> IOMMU enabled:
>> >>> [0.880000] [drm:lowlevel_buffer_allocate] *ERROR* failed to allocate
>> >>> buffer. [0.890000] [drm] Initialized exynos 1.0.0 20110530 on minor 0
>> >>>
>> >>> This patch fixes the issue by adding a check for IOMMU.
>> >>>
>> >>> Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
>> >>> Signed-off-by: Arun Kumar <arun.kk@samsung.com>
>> >>> ---
>> >>>  drivers/gpu/drm/exynos/exynos_drm_fbdev.c |    9 ++++++++-
>> >>>  1 file changed, 8 insertions(+), 1 deletion(-)
>> >>>
>> >>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> >>> b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c index 8e60bd6..2a86666
>> >>> 100644
>> >>> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> >>> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> >>> @@ -16,6 +16,7 @@
>> >>>  #include <drm/drm_crtc.h>
>> >>>  #include <drm/drm_fb_helper.h>
>> >>>  #include <drm/drm_crtc_helper.h>
>> >>> +#include <drm/exynos_drm.h>
>> >>>
>> >>>  #include "exynos_drm_drv.h"
>> >>>  #include "exynos_drm_fb.h"
>> >>> @@ -143,6 +144,7 @@ static int exynos_drm_fbdev_create(struct
>> >>> drm_fb_helper *helper, struct platform_device *pdev =
>> >>> dev->platformdev;
>> >>>       unsigned long size;
>> >>>       int ret;
>> >>> +     unsigned int flag;
>> >>>
>> >>>       DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d\n",
>> >>>                       sizes->surface_width, sizes->surface_height,
>> >>> @@ -166,7 +168,12 @@ static int exynos_drm_fbdev_create(struct
>> >>> drm_fb_helper *helper, size = mode_cmd.pitches[0] * mode_cmd.height;
>> >>>
>> >>>       /* 0 means to allocate physically continuous memory */
>> >>> -     exynos_gem_obj = exynos_drm_gem_create(dev, 0, size);
>> >>> +     if (!is_drm_iommu_supported(dev))
>> >>> +             flag = 0;
>> >>> +     else
>> >>> +             flag = EXYNOS_BO_NONCONTIG;
>> >>
>> >> While noncontig memory might be used for devices that support IOMMU,
>> >> there
>> >> should be no problem with using contig memory for them, so this seems
>> >> more
>> >> like masking the original problem rather than tracking it down.
>> >
>> > it is probably a good idea to not require contig memory when it is not
>> > needed for performance or functionality (and if it is only
>> > performance, then fallback gracefully to non-contig).. but yeah, would
>> > be good to know if this is masking another issue all the same
>> >
>>
>> Whats happening with CONTIG flag and with IOMMU,  is
>>
>>  __iommu_alloc_buffer() ---> dma_alloc_from_contiguous() and in this
>> function it fails at
>> this condition check  if (pageno >= cma->count)
>>
>> So I tried increasing the CONFIG_CMA_SIZE_MBYTES to 24,  this check
>> succeeds and it works well without my patch.
>>
>> But what about the case where CONFIG_CMA is disabled , yet i want
>> bigger memory for a device.
>>  I think using IOMMU we can achieve this.
>>
>>  correct me, if i am wrong.
>>
>
> I'm on summer vacation so I'm afraid that I cannot test and look into it but
> I guess you guy didn't declare CMA region for Exynos drm. And in this case,
> the size of CMA declared region is 16MB as default. That is why works well
> after increasing default size, CONFIG_CMA_SIZE_MBYTES, to 24MB. And I
> mentioned long time ago, we are required to use physically contiguous memory
> in case that bootloader uses physically contiguous memory for its own
> framebuffer, and kernel wants to share the bootloader's framebuffer region
> to resolve flickering issue while booted; that is required for product. And
> one question, is there any reason that you guy should use non-contiguous
> memory for framebuffer with iommu?
>

yeah, we could not allocate CMA region for FIMD, because the function
dma_declare_contiguous() needs "dev" as the first argument and we have
access to "dev" node only if it is NON-DT way of probing like the way
it is done in arch/arm/mach-davinci/devices-da8xx.c
But now, since the probing is through DT way, there is NO way ( Let me
know if something is newly added ) to call dma_declare_contiguous()
and reserve CMA region .

we don't have any specific requirement for NON_CONTIG or CONTIG
memory, but only requirement was to allocate a bigger memory like (
2560 * 1600 * 4 ) for FB.

But as Rob suggested, we should have fall-back case if CONTIG memory
allocation fails, as below

> Inki Dae
>
>>
>>
>> > BR,
>> > -R
>> >
>> >> Could you check why the allocation fails when requesting contiguous
>> >> memory?
>> >>
>> >> Best regards,
>> >> Tomasz
>> >>
>> >> --
>> >> To unsubscribe from this list: send the line "unsubscribe linux-media"
>> >> in
>> >> the body of a message to majordomo@vger.kernel.org
>> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>>
>> --
>> Thanks and Regards
>>  Vikas Sajjan
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-media" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>

Comments

Sylwester Nawrocki/Kernel \(PLT\) /SRPOL/Staff Engineer/Samsung Electronics Aug. 2, 2013, 10:58 a.m. UTC | #1 
Hi Vikas,

On 08/02/2013 12:10 PM, Vikas Sajjan wrote:
> yeah, we could not allocate CMA region for FIMD, because the function
> dma_declare_contiguous() needs "dev" as the first argument and we have
> access to "dev" node only if it is NON-DT way of probing like the way
> it is done in arch/arm/mach-davinci/devices-da8xx.c
> But now, since the probing is through DT way, there is NO way ( Let me
> know if something is newly added ) to call dma_declare_contiguous()
> and reserve CMA region .

See this patch series [1]. We have have been using this kind of bindings
for assigning physically contiguous memory regions to the Exynos 
multimedia devices, instead of what's currently in mainline where same
physical addresses are repeated in dts for various boards without much
thought. And where custom device specific parsing code is required at 
arch side.

$ git grep mfc\-[lr] arch/arm/boot/dts

arch/arm/boot/dts/exynos4210-origen.dts:     samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos4210-origen.dts:     samsung,mfc-l = <0x51000000 0x800000>;
arch/arm/boot/dts/exynos4210-smdkv310.dts:   samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos4210-smdkv310.dts:   samsung,mfc-l = <0x51000000 0x800000>;
arch/arm/boot/dts/exynos4412-origen.dts:     samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos4412-origen.dts:     samsung,mfc-l = <0x51000000 0x800000>;
arch/arm/boot/dts/exynos4412-smdk4412.dts:   samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos4412-smdk4412.dts:   samsung,mfc-l = <0x51000000 0x800000>;
arch/arm/boot/dts/exynos5250-arndale.dts:    samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos5250-arndale.dts:    samsung,mfc-l = <0x51000000 0x800000>;
arch/arm/boot/dts/exynos5250-smdk5250.dts:   samsung,mfc-r = <0x43000000 0x800000>;
arch/arm/boot/dts/exynos5250-smdk5250.dts:   samsung,mfc-l = <0x51000000 0x800000>;


[1] http://www.spinics.net/lists/arm-kernel/msg263130.html

Regards,
Sylwester
Vikas C Sajjan Aug. 5, 2013, 7:14 a.m. UTC | #2 
Hi Sylwester,

On 2 August 2013 16:28, Sylwester Nawrocki <s.nawrocki@samsung.com> wrote:
> Hi Vikas,
>
> On 08/02/2013 12:10 PM, Vikas Sajjan wrote:
>> yeah, we could not allocate CMA region for FIMD, because the function
>> dma_declare_contiguous() needs "dev" as the first argument and we have
>> access to "dev" node only if it is NON-DT way of probing like the way
>> it is done in arch/arm/mach-davinci/devices-da8xx.c
>> But now, since the probing is through DT way, there is NO way ( Let me
>> know if something is newly added ) to call dma_declare_contiguous()
>> and reserve CMA region .
>
> See this patch series [1]. We have have been using this kind of bindings
> for assigning physically contiguous memory regions to the Exynos
> multimedia devices, instead of what's currently in mainline where same
> physical addresses are repeated in dts for various boards without much
> thought. And where custom device specific parsing code is required at
> arch side.
>
> $ git grep mfc\-[lr] arch/arm/boot/dts
>
> arch/arm/boot/dts/exynos4210-origen.dts:     samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos4210-origen.dts:     samsung,mfc-l = <0x51000000 0x800000>;
> arch/arm/boot/dts/exynos4210-smdkv310.dts:   samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos4210-smdkv310.dts:   samsung,mfc-l = <0x51000000 0x800000>;
> arch/arm/boot/dts/exynos4412-origen.dts:     samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos4412-origen.dts:     samsung,mfc-l = <0x51000000 0x800000>;
> arch/arm/boot/dts/exynos4412-smdk4412.dts:   samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos4412-smdk4412.dts:   samsung,mfc-l = <0x51000000 0x800000>;
> arch/arm/boot/dts/exynos5250-arndale.dts:    samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos5250-arndale.dts:    samsung,mfc-l = <0x51000000 0x800000>;
> arch/arm/boot/dts/exynos5250-smdk5250.dts:   samsung,mfc-r = <0x43000000 0x800000>;
> arch/arm/boot/dts/exynos5250-smdk5250.dts:   samsung,mfc-l = <0x51000000 0x800000>;
>
>
> [1] http://www.spinics.net/lists/arm-kernel/msg263130.html
>


Thanks, its good that now we have a new way to reserve CMA region.


> Regards,
> Sylwester
diff mbox

Patch

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index df43fa9..15de626 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -144,7 +144,6 @@  static int exynos_drm_fbdev_create(struct
drm_fb_helper *helper,
        struct platform_device *pdev = dev->platformdev;
        unsigned long size;
        int ret;

        DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d\n",
                        sizes->surface_width, sizes->surface_height,
@@ -167,16 +166,14 @@  static int exynos_drm_fbdev_create(struct
drm_fb_helper *helper,

        size = mode_cmd.pitches[0] * mode_cmd.height;

-       /* 0 means to allocate physically continuous memory */
-       exynos_gem_obj = exynos_drm_gem_create(dev, 0, size);
+       exynos_gem_obj = exynos_drm_gem_create(dev, EXYNOS_BO_CONTIG, size);
        if (IS_ERR(exynos_gem_obj)) {
-               ret = PTR_ERR(exynos_gem_obj);
-               goto err_release_framebuffer;
+               if(is_drm_iommu_supported(dev))
+                       exynos_gem_obj = exynos_drm_gem_create(dev,
EXYNOS_BO_NONCONTIG, size);
+               if (IS_ERR(exynos_gem_obj)) {
+                       ret = PTR_ERR(exynos_gem_obj);
+                       goto err_release_framebuffer;
+               }
+               dev_warn("\n exynos_gem_obj for FB is allocated with
non physically continuous       +               memory \n");
        }



> Thanks,