Re: [PATCH 14/21] drm/i915/gtt: Make scratch page i915_page_dma compatible

[Michel Thierry <michel.thierry@intel.com>]

On 6/11/2015 5:30 PM, Mika Kuoppala wrote:
> Michel Thierry <michel.thierry@intel.com> writes:
>
>> On 5/22/2015 6:05 PM, Mika Kuoppala wrote:
>>> Lay out scratch page structure in similar manner than other
>>> paging structures. This allows us to use the same tools for
>>> setup and teardown.
>>>
>>> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
>>> ---
>>>    drivers/gpu/drm/i915/i915_gem_gtt.c | 89 ++++++++++++++++++++-----------------
>>>    drivers/gpu/drm/i915/i915_gem_gtt.h |  9 ++--
>>>    2 files changed, 54 insertions(+), 44 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
>>> index 4f9a000..43fa543 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
>>> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
>>> @@ -301,11 +301,12 @@ static gen6_pte_t iris_pte_encode(dma_addr_t addr,
>>>           return pte;
>>>    }
>>>
>>> -static int setup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>>> +static int __setup_page_dma(struct drm_device *dev,
>>> +                           struct i915_page_dma *p, gfp_t flags)
>>>    {
>>>           struct device *device = &dev->pdev->dev;
>>>
>>> -       p->page = alloc_page(GFP_KERNEL);
>>> +       p->page = alloc_page(flags);
>>>           if (!p->page)
>>>                   return -ENOMEM;
>>>
>>> @@ -320,6 +321,11 @@ static int setup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>>>           return 0;
>>>    }
>>>
>>> +static int setup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>>> +{
>>> +       return __setup_page_dma(dev, p, GFP_KERNEL);
>>> +}
>>> +
>>>    static void cleanup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>>>    {
>>>           if (WARN_ON(!p->page))
>>> @@ -388,7 +394,8 @@ static void gen8_initialize_pt(struct i915_address_space *vm,
>>>    {
>>>           gen8_pte_t scratch_pte;
>>>
>>> -       scratch_pte = gen8_pte_encode(vm->scratch.addr, I915_CACHE_LLC, true);
>>> +       scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
>>> +                                     I915_CACHE_LLC, true);
>>>
>>>           fill_px(vm->dev, pt, scratch_pte);
>>>    }
>>> @@ -515,7 +522,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
>>>           unsigned num_entries = length >> PAGE_SHIFT;
>>>           unsigned last_pte, i;
>>>
>>> -       scratch_pte = gen8_pte_encode(ppgtt->base.scratch.addr,
>>> +       scratch_pte = gen8_pte_encode(px_dma(ppgtt->base.scratch_page),
>>>                                         I915_CACHE_LLC, use_scratch);
>>>
>>>           while (num_entries) {
>>> @@ -1021,7 +1028,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
>>>           uint32_t  pte, pde, temp;
>>>           uint32_t start = ppgtt->base.start, length = ppgtt->base.total;
>>>
>>> -       scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true, 0);
>>> +       scratch_pte = vm->pte_encode(px_dma(vm->scratch_page), I915_CACHE_LLC, true, 0);
>>>
>>>           gen6_for_each_pde(unused, &ppgtt->pd, start, length, temp, pde) {
>>>                   u32 expected;
>>> @@ -1256,7 +1263,8 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
>>>           unsigned first_pte = first_entry % GEN6_PTES;
>>>           unsigned last_pte, i;
>>>
>>> -       scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true, 0);
>>> +       scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
>>> +                                    I915_CACHE_LLC, true, 0);
>>>
>>>           while (num_entries) {
>>>                   last_pte = first_pte + num_entries;
>>> @@ -1314,9 +1322,10 @@ static void gen6_initialize_pt(struct i915_address_space *vm,
>>>    {
>>>           gen6_pte_t scratch_pte;
>>>
>>> -       WARN_ON(vm->scratch.addr == 0);
>>> +       WARN_ON(px_dma(vm->scratch_page) == 0);
>>>
>>> -       scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true, 0);
>>> +       scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
>>> +                                    I915_CACHE_LLC, true, 0);
>>>
>>>           fill32_px(vm->dev, pt, scratch_pte);
>>>    }
>>> @@ -1553,13 +1562,14 @@ static int __hw_ppgtt_init(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
>>>           struct drm_i915_private *dev_priv = dev->dev_private;
>>>
>>>           ppgtt->base.dev = dev;
>>> -       ppgtt->base.scratch = dev_priv->gtt.base.scratch;
>>> +       ppgtt->base.scratch_page = dev_priv->gtt.base.scratch_page;
>>>
>>>           if (INTEL_INFO(dev)->gen < 8)
>>>                   return gen6_ppgtt_init(ppgtt);
>>>           else
>>>                   return gen8_ppgtt_init(ppgtt);
>>>    }
>>> +
>>>    int i915_ppgtt_init(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
>>>    {
>>>           struct drm_i915_private *dev_priv = dev->dev_private;
>>> @@ -1874,7 +1884,7 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm,
>>>                    first_entry, num_entries, max_entries))
>>>                   num_entries = max_entries;
>>>
>>> -       scratch_pte = gen8_pte_encode(vm->scratch.addr,
>>> +       scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
>>>                                         I915_CACHE_LLC,
>>>                                         use_scratch);
>>>           for (i = 0; i < num_entries; i++)
>>> @@ -1900,7 +1910,8 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
>>>                    first_entry, num_entries, max_entries))
>>>                   num_entries = max_entries;
>>>
>>> -       scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, use_scratch, 0);
>>> +       scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
>>> +                                    I915_CACHE_LLC, use_scratch, 0);
>>>
>>>           for (i = 0; i < num_entries; i++)
>>>                   iowrite32(scratch_pte, &gtt_base[i]);
>>> @@ -2157,42 +2168,40 @@ void i915_global_gtt_cleanup(struct drm_device *dev)
>>>           vm->cleanup(vm);
>>>    }
>>>
>>> -static int setup_scratch_page(struct drm_device *dev)
>>> +static int alloc_scratch_page(struct i915_address_space *vm)
>>>    {
>>> -       struct drm_i915_private *dev_priv = dev->dev_private;
>>> -       struct page *page;
>>> -       dma_addr_t dma_addr;
>>> +       struct i915_page_scratch *sp;
>>> +       int ret;
>>> +
>>> +       WARN_ON(vm->scratch_page);
>>>
>>> -       page = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
>>> -       if (page == NULL)
>>> +       sp = kzalloc(sizeof(*sp), GFP_KERNEL);
>>> +       if (sp == NULL)
>>>                   return -ENOMEM;
>>> -       set_pages_uc(page, 1);
>>>
>>> -#ifdef CONFIG_INTEL_IOMMU
>>> -       dma_addr = pci_map_page(dev->pdev, page, 0, PAGE_SIZE,
>>> -                               PCI_DMA_BIDIRECTIONAL);
>>> -       if (pci_dma_mapping_error(dev->pdev, dma_addr)) {
>>> -               __free_page(page);
>>> -               return -EINVAL;
>>> +       ret = __setup_page_dma(vm->dev, px_base(sp), GFP_DMA32 | __GFP_ZERO);
>>> +       if (ret) {
>>> +               kfree(sp);
>>> +               return ret;
>>>           }
>>> -#else
>>> -       dma_addr = page_to_phys(page);
>>> -#endif
>>
>> Should we keep a no-iommu option?
>> This seems to have been added for gen6 (gtt).
>>
>
> The dma_map_page should do the right thing with and
> without iommu. I really don't understand why we
> would need the no-iommu option.
>
> If there is no iommu, we get nommu_map_page()
> which is effectively page_to_phys().

Thanks for clear this up.

Reviewed-by: Michel Thierry <michel.thierry@intel.com>

>
> -Mika
>
>
>>> -       dev_priv->gtt.base.scratch.page = page;
>>> -       dev_priv->gtt.base.scratch.addr = dma_addr;
>>> +
>>> +       set_pages_uc(px_page(sp), 1);
>>> +
>>> +       vm->scratch_page = sp;
>>>
>>>           return 0;
>>>    }
>>>
>>> -static void teardown_scratch_page(struct drm_device *dev)
>>> +static void free_scratch_page(struct i915_address_space *vm)
>>>    {
>>> -       struct drm_i915_private *dev_priv = dev->dev_private;
>>> -       struct page *page = dev_priv->gtt.base.scratch.page;
>>> +       struct i915_page_scratch *sp = vm->scratch_page;
>>>
>>> -       set_pages_wb(page, 1);
>>> -       pci_unmap_page(dev->pdev, dev_priv->gtt.base.scratch.addr,
>>> -                      PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
>>> -       __free_page(page);
>>> +       set_pages_wb(px_page(sp), 1);
>>> +
>>> +       cleanup_px(vm->dev, sp);
>>> +       kfree(sp);
>>> +
>>> +       vm->scratch_page = NULL;
>>>    }
>>>
>>>    static unsigned int gen6_get_total_gtt_size(u16 snb_gmch_ctl)
>>> @@ -2300,7 +2309,7 @@ static int ggtt_probe_common(struct drm_device *dev,
>>>                   return -ENOMEM;
>>>           }
>>>
>>> -       ret = setup_scratch_page(dev);
>>> +       ret = alloc_scratch_page(&dev_priv->gtt.base);
>>>           if (ret) {
>>>                   DRM_ERROR("Scratch setup failed\n");
>>>                   /* iounmap will also get called at remove, but meh */
>>> @@ -2479,7 +2488,7 @@ static void gen6_gmch_remove(struct i915_address_space *vm)
>>>           struct i915_gtt *gtt = container_of(vm, struct i915_gtt, base);
>>>
>>>           iounmap(gtt->gsm);
>>> -       teardown_scratch_page(vm->dev);
>>> +       free_scratch_page(vm);
>>>    }
>>>
>>>    static int i915_gmch_probe(struct drm_device *dev,
>>> @@ -2543,13 +2552,13 @@ int i915_gem_gtt_init(struct drm_device *dev)
>>>                   dev_priv->gtt.base.cleanup = gen6_gmch_remove;
>>>           }
>>>
>>> +       gtt->base.dev = dev;
>>> +
>>>           ret = gtt->gtt_probe(dev, &gtt->base.total, &gtt->stolen_size,
>>>                                &gtt->mappable_base, &gtt->mappable_end);
>>>           if (ret)
>>>                   return ret;
>>>
>>> -       gtt->base.dev = dev;
>>> -
>>>           /* GMADR is the PCI mmio aperture into the global GTT. */
>>>           DRM_INFO("Memory usable by graphics device = %lluM\n",
>>>                    gtt->base.total >> 20);
>>> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
>>> index 006b839..1fd4041 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
>>> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
>>> @@ -217,6 +217,10 @@ struct i915_page_dma {
>>>    #define px_page(px) (px_base(px)->page)
>>>    #define px_dma(px) (px_base(px)->daddr)
>>>
>>> +struct i915_page_scratch {
>>> +       struct i915_page_dma base;
>>> +};
>>> +
>>>    struct i915_page_table {
>>>           struct i915_page_dma base;
>>>
>>> @@ -243,10 +247,7 @@ struct i915_address_space {
>>>           u64 start;              /* Start offset always 0 for dri2 */
>>>           u64 total;              /* size addr space maps (ex. 2GB for ggtt) */
>>>
>>> -       struct {
>>> -               dma_addr_t addr;
>>> -               struct page *page;
>>> -       } scratch;
>>> +       struct i915_page_scratch *scratch_page;
>>>
>>>           /**
>>>            * List of objects currently involved in rendering.
>>> --
>>> 1.9.1
>>>
>>> _______________________________________________
>>> Intel-gfx mailing list
>>> Intel-gfx@lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>>>
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