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

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

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().

-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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