Re: [PATCH 08/21] drm/i915/gtt: Introduce struct i915_page_dma

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

On 6/11/2015 6:48 PM, Mika Kuoppala wrote:
> All our paging structures have struct page and dma address
> for that page.
>
> Add struct for page/dma address pairs and use it to make
> the setup and teardown for different paging structures
> identical.
>
> Include the page directory offset also in the struct for legacy
> gens. Rename it to clearly point out that it is offset into the
> ggtt.
>
> v2: Add comment about ggtt_offset (Michel)
>

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

> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_debugfs.c |   2 +-
>   drivers/gpu/drm/i915/i915_gem_gtt.c | 120 ++++++++++++++----------------------
>   drivers/gpu/drm/i915/i915_gem_gtt.h |  25 +++++---
>   3 files changed, 64 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 14f5d16..5a7a20a 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -2248,7 +2248,7 @@ static void gen6_ppgtt_info(struct seq_file *m, struct drm_device *dev)
>   		struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
>
>   		seq_puts(m, "aliasing PPGTT:\n");
> -		seq_printf(m, "pd gtt offset: 0x%08x\n", ppgtt->pd.pd_offset);
> +		seq_printf(m, "pd gtt offset: 0x%08x\n", ppgtt->pd.base.ggtt_offset);
>
>   		ppgtt->debug_dump(ppgtt, m);
>   	}
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 5832f53..65ee92f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -301,52 +301,39 @@ static gen6_pte_t iris_pte_encode(dma_addr_t addr,
>   	return pte;
>   }
>
> -#define i915_dma_unmap_single(px, dev) \
> -	__i915_dma_unmap_single((px)->daddr, dev)
> -
> -static void __i915_dma_unmap_single(dma_addr_t daddr,
> -				    struct drm_device *dev)
> +static int setup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>   {
>   	struct device *device = &dev->pdev->dev;
>
> -	dma_unmap_page(device, daddr, 4096, PCI_DMA_BIDIRECTIONAL);
> -}
> -
> -/**
> - * i915_dma_map_single() - Create a dma mapping for a page table/dir/etc.
> - * @px:	Page table/dir/etc to get a DMA map for
> - * @dev:	drm device
> - *
> - * Page table allocations are unified across all gens. They always require a
> - * single 4k allocation, as well as a DMA mapping. If we keep the structs
> - * symmetric here, the simple macro covers us for every page table type.
> - *
> - * Return: 0 if success.
> - */
> -#define i915_dma_map_single(px, dev) \
> -	i915_dma_map_page_single((px)->page, (dev), &(px)->daddr)
> +	p->page = alloc_page(GFP_KERNEL);
> +	if (!p->page)
> +		return -ENOMEM;
>
> -static int i915_dma_map_page_single(struct page *page,
> -				    struct drm_device *dev,
> -				    dma_addr_t *daddr)
> -{
> -	struct device *device = &dev->pdev->dev;
> +	p->daddr = dma_map_page(device,
> +				p->page, 0, 4096, PCI_DMA_BIDIRECTIONAL);
>
> -	*daddr = dma_map_page(device, page, 0, 4096, PCI_DMA_BIDIRECTIONAL);
> -	if (dma_mapping_error(device, *daddr))
> -		return -ENOMEM;
> +	if (dma_mapping_error(device, p->daddr)) {
> +		__free_page(p->page);
> +		return -EINVAL;
> +	}
>
>   	return 0;
>   }
>
> -static void unmap_and_free_pt(struct i915_page_table *pt,
> -			       struct drm_device *dev)
> +static void cleanup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>   {
> -	if (WARN_ON(!pt->page))
> +	if (WARN_ON(!p->page))
>   		return;
>
> -	i915_dma_unmap_single(pt, dev);
> -	__free_page(pt->page);
> +	dma_unmap_page(&dev->pdev->dev, p->daddr, 4096, PCI_DMA_BIDIRECTIONAL);
> +	__free_page(p->page);
> +	memset(p, 0, sizeof(*p));
> +}
> +
> +static void unmap_and_free_pt(struct i915_page_table *pt,
> +			       struct drm_device *dev)
> +{
> +	cleanup_page_dma(dev, &pt->base);
>   	kfree(pt->used_ptes);
>   	kfree(pt);
>   }
> @@ -357,7 +344,7 @@ static void gen8_initialize_pt(struct i915_address_space *vm,
>   	gen8_pte_t *pt_vaddr, scratch_pte;
>   	int i;
>
> -	pt_vaddr = kmap_atomic(pt->page);
> +	pt_vaddr = kmap_atomic(pt->base.page);
>   	scratch_pte = gen8_pte_encode(vm->scratch.addr,
>   				      I915_CACHE_LLC, true);
>
> @@ -386,19 +373,13 @@ static struct i915_page_table *alloc_pt(struct drm_device *dev)
>   	if (!pt->used_ptes)
>   		goto fail_bitmap;
>
> -	pt->page = alloc_page(GFP_KERNEL);
> -	if (!pt->page)
> -		goto fail_page;
> -
> -	ret = i915_dma_map_single(pt, dev);
> +	ret = setup_page_dma(dev, &pt->base);
>   	if (ret)
> -		goto fail_dma;
> +		goto fail_page_m;
>
>   	return pt;
>
> -fail_dma:
> -	__free_page(pt->page);
> -fail_page:
> +fail_page_m:
>   	kfree(pt->used_ptes);
>   fail_bitmap:
>   	kfree(pt);
> @@ -409,9 +390,8 @@ fail_bitmap:
>   static void unmap_and_free_pd(struct i915_page_directory *pd,
>   			      struct drm_device *dev)
>   {
> -	if (pd->page) {
> -		i915_dma_unmap_single(pd, dev);
> -		__free_page(pd->page);
> +	if (pd->base.page) {
> +		cleanup_page_dma(dev, &pd->base);
>   		kfree(pd->used_pdes);
>   		kfree(pd);
>   	}
> @@ -431,18 +411,12 @@ static struct i915_page_directory *alloc_pd(struct drm_device *dev)
>   	if (!pd->used_pdes)
>   		goto free_pd;
>
> -	pd->page = alloc_page(GFP_KERNEL);
> -	if (!pd->page)
> -		goto free_bitmap;
> -
> -	ret = i915_dma_map_single(pd, dev);
> +	ret = setup_page_dma(dev, &pd->base);
>   	if (ret)
> -		goto free_page;
> +		goto free_bitmap;
>
>   	return pd;
>
> -free_page:
> -	__free_page(pd->page);
>   free_bitmap:
>   	kfree(pd->used_pdes);
>   free_pd:
> @@ -523,10 +497,10 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
>
>   		pt = pd->page_table[pde];
>
> -		if (WARN_ON(!pt->page))
> +		if (WARN_ON(!pt->base.page))
>   			continue;
>
> -		page_table = pt->page;
> +		page_table = pt->base.page;
>
>   		last_pte = pte + num_entries;
>   		if (last_pte > GEN8_PTES)
> @@ -573,7 +547,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
>   		if (pt_vaddr == NULL) {
>   			struct i915_page_directory *pd = ppgtt->pdp.page_directory[pdpe];
>   			struct i915_page_table *pt = pd->page_table[pde];
> -			struct page *page_table = pt->page;
> +			struct page *page_table = pt->base.page;
>
>   			pt_vaddr = kmap_atomic(page_table);
>   		}
> @@ -605,7 +579,7 @@ static void __gen8_do_map_pt(gen8_pde_t * const pde,
>   			     struct drm_device *dev)
>   {
>   	gen8_pde_t entry =
> -		gen8_pde_encode(dev, pt->daddr, I915_CACHE_LLC);
> +		gen8_pde_encode(dev, pt->base.daddr, I915_CACHE_LLC);
>   	*pde = entry;
>   }
>
> @@ -618,7 +592,7 @@ static void gen8_initialize_pd(struct i915_address_space *vm,
>   	struct i915_page_table *pt;
>   	int i;
>
> -	page_directory = kmap_atomic(pd->page);
> +	page_directory = kmap_atomic(pd->base.page);
>   	pt = ppgtt->scratch_pt;
>   	for (i = 0; i < I915_PDES; i++)
>   		/* Map the PDE to the page table */
> @@ -633,7 +607,7 @@ static void gen8_free_page_tables(struct i915_page_directory *pd, struct drm_dev
>   {
>   	int i;
>
> -	if (!pd->page)
> +	if (!pd->base.page)
>   		return;
>
>   	for_each_set_bit(i, pd->used_pdes, I915_PDES) {
> @@ -884,7 +858,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>   	/* Allocations have completed successfully, so set the bitmaps, and do
>   	 * the mappings. */
>   	gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
> -		gen8_pde_t *const page_directory = kmap_atomic(pd->page);
> +		gen8_pde_t *const page_directory = kmap_atomic(pd->base.page);
>   		struct i915_page_table *pt;
>   		uint64_t pd_len = gen8_clamp_pd(start, length);
>   		uint64_t pd_start = start;
> @@ -995,7 +969,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
>   	gen6_for_each_pde(unused, &ppgtt->pd, start, length, temp, pde) {
>   		u32 expected;
>   		gen6_pte_t *pt_vaddr;
> -		dma_addr_t pt_addr = ppgtt->pd.page_table[pde]->daddr;
> +		dma_addr_t pt_addr = ppgtt->pd.page_table[pde]->base.daddr;
>   		pd_entry = readl(ppgtt->pd_addr + pde);
>   		expected = (GEN6_PDE_ADDR_ENCODE(pt_addr) | GEN6_PDE_VALID);
>
> @@ -1006,7 +980,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
>   				   expected);
>   		seq_printf(m, "\tPDE: %x\n", pd_entry);
>
> -		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[pde]->page);
> +		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[pde]->base.page);
>   		for (pte = 0; pte < GEN6_PTES; pte+=4) {
>   			unsigned long va =
>   				(pde * PAGE_SIZE * GEN6_PTES) +
> @@ -1041,7 +1015,7 @@ static void gen6_write_pde(struct i915_page_directory *pd,
>   		container_of(pd, struct i915_hw_ppgtt, pd);
>   	u32 pd_entry;
>
> -	pd_entry = GEN6_PDE_ADDR_ENCODE(pt->daddr);
> +	pd_entry = GEN6_PDE_ADDR_ENCODE(pt->base.daddr);
>   	pd_entry |= GEN6_PDE_VALID;
>
>   	writel(pd_entry, ppgtt->pd_addr + pde);
> @@ -1066,9 +1040,9 @@ static void gen6_write_page_range(struct drm_i915_private *dev_priv,
>
>   static uint32_t get_pd_offset(struct i915_hw_ppgtt *ppgtt)
>   {
> -	BUG_ON(ppgtt->pd.pd_offset & 0x3f);
> +	BUG_ON(ppgtt->pd.base.ggtt_offset & 0x3f);
>
> -	return (ppgtt->pd.pd_offset / 64) << 16;
> +	return (ppgtt->pd.base.ggtt_offset / 64) << 16;
>   }
>
>   static int hsw_mm_switch(struct i915_hw_ppgtt *ppgtt,
> @@ -1231,7 +1205,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
>   		if (last_pte > GEN6_PTES)
>   			last_pte = GEN6_PTES;
>
> -		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->page);
> +		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->base.page);
>
>   		for (i = first_pte; i < last_pte; i++)
>   			pt_vaddr[i] = scratch_pte;
> @@ -1260,7 +1234,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
>   	pt_vaddr = NULL;
>   	for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
>   		if (pt_vaddr == NULL)
> -			pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->page);
> +			pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->base.page);
>
>   		pt_vaddr[act_pte] =
>   			vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
> @@ -1288,7 +1262,7 @@ static void gen6_initialize_pt(struct i915_address_space *vm,
>   	scratch_pte = vm->pte_encode(vm->scratch.addr,
>   			I915_CACHE_LLC, true, 0);
>
> -	pt_vaddr = kmap_atomic(pt->page);
> +	pt_vaddr = kmap_atomic(pt->base.page);
>
>   	for (i = 0; i < GEN6_PTES; i++)
>   		pt_vaddr[i] = scratch_pte;
> @@ -1504,11 +1478,11 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
>   	ppgtt->base.total = I915_PDES * GEN6_PTES * PAGE_SIZE;
>   	ppgtt->debug_dump = gen6_dump_ppgtt;
>
> -	ppgtt->pd.pd_offset =
> +	ppgtt->pd.base.ggtt_offset =
>   		ppgtt->node.start / PAGE_SIZE * sizeof(gen6_pte_t);
>
>   	ppgtt->pd_addr = (gen6_pte_t __iomem *)dev_priv->gtt.gsm +
> -		ppgtt->pd.pd_offset / sizeof(gen6_pte_t);
> +		ppgtt->pd.base.ggtt_offset / sizeof(gen6_pte_t);
>
>   	gen6_scratch_va_range(ppgtt, 0, ppgtt->base.total);
>
> @@ -1519,7 +1493,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
>   			 ppgtt->node.start / PAGE_SIZE);
>
>   	DRM_DEBUG("Adding PPGTT at offset %x\n",
> -		  ppgtt->pd.pd_offset << 10);
> +		  ppgtt->pd.base.ggtt_offset << 10);
>
>   	return 0;
>   }
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index da67542..0ccdf54 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -205,19 +205,26 @@ struct i915_vma {
>   #define DRM_I915_GEM_OBJECT_MAX_PIN_COUNT 0xf
>   };
>
> -struct i915_page_table {
> +struct i915_page_dma {
>   	struct page *page;
> -	dma_addr_t daddr;
> +	union {
> +		dma_addr_t daddr;
> +
> +		/* For gen6/gen7 only. This is the offset in the GGTT
> +		 * where the page directory entries for PPGTT begin
> +		 */
> +		uint32_t ggtt_offset;
> +	};
> +};
> +
> +struct i915_page_table {
> +	struct i915_page_dma base;
>
>   	unsigned long *used_ptes;
>   };
>
>   struct i915_page_directory {
> -	struct page *page; /* NULL for GEN6-GEN7 */
> -	union {
> -		uint32_t pd_offset;
> -		dma_addr_t daddr;
> -	};
> +	struct i915_page_dma base;
>
>   	unsigned long *used_pdes;
>   	struct i915_page_table *page_table[I915_PDES]; /* PDEs */
> @@ -472,8 +479,8 @@ static inline dma_addr_t
>   i915_page_dir_dma_addr(const struct i915_hw_ppgtt *ppgtt, const unsigned n)
>   {
>   	return test_bit(n, ppgtt->pdp.used_pdpes) ?
> -		ppgtt->pdp.page_directory[n]->daddr :
> -		ppgtt->scratch_pd->daddr;
> +		ppgtt->pdp.page_directory[n]->base.daddr :
> +		ppgtt->scratch_pd->base.daddr;
>   }
>
>   int i915_gem_gtt_init(struct drm_device *dev);
>
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