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Message-ID: <CACAvsv56MLoHMiQ8grnhN5V3QBW22-GQGeLAHwAwfaAkYsrNoQ@mail.gmail.com>
Date: Tue, 5 Aug 2014 09:20:57 +1000
From: Ben Skeggs <skeggsb@...il.com>
To: Alexandre Courbot <acourbot@...dia.com>
Cc: David Airlie <airlied@...ux.ie>, Ben Skeggs <bskeggs@...hat.com>,
David Herrmann <dh.herrmann@...il.com>,
Alexandre Courbot <gnurou@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v2] drm/ttm: expose CPU address of DMA-allocated pages
On Mon, Aug 4, 2014 at 7:28 PM, Alexandre Courbot <acourbot@...dia.com> wrote:
> Pages allocated using the DMA API have a coherent memory mapping. Make
> this mapping visible to drivers so they can decide to use it instead of
> creating their own redundant one.
I've picked this up in nouveau's linux-3.17 staging branch as per
Dave's request.
Thanks Alex,
Ben.
>
> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>
> Acked-by: David Airlie <airlied@...ux.ie>
> ---
> Changes since v1:
> - Perform only one allocation for pages, CPU and DMA addresses
> - Added David's ack
>
> drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 2 ++
> drivers/gpu/drm/ttm/ttm_tt.c | 13 ++++++++-----
> include/drm/ttm/ttm_bo_driver.h | 2 ++
> 3 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> index fb8259f69839..0301fac5badd 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> @@ -847,6 +847,7 @@ static int ttm_dma_pool_get_pages(struct dma_pool *pool,
> if (count) {
> d_page = list_first_entry(&pool->free_list, struct dma_page, page_list);
> ttm->pages[index] = d_page->p;
> + ttm_dma->cpu_address[index] = d_page->vaddr;
> ttm_dma->dma_address[index] = d_page->dma;
> list_move_tail(&d_page->page_list, &ttm_dma->pages_list);
> r = 0;
> @@ -978,6 +979,7 @@ void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev)
> INIT_LIST_HEAD(&ttm_dma->pages_list);
> for (i = 0; i < ttm->num_pages; i++) {
> ttm->pages[i] = NULL;
> + ttm_dma->cpu_address[i] = 0;
> ttm_dma->dma_address[i] = 0;
> }
>
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index 75f319090043..bf080abc86d1 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -55,9 +55,12 @@ static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
>
> static void ttm_dma_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
> {
> - ttm->ttm.pages = drm_calloc_large(ttm->ttm.num_pages, sizeof(void*));
> - ttm->dma_address = drm_calloc_large(ttm->ttm.num_pages,
> - sizeof(*ttm->dma_address));
> + ttm->ttm.pages = drm_calloc_large(ttm->ttm.num_pages,
> + sizeof(*ttm->ttm.pages) +
> + sizeof(*ttm->dma_address) +
> + sizeof(*ttm->cpu_address));
> + ttm->cpu_address = (void *) (ttm->ttm.pages + ttm->ttm.num_pages);
> + ttm->dma_address = (void *) (ttm->cpu_address + ttm->ttm.num_pages);
> }
>
> #ifdef CONFIG_X86
> @@ -228,7 +231,7 @@ int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
>
> INIT_LIST_HEAD(&ttm_dma->pages_list);
> ttm_dma_tt_alloc_page_directory(ttm_dma);
> - if (!ttm->pages || !ttm_dma->dma_address) {
> + if (!ttm->pages) {
> ttm_tt_destroy(ttm);
> pr_err("Failed allocating page table\n");
> return -ENOMEM;
> @@ -243,7 +246,7 @@ void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
>
> drm_free_large(ttm->pages);
> ttm->pages = NULL;
> - drm_free_large(ttm_dma->dma_address);
> + ttm_dma->cpu_address = NULL;
> ttm_dma->dma_address = NULL;
> }
> EXPORT_SYMBOL(ttm_dma_tt_fini);
> diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> index 202f0a7171e8..1d9f0f1ff52d 100644
> --- a/include/drm/ttm/ttm_bo_driver.h
> +++ b/include/drm/ttm/ttm_bo_driver.h
> @@ -133,6 +133,7 @@ struct ttm_tt {
> * struct ttm_dma_tt
> *
> * @ttm: Base ttm_tt struct.
> + * @cpu_address: The CPU address of the pages
> * @dma_address: The DMA (bus) addresses of the pages
> * @pages_list: used by some page allocation backend
> *
> @@ -142,6 +143,7 @@ struct ttm_tt {
> */
> struct ttm_dma_tt {
> struct ttm_tt ttm;
> + void **cpu_address;
> dma_addr_t *dma_address;
> struct list_head pages_list;
> };
> --
> 2.0.3
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
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