From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Widawsky Subject: Re: [PATCH 13/18] drm/i915: Introduce i915_gem_object_create_stolen() Date: Mon, 5 Nov 2012 16:32:26 +0000 Message-ID: <20121105163226.4a38c7c7@bwidawsk.net> References: <1350666204-8101-1-git-send-email-chris@chris-wilson.co.uk> <1350666204-8101-13-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from shiva.chad-versace.us (209-20-75-48.static.cloud-ips.com [209.20.75.48]) by gabe.freedesktop.org (Postfix) with ESMTP id 1E3F89E95F for ; Mon, 5 Nov 2012 08:32:02 -0800 (PST) In-Reply-To: <1350666204-8101-13-git-send-email-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Fri, 19 Oct 2012 18:03:19 +0100 Chris Wilson wrote: > Allow for the creation of GEM objects backed by stolen memory. As these > are not backed by ordinary pages, we create a fake dma mapping and store > the address in the scatterlist rather than obj->pages. > > v2: Mark _i915_gem_object_create_stolen() as static, as noticed by Jesse > Barnes. > > Signed-off-by: Chris Wilson > Reviewed-by: Jesse Barnes Deferring on an r-b for now until I understand the point of most of this patch. Some comments below however. > --- > drivers/gpu/drm/i915/i915_drv.h | 3 + > drivers/gpu/drm/i915/i915_gem.c | 1 + > drivers/gpu/drm/i915/i915_gem_stolen.c | 122 ++++++++++++++++++++++++++++++++ > 3 files changed, 126 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index 6b893c7..5a0e0cd 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -1526,6 +1526,9 @@ int i915_gem_init_stolen(struct drm_device *dev); > int i915_gem_stolen_setup_compression(struct drm_device *dev); > void i915_gem_stolen_cleanup_compression(struct drm_device *dev); > void i915_gem_cleanup_stolen(struct drm_device *dev); > +struct drm_i915_gem_object * > +i915_gem_object_create_stolen(struct drm_device *dev, u32 size); > +void i915_gem_object_release_stolen(struct drm_i915_gem_object *obj); > > /* i915_gem_tiling.c */ > void i915_gem_detect_bit_6_swizzle(struct drm_device *dev); > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index d75c5c3..0349899 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -3857,6 +3857,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj) > obj->pages_pin_count = 0; > i915_gem_object_put_pages(obj); > i915_gem_object_free_mmap_offset(obj); > + i915_gem_object_release_stolen(obj); > > BUG_ON(obj->pages); > > diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c > index 68ef22a..86c4af4 100644 > --- a/drivers/gpu/drm/i915/i915_gem_stolen.c > +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c > @@ -204,3 +204,125 @@ int i915_gem_init_stolen(struct drm_device *dev) > > return 0; > } > + > +static struct sg_table * > +i915_pages_create_for_stolen(struct drm_device *dev, > + u32 offset, u32 size) > +{ > + struct drm_i915_private *dev_priv = dev->dev_private; > + struct sg_table *st; > + struct scatterlist *sg; > + BUG_ON(offset + size <= dev_priv->mm.gtt->stolen_size); > + /* We hide that we have no struct page backing our stolen object > + * by wrapping the contiguous physical allocation with a fake > + * dma mapping in a single scatterlist. > + */ > + > + st = kmalloc(sizeof(*st), GFP_KERNEL); > + if (st == NULL) > + return NULL; > + > + if (!sg_alloc_table(st, 1, GFP_KERNEL)) { > + kfree(st); > + return NULL; > + } > + > + sg = st->sgl; > + sg->offset = offset; > + sg->length = size; > + > + sg_dma_address(sg) = dev_priv->mm.stolen_base + offset; > + sg_dma_len(sg) = size; > + Do we want to make stolen_base a dma_addr_t (or at least typecast it)? > + return st; > +} > + > +static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj) > +{ > + BUG(); > + return -EINVAL; > +} > + __noreturn, or maybe just make .get_pages = NULL, and do the check in the upper layer get_pages? > +static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj) > +{ > + /* Should only be called during free */ > + sg_free_table(obj->pages); > + kfree(obj->pages); > +} > + > +static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = { > + .get_pages = i915_gem_object_get_pages_stolen, > + .put_pages = i915_gem_object_put_pages_stolen, > +}; > + > +static struct drm_i915_gem_object * > +_i915_gem_object_create_stolen(struct drm_device *dev, > + struct drm_mm_node *stolen) > +{ > + struct drm_i915_gem_object *obj; > + > + obj = kzalloc(sizeof(*obj), GFP_KERNEL); > + if (obj == NULL) > + return NULL; > + > + if (drm_gem_private_object_init(dev, &obj->base, stolen->size)) > + goto cleanup; > + > + i915_gem_object_init(obj, &i915_gem_object_stolen_ops); > + > + obj->pages = i915_pages_create_for_stolen(dev, > + stolen->start, stolen->size); > + if (obj->pages == NULL) > + goto cleanup; > + > + obj->has_dma_mapping = true; > + obj->pages_pin_count = 1; > + obj->stolen = stolen; > + > + obj->base.write_domain = I915_GEM_DOMAIN_GTT; > + obj->base.read_domains = I915_GEM_DOMAIN_GTT; > + obj->cache_level = I915_CACHE_NONE; > + > + return obj; > + > +cleanup: > + kfree(obj); > + return NULL; > +} > + > +struct drm_i915_gem_object * > +i915_gem_object_create_stolen(struct drm_device *dev, u32 size) > +{ > + struct drm_i915_private *dev_priv = dev->dev_private; > + struct drm_i915_gem_object *obj; > + struct drm_mm_node *stolen; > + > + if (dev_priv->mm.stolen_base == 0) > + return 0; > + > + DRM_DEBUG_KMS("creating stolen object: size=%x\n", size); > + if (size == 0) > + return NULL; > + > + stolen = drm_mm_search_free(&dev_priv->mm.stolen, size, 4096, 0); > + if (stolen) > + stolen = drm_mm_get_block(stolen, size, 4096); > + if (stolen == NULL) > + return NULL; Could probably do slightly better here with ERR_PTR(-ENOMEM) but since we don't do that elsewhere, I guess it doesn't matter. > + > + obj = _i915_gem_object_create_stolen(dev, stolen); > + if (obj) > + return obj; > + > + drm_mm_put_block(stolen); > + return NULL; Similarly here maybe use PTR_ERR(obj) and return something meaningful in _i915_gem_object_create_stolen. Since just about everything is more or less, ENOMEM, maybe it doesn't matter. > +} > + > +void > +i915_gem_object_release_stolen(struct drm_i915_gem_object *obj) > +{ > + if (obj->stolen) { > + drm_mm_put_block(obj->stolen); > + obj->stolen = NULL; > + } > +} -- Ben Widawsky, Intel Open Source Technology Center