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Message-ID: <577EF9DD.1010506@rock-chips.com>
Date: Fri, 8 Jul 2016 08:54:53 +0800
From: Mark yao <mark.yao@...k-chips.com>
To: Shunqian Zheng <zhengsq@...k-chips.com>, joro@...tes.org,
heiko@...ech.de, robh+dt@...nel.org, mark.rutland@....com,
linux@...linux.org.uk, airlied@...ux.ie, tfiga@...gle.com,
xxm@...k-chips.com
Cc: linux-arm-kernel@...ts.infradead.org,
iommu@...ts.linux-foundation.org, devicetree@...r.kernel.org,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-rockchip@...ts.infradead.org,
Tomasz Figa <tfiga@...omium.org>
Subject: Re: [PATCH v5 6/8] drm/rockchip: Do not use DMA mapping API if
attached to IOMMU domain
On 2016年06月24日 10:13, Shunqian Zheng wrote:
> From: Tomasz Figa <tfiga@...omium.org>
>
> The API is not suitable for subsystems consisting of multiple devices
> and requires severe hacks to use it. To mitigate this, this patch
> implements allocation and address space management locally by using
> helpers provided by DRM framework, like other DRM drivers do, e.g.
> Tegra.
>
> This patch should not introduce any functional changes until the driver
> is made to attach subdevices into an IOMMU domain with the generic IOMMU
> API, which will happen in following patch. Based heavily on GEM
> implementation of Tegra DRM driver.
Acked-by: Mark Yao <mark.yao@...k-chips.com>
>
> Signed-off-by: Tomasz Figa <tfiga@...omium.org>
> Signed-off-by: Shunqian Zheng <zhengsq@...k-chips.com>
> ---
> drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 3 +
> drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 221 ++++++++++++++++++++++++++--
> drivers/gpu/drm/rockchip/rockchip_drm_gem.h | 9 ++
> 3 files changed, 222 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
> index ea39329..5ab1223 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
> @@ -30,6 +30,7 @@
>
> struct drm_device;
> struct drm_connector;
> +struct iommu_domain;
>
> /*
> * Rockchip drm private crtc funcs.
> @@ -61,6 +62,8 @@ struct rockchip_drm_private {
> struct drm_gem_object *fbdev_bo;
> const struct rockchip_crtc_funcs *crtc_funcs[ROCKCHIP_MAX_CRTC];
> struct drm_atomic_state *state;
> + struct iommu_domain *domain;
> + struct drm_mm mm;
> };
>
> int rockchip_register_crtc_funcs(struct drm_crtc *crtc,
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> index 394f92b..e7cd93d 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> @@ -19,11 +19,135 @@
> #include <drm/rockchip_drm.h>
>
> #include <linux/dma-attrs.h>
> +#include <linux/iommu.h>
>
> #include "rockchip_drm_drv.h"
> #include "rockchip_drm_gem.h"
>
> -static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
> +static int rockchip_gem_iommu_map(struct rockchip_gem_object *rk_obj)
> +{
> + struct drm_device *drm = rk_obj->base.dev;
> + struct rockchip_drm_private *private = drm->dev_private;
> + int prot = IOMMU_READ | IOMMU_WRITE;
> + ssize_t ret;
> +
> + ret = drm_mm_insert_node_generic(&private->mm, &rk_obj->mm,
> + rk_obj->base.size, PAGE_SIZE,
> + 0, 0, 0);
> + if (ret < 0) {
> + DRM_ERROR("out of I/O virtual memory: %zd\n", ret);
> + return ret;
> + }
> +
> + rk_obj->dma_addr = rk_obj->mm.start;
> +
> + ret = iommu_map_sg(private->domain, rk_obj->dma_addr, rk_obj->sgt->sgl,
> + rk_obj->sgt->nents, prot);
> + if (ret < 0) {
> + DRM_ERROR("failed to map buffer: %zd\n", ret);
> + goto err_remove_node;
> + }
> +
> + rk_obj->size = ret;
> +
> + return 0;
> +
> +err_remove_node:
> + drm_mm_remove_node(&rk_obj->mm);
> +
> + return ret;
> +}
> +
> +static int rockchip_gem_iommu_unmap(struct rockchip_gem_object *rk_obj)
> +{
> + struct drm_device *drm = rk_obj->base.dev;
> + struct rockchip_drm_private *private = drm->dev_private;
> +
> + iommu_unmap(private->domain, rk_obj->dma_addr, rk_obj->size);
> + drm_mm_remove_node(&rk_obj->mm);
> +
> + return 0;
> +}
> +
> +static int rockchip_gem_get_pages(struct rockchip_gem_object *rk_obj)
> +{
> + struct drm_device *drm = rk_obj->base.dev;
> + int ret, i;
> + struct scatterlist *s;
> +
> + rk_obj->pages = drm_gem_get_pages(&rk_obj->base);
> + if (IS_ERR(rk_obj->pages))
> + return PTR_ERR(rk_obj->pages);
> +
> + rk_obj->num_pages = rk_obj->base.size >> PAGE_SHIFT;
> +
> + rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);
> + if (IS_ERR(rk_obj->sgt)) {
> + ret = PTR_ERR(rk_obj->sgt);
> + goto err_put_pages;
> + }
> +
> + /*
> + * Fake up the SG table so that dma_sync_sg_for_device() can be used
> + * to flush the pages associated with it.
> + *
> + * TODO: Replace this by drm_clflush_sg() once it can be implemented
> + * without relying on symbols that are not exported.
> + */
> + for_each_sg(rk_obj->sgt->sgl, s, rk_obj->sgt->nents, i)
> + sg_dma_address(s) = sg_phys(s);
> +
> + dma_sync_sg_for_device(drm->dev, rk_obj->sgt->sgl, rk_obj->sgt->nents,
> + DMA_TO_DEVICE);
> +
> + return 0;
> +
> +err_put_pages:
> + drm_gem_put_pages(&rk_obj->base, rk_obj->pages, false, false);
> + return ret;
> +}
> +
> +static void rockchip_gem_put_pages(struct rockchip_gem_object *rk_obj)
> +{
> + sg_free_table(rk_obj->sgt);
> + kfree(rk_obj->sgt);
> + drm_gem_put_pages(&rk_obj->base, rk_obj->pages, false, false);
> +}
> +
> +static int rockchip_gem_alloc_iommu(struct rockchip_gem_object *rk_obj,
> + bool alloc_kmap)
> +{
> + int ret;
> +
> + ret = rockchip_gem_get_pages(rk_obj);
> + if (ret < 0)
> + return ret;
> +
> + ret = rockchip_gem_iommu_map(rk_obj);
> + if (ret < 0)
> + goto err_free;
> +
> + if (alloc_kmap) {
> + rk_obj->kvaddr = vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
> + pgprot_writecombine(PAGE_KERNEL));
> + if (!rk_obj->kvaddr) {
> + DRM_ERROR("failed to vmap() buffer\n");
> + ret = -ENOMEM;
> + goto err_unmap;
> + }
> + }
> +
> + return 0;
> +
> +err_unmap:
> + rockchip_gem_iommu_unmap(rk_obj);
> +err_free:
> + rockchip_gem_put_pages(rk_obj);
> +
> + return ret;
> +}
> +
> +static int rockchip_gem_alloc_dma(struct rockchip_gem_object *rk_obj,
> bool alloc_kmap)
> {
> struct drm_gem_object *obj = &rk_obj->base;
> @@ -46,32 +170,93 @@ static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
> return 0;
> }
>
> -static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
> +static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
> + bool alloc_kmap)
> {
> struct drm_gem_object *obj = &rk_obj->base;
> struct drm_device *drm = obj->dev;
> + struct rockchip_drm_private *private = drm->dev_private;
>
> - dma_free_attrs(drm->dev, obj->size, rk_obj->kvaddr, rk_obj->dma_addr,
> - &rk_obj->dma_attrs);
> + if (private->domain)
> + return rockchip_gem_alloc_iommu(rk_obj, alloc_kmap);
> + else
> + return rockchip_gem_alloc_dma(rk_obj, alloc_kmap);
> }
>
> -static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
> - struct vm_area_struct *vma)
> +static void rockchip_gem_free_iommu(struct rockchip_gem_object *rk_obj)
> +{
> + vunmap(rk_obj->kvaddr);
> + rockchip_gem_iommu_unmap(rk_obj);
> + rockchip_gem_put_pages(rk_obj);
> +}
>
> +static void rockchip_gem_free_dma(struct rockchip_gem_object *rk_obj)
> {
> + struct drm_gem_object *obj = &rk_obj->base;
> + struct drm_device *drm = obj->dev;
> +
> + dma_free_attrs(drm->dev, obj->size, rk_obj->kvaddr,
> + rk_obj->dma_addr, &rk_obj->dma_attrs);
> +}
> +
> +static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
> +{
> + if (rk_obj->pages)
> + rockchip_gem_free_iommu(rk_obj);
> + else
> + rockchip_gem_free_dma(rk_obj);
> +}
> +
> +static int rockchip_drm_gem_object_mmap_iommu(struct drm_gem_object *obj,
> + struct vm_area_struct *vma)
> +{
> + struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
> + unsigned int i, count = obj->size >> PAGE_SHIFT;
> + unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
> + unsigned long uaddr = vma->vm_start;
> int ret;
> +
> + if (user_count == 0 || user_count > count)
> + return -ENXIO;
> +
> + for (i = 0; i < user_count; i++) {
> + ret = vm_insert_page(vma, uaddr, rk_obj->pages[i]);
> + if (ret)
> + return ret;
> + uaddr += PAGE_SIZE;
> + }
> +
> + return 0;
> +}
> +
> +static int rockchip_drm_gem_object_mmap_dma(struct drm_gem_object *obj,
> + struct vm_area_struct *vma)
> +{
> struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
> struct drm_device *drm = obj->dev;
>
> + return dma_mmap_attrs(drm->dev, vma, rk_obj->kvaddr, rk_obj->dma_addr,
> + obj->size, &rk_obj->dma_attrs);
> +}
> +
> +static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
> + struct vm_area_struct *vma)
> +{
> + int ret;
> + struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
> +
> /*
> - * dma_alloc_attrs() allocated a struct page table for rk_obj, so clear
> + * We allocated a struct page table for rk_obj, so clear
> * VM_PFNMAP flag that was set by drm_gem_mmap_obj()/drm_gem_mmap().
> */
> vma->vm_flags &= ~VM_PFNMAP;
> vma->vm_pgoff = 0;
>
> - ret = dma_mmap_attrs(drm->dev, vma, rk_obj->kvaddr, rk_obj->dma_addr,
> - obj->size, &rk_obj->dma_attrs);
> + if (rk_obj->pages)
> + ret = rockchip_drm_gem_object_mmap_iommu(obj, vma);
> + else
> + ret = rockchip_drm_gem_object_mmap_dma(obj, vma);
> +
> if (ret)
> drm_gem_vm_close(vma);
>
> @@ -121,7 +306,7 @@ struct rockchip_gem_object *
>
> obj = &rk_obj->base;
>
> - drm_gem_private_object_init(drm, obj, size);
> + drm_gem_object_init(drm, obj, size);
>
> ret = rockchip_gem_alloc_buf(rk_obj, alloc_kmap);
> if (ret)
> @@ -277,6 +462,9 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj)
> struct sg_table *sgt;
> int ret;
>
> + if (rk_obj->pages)
> + return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);
> +
> sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> if (!sgt)
> return ERR_PTR(-ENOMEM);
> @@ -297,6 +485,10 @@ void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
> {
> struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
>
> + if (rk_obj->pages)
> + return vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
> + pgprot_writecombine(PAGE_KERNEL));
> +
> if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, &rk_obj->dma_attrs))
> return NULL;
>
> @@ -305,5 +497,12 @@ void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
>
> void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> {
> - /* Nothing to do */
> + struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
> +
> + if (rk_obj->pages) {
> + vunmap(vaddr);
> + return;
> + }
> +
> + /* Nothing to do if allocated by DMA mapping API. */
> }
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> index 3584b94..6aa61b2 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> @@ -23,7 +23,16 @@ struct rockchip_gem_object {
>
> void *kvaddr;
> dma_addr_t dma_addr;
> +
> + /* Used when IOMMU is disabled */
> struct dma_attrs dma_attrs;
> +
> + /* Used when IOMMU is enabled */
> + struct drm_mm_node mm;
> + unsigned long num_pages;
> + struct page **pages;
> + struct sg_table *sgt;
> + size_t size;
> };
>
> struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj);
--
Ｍark Yao
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