On 11/11/2015 06:07 PM, Alexandre Courbot wrote:
> Commit 69c4938249fb ("drm/nouveau/instmem/gk20a: use direct CPU access")
> tried to be smart while using the DMA-API by managing the CPU mappings of
> buffers allocated with the DMA-API by itself. In doing so, it relied
> on dma_to_phys() which is an architecture-private function not
> available everywhere. This broke the build on several architectures.
>
> Since there is no reliable and portable way to obtain the physical
> address of a DMA-API buffer, stop trying to be smart and just use the
> CPU mapping that the DMA-API can provide. This means that buffers will
> be CPU-mapped for all their life as opposed to when we need them, but
> anyway using the DMA-API here is a fallback for when no IOMMU is
> available so we should not expect optimal behavior.
>
> This makes the IOMMU and DMA-API implementations of instmem diverge
> enough that we should maybe put them into separate files...
>
> Signed-off-by: Alexandre Courbot <acour...@nvidia.com>
> ---
> Ben/Dave, since Dave's fix has reached mainline and builds are not
> broken anymore, we can proceed one of two ways:
>
> 1) Ben merges this for 4.4 and let it flow for -rc2
> 2) I send another fix against the kernel tree
I just spoke to Dave, and I'll take this in my tree for 4.5 if
everything works fine with the temporary hack fix. Does that sound OK
to you?
Ben.
>
> Which one shall I do?
>
> drm/nouveau/nvkm/subdev/instmem/gk20a.c | 148
> +++++++++++++-------------------
> lib/include/nvif/os.h | 6 --
> 2 files changed, 62 insertions(+), 92 deletions(-)
>
> diff --git a/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> b/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> index 681b2541229a..4c20fec64d96 100644
> --- a/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> +++ b/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> @@ -56,9 +56,6 @@ struct gk20a_instobj {
>
> /* CPU mapping */
> u32 *vaddr;
> - struct list_head vaddr_node;
> - /* How many clients are using vaddr? */
> - u32 use_cpt;
> };
> #define gk20a_instobj(p) container_of((p), struct gk20a_instobj, memory)
>
> @@ -68,7 +65,6 @@ struct gk20a_instobj {
> struct gk20a_instobj_dma {
> struct gk20a_instobj base;
>
> - u32 *cpuaddr;
> dma_addr_t handle;
> struct nvkm_mm_node r;
> };
> @@ -81,6 +77,11 @@ struct gk20a_instobj_dma {
> struct gk20a_instobj_iommu {
> struct gk20a_instobj base;
>
> + /* to link into gk20a_instmem::vaddr_lru */
> + struct list_head vaddr_node;
> + /* how many clients are using vaddr? */
> + u32 use_cpt;
> +
> /* will point to the higher half of pages */
> dma_addr_t *dma_addrs;
> /* array of base.mem->size pages (+ dma_addr_ts) */
> @@ -109,8 +110,6 @@ struct gk20a_instmem {
>
> /* Only used by DMA API */
> struct dma_attrs attrs;
> -
> - void __iomem * (*cpu_map)(struct nvkm_memory *);
> };
> #define gk20a_instmem(p) container_of((p), struct gk20a_instmem, base)
>
> @@ -132,46 +131,19 @@ gk20a_instobj_size(struct nvkm_memory *memory)
> return (u64)gk20a_instobj(memory)->mem.size << 12;
> }
>
> -static void __iomem *
> -gk20a_instobj_cpu_map_dma(struct nvkm_memory *memory)
> -{
> - struct gk20a_instobj_dma *node = gk20a_instobj_dma(memory);
> - struct device *dev = node->base.imem->base.subdev.device->dev;
> - int npages = nvkm_memory_size(memory) >> 12;
> - struct page *pages[npages];
> - int i;
> -
> - /* phys_to_page does not exist on all platforms... */
> - pages[0] = pfn_to_page(dma_to_phys(dev, node->handle) >> PAGE_SHIFT);
> - for (i = 1; i < npages; i++)
> - pages[i] = pages[0] + i;
> -
> - return vmap(pages, npages, VM_MAP, pgprot_writecombine(PAGE_KERNEL));
> -}
> -
> -static void __iomem *
> -gk20a_instobj_cpu_map_iommu(struct nvkm_memory *memory)
> -{
> - struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
> - int npages = nvkm_memory_size(memory) >> 12;
> -
> - return vmap(node->pages, npages, VM_MAP,
> - pgprot_writecombine(PAGE_KERNEL));
> -}
> -
> /*
> * Recycle the vaddr of obj. Must be called with gk20a_instmem::lock held.
> */
> static void
> -gk20a_instobj_recycle_vaddr(struct gk20a_instobj *obj)
> +gk20a_instobj_iommu_recycle_vaddr(struct gk20a_instobj_iommu *obj)
> {
> - struct gk20a_instmem *imem = obj->imem;
> + struct gk20a_instmem *imem = obj->base.imem;
> /* there should not be any user left... */
> WARN_ON(obj->use_cpt);
> list_del(&obj->vaddr_node);
> - vunmap(obj->vaddr);
> - obj->vaddr = NULL;
> - imem->vaddr_use -= nvkm_memory_size(&obj->memory);
> + vunmap(obj->base.vaddr);
> + obj->base.vaddr = NULL;
> + imem->vaddr_use -= nvkm_memory_size(&obj->base.memory);
> nvkm_debug(&imem->base.subdev, "vaddr used: %x/%x\n", imem->vaddr_use,
> imem->vaddr_max);
> }
> @@ -187,17 +159,30 @@ gk20a_instmem_vaddr_gc(struct gk20a_instmem *imem,
> const u64 size)
> if (list_empty(&imem->vaddr_lru))
> break;
>
> - gk20a_instobj_recycle_vaddr(list_first_entry(&imem->vaddr_lru,
> - struct gk20a_instobj, vaddr_node));
> + gk20a_instobj_iommu_recycle_vaddr(
> + list_first_entry(&imem->vaddr_lru,
> + struct gk20a_instobj_iommu, vaddr_node));
> }
> }
>
> static void __iomem *
> -gk20a_instobj_acquire(struct nvkm_memory *memory)
> +gk20a_instobj_acquire_dma(struct nvkm_memory *memory)
> {
> struct gk20a_instobj *node = gk20a_instobj(memory);
> struct gk20a_instmem *imem = node->imem;
> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> +
> + nvkm_ltc_flush(ltc);
> +
> + return node->vaddr;
> +}
> +
> +static void __iomem *
> +gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
> +{
> + struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
> + struct gk20a_instmem *imem = node->base.imem;
> + struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> const u64 size = nvkm_memory_size(memory);
> unsigned long flags;
>
> @@ -205,7 +190,7 @@ gk20a_instobj_acquire(struct nvkm_memory *memory)
>
> spin_lock_irqsave(&imem->lock, flags);
>
> - if (node->vaddr) {
> + if (node->base.vaddr) {
> if (!node->use_cpt) {
> /* remove from LRU list since mapping in use again */
> list_del(&node->vaddr_node);
> @@ -216,9 +201,10 @@ gk20a_instobj_acquire(struct nvkm_memory *memory)
> /* try to free some address space if we reached the limit */
> gk20a_instmem_vaddr_gc(imem, size);
>
> - node->vaddr = imem->cpu_map(memory);
> -
> - if (!node->vaddr) {
> + /* map the pages */
> + node->base.vaddr = vmap(node->pages, size >> PAGE_SHIFT, VM_MAP,
> + pgprot_writecombine(PAGE_KERNEL));
> + if (!node->base.vaddr) {
> nvkm_error(&imem->base.subdev, "cannot map instobj - "
> "this is not going to end well...\n");
> goto out;
> @@ -232,15 +218,25 @@ out:
> node->use_cpt++;
> spin_unlock_irqrestore(&imem->lock, flags);
>
> - return node->vaddr;
> + return node->base.vaddr;
> }
>
> static void
> -gk20a_instobj_release(struct nvkm_memory *memory)
> +gk20a_instobj_release_dma(struct nvkm_memory *memory)
> {
> struct gk20a_instobj *node = gk20a_instobj(memory);
> struct gk20a_instmem *imem = node->imem;
> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> +
> + nvkm_ltc_invalidate(ltc);
> +}
> +
> +static void
> +gk20a_instobj_release_iommu(struct nvkm_memory *memory)
> +{
> + struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
> + struct gk20a_instmem *imem = node->base.imem;
> + struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> unsigned long flags;
>
> spin_lock_irqsave(&imem->lock, flags);
> @@ -284,27 +280,6 @@ gk20a_instobj_map(struct nvkm_memory *memory, struct
> nvkm_vma *vma, u64 offset)
> nvkm_vm_map_at(vma, offset, &node->mem);
> }
>
> -/*
> - * Clear the CPU mapping of an instobj if it exists
> - */
> -static void
> -gk20a_instobj_dtor(struct gk20a_instobj *node)
> -{
> - struct gk20a_instmem *imem = node->imem;
> - unsigned long flags;
> -
> - spin_lock_irqsave(&imem->lock, flags);
> -
> - /* vaddr has already been recycled */
> - if (!node->vaddr)
> - goto out;
> -
> - gk20a_instobj_recycle_vaddr(node);
> -
> -out:
> - spin_unlock_irqrestore(&imem->lock, flags);
> -}
> -
> static void *
> gk20a_instobj_dtor_dma(struct nvkm_memory *memory)
> {
> @@ -312,12 +287,10 @@ gk20a_instobj_dtor_dma(struct nvkm_memory *memory)
> struct gk20a_instmem *imem = node->base.imem;
> struct device *dev = imem->base.subdev.device->dev;
>
> - gk20a_instobj_dtor(&node->base);
> -
> - if (unlikely(!node->cpuaddr))
> + if (unlikely(!node->base.vaddr))
> goto out;
>
> - dma_free_attrs(dev, node->base.mem.size << PAGE_SHIFT, node->cpuaddr,
> + dma_free_attrs(dev, node->base.mem.size << PAGE_SHIFT, node->base.vaddr,
> node->handle, &imem->attrs);
>
> out:
> @@ -331,13 +304,20 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
> struct gk20a_instmem *imem = node->base.imem;
> struct device *dev = imem->base.subdev.device->dev;
> struct nvkm_mm_node *r;
> + unsigned long flags;
> int i;
>
> - gk20a_instobj_dtor(&node->base);
> -
> if (unlikely(list_empty(&node->base.mem.regions)))
> goto out;
>
> + spin_lock_irqsave(&imem->lock, flags);
> +
> + /* vaddr has already been recycled */
> + if (node->base.vaddr)
> + gk20a_instobj_iommu_recycle_vaddr(node);
> +
> + spin_unlock_irqrestore(&imem->lock, flags);
> +
> r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
> rl_entry);
>
> @@ -368,8 +348,8 @@ gk20a_instobj_func_dma = {
> .target = gk20a_instobj_target,
> .addr = gk20a_instobj_addr,
> .size = gk20a_instobj_size,
> - .acquire = gk20a_instobj_acquire,
> - .release = gk20a_instobj_release,
> + .acquire = gk20a_instobj_acquire_dma,
> + .release = gk20a_instobj_release_dma,
> .rd32 = gk20a_instobj_rd32,
> .wr32 = gk20a_instobj_wr32,
> .map = gk20a_instobj_map,
> @@ -381,8 +361,8 @@ gk20a_instobj_func_iommu = {
> .target = gk20a_instobj_target,
> .addr = gk20a_instobj_addr,
> .size = gk20a_instobj_size,
> - .acquire = gk20a_instobj_acquire,
> - .release = gk20a_instobj_release,
> + .acquire = gk20a_instobj_acquire_iommu,
> + .release = gk20a_instobj_release_iommu,
> .rd32 = gk20a_instobj_rd32,
> .wr32 = gk20a_instobj_wr32,
> .map = gk20a_instobj_map,
> @@ -402,10 +382,10 @@ gk20a_instobj_ctor_dma(struct gk20a_instmem *imem, u32
> npages, u32 align,
>
> nvkm_memory_ctor(&gk20a_instobj_func_dma, &node->base.memory);
>
> - node->cpuaddr = dma_alloc_attrs(dev, npages << PAGE_SHIFT,
> - &node->handle, GFP_KERNEL,
> - &imem->attrs);
> - if (!node->cpuaddr) {
> + node->base.vaddr = dma_alloc_attrs(dev, npages << PAGE_SHIFT,
> + &node->handle, GFP_KERNEL,
> + &imem->attrs);
> + if (!node->base.vaddr) {
> nvkm_error(subdev, "cannot allocate DMA memory\n");
> return -ENOMEM;
> }
> @@ -611,18 +591,14 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
> imem->mm = &tdev->iommu.mm;
> imem->domain = tdev->iommu.domain;
> imem->iommu_pgshift = tdev->iommu.pgshift;
> - imem->cpu_map = gk20a_instobj_cpu_map_iommu;
> imem->iommu_bit = tdev->func->iommu_bit;
>
> nvkm_info(&imem->base.subdev, "using IOMMU\n");
> } else {
> init_dma_attrs(&imem->attrs);
> - /* We will access the memory through our own mapping */
> dma_set_attr(DMA_ATTR_NON_CONSISTENT, &imem->attrs);
> dma_set_attr(DMA_ATTR_WEAK_ORDERING, &imem->attrs);
> dma_set_attr(DMA_ATTR_WRITE_COMBINE, &imem->attrs);
> - dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &imem->attrs);
> - imem->cpu_map = gk20a_instobj_cpu_map_dma;
>
> nvkm_info(&imem->base.subdev, "using DMA API\n");
> }
> diff --git a/lib/include/nvif/os.h b/lib/include/nvif/os.h
> index 2df30489179a..e8c06cb254dc 100644
> --- a/lib/include/nvif/os.h
> +++ b/lib/include/nvif/os.h
> @@ -943,12 +943,6 @@ dma_unmap_page(struct device *pdev, dma_addr_t addr, int
> size, unsigned flags)
> {
> }
>
> -static inline phys_addr_t
> -dma_to_phys(struct device *dev, dma_addr_t addr)
> -{
> - return 0;
> -}
> -
>
> /******************************************************************************
> * PCI
>
> *****************************************************************************/
>
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