gpu: nvgpu: Make buf alignment generic

Drastically simplify and move the aligment computation for buffers
getting mapped into the SGT code. An SGT is all that is needed for
computing the alignment.

However, this did require that a new SGT op was added:

  nvgpu_sgt_iommuable()

This function returns true if the passed SGT is IOMMU'able and must
be implemented by an SGT implementation that has IOMMU'able buffers.
If this function is left as NULL then it is assumed that the buffer
is not IOMMU'able.

Also cleanup the parameter ordering convention among all nvgpu_sgt
functions. Previously there was a mishmash of different parameter
orderings. This patch now standardizes on the gk20a first approach
seen everywhere else in the driver.

JIRA NVGPU-30
JIRA NVGPU-246
JIRA NVGPU-71

Change-Id: Ic4ab7b752847cf795c7cfafed5a07818217bba86
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1583985
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

6 files changed, 86 insertions, 74 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c b/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
index 1dbbd1a0..2587d56a 100644
--- a/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
+++ b/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
@@ -529,6 +529,12 @@ static u64 nvgpu_mem_linux_sgl_gpu_addr(struct gk20a *g, void *sgl,
                                 sg_dma_address((struct scatterlist *)sgl));
 }
 
+static bool nvgpu_mem_linux_sgt_iommuable(struct gk20a *g,
+                                          struct nvgpu_sgt *sgt)
+{
+        return true;
+}
+
 static void nvgpu_mem_linux_sgl_free(struct gk20a *g, struct nvgpu_sgt *sgt)
 {
         /*
@@ -539,12 +545,13 @@ static void nvgpu_mem_linux_sgl_free(struct gk20a *g, struct nvgpu_sgt *sgt)
 }
 
 static const struct nvgpu_sgt_ops nvgpu_linux_sgt_ops = {
-        .sgl_next     = nvgpu_mem_linux_sgl_next,
-        .sgl_phys     = nvgpu_mem_linux_sgl_phys,
-        .sgl_dma      = nvgpu_mem_linux_sgl_dma,
-        .sgl_length   = nvgpu_mem_linux_sgl_length,
-        .sgl_gpu_addr = nvgpu_mem_linux_sgl_gpu_addr,
-        .sgt_free     = nvgpu_mem_linux_sgl_free,
+        .sgl_next      = nvgpu_mem_linux_sgl_next,
+        .sgl_phys      = nvgpu_mem_linux_sgl_phys,
+        .sgl_dma       = nvgpu_mem_linux_sgl_dma,
+        .sgl_length    = nvgpu_mem_linux_sgl_length,
+        .sgl_gpu_addr  = nvgpu_mem_linux_sgl_gpu_addr,
+        .sgt_iommuable = nvgpu_mem_linux_sgt_iommuable,
+        .sgt_free      = nvgpu_mem_linux_sgl_free,
 };
 
 static struct nvgpu_sgt *__nvgpu_mem_get_sgl_from_vidmem(
diff --git a/drivers/gpu/nvgpu/common/linux/vm.c b/drivers/gpu/nvgpu/common/linux/vm.c
index 895a5771..006216c2 100644
--- a/drivers/gpu/nvgpu/common/linux/vm.c
+++ b/drivers/gpu/nvgpu/common/linux/vm.c
@@ -59,62 +59,6 @@ static struct nvgpu_mapped_buf *__nvgpu_vm_find_mapped_buf_reverse(
         return NULL;
 }
 
-/*
- * Determine alignment for a passed buffer. Necessary since the buffer may
- * appear big to map with large pages but the SGL may have chunks that are not
- * aligned on a 64/128kB large page boundary.
- */
-static u64 nvgpu_get_buffer_alignment(struct gk20a *g, struct scatterlist *sgl,
-                                      enum nvgpu_aperture aperture)
-{
-        u64 align = 0, chunk_align = 0;
-        u64 buf_addr;
-
-        if (aperture == APERTURE_VIDMEM) {
-                struct nvgpu_page_alloc *alloc =
-                        nvgpu_vidmem_get_page_alloc(sgl);
-                struct nvgpu_sgt *sgt = &alloc->sgt;
-                void *sgl_vid = sgt->sgl;
-
-                while (sgl_vid) {
-                        chunk_align = 1ULL <<
-                                __ffs(nvgpu_sgt_get_phys(sgt, sgl_vid)) |
-                                nvgpu_sgt_get_length(sgt, sgl_vid);
-
-                        if (align)
-                                align = min(align, chunk_align);
-                        else
-                                align = chunk_align;
-
-                        sgl_vid = nvgpu_sgt_get_next(sgt, sgl_vid);
-                }
-
-                return align;
-        }
-
-        buf_addr = (u64)sg_dma_address(sgl);
-
-        if (g->mm.bypass_smmu || buf_addr == DMA_ERROR_CODE || !buf_addr) {
-                while (sgl) {
-                        buf_addr = (u64)sg_phys(sgl);
-                        chunk_align = 1ULL << __ffs(buf_addr |
-                                                    (u64)sgl->length);
-
-                        if (align)
-                                align = min(align, chunk_align);
-                        else
-                                align = chunk_align;
-                        sgl = sg_next(sgl);
-                }
-
-                return align;
-        }
-
-        align = 1ULL << __ffs(buf_addr);
-
-        return align;
-}
-
 int nvgpu_vm_find_buf(struct vm_gk20a *vm, u64 gpu_va,
                       struct dma_buf **dmabuf,
                       u64 *offset)
@@ -218,7 +162,7 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
         struct nvgpu_ctag_buffer_info binfo = { 0 };
         struct gk20a_comptags comptags;
         struct nvgpu_vm_area *vm_area = NULL;
-        struct nvgpu_sgt *nvgpu_sgt;
+        struct nvgpu_sgt *nvgpu_sgt = NULL;
         struct sg_table *sgt;
         struct nvgpu_mapped_buf *mapped_buffer = NULL;
         enum nvgpu_aperture aperture;
@@ -279,6 +223,10 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
                 goto clean_up;
         }
 
+        nvgpu_sgt = nvgpu_linux_sgt_create(g, sgt);
+        if (!nvgpu_sgt)
+                goto clean_up;
+
         aperture = gk20a_dmabuf_aperture(g, dmabuf);
         if (aperture == APERTURE_INVALID) {
                 err = -EINVAL;
@@ -288,7 +236,7 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
         if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)
                 map_offset = offset_align;
 
-        align = nvgpu_get_buffer_alignment(g, sgt->sgl, aperture);
+        align = nvgpu_sgt_alignment(g, nvgpu_sgt);
         if (g->mm.disable_bigpage)
                 binfo.pgsz_idx = gmmu_page_size_small;
         else
@@ -370,8 +318,6 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
                 ctag_offset += buffer_offset >>
                                ilog2(g->ops.fb.compression_page_size(g));
 
-        nvgpu_sgt = nvgpu_linux_sgt_create(g, sgt);
-
         /* update gmmu ptes */
         map_offset = g->ops.mm.gmmu_map(vm,
                                         map_offset,
@@ -391,7 +337,7 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
         if (!map_offset)
                 goto clean_up;
 
-        nvgpu_sgt_free(nvgpu_sgt, g);
+        nvgpu_sgt_free(g, nvgpu_sgt);
 
         mapped_buffer = nvgpu_kzalloc(g, sizeof(*mapped_buffer));
         if (!mapped_buffer) {
@@ -434,6 +380,9 @@ int nvgpu_vm_map_linux(struct vm_gk20a *vm,
 
 clean_up:
         nvgpu_kfree(g, mapped_buffer);
+
+        if (nvgpu_sgt)
+                nvgpu_sgt_free(g, nvgpu_sgt);
         if (va_allocated)
                 __nvgpu_vm_free_va(vm, map_offset, binfo.pgsz_idx);
         if (!IS_ERR(sgt))
diff --git a/drivers/gpu/nvgpu/common/mm/gmmu.c b/drivers/gpu/nvgpu/common/mm/gmmu.c
index 875bcc4e..4289104d 100644
--- a/drivers/gpu/nvgpu/common/mm/gmmu.c
+++ b/drivers/gpu/nvgpu/common/mm/gmmu.c
@@ -93,7 +93,7 @@ static u64 __nvgpu_gmmu_map(struct vm_gk20a *vm,
                                    aperture);
         nvgpu_mutex_release(&vm->update_gmmu_lock);
 
-        nvgpu_sgt_free(sgt, g);
+        nvgpu_sgt_free(g, sgt);
 
         if (!vaddr) {
                 nvgpu_err(g, "failed to map buffer!");
@@ -500,7 +500,7 @@ static int __nvgpu_gmmu_do_update_page_table(struct vm_gk20a *vm,
          * IO address and will be contiguous.
          */
         if (attrs->aperture == APERTURE_SYSMEM && !g->mm.bypass_smmu) {
-                u64 io_addr = nvgpu_sgt_get_gpu_addr(sgt, g, sgt->sgl, attrs);
+                u64 io_addr = nvgpu_sgt_get_gpu_addr(g, sgt, sgt->sgl, attrs);
 
                 io_addr += space_to_skip;
 
diff --git a/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c b/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
index 9f677058..b4e718b4 100644
--- a/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
+++ b/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
@@ -47,13 +47,20 @@ u64 nvgpu_sgt_get_length(struct nvgpu_sgt *sgt, void *sgl)
         return sgt->ops->sgl_length(sgl);
 }
 
-u64 nvgpu_sgt_get_gpu_addr(struct nvgpu_sgt *sgt, struct gk20a *g, void *sgl,
+u64 nvgpu_sgt_get_gpu_addr(struct gk20a *g, struct nvgpu_sgt *sgt, void *sgl,
                            struct nvgpu_gmmu_attrs *attrs)
 {
         return sgt->ops->sgl_gpu_addr(g, sgl, attrs);
 }
 
-void nvgpu_sgt_free(struct nvgpu_sgt *sgt, struct gk20a *g)
+bool nvgpu_sgt_iommuable(struct gk20a *g, struct nvgpu_sgt *sgt)
+{
+        if (sgt->ops->sgt_iommuable)
+                return sgt->ops->sgt_iommuable(g, sgt);
+        return false;
+}
+
+void nvgpu_sgt_free(struct gk20a *g, struct nvgpu_sgt *sgt)
 {
         if (sgt && sgt->ops->sgt_free)
                 sgt->ops->sgt_free(g, sgt);
@@ -69,3 +76,44 @@ u64 nvgpu_mem_iommu_translate(struct gk20a *g, u64 phys)
 
         return phys;
 }
+
+/*
+ * Determine alignment for a passed buffer. Necessary since the buffer may
+ * appear big enough to map with large pages but the SGL may have chunks that
+ * are not aligned on a 64/128kB large page boundary. There's also the
+ * possibility chunks are odd sizes which will necessitate small page mappings
+ * to correctly glue them together into a contiguous virtual mapping.
+ */
+u64 nvgpu_sgt_alignment(struct gk20a *g, struct nvgpu_sgt *sgt)
+{
+        u64 align = 0, chunk_align = 0;
+        void *sgl;
+
+        /*
+         * If this SGT is iommuable and we want to use the IOMMU address then
+         * the SGT's first entry has the IOMMU address. We will align on this
+         * and double check length of buffer later. Also, since there's an
+         * IOMMU we know that this DMA address is contiguous.
+         */
+        if (!g->mm.bypass_smmu &&
+            nvgpu_sgt_iommuable(g, sgt) &&
+            nvgpu_sgt_get_dma(sgt, sgt->sgl))
+                return 1ULL << __ffs(nvgpu_sgt_get_dma(sgt, sgt->sgl));
+
+        /*
+         * Otherwise the buffer is not iommuable (VIDMEM, for example) or we are
+         * bypassing the IOMMU and need to use the underlying physical entries
+         * of the SGT.
+         */
+        nvgpu_sgt_for_each_sgl(sgl, sgt) {
+                chunk_align = 1ULL << __ffs(nvgpu_sgt_get_phys(sgt, sgl) |
+                                            nvgpu_sgt_get_length(sgt, sgl));
+
+                if (align)
+                        align = min(align, chunk_align);
+                else
+                        align = chunk_align;
+        }
+
+        return align;
+}
diff --git a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
index 6feacff7..2b8b7015 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
@@ -62,6 +62,11 @@ struct nvgpu_sgt_ops {
         u64   (*sgl_gpu_addr)(struct gk20a *g, void *sgl,
                               struct nvgpu_gmmu_attrs *attrs);
         /*
+         * If left NULL then iommuable is assumed to be false.
+         */
+        bool  (*sgt_iommuable)(struct gk20a *g, struct nvgpu_sgt *sgt);
+
+        /*
          * Note: this operates on the whole SGT not a specific SGL entry.
          */
         void  (*sgt_free)(struct gk20a *g, struct nvgpu_sgt *sgt);
@@ -232,9 +237,12 @@ void *nvgpu_sgt_get_next(struct nvgpu_sgt *sgt, void *sgl);
 u64 nvgpu_sgt_get_phys(struct nvgpu_sgt *sgt, void *sgl);
 u64 nvgpu_sgt_get_dma(struct nvgpu_sgt *sgt, void *sgl);
 u64 nvgpu_sgt_get_length(struct nvgpu_sgt *sgt, void *sgl);
-u64 nvgpu_sgt_get_gpu_addr(struct nvgpu_sgt *sgt, struct gk20a *g, void *sgl,
+u64 nvgpu_sgt_get_gpu_addr(struct gk20a *g, struct nvgpu_sgt *sgt, void *sgl,
                            struct nvgpu_gmmu_attrs *attrs);
-void nvgpu_sgt_free(struct nvgpu_sgt *sgt, struct gk20a *g);
+void nvgpu_sgt_free(struct gk20a *g, struct nvgpu_sgt *sgt);
+
+bool nvgpu_sgt_iommuable(struct gk20a *g, struct nvgpu_sgt *sgt);
+u64 nvgpu_sgt_alignment(struct gk20a *g, struct nvgpu_sgt *sgt);
 
 /**
  * nvgpu_mem_create_from_mem - Create a new nvgpu_mem struct from an old one.
diff --git a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
index 498a1528..a125366a 100644
--- a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
+++ b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
@@ -107,7 +107,7 @@ u64 vgpu_locked_gmmu_map(struct vm_gk20a *vm,
         struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(d);
         struct tegra_vgpu_cmd_msg msg;
         struct tegra_vgpu_as_map_params *p = &msg.params.as_map;
-        u64 addr = nvgpu_sgt_get_gpu_addr(sgt, g, sgt->sgl, NULL);
+        u64 addr = nvgpu_sgt_get_gpu_addr(g, sgt, sgt->sgl, NULL);
         u8 prot;
 
         gk20a_dbg_fn("");