[PATCH] drm/amd/amdgpu: Code comments for the amdgpu_ttm.c driver. (v2)
Tom St Denis
tom.stdenis at amd.com
Tue May 15 14:02:15 UTC 2018
NFC just comments.
(v2): Updated based on feedback from Alex Deucher.
Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 347 +++++++++++++++++++++++++++++++-
1 file changed, 340 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index dfd22db13fb1..2eaaa1fb7b59 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -63,16 +63,44 @@ static void amdgpu_ttm_debugfs_fini(struct amdgpu_device *adev);
/*
* Global memory.
*/
+
+/**
+ * amdgpu_ttm_mem_global_init - Initialize and acquire reference to
+ * memory object
+ *
+ * @ref: Object for initialization.
+ *
+ * This is called by drm_global_item_ref() when an object is being
+ * initialized.
+ */
static int amdgpu_ttm_mem_global_init(struct drm_global_reference *ref)
{
return ttm_mem_global_init(ref->object);
}
+/**
+ * amdgpu_ttm_mem_global_release - Drop reference to a memory object
+ *
+ * @ref: Object being removed
+ *
+ * This is called by drm_global_item_unref() when an object is being
+ * released.
+ */
static void amdgpu_ttm_mem_global_release(struct drm_global_reference *ref)
{
ttm_mem_global_release(ref->object);
}
+/**
+ * amdgpu_ttm_global_init - Initialize global TTM memory reference
+ * structures.
+ *
+ * @adev: AMDGPU device for which the global structures need to be
+ * registered.
+ *
+ * This is called as part of the AMDGPU ttm init from amdgpu_ttm_init()
+ * during bring up.
+ */
static int amdgpu_ttm_global_init(struct amdgpu_device *adev)
{
struct drm_global_reference *global_ref;
@@ -80,7 +108,9 @@ static int amdgpu_ttm_global_init(struct amdgpu_device *adev)
struct drm_sched_rq *rq;
int r;
+ /* ensure reference is false in case init fails */
adev->mman.mem_global_referenced = false;
+
global_ref = &adev->mman.mem_global_ref;
global_ref->global_type = DRM_GLOBAL_TTM_MEM;
global_ref->size = sizeof(struct ttm_mem_global);
@@ -146,6 +176,18 @@ static int amdgpu_invalidate_caches(struct ttm_bo_device *bdev, uint32_t flags)
return 0;
}
+/**
+ * amdgpu_init_mem_type - Initialize a memory manager for a specific
+ * type of memory request.
+ *
+ * @bdev: The TTM BO device object (contains a reference to
+ * amdgpu_device)
+ * @type: The type of memory requested
+ * @man:
+ *
+ * This is called by ttm_bo_init_mm() when a buffer object is being
+ * initialized.
+ */
static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
struct ttm_mem_type_manager *man)
{
@@ -161,6 +203,7 @@ static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
man->default_caching = TTM_PL_FLAG_CACHED;
break;
case TTM_PL_TT:
+ /* GTT memory */
man->func = &amdgpu_gtt_mgr_func;
man->gpu_offset = adev->gmc.gart_start;
man->available_caching = TTM_PL_MASK_CACHING;
@@ -193,6 +236,14 @@ static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
return 0;
}
+/**
+ * amdgpu_evict_flags - Compute placement flags
+ *
+ * @bo: The buffer object to evict
+ * @placement: Possible destination(s) for evicted BO
+ *
+ * Fill in placement data when ttm_bo_evict() is called
+ */
static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
struct ttm_placement *placement)
{
@@ -204,12 +255,14 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM
};
+ /* Don't handle scatter gather BOs */
if (bo->type == ttm_bo_type_sg) {
placement->num_placement = 0;
placement->num_busy_placement = 0;
return;
}
+ /* Object isn't an AMDGPU object so ignore */
if (!amdgpu_ttm_bo_is_amdgpu_bo(bo)) {
placement->placement = &placements;
placement->busy_placement = &placements;
@@ -217,10 +270,12 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
placement->num_busy_placement = 1;
return;
}
+
abo = ttm_to_amdgpu_bo(bo);
switch (bo->mem.mem_type) {
case TTM_PL_VRAM:
if (!adev->mman.buffer_funcs_enabled) {
+ /* Move to system memory */
amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_CPU);
} else if (adev->gmc.visible_vram_size < adev->gmc.real_vram_size &&
!(abo->flags & AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED) &&
@@ -238,6 +293,7 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
abo->placement.busy_placement = &abo->placements[1];
abo->placement.num_busy_placement = 1;
} else {
+ /* Move to GTT memory */
amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_GTT);
}
break;
@@ -248,6 +304,15 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
*placement = abo->placement;
}
+/**
+ * amdgpu_verify_access - Verify access for a mmap call
+ *
+ * @bo: The buffer object to map
+ * @filp: The file pointer from the process performing the mmap
+ *
+ * This is called by ttm_bo_mmap() to verify whether a process
+ * has the right to mmap a BO to their process space.
+ */
static int amdgpu_verify_access(struct ttm_buffer_object *bo, struct file *filp)
{
struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
@@ -265,6 +330,15 @@ static int amdgpu_verify_access(struct ttm_buffer_object *bo, struct file *filp)
filp->private_data);
}
+/**
+ * amdgpu_move_null - Register memory for a buffer object
+ *
+ * @bo: The bo to assign the memory to
+ * @new_mem: The memory to be assigned.
+ *
+ * Assign the memory from new_mem to the memory of the buffer object
+ * bo.
+ */
static void amdgpu_move_null(struct ttm_buffer_object *bo,
struct ttm_mem_reg *new_mem)
{
@@ -275,6 +349,10 @@ static void amdgpu_move_null(struct ttm_buffer_object *bo,
new_mem->mm_node = NULL;
}
+/**
+ * amdgpu_mm_node_addr - Compute the GPU relative offset of a GTT
+ * buffer.
+ */
static uint64_t amdgpu_mm_node_addr(struct ttm_buffer_object *bo,
struct drm_mm_node *mm_node,
struct ttm_mem_reg *mem)
@@ -289,9 +367,10 @@ static uint64_t amdgpu_mm_node_addr(struct ttm_buffer_object *bo,
}
/**
- * amdgpu_find_mm_node - Helper function finds the drm_mm_node
- * corresponding to @offset. It also modifies the offset to be
- * within the drm_mm_node returned
+ * amdgpu_find_mm_node - Helper function finds the drm_mm_node
+ * corresponding to @offset. It also modifies
+ * the offset to be within the drm_mm_node
+ * returned
*/
static struct drm_mm_node *amdgpu_find_mm_node(struct ttm_mem_reg *mem,
unsigned long *offset)
@@ -430,7 +509,12 @@ int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
return r;
}
-
+/**
+ * amdgpu_move_blit - Copy an entire buffer to another buffer
+ *
+ * This is a helper called by amdgpu_bo_move() and
+ * amdgpu_move_vram_ram() to help move buffers to and from VRAM.
+ */
static int amdgpu_move_blit(struct ttm_buffer_object *bo,
bool evict, bool no_wait_gpu,
struct ttm_mem_reg *new_mem,
@@ -465,6 +549,11 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
return r;
}
+/**
+ * amdgpu_move_vram_ram - Copy VRAM buffer to RAM buffer
+ *
+ * Called by amdgpu_bo_move().
+ */
static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
struct ttm_operation_ctx *ctx,
struct ttm_mem_reg *new_mem)
@@ -477,6 +566,8 @@ static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
int r;
adev = amdgpu_ttm_adev(bo->bdev);
+
+ /* create space/pages for new_mem in GTT space */
tmp_mem = *new_mem;
tmp_mem.mm_node = NULL;
placement.num_placement = 1;
@@ -491,25 +582,36 @@ static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
return r;
}
+ /* set caching flags */
r = ttm_tt_set_placement_caching(bo->ttm, tmp_mem.placement);
if (unlikely(r)) {
goto out_cleanup;
}
+ /* Bind the memory to the GTT space */
r = ttm_tt_bind(bo->ttm, &tmp_mem, ctx);
if (unlikely(r)) {
goto out_cleanup;
}
+
+ /* blit VRAM to GTT */
r = amdgpu_move_blit(bo, true, ctx->no_wait_gpu, &tmp_mem, old_mem);
if (unlikely(r)) {
goto out_cleanup;
}
+
+ /* move BO (in tmp_mem) to new_mem */
r = ttm_bo_move_ttm(bo, ctx, new_mem);
out_cleanup:
ttm_bo_mem_put(bo, &tmp_mem);
return r;
}
+/**
+ * amdgpu_move_ram_vram - Copy buffer from RAM to VRAM
+ *
+ * Called by amdgpu_bo_move().
+ */
static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
struct ttm_operation_ctx *ctx,
struct ttm_mem_reg *new_mem)
@@ -522,6 +624,8 @@ static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
int r;
adev = amdgpu_ttm_adev(bo->bdev);
+
+ /* make space in GTT for old_mem buffer */
tmp_mem = *new_mem;
tmp_mem.mm_node = NULL;
placement.num_placement = 1;
@@ -535,10 +639,14 @@ static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
if (unlikely(r)) {
return r;
}
+
+ /* move/bind old memory to GTT space */
r = ttm_bo_move_ttm(bo, ctx, &tmp_mem);
if (unlikely(r)) {
goto out_cleanup;
}
+
+ /* copy to VRAM */
r = amdgpu_move_blit(bo, true, ctx->no_wait_gpu, new_mem, old_mem);
if (unlikely(r)) {
goto out_cleanup;
@@ -548,6 +656,11 @@ static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
return r;
}
+/**
+ * amdgpu_bo_move - Move a buffer object to a new memory location
+ *
+ * Called by ttm_bo_handle_move_mem()
+ */
static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
struct ttm_operation_ctx *ctx,
struct ttm_mem_reg *new_mem)
@@ -613,6 +726,11 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
return 0;
}
+/**
+ * amdgpu_ttm_io_mem_reserve - Reserve a block of memory during a fault
+ *
+ * Called by ttm_mem_io_reserve() ultimately via ttm_bo_vm_fault()
+ */
static int amdgpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
{
struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
@@ -690,6 +808,14 @@ struct amdgpu_ttm_tt {
uint32_t last_set_pages;
};
+/**
+ * amdgpu_ttm_tt_get_user_pages - Pin pages of memory pointed to
+ * by a USERPTR pointer to memory
+ *
+ * Called by amdgpu_gem_userptr_ioctl() and amdgpu_cs_parser_bos().
+ * This provides a wrapper around the get_user_pages() call to provide
+ * device accessible pages that back user memory.
+ */
int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -715,6 +841,7 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
}
}
+ /* loop enough times using contiguous pages of memory */
do {
unsigned num_pages = ttm->num_pages - pinned;
uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
@@ -748,6 +875,14 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
return r;
}
+/**
+ * amdgpu_ttm_tt_set_user_pages - Copy pages in, putting old pages
+ * as necessary.
+ *
+ * Called by amdgpu_cs_list_validate(). This creates the page list
+ * that backs user memory and will ultimately be mapped into the device
+ * address space.
+ */
void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -762,6 +897,11 @@ void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages)
}
}
+/**
+ * amdgpu_ttm_tt_mark_user_page - Mark pages as dirty
+ *
+ * Called while unpinning userptr pages
+ */
void amdgpu_ttm_tt_mark_user_pages(struct ttm_tt *ttm)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -780,7 +920,12 @@ void amdgpu_ttm_tt_mark_user_pages(struct ttm_tt *ttm)
}
}
-/* prepare the sg table with the user pages */
+/**
+ * amdgpu_ttm_tt_pin_userptr - prepare the sg table with the
+ * user pages
+ *
+ * Called by amdgpu_ttm_backend_bind()
+ **/
static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
{
struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
@@ -792,17 +937,20 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
enum dma_data_direction direction = write ?
DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
+ /* Allocate an SG array and squash pages into it */
r = sg_alloc_table_from_pages(ttm->sg, ttm->pages, ttm->num_pages, 0,
ttm->num_pages << PAGE_SHIFT,
GFP_KERNEL);
if (r)
goto release_sg;
+ /* Map SG to device */
r = -ENOMEM;
nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
if (nents != ttm->sg->nents)
goto release_sg;
+ /* convert SG to linear array of pages and dma addresses */
drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
gtt->ttm.dma_address, ttm->num_pages);
@@ -813,6 +961,9 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
return r;
}
+/**
+ * amdgpu_ttm_tt_unpin_userptr - Unpin and unmap userptr pages
+ */
static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
{
struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
@@ -826,14 +977,22 @@ static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
if (!ttm->sg->sgl)
return;
- /* free the sg table and pages again */
+ /* unmap the pages mapped to the device */
dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
+ /* mark the pages as dirty */
amdgpu_ttm_tt_mark_user_pages(ttm);
sg_free_table(ttm->sg);
}
+
+/**
+ * amdgpu_ttm_backend_bind - Bind GTT memory
+ *
+ * Called by ttm_tt_bind() on behalf of ttm_bo_handle_move_mem().
+ * This handles binding GTT memory to the device address space.
+ */
static int amdgpu_ttm_backend_bind(struct ttm_tt *ttm,
struct ttm_mem_reg *bo_mem)
{
@@ -864,7 +1023,10 @@ static int amdgpu_ttm_backend_bind(struct ttm_tt *ttm,
return 0;
}
+ /* compute PTE flags relevant to this BO memory */
flags = amdgpu_ttm_tt_pte_flags(adev, ttm, bo_mem);
+
+ /* bind pages into GART page tables */
gtt->offset = (u64)bo_mem->start << PAGE_SHIFT;
r = amdgpu_gart_bind(adev, gtt->offset, ttm->num_pages,
ttm->pages, gtt->ttm.dma_address, flags);
@@ -875,6 +1037,9 @@ static int amdgpu_ttm_backend_bind(struct ttm_tt *ttm,
return r;
}
+/**
+ * amdgpu_ttm_alloc_gart - Allocate GART memory for buffer object
+ */
int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
{
struct amdgpu_device *adev = amdgpu_ttm_adev(bo->bdev);
@@ -890,6 +1055,7 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
amdgpu_gtt_mgr_has_gart_addr(&bo->mem))
return 0;
+ /* allocate GTT space */
tmp = bo->mem;
tmp.mm_node = NULL;
placement.num_placement = 1;
@@ -905,7 +1071,10 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
if (unlikely(r))
return r;
+ /* compute PTE flags for this buffer object */
flags = amdgpu_ttm_tt_pte_flags(adev, bo->ttm, &tmp);
+
+ /* Bind pages */
gtt->offset = (u64)tmp.start << PAGE_SHIFT;
r = amdgpu_gart_bind(adev, gtt->offset, bo->ttm->num_pages,
bo->ttm->pages, gtt->ttm.dma_address, flags);
@@ -922,6 +1091,12 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
return 0;
}
+/**
+ * amdgpu_ttm_recover_gart - Rebind GTT pages
+ *
+ * Called by amdgpu_gtt_mgr_recover() from amdgpu_device_reset() to
+ * rebind GTT pages during a GPU reset.
+ */
int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo)
{
struct amdgpu_device *adev = amdgpu_ttm_adev(tbo->bdev);
@@ -941,12 +1116,19 @@ int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo)
return r;
}
+/**
+ * amdgpu_ttm_backend_unbind - Unbind GTT mapped pages
+ *
+ * Called by ttm_tt_unbind() on behalf of ttm_bo_move_ttm() and
+ * ttm_tt_destroy().
+ */
static int amdgpu_ttm_backend_unbind(struct ttm_tt *ttm)
{
struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
struct amdgpu_ttm_tt *gtt = (void *)ttm;
int r;
+ /* if the pages have userptr pinning then clear that first */
if (gtt->userptr)
amdgpu_ttm_tt_unpin_userptr(ttm);
@@ -975,6 +1157,13 @@ static struct ttm_backend_func amdgpu_backend_func = {
.destroy = &amdgpu_ttm_backend_destroy,
};
+/**
+ * amdgpu_ttm_tt_create - Create a ttm_tt object for a given BO
+ *
+ * @bo: The buffer object to create a GTT ttm_tt object around
+ *
+ * Called by ttm_tt_create().
+ */
static struct ttm_tt *amdgpu_ttm_tt_create(struct ttm_buffer_object *bo,
uint32_t page_flags)
{
@@ -988,6 +1177,8 @@ static struct ttm_tt *amdgpu_ttm_tt_create(struct ttm_buffer_object *bo,
return NULL;
}
gtt->ttm.ttm.func = &amdgpu_backend_func;
+
+ /* allocate space for the uninitialized page entries */
if (ttm_sg_tt_init(>t->ttm, bo, page_flags)) {
kfree(gtt);
return NULL;
@@ -995,6 +1186,12 @@ static struct ttm_tt *amdgpu_ttm_tt_create(struct ttm_buffer_object *bo,
return >t->ttm.ttm;
}
+/**
+ * amdgpu_ttm_tt_populate - Map GTT pages visible to the device
+ *
+ * Map the pages of a ttm_tt object to an address space visible
+ * to the underlying device.
+ */
static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm,
struct ttm_operation_ctx *ctx)
{
@@ -1002,6 +1199,7 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm,
struct amdgpu_ttm_tt *gtt = (void *)ttm;
bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
+ /* user pages are bound by amdgpu_ttm_tt_pin_userptr() */
if (gtt && gtt->userptr) {
ttm->sg = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
if (!ttm->sg)
@@ -1026,9 +1224,17 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm,
}
#endif
+ /* fall back to generic helper to populate the page array
+ * and map them to the device */
return ttm_populate_and_map_pages(adev->dev, >t->ttm, ctx);
}
+/**
+ * amdgpu_ttm_tt_unpopulate - unmap GTT pages and unpopulate page arrays
+ *
+ * Unmaps pages of a ttm_tt object from the device address space and
+ * unpopulates the page array backing it.
+ */
static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
{
struct amdgpu_device *adev;
@@ -1054,9 +1260,21 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
}
#endif
+ /* fall back to generic helper to unmap and unpopulate array */
ttm_unmap_and_unpopulate_pages(adev->dev, >t->ttm);
}
+/**
+ * amdgpu_ttm_tt_set_userptr - Initialize userptr GTT ttm_tt
+ * for the current task
+ *
+ * @ttm: The ttm_tt object to bind this userptr object to
+ * @addr: The address in the current tasks VM space to use
+ * @flags: Requirements of userptr object.
+ *
+ * Called by amdgpu_gem_userptr_ioctl() to bind userptr pages
+ * to current task
+ */
int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
uint32_t flags)
{
@@ -1076,6 +1294,9 @@ int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
return 0;
}
+/**
+ * amdgpu_ttm_tt_get_usermm - Return memory manager for ttm_tt object
+ */
struct mm_struct *amdgpu_ttm_tt_get_usermm(struct ttm_tt *ttm)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -1086,6 +1307,12 @@ struct mm_struct *amdgpu_ttm_tt_get_usermm(struct ttm_tt *ttm)
return gtt->usermm;
}
+/**
+ * amdgpu_ttm_tt_affect_userptr - Determine if a ttm_tt object lays
+ * inside an address range for the
+ * current task.
+ *
+ */
bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
unsigned long end)
{
@@ -1096,10 +1323,14 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
if (gtt == NULL || !gtt->userptr)
return false;
+ /* does the address lie within the span for the userptr memory? */
size = (unsigned long)gtt->ttm.ttm.num_pages * PAGE_SIZE;
if (gtt->userptr > end || gtt->userptr + size <= start)
return false;
+ /* Search the lists of tasks that hold this mapping and see
+ * if current is one of them. If it is return false.
+ */
spin_lock(>t->guptasklock);
list_for_each_entry(entry, >t->guptasks, list) {
if (entry->task == current) {
@@ -1114,6 +1345,10 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
return true;
}
+/**
+ * amdgpu_ttm_tt_userptr_invalidated - Has the ttm_tt object been
+ * invalidated?
+ */
bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
int *last_invalidated)
{
@@ -1124,6 +1359,12 @@ bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
return prev_invalidated != *last_invalidated;
}
+/**
+ * amdgpu_ttm_tt_userptr_needs_pages - Have the pages backing this
+ * ttm_tt object been invalidated
+ * since the last time they've
+ * been set?
+ */
bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -1134,6 +1375,9 @@ bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm)
return atomic_read(>t->mmu_invalidations) != gtt->last_set_pages;
}
+/**
+ * amdgpu_ttm_tt_is_readonly - Is the ttm_tt object read only?
+ */
bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm)
{
struct amdgpu_ttm_tt *gtt = (void *)ttm;
@@ -1144,6 +1388,12 @@ bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm)
return !!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
}
+/**
+ * amdgpu_ttm_tt_pte_flags - Compute PTE flags for ttm_tt object
+ *
+ * @ttm: The ttm_tt object to compute the flags for
+ * @mem: The memory registry backing this ttm_tt object
+ */
uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
struct ttm_mem_reg *mem)
{
@@ -1168,6 +1418,16 @@ uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
return flags;
}
+/**
+ * amdgpu_ttm_bo_eviction_valuable - Check to see if we can evict
+ * a buffer object.
+ *
+ * Return true if eviction is sensible. Called by
+ * ttm_mem_evict_first() on behalf of ttm_bo_mem_force_space()
+ * which tries to evict buffer objects until it can find space
+ * for a new object and by ttm_bo_force_list_clean() which is
+ * used to clean out a memory space.
+ */
static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
const struct ttm_place *place)
{
@@ -1214,6 +1474,19 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
return ttm_bo_eviction_valuable(bo, place);
}
+/**
+ * amdgpu_ttm_access_memory - Read or Write memory that backs a
+ * buffer object.
+ *
+ * @bo: The buffer object to read/write
+ * @offset: Offset into buffer object
+ * @buf: Secondary buffer to write/read from
+ * @len: Length in bytes of access
+ * @write: true if writing
+ *
+ * This is used to access VRAM that backs a buffer object via MMIO
+ * access for debugging purposes.
+ */
static int amdgpu_ttm_access_memory(struct ttm_buffer_object *bo,
unsigned long offset,
void *buf, int len, int write)
@@ -1390,13 +1663,22 @@ static int amdgpu_ttm_fw_reserve_vram_init(struct amdgpu_device *adev)
adev->fw_vram_usage.reserved_bo = NULL;
return r;
}
-
+/**
+ * amdgpu_ttm_init - Init the memory management (ttm) as well as
+ * various gtt/vram related fields.
+ *
+ * This initializes all of the memory space pools that the TTM layer
+ * will need such as the GTT space (system memory mapped to the device),
+ * VRAM (on-board memory), and on-chip memories (GDS, GWS, OA) which
+ * can be mapped per VMID.
+ */
int amdgpu_ttm_init(struct amdgpu_device *adev)
{
uint64_t gtt_size;
int r;
u64 vis_vram_limit;
+ /* initialize global references for vram/gtt */
r = amdgpu_ttm_global_init(adev);
if (r) {
return r;
@@ -1417,6 +1699,7 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
/* We opt to avoid OOM on system pages allocations */
adev->mman.bdev.no_retry = true;
+ /* Initialize VRAM pool with all of VRAM divided into pages */
r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_VRAM,
adev->gmc.real_vram_size >> PAGE_SHIFT);
if (r) {
@@ -1446,6 +1729,10 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
return r;
}
+ /* allocate memory as required for VGA
+ * This is used for VGA emulation and pre-OS scanout buffers to
+ * avoid display artifacts while transitioning between pre-OS
+ * and driver. */
if (adev->gmc.stolen_size) {
r = amdgpu_bo_create_kernel(adev, adev->gmc.stolen_size, PAGE_SIZE,
AMDGPU_GEM_DOMAIN_VRAM,
@@ -1457,6 +1744,8 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
DRM_INFO("amdgpu: %uM of VRAM memory ready\n",
(unsigned) (adev->gmc.real_vram_size / (1024 * 1024)));
+ /* Compute GTT size, either bsaed on 3/4th the size of RAM size
+ * or whatever the user passed on module init */
if (amdgpu_gtt_size == -1) {
struct sysinfo si;
@@ -1467,6 +1756,8 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
}
else
gtt_size = (uint64_t)amdgpu_gtt_size << 20;
+
+ /* Initialize GTT memory pool */
r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_TT, gtt_size >> PAGE_SHIFT);
if (r) {
DRM_ERROR("Failed initializing GTT heap.\n");
@@ -1475,6 +1766,7 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
DRM_INFO("amdgpu: %uM of GTT memory ready.\n",
(unsigned)(gtt_size / (1024 * 1024)));
+ /* Initialize various on-chip memory pools */
adev->gds.mem.total_size = adev->gds.mem.total_size << AMDGPU_GDS_SHIFT;
adev->gds.mem.gfx_partition_size = adev->gds.mem.gfx_partition_size << AMDGPU_GDS_SHIFT;
adev->gds.mem.cs_partition_size = adev->gds.mem.cs_partition_size << AMDGPU_GDS_SHIFT;
@@ -1514,6 +1806,7 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
}
}
+ /* Register debugfs entries for amdgpu_ttm */
r = amdgpu_ttm_debugfs_init(adev);
if (r) {
DRM_ERROR("Failed to init debugfs\n");
@@ -1522,11 +1815,19 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
return 0;
}
+/**
+ * amdgpu_ttm_late_init - Handle any late initialization for
+ * amdgpu_ttm
+ */
void amdgpu_ttm_late_init(struct amdgpu_device *adev)
{
+ /* return the VGA stolen memory (if any) back to VRAM */
amdgpu_bo_free_kernel(&adev->stolen_vga_memory, NULL, NULL);
}
+/**
+ * amdgpu_ttm_fini - De-initialize the TTM memory pools
+ */
void amdgpu_ttm_fini(struct amdgpu_device *adev)
{
if (!adev->mman.initialized)
@@ -1854,6 +2155,11 @@ static const struct drm_info_list amdgpu_ttm_debugfs_list[] = {
#endif
};
+/**
+ * amdgpu_ttm_vram_read - Linear read access to VRAM
+ *
+ * Accesses VRAM via MMIO for debugging purposes.
+ */
static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
size_t size, loff_t *pos)
{
@@ -1893,6 +2199,11 @@ static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
return result;
}
+/**
+ * amdgpu_ttm_vram_write - Linear write access to VRAM
+ *
+ * Accesses VRAM via MMIO for debugging purposes.
+ */
static ssize_t amdgpu_ttm_vram_write(struct file *f, const char __user *buf,
size_t size, loff_t *pos)
{
@@ -1941,6 +2252,9 @@ static const struct file_operations amdgpu_ttm_vram_fops = {
#ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
+/**
+ * amdgpu_ttm_gtt_read - Linear read access to GTT memory
+ */
static ssize_t amdgpu_ttm_gtt_read(struct file *f, char __user *buf,
size_t size, loff_t *pos)
{
@@ -1988,6 +2302,13 @@ static const struct file_operations amdgpu_ttm_gtt_fops = {
#endif
+/**
+ * amdgpu_iomem_read - Virtual read access to GPU mapped memory
+ *
+ * This function is used to read memory that has been mapped to the
+ * GPU and the known addresses are not physical addresses but instead
+ * bus addresses (e.g., what you'd put in an IB or ring buffer).
+ */
static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
size_t size, loff_t *pos)
{
@@ -1996,6 +2317,7 @@ static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
ssize_t result = 0;
int r;
+ /* retrieve the IOMMU domain if any for this device */
dom = iommu_get_domain_for_dev(adev->dev);
while (size) {
@@ -2008,6 +2330,10 @@ static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
bytes = bytes < size ? bytes : size;
+ /* Translate the bus address to a physical address. If
+ * the domain is NULL it means there is no IOMMU active
+ * and the address translation is the identity
+ */
addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
pfn = addr >> PAGE_SHIFT;
@@ -2032,6 +2358,13 @@ static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
return result;
}
+/**
+ * amdgpu_iomem_write - Virtual write access to GPU mapped memory
+ *
+ * This function is used to write memory that has been mapped to the
+ * GPU and the known addresses are not physical addresses but instead
+ * bus addresses (e.g., what you'd put in an IB or ring buffer).
+ */
static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
size_t size, loff_t *pos)
{
--
2.14.3
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