From: Akash Goel <akash.goel@xxxxxxxxx>
This adds support for a write-enable bit in the entry of GTT.
This is handled via a read-only flag in the GEM buffer object which
is then used to see how to set the bit when writing the GTT entries.
Currently by default the Batch buffer & Ring buffers are marked as read only.
v2: Moved the pte override code for read-only bit to 'byt_pte_encode'. (Chris)
Fixed the issue of leaving 'gt_old_ro' as unused. (Chris)
v3: Removed the 'gt_old_ro' field, now setting RO bit only for Ring Buffers(Daniel).
v4: Added a new 'flags' parameter to all the pte(gen6) encode & insert_entries functions,
in lieu of overloading the cache_level enum (Daniel).
v5: Removed the superfluous VLV check & changed the definition location of PTE_READ_ONLY flag (Imre)
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
Signed-off-by: Akash Goel <akash.goel@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 6 +++++
drivers/gpu/drm/i915/i915_gem_gtt.c | 48 ++++++++++++++++++++-------------
drivers/gpu/drm/i915/i915_gem_gtt.h | 5 ++--
drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
4 files changed, 41 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 64d520f..7e4c272 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1661,6 +1661,12 @@ struct drm_i915_gem_object {
unsigned int pin_display:1;
/*
+ * Is the object to be mapped as read-only to the GPU
+ * Only honoured if hardware has relevant pte bit
+ */
+ unsigned long gt_ro:1;
+
+ /*
* Is the GPU currently using a fence to access this buffer,
*/
unsigned int pending_fenced_gpu_access:1;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 7f226fa..a4153ee 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -116,7 +116,7 @@ static inline gen8_ppgtt_pde_t gen8_pde_encode(struct drm_device *dev,
static gen6_gtt_pte_t snb_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
- bool valid)
+ bool valid, u32 unused)
{
gen6_gtt_pte_t pte = valid ? GEN6_PTE_VALID : 0;
pte |= GEN6_PTE_ADDR_ENCODE(addr);
@@ -138,7 +138,7 @@ static gen6_gtt_pte_t snb_pte_encode(dma_addr_t addr,
static gen6_gtt_pte_t ivb_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
- bool valid)
+ bool valid, u32 unused)
{
gen6_gtt_pte_t pte = valid ? GEN6_PTE_VALID : 0;
pte |= GEN6_PTE_ADDR_ENCODE(addr);
@@ -162,7 +162,7 @@ static gen6_gtt_pte_t ivb_pte_encode(dma_addr_t addr,
static gen6_gtt_pte_t byt_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
- bool valid)
+ bool valid, u32 flags)
{
gen6_gtt_pte_t pte = valid ? GEN6_PTE_VALID : 0;
pte |= GEN6_PTE_ADDR_ENCODE(addr);
@@ -170,7 +170,8 @@ static gen6_gtt_pte_t byt_pte_encode(dma_addr_t addr,
/* Mark the page as writeable. Other platforms don't have a
* setting for read-only/writable, so this matches that behavior.
*/
- pte |= BYT_PTE_WRITEABLE;
+ if (!(flags & PTE_READ_ONLY))
+ pte |= BYT_PTE_WRITEABLE;
if (level != I915_CACHE_NONE)
pte |= BYT_PTE_SNOOPED_BY_CPU_CACHES;
@@ -180,7 +181,7 @@ static gen6_gtt_pte_t byt_pte_encode(dma_addr_t addr,
static gen6_gtt_pte_t hsw_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
- bool valid)
+ bool valid, u32 unused)
{
gen6_gtt_pte_t pte = valid ? GEN6_PTE_VALID : 0;
pte |= HSW_PTE_ADDR_ENCODE(addr);
@@ -193,7 +194,7 @@ static gen6_gtt_pte_t hsw_pte_encode(dma_addr_t addr,
static gen6_gtt_pte_t iris_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
- bool valid)
+ bool valid, u32 unused)
{
gen6_gtt_pte_t pte = valid ? GEN6_PTE_VALID : 0;
pte |= HSW_PTE_ADDR_ENCODE(addr);
@@ -307,7 +308,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
struct sg_table *pages,
uint64_t start,
- enum i915_cache_level cache_level)
+ enum i915_cache_level cache_level, u32 unused)
{
struct i915_hw_ppgtt *ppgtt =
container_of(vm, struct i915_hw_ppgtt, base);
@@ -645,7 +646,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
uint32_t pd_entry;
int pte, pde;
- scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true);
+ scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true, 0);
pd_addr = (gen6_gtt_pte_t __iomem *)dev_priv->gtt.gsm +
ppgtt->pd_offset / sizeof(gen6_gtt_pte_t);
@@ -947,7 +948,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
unsigned last_pte, i;
- scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true);
+ scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true, 0);
while (num_entries) {
last_pte = first_pte + num_entries;
@@ -970,7 +971,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
struct sg_table *pages,
uint64_t start,
- enum i915_cache_level cache_level)
+ enum i915_cache_level cache_level, u32 flags)
{
struct i915_hw_ppgtt *ppgtt =
container_of(vm, struct i915_hw_ppgtt, base);
@@ -987,7 +988,8 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
pt_vaddr[act_pte] =
vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
- cache_level, true);
+ cache_level, true, flags);
+
if (++act_pte == I915_PPGTT_PT_ENTRIES) {
kunmap_atomic(pt_vaddr);
pt_vaddr = NULL;
@@ -1224,8 +1226,12 @@ ppgtt_bind_vma(struct i915_vma *vma,
enum i915_cache_level cache_level,
u32 flags)
{
+ /* Currently applicable only to VLV */
+ if (vma->obj->gt_ro)
+ flags |= PTE_READ_ONLY;
+
vma->vm->insert_entries(vma->vm, vma->obj->pages, vma->node.start,
- cache_level);
+ cache_level, flags);
}
static void ppgtt_unbind_vma(struct i915_vma *vma)
@@ -1400,7 +1406,7 @@ static inline void gen8_set_pte(void __iomem *addr, gen8_gtt_pte_t pte)
static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
struct sg_table *st,
uint64_t start,
- enum i915_cache_level level)
+ enum i915_cache_level level, u32 unused)
{
struct drm_i915_private *dev_priv = vm->dev->dev_private;
unsigned first_entry = start >> PAGE_SHIFT;
@@ -1446,7 +1452,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
struct sg_table *st,
uint64_t start,
- enum i915_cache_level level)
+ enum i915_cache_level level, u32 flags)
{
struct drm_i915_private *dev_priv = vm->dev->dev_private;
unsigned first_entry = start >> PAGE_SHIFT;
@@ -1458,7 +1464,7 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
addr = sg_page_iter_dma_address(&sg_iter);
- iowrite32(vm->pte_encode(addr, level, true), >t_entries[i]);
+ iowrite32(vm->pte_encode(addr, level, true, flags), >t_entries[i]);
i++;
}
@@ -1470,7 +1476,7 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
*/
if (i != 0)
WARN_ON(readl(>t_entries[i-1]) !=
- vm->pte_encode(addr, level, true));
+ vm->pte_encode(addr, level, true, flags));
/* This next bit makes the above posting read even more important. We
* want to flush the TLBs only after we're certain all the PTE updates
@@ -1524,7 +1530,7 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
first_entry, num_entries, max_entries))
num_entries = max_entries;
- scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, use_scratch);
+ scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, use_scratch, 0);
for (i = 0; i < num_entries; i++)
iowrite32(scratch_pte, >t_base[i]);
@@ -1573,6 +1579,10 @@ static void ggtt_bind_vma(struct i915_vma *vma,
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_gem_object *obj = vma->obj;
+ /* Currently applicable only to VLV */
+ if (obj->gt_ro)
+ flags |= PTE_READ_ONLY;
+
/* If there is no aliasing PPGTT, or the caller needs a global mapping,
* or we have a global mapping already but the cacheability flags have
* changed, set the global PTEs.
@@ -1589,7 +1599,7 @@ static void ggtt_bind_vma(struct i915_vma *vma,
(cache_level != obj->cache_level)) {
vma->vm->insert_entries(vma->vm, obj->pages,
vma->node.start,
- cache_level);
+ cache_level, flags);
obj->has_global_gtt_mapping = 1;
}
}
@@ -1601,7 +1611,7 @@ static void ggtt_bind_vma(struct i915_vma *vma,
appgtt->base.insert_entries(&appgtt->base,
vma->obj->pages,
vma->node.start,
- cache_level);
+ cache_level, flags);
vma->obj->has_aliasing_ppgtt_mapping = 1;
}
}
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 1b96a06..8d6f7c1 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -154,6 +154,7 @@ struct i915_vma {
void (*unbind_vma)(struct i915_vma *vma);
/* Map an object into an address space with the given cache flags. */
#define GLOBAL_BIND (1<<0)
+#define PTE_READ_ONLY (1<<1)
void (*bind_vma)(struct i915_vma *vma,
enum i915_cache_level cache_level,
u32 flags);
@@ -197,7 +198,7 @@ struct i915_address_space {
/* FIXME: Need a more generic return type */
gen6_gtt_pte_t (*pte_encode)(dma_addr_t addr,
enum i915_cache_level level,
- bool valid); /* Create a valid PTE */
+ bool valid, u32 flags); /* Create a valid PTE */
void (*clear_range)(struct i915_address_space *vm,
uint64_t start,
uint64_t length,
@@ -205,7 +206,7 @@ struct i915_address_space {
void (*insert_entries)(struct i915_address_space *vm,
struct sg_table *st,
uint64_t start,
- enum i915_cache_level cache_level);
+ enum i915_cache_level cache_level, u32 flags);
void (*cleanup)(struct i915_address_space *vm);
};
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 0eaaaec..b96edaf 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1397,6 +1397,9 @@ static int allocate_ring_buffer(struct intel_engine_cs *ring)
if (obj == NULL)
return -ENOMEM;
+ /* mark ring buffers as read-only from GPU side by default */
+ obj->gt_ro = 1;
+
ret = i915_gem_obj_ggtt_pin(obj, PAGE_SIZE, PIN_MAPPABLE);
if (ret)
goto err_unref;
--
1.9.2
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