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drm/i915/bdw: implement semaphore signal
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Semaphore signalling works similarly to previous GENs with the exception
that the per ring mailboxes no longer exist. Instead you must define
your own space, somewhere in the GTT.

The comments in the code define the layout I've opted for, which should
be fairly future proof. Ie. I tried to define offsets in abstract terms
(NUM_RINGS, seqno size, etc).

NOTE: If one wanted to move this to the HWSP they could. I've decided
one 4k object would be easier to deal with, and provide potential wins
with cache locality, but that's all speculative.

v2: Update the macro to not need the other ring's ring->id (Chris)
Update the comment to use the correct formula (Chris)

v3: Move the macros the ringbuffer.h to prevent churn in next patch
(Ville)

v4: Fixed compilation rebase conflict
commit 1ec9e26
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Feb 14 14:01:11 2014 +0100

    drm/i915: Consolidate binding parameters into flags

v5: VCS2 rebase
Replace hweight_long with hweight32

v6 (Rodrigo): * Add missed VC2 gen8 ring signal init
   	      * fixing conflicst on rebase
    	      * minor fixes on address table
	      * remove WARN_ON

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[danvet: s/BUG_ON/WARN_ON/]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Ben Widawsky authored and Daniel Vetter committed Jul 7, 2014
1 parent a1444b7 commit 3e78998
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Showing 4 changed files with 189 additions and 80 deletions.
1 change: 1 addition & 0 deletions drivers/gpu/drm/i915/i915_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1375,6 +1375,7 @@ struct drm_i915_private {

struct pci_dev *bridge_dev;
struct intel_engine_cs ring[I915_NUM_RINGS];
struct drm_i915_gem_object *semaphore_obj;
uint32_t last_seqno, next_seqno;

drm_dma_handle_t *status_page_dmah;
Expand Down
5 changes: 4 additions & 1 deletion drivers/gpu/drm/i915/i915_reg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -240,7 +240,7 @@
#define MI_DISPLAY_FLIP_IVB_SPRITE_B (3 << 19)
#define MI_DISPLAY_FLIP_IVB_PLANE_C (4 << 19)
#define MI_DISPLAY_FLIP_IVB_SPRITE_C (5 << 19)
#define MI_SEMAPHORE_MBOX MI_INSTR(0x16, 1) /* gen6+ */
#define MI_SEMAPHORE_MBOX MI_INSTR(0x16, 1) /* gen6, gen7 */
#define MI_SEMAPHORE_GLOBAL_GTT (1<<22)
#define MI_SEMAPHORE_UPDATE (1<<21)
#define MI_SEMAPHORE_COMPARE (1<<20)
Expand All @@ -266,6 +266,8 @@
#define MI_RESTORE_EXT_STATE_EN (1<<2)
#define MI_FORCE_RESTORE (1<<1)
#define MI_RESTORE_INHIBIT (1<<0)
#define MI_SEMAPHORE_SIGNAL MI_INSTR(0x1b, 0) /* GEN8+ */
#define MI_SEMAPHORE_TARGET(engine) ((engine)<<15)
#define MI_STORE_DWORD_IMM MI_INSTR(0x20, 1)
#define MI_MEM_VIRTUAL (1 << 22) /* 965+ only */
#define MI_STORE_DWORD_INDEX MI_INSTR(0x21, 1)
Expand Down Expand Up @@ -360,6 +362,7 @@
#define PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE (1<<10) /* GM45+ only */
#define PIPE_CONTROL_INDIRECT_STATE_DISABLE (1<<9)
#define PIPE_CONTROL_NOTIFY (1<<8)
#define PIPE_CONTROL_FLUSH_ENABLE (1<<7) /* gen7+ */
#define PIPE_CONTROL_VF_CACHE_INVALIDATE (1<<4)
#define PIPE_CONTROL_CONST_CACHE_INVALIDATE (1<<3)
#define PIPE_CONTROL_STATE_CACHE_INVALIDATE (1<<2)
Expand Down
185 changes: 112 additions & 73 deletions drivers/gpu/drm/i915/intel_ringbuffer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -660,6 +660,13 @@ static int init_render_ring(struct intel_engine_cs *ring)
static void render_ring_cleanup(struct intel_engine_cs *ring)
{
struct drm_device *dev = ring->dev;
struct drm_i915_private *dev_priv = dev->dev_private;

if (dev_priv->semaphore_obj) {
i915_gem_object_ggtt_unpin(dev_priv->semaphore_obj);
drm_gem_object_unreference(&dev_priv->semaphore_obj->base);
dev_priv->semaphore_obj = NULL;
}

if (ring->scratch.obj == NULL)
return;
Expand All @@ -673,6 +680,80 @@ static void render_ring_cleanup(struct intel_engine_cs *ring)
ring->scratch.obj = NULL;
}

static int gen8_rcs_signal(struct intel_engine_cs *signaller,
unsigned int num_dwords)
{
#define MBOX_UPDATE_DWORDS 8
struct drm_device *dev = signaller->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_engine_cs *waiter;
int i, ret, num_rings;

num_rings = hweight32(INTEL_INFO(dev)->ring_mask);
num_dwords += (num_rings-1) * MBOX_UPDATE_DWORDS;
#undef MBOX_UPDATE_DWORDS

ret = intel_ring_begin(signaller, num_dwords);
if (ret)
return ret;

for_each_ring(waiter, dev_priv, i) {
u64 gtt_offset = signaller->semaphore.signal_ggtt[i];
if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
continue;

intel_ring_emit(signaller, GFX_OP_PIPE_CONTROL(6));
intel_ring_emit(signaller, PIPE_CONTROL_GLOBAL_GTT_IVB |
PIPE_CONTROL_QW_WRITE |
PIPE_CONTROL_FLUSH_ENABLE);
intel_ring_emit(signaller, lower_32_bits(gtt_offset));
intel_ring_emit(signaller, upper_32_bits(gtt_offset));
intel_ring_emit(signaller, signaller->outstanding_lazy_seqno);
intel_ring_emit(signaller, 0);
intel_ring_emit(signaller, MI_SEMAPHORE_SIGNAL |
MI_SEMAPHORE_TARGET(waiter->id));
intel_ring_emit(signaller, 0);
}

return 0;
}

static int gen8_xcs_signal(struct intel_engine_cs *signaller,
unsigned int num_dwords)
{
#define MBOX_UPDATE_DWORDS 6
struct drm_device *dev = signaller->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_engine_cs *waiter;
int i, ret, num_rings;

num_rings = hweight32(INTEL_INFO(dev)->ring_mask);
num_dwords += (num_rings-1) * MBOX_UPDATE_DWORDS;
#undef MBOX_UPDATE_DWORDS

ret = intel_ring_begin(signaller, num_dwords);
if (ret)
return ret;

for_each_ring(waiter, dev_priv, i) {
u64 gtt_offset = signaller->semaphore.signal_ggtt[i];
if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
continue;

intel_ring_emit(signaller, (MI_FLUSH_DW + 1) |
MI_FLUSH_DW_OP_STOREDW);
intel_ring_emit(signaller, lower_32_bits(gtt_offset) |
MI_FLUSH_DW_USE_GTT);
intel_ring_emit(signaller, upper_32_bits(gtt_offset));
intel_ring_emit(signaller, signaller->outstanding_lazy_seqno);
intel_ring_emit(signaller, MI_SEMAPHORE_SIGNAL |
MI_SEMAPHORE_TARGET(waiter->id));
intel_ring_emit(signaller, 0);
}

return 0;
}

static int gen6_signal(struct intel_engine_cs *signaller,
unsigned int num_dwords)
{
Expand Down Expand Up @@ -1942,12 +2023,30 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_engine_cs *ring = &dev_priv->ring[RCS];
struct drm_i915_gem_object *obj;
int ret;

ring->name = "render ring";
ring->id = RCS;
ring->mmio_base = RENDER_RING_BASE;

if (INTEL_INFO(dev)->gen >= 8) {
if (i915_semaphore_is_enabled(dev)) {
obj = i915_gem_alloc_object(dev, 4096);
if (obj == NULL) {
DRM_ERROR("Failed to allocate semaphore bo. Disabling semaphores\n");
i915.semaphores = 0;
} else {
i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);
ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_NONBLOCK);
if (ret != 0) {
drm_gem_object_unreference(&obj->base);
DRM_ERROR("Failed to pin semaphore bo. Disabling semaphores\n");
i915.semaphores = 0;
} else
dev_priv->semaphore_obj = obj;
}
}
ring->add_request = gen6_add_request;
ring->flush = gen8_render_ring_flush;
ring->irq_get = gen8_ring_get_irq;
Expand All @@ -1956,18 +2055,10 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
ring->get_seqno = gen6_ring_get_seqno;
ring->set_seqno = ring_set_seqno;
if (i915_semaphore_is_enabled(dev)) {
WARN_ON(!dev_priv->semaphore_obj);
ring->semaphore.sync_to = gen6_ring_sync;
ring->semaphore.signal = gen6_signal;
ring->semaphore.mbox.wait[RCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[BCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VECS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS2] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.signal[RCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[BCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VECS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS2] = GEN6_NOSYNC;
ring->semaphore.signal = gen8_rcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
} else if (INTEL_INFO(dev)->gen >= 6) {
ring->add_request = gen6_add_request;
Expand Down Expand Up @@ -2045,9 +2136,6 @@ int intel_init_render_ring_buffer(struct drm_device *dev)

/* Workaround batchbuffer to combat CS tlb bug. */
if (HAS_BROKEN_CS_TLB(dev)) {
struct drm_i915_gem_object *obj;
int ret;

obj = i915_gem_alloc_object(dev, I830_BATCH_LIMIT);
if (obj == NULL) {
DRM_ERROR("Failed to allocate batch bo\n");
Expand Down Expand Up @@ -2180,25 +2268,8 @@ int intel_init_bsd_ring_buffer(struct drm_device *dev)
gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
ring->semaphore.sync_to = gen6_ring_sync;
ring->semaphore.signal = gen6_signal;
/*
* The current semaphore is only applied on
* pre-gen8 platform. And there is no VCS2 ring
* on the pre-gen8 platform. So the semaphore
* between VCS and VCS2 is initialized as
* INVALID. Gen8 will initialize the sema
* between VCS2 and VCS later.
*/
ring->semaphore.mbox.wait[RCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[BCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VECS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS2] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.signal[RCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[BCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VECS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS2] = GEN6_NOSYNC;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
} else {
ring->irq_enable_mask = GT_BSD_USER_INTERRUPT;
Expand Down Expand Up @@ -2273,24 +2344,10 @@ int intel_init_bsd2_ring_buffer(struct drm_device *dev)
ring->dispatch_execbuffer =
gen8_ring_dispatch_execbuffer;
ring->semaphore.sync_to = gen6_ring_sync;
ring->semaphore.signal = gen6_signal;
/*
* The current semaphore is only applied on the pre-gen8. And there
* is no bsd2 ring on the pre-gen8. So now the semaphore_register
* between VCS2 and other ring is initialized as invalid.
* Gen8 will initialize the sema between VCS2 and other ring later.
*/
ring->semaphore.mbox.wait[RCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[BCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VECS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS2] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.signal[RCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[BCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VECS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS2] = GEN6_NOSYNC;

if (i915_semaphore_is_enabled(dev)) {
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
ring->init = init_ring_common;

return intel_init_ring_buffer(dev, ring);
Expand Down Expand Up @@ -2318,17 +2375,8 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
ring->semaphore.sync_to = gen6_ring_sync;
ring->semaphore.signal = gen6_signal;
ring->semaphore.mbox.wait[RCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[BCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VECS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS2] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.signal[RCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[BCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VECS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS2] = GEN6_NOSYNC;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
} else {
ring->irq_enable_mask = GT_BLT_USER_INTERRUPT;
Expand Down Expand Up @@ -2385,17 +2433,8 @@ int intel_init_vebox_ring_buffer(struct drm_device *dev)
ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
ring->semaphore.sync_to = gen6_ring_sync;
ring->semaphore.signal = gen6_signal;
ring->semaphore.mbox.wait[RCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[BCS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VECS] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.wait[VCS2] = MI_SEMAPHORE_SYNC_INVALID;
ring->semaphore.mbox.signal[RCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[BCS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VECS] = GEN6_NOSYNC;
ring->semaphore.mbox.signal[VCS2] = GEN6_NOSYNC;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
} else {
ring->irq_enable_mask = PM_VEBOX_USER_INTERRUPT;
Expand Down
78 changes: 72 additions & 6 deletions drivers/gpu/drm/i915/intel_ringbuffer.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,32 @@ struct intel_hw_status_page {
#define I915_READ_MODE(ring) I915_READ(RING_MI_MODE((ring)->mmio_base))
#define I915_WRITE_MODE(ring, val) I915_WRITE(RING_MI_MODE((ring)->mmio_base), val)

/* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
* do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
*/
#define i915_semaphore_seqno_size sizeof(uint64_t)
#define GEN8_SIGNAL_OFFSET(__ring, to) \
(i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
((__ring)->id * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
(i915_semaphore_seqno_size * (to)))

#define GEN8_WAIT_OFFSET(__ring, from) \
(i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
((from) * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
(i915_semaphore_seqno_size * (__ring)->id))

#define GEN8_RING_SEMAPHORE_INIT do { \
if (!dev_priv->semaphore_obj) { \
break; \
} \
ring->semaphore.signal_ggtt[RCS] = GEN8_SIGNAL_OFFSET(ring, RCS); \
ring->semaphore.signal_ggtt[VCS] = GEN8_SIGNAL_OFFSET(ring, VCS); \
ring->semaphore.signal_ggtt[BCS] = GEN8_SIGNAL_OFFSET(ring, BCS); \
ring->semaphore.signal_ggtt[VECS] = GEN8_SIGNAL_OFFSET(ring, VECS); \
ring->semaphore.signal_ggtt[VCS2] = GEN8_SIGNAL_OFFSET(ring, VCS2); \
ring->semaphore.signal_ggtt[ring->id] = MI_SEMAPHORE_SYNC_INVALID; \
} while(0)

enum intel_ring_hangcheck_action {
HANGCHECK_IDLE = 0,
HANGCHECK_WAIT,
Expand Down Expand Up @@ -127,15 +153,55 @@ struct intel_engine_cs {
#define I915_DISPATCH_PINNED 0x2
void (*cleanup)(struct intel_engine_cs *ring);

/* GEN8 signal/wait table - never trust comments!
* signal to signal to signal to signal to signal to
* RCS VCS BCS VECS VCS2
* --------------------------------------------------------------------
* RCS | NOP (0x00) | VCS (0x08) | BCS (0x10) | VECS (0x18) | VCS2 (0x20) |
* |-------------------------------------------------------------------
* VCS | RCS (0x28) | NOP (0x30) | BCS (0x38) | VECS (0x40) | VCS2 (0x48) |
* |-------------------------------------------------------------------
* BCS | RCS (0x50) | VCS (0x58) | NOP (0x60) | VECS (0x68) | VCS2 (0x70) |
* |-------------------------------------------------------------------
* VECS | RCS (0x78) | VCS (0x80) | BCS (0x88) | NOP (0x90) | VCS2 (0x98) |
* |-------------------------------------------------------------------
* VCS2 | RCS (0xa0) | VCS (0xa8) | BCS (0xb0) | VECS (0xb8) | NOP (0xc0) |
* |-------------------------------------------------------------------
*
* Generalization:
* f(x, y) := (x->id * NUM_RINGS * seqno_size) + (seqno_size * y->id)
* ie. transpose of g(x, y)
*
* sync from sync from sync from sync from sync from
* RCS VCS BCS VECS VCS2
* --------------------------------------------------------------------
* RCS | NOP (0x00) | VCS (0x28) | BCS (0x50) | VECS (0x78) | VCS2 (0xa0) |
* |-------------------------------------------------------------------
* VCS | RCS (0x08) | NOP (0x30) | BCS (0x58) | VECS (0x80) | VCS2 (0xa8) |
* |-------------------------------------------------------------------
* BCS | RCS (0x10) | VCS (0x38) | NOP (0x60) | VECS (0x88) | VCS2 (0xb0) |
* |-------------------------------------------------------------------
* VECS | RCS (0x18) | VCS (0x40) | BCS (0x68) | NOP (0x90) | VCS2 (0xb8) |
* |-------------------------------------------------------------------
* VCS2 | RCS (0x20) | VCS (0x48) | BCS (0x70) | VECS (0x98) | NOP (0xc0) |
* |-------------------------------------------------------------------
*
* Generalization:
* g(x, y) := (y->id * NUM_RINGS * seqno_size) + (seqno_size * x->id)
* ie. transpose of f(x, y)
*/
struct {
u32 sync_seqno[I915_NUM_RINGS-1];

struct {
/* our mbox written by others */
u32 wait[I915_NUM_RINGS];
/* mboxes this ring signals to */
u32 signal[I915_NUM_RINGS];
} mbox;
union {
struct {
/* our mbox written by others */
u32 wait[I915_NUM_RINGS];
/* mboxes this ring signals to */
u32 signal[I915_NUM_RINGS];
} mbox;
u64 signal_ggtt[I915_NUM_RINGS];
};

/* AKA wait() */
int (*sync_to)(struct intel_engine_cs *ring,
Expand Down

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