Re: [PATCH] drm/i915: Replace gen6 semaphore signal table with code

Ville Syrjälä
2016-07-21T10:14:21Z

On Thu, Jul 21, 2016 at 10:31:35AM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Static table wastes space for invalid combinations and
> engines which are not supported by Gen6 (legacy semaphores).
>
> Replace it with a function devised by Dave Gordon.
>
> I have verified that it generates the same mappings between
> mbox selectors and signalling registers.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Dave Gordon <david.s.gordon@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 7 ++---
> drivers/gpu/drm/i915/intel_engine_cs.c | 48 +++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_ringbuffer.c | 40 ++-------------------------
> drivers/gpu/drm/i915/intel_ringbuffer.h | 3 +++
> 4 files changed, 57 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 8bfde75789f6..28aa876e2d87 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1604,9 +1604,10 @@ enum skl_disp_power_wells {
> #define RING_HEAD(base) _MMIO((base)+0x34)
> #define RING_START(base) _MMIO((base)+0x38)
> #define RING_CTL(base) _MMIO((base)+0x3c)
> -#define RING_SYNC_0(base) _MMIO((base)+0x40)
> -#define RING_SYNC_1(base) _MMIO((base)+0x44)
> -#define RING_SYNC_2(base) _MMIO((base)+0x48)
> +#define RING_SYNC(base, n) _MMIO((base) + 0x40 + (n) * 4)
> +#define RING_SYNC_0(base) RING_SYNC(base, 0)
> +#define RING_SYNC_1(base) RING_SYNC(base, 1)
> +#define RING_SYNC_2(base) RING_SYNC(base, 2)
> #define GEN6_RVSYNC (RING_SYNC_0(RENDER_RING_BASE))
> #define GEN6_RBSYNC (RING_SYNC_1(RENDER_RING_BASE))
> #define GEN6_RVESYNC (RING_SYNC_2(RENDER_RING_BASE))
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index f4a35ec78481..9837fddae259 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -209,3 +209,51 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
>
> return i915_cmd_parser_init_ring(engine);
> }
> +
> +#define I915_NUM_GEN6_SEMAPHORE_ENGINES (4)
> +
> +static int gen6_sem_f(unsigned int x, unsigned int y)
> +{
> + if (x == y)
> + return -1;
> +
> + x = intel_engines[x].guc_id;
> + y = intel_engines[y].guc_id;
> +
> + if (x >= I915_NUM_GEN6_SEMAPHORE_ENGINES ||
> + y >= I915_NUM_GEN6_SEMAPHORE_ENGINES)
> + return -1;
> +
> + x -= x >= y;
> + if (y == 1)
> + x = 3 - x;
> + x += y & 1;
> + return x % 3;
> +}

Are we trying to submit i915 into IOCCC?

> +
> +u32 gen6_wait_mbox(enum intel_engine_id x, enum intel_engine_id y)
> +{
> + int r;
> +
> + r = gen6_sem_f(x, y);
> + if (r < 0)
> + return MI_SEMAPHORE_SYNC_INVALID;
> +
> + if (r == 1)
> + r = 2;
> + else if (r == 2)
> + r = 1;
> +
> + return r << 16;
> +}
> +
> +i915_reg_t gen6_signal_reg(enum intel_engine_id x, enum intel_engine_id y)
> +{
> + int r;
> +
> + r = gen6_sem_f(x, y);
> + if (r < 0)
> + return GEN6_NOSYNC;
> +
> + return RING_SYNC(intel_engines[y].mmio_base, r);
> +}
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index b844e6984ae7..049527d381de 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -2731,44 +2731,8 @@ static void intel_ring_init_semaphores(struct drm_i915_private *dev_priv,
> * sema between VCS2 and RCS later.
> */
> for (i = 0; i < I915_NUM_ENGINES; i++) {
> - static const struct {
> - u32 wait_mbox;
> - i915_reg_t mbox_reg;
> - } sem_data[I915_NUM_ENGINES][I915_NUM_ENGINES] = {
> - [RCS] = {
> - [VCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_RV, .mbox_reg = GEN6_VRSYNC },
> - [BCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_RB, .mbox_reg = GEN6_BRSYNC },
> - [VECS] = { .wait_mbox = MI_SEMAPHORE_SYNC_RVE, .mbox_reg = GEN6_VERSYNC },
> - },
> - [VCS] = {
> - [RCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VR, .mbox_reg = GEN6_RVSYNC },
> - [BCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VB, .mbox_reg = GEN6_BVSYNC },
> - [VECS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VVE, .mbox_reg = GEN6_VEVSYNC },
> - },
> - [BCS] = {
> - [RCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_BR, .mbox_reg = GEN6_RBSYNC },
> - [VCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_BV, .mbox_reg = GEN6_VBSYNC },
> - [VECS] = { .wait_mbox = MI_SEMAPHORE_SYNC_BVE, .mbox_reg = GEN6_VEBSYNC },
> - },
> - [VECS] = {
> - [RCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VER, .mbox_reg = GEN6_RVESYNC },
> - [VCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VEV, .mbox_reg = GEN6_VVESYNC },
> - [BCS] = { .wait_mbox = MI_SEMAPHORE_SYNC_VEB, .mbox_reg = GEN6_BVESYNC },
> - },
> - };
> - u32 wait_mbox;
> - i915_reg_t mbox_reg;
> -
> - if (i == engine->id || i == VCS2) {
> - wait_mbox = MI_SEMAPHORE_SYNC_INVALID;
> - mbox_reg = GEN6_NOSYNC;
> - } else {
> - wait_mbox = sem_data[engine->id][i].wait_mbox;
> - mbox_reg = sem_data[engine->id][i].mbox_reg;
> - }
> -
> - engine->semaphore.mbox.wait[i] = wait_mbox;
> - engine->semaphore.mbox.signal[i] = mbox_reg;
> + engine->semaphore.mbox.wait[i] = gen6_wait_mbox(engine->id, i);
> + engine->semaphore.mbox.signal[i] = gen6_signal_reg(engine->id, i);
> }
> }
> }
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 05bab8bda63d..802adcd51569 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -493,6 +493,9 @@ int intel_ring_invalidate_all_caches(struct drm_i915_gem_request *req);
> int intel_init_pipe_control(struct intel_engine_cs *engine, int size);
> void intel_fini_pipe_control(struct intel_engine_cs *engine);
>
> +u32 gen6_wait_mbox(enum intel_engine_id x, enum intel_engine_id y);
> +i915_reg_t gen6_signal_reg(enum intel_engine_id x, enum intel_engine_id y);
> +
> void intel_engine_setup_common(struct intel_engine_cs *engine);
> int intel_engine_init_common(struct intel_engine_cs *engine);
>
> --
> 1.9.1
>
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--
Ville Syrjälä
Intel OTC