[PATCH v5] drm/i915/icl: Enhanced execution list support

Daniele Ceraolo Spurio
2018-01-17T21:54:02Z

From: Thomas Daniel <thomas.daniel@intel.com>

Enhanced Execlists is an upgraded version of execlists which supports
up to 8 ports. The lrcs to be submitted are written to a submit queue,
which is then loaded on the HW. When writing to the ELSP register, the
lrcs are written cyclically in the queue from position 0 to position 7.
Alternatively, it is possible to write directly in the individual
positions of the queue using the ELSQ registers. To be able to re-use
all the existing code we're using the latter method and we're currently
limiting ourself to only using 2 elements.

The preemption flow is sligthly different with enhanced execlists, so
this patch turns preemption off temporarily for Gen11+ while we wait for
the new mechanism to land.

v2: Rebase.
v3: Switch from !IS_GEN11 to GEN < 11 (Daniele Ceraolo Spurio).
v4: Use the elsq registers instead of elsp. (Daniele Ceraolo Spurio)
v5: Reword commit, rename regs to be closer to specs, turn off
preemption (Daniele), reuse engine->execlists.elsp (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 5 ++++-
drivers/gpu/drm/i915/intel_lrc.c | 35 ++++++++++++++++++++++++++++-----
drivers/gpu/drm/i915/intel_lrc.h | 3 +++
drivers/gpu/drm/i915/intel_ringbuffer.h | 6 ++++--
4 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c42015b..3163543 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2738,8 +2738,11 @@ static inline unsigned int i915_sg_segment_size(void)

#define HAS_LOGICAL_RING_CONTEXTS(dev_priv) \
((dev_priv)->info.has_logical_ring_contexts)
+
+/* XXX: Preemption disabled for Gen11+ until support for new flow lands */
#define HAS_LOGICAL_RING_PREEMPTION(dev_priv) \
- ((dev_priv)->info.has_logical_ring_preemption)
+ ((dev_priv)->info.has_logical_ring_preemption && \
+ INTEL_GEN(dev_priv) < 11)

#define HAS_EXECLISTS(dev_priv) HAS_LOGICAL_RING_CONTEXTS(dev_priv)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index ff25f20..67ad7c9 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -428,11 +428,24 @@ static inline void elsp_write(u64 desc, u32 __iomem *elsp)
writel(lower_32_bits(desc), elsp);
}

+static inline void elsqc_write(u64 desc, u32 __iomem *elsqc, u32 port)
+{
+ writel(lower_32_bits(desc), elsqc + port * 2);
+ writel(upper_32_bits(desc), elsqc + port * 2 + 1);
+}
+
static void execlists_submit_ports(struct intel_engine_cs *engine)
{
+ struct drm_i915_private *dev_priv = engine->i915;
struct execlist_port *port = engine->execlists.port;
unsigned int n;

+ /*
+ * Gen11+ note: the submit queue is not cleared after being submitted
+ * to the HW so we need to make sure we always clean it up. This is
+ * currently ensured by the fact that we always write the same number
+ * of elsq entries, keep this in mind before changing the loop below.
+ */
for (n = execlists_num_ports(&engine->execlists); n--; ) {
struct drm_i915_gem_request *rq;
unsigned int count;
@@ -456,8 +469,16 @@ static void execlists_submit_ports(struct intel_engine_cs *engine)
desc = 0;
}

- elsp_write(desc, engine->execlists.elsp);
+ if (INTEL_GEN(dev_priv) >= 11)
+ elsqc_write(desc, engine->execlists.els, n);
+ else
+ elsp_write(desc, engine->execlists.els);
}
+
+ /* for gen11+ we need to manually load the submit queue */
+ if (INTEL_GEN(dev_priv) >= 11)
+ I915_WRITE_FW(RING_EXECLIST_CONTROL(engine), EL_CTRL_LOAD);
+
execlists_clear_active(&engine->execlists, EXECLISTS_ACTIVE_HWACK);
}

@@ -506,9 +527,9 @@ static void inject_preempt_context(struct intel_engine_cs *engine)

GEM_TRACE("%s\n", engine->name);
for (n = execlists_num_ports(&engine->execlists); --n; )
- elsp_write(0, engine->execlists.elsp);
+ elsp_write(0, engine->execlists.els);

- elsp_write(ce->lrc_desc, engine->execlists.elsp);
+ elsp_write(ce->lrc_desc, engine->execlists.els);
execlists_clear_active(&engine->execlists, EXECLISTS_ACTIVE_HWACK);
}

@@ -2016,8 +2037,12 @@ static int logical_ring_init(struct intel_engine_cs *engine)
if (ret)
goto error;

- engine->execlists.elsp =
- engine->i915->regs + i915_mmio_reg_offset(RING_ELSP(engine));
+ if (INTEL_GEN(engine->i915) >= 11)
+ engine->execlists.els = engine->i915->regs +
+ i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(engine));
+ else
+ engine->execlists.els = engine->i915->regs +
+ i915_mmio_reg_offset(RING_ELSP(engine));

return 0;

diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 6d4f9b9..3ab4266 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -38,6 +38,9 @@
#define CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT (1 << 0)
#define CTX_CTRL_RS_CTX_ENABLE (1 << 1)
#define RING_CONTEXT_STATUS_BUF_BASE(engine) _MMIO((engine)->mmio_base + 0x370)
+#define RING_EXECLIST_SQ_CONTENTS(engine) _MMIO((engine)->mmio_base + 0x510)
+#define RING_EXECLIST_CONTROL(engine) _MMIO((engine)->mmio_base + 0x550)
+#define EL_CTRL_LOAD (1 << 0)
#define RING_CONTEXT_STATUS_BUF_LO(engine, i) _MMIO((engine)->mmio_base + 0x370 + (i) * 8)
#define RING_CONTEXT_STATUS_BUF_HI(engine, i) _MMIO((engine)->mmio_base + 0x370 + (i) * 8 + 4)
#define RING_CONTEXT_STATUS_PTR(engine) _MMIO((engine)->mmio_base + 0x3a0)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index c5ff203..d36bb73 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -200,9 +200,11 @@ struct intel_engine_execlists {
bool no_priolist;

/**
- * @elsp: the ExecList Submission Port register
+ * @els: gen-specific execlist submission register
+ * set to the ExecList Submission Port (elsp) register pre-Gen11 and to
+ * the ExecList Submission Queue Contents register array for Gen11+
*/
- u32 __iomem *elsp;
+ u32 __iomem *els;

/**
* @port: execlist port states
--
1.9.1