[PATCH 15/76] drm/i915/execlists: Unify CSB access pointers
Chris Wilson
chris at chris-wilson.co.uk
Sat Jun 2 09:37:18 UTC 2018
Following the removal of the last workarounds, the only CSB mmio access
is for the old vGPU interface. The mmio registers presented by vGPU do
not require forcewake and can be treated as ordinary volatile memory,
i.e. they behave just like the HWSP access just at a different location.
We can reduce the CSB access inside the irq handler to a set of
read/write/buffer pointers and treat the various paths identically and
not worry about forcewake.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_engine_cs.c | 12 ---
drivers/gpu/drm/i915/intel_lrc.c | 116 ++++++++++--------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 23 +++--
3 files changed, 65 insertions(+), 86 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 13448ea76f57..bc0193199a03 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -25,7 +25,6 @@
#include <drm/drm_print.h>
#include "i915_drv.h"
-#include "i915_vgpu.h"
#include "intel_ringbuffer.h"
#include "intel_lrc.h"
@@ -456,21 +455,10 @@ static void intel_engine_init_batch_pool(struct intel_engine_cs *engine)
i915_gem_batch_pool_init(&engine->batch_pool, engine);
}
-static bool csb_force_mmio(struct drm_i915_private *i915)
-{
- /* Older GVT emulation depends upon intercepting CSB mmio */
- if (intel_vgpu_active(i915) && !intel_vgpu_has_hwsp_emulation(i915))
- return true;
-
- return false;
-}
-
static void intel_engine_init_execlist(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
- execlists->csb_use_mmio = csb_force_mmio(engine->i915);
-
execlists->port_mask = 1;
BUILD_BUG_ON_NOT_POWER_OF_2(execlists_num_ports(execlists));
GEM_BUG_ON(execlists_num_ports(execlists) > EXECLIST_MAX_PORTS);
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 280c852e34cd..acc0643fa604 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -137,6 +137,7 @@
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_gem_render_state.h"
+#include "i915_vgpu.h"
#include "intel_lrc_reg.h"
#include "intel_mocs.h"
#include "intel_workarounds.h"
@@ -952,44 +953,23 @@ static void process_csb(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
- struct drm_i915_private *i915 = engine->i915;
-
- /* The HWSP contains a (cacheable) mirror of the CSB */
- const u32 *buf =
- &engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX];
- unsigned int head, tail;
- bool fw = false;
+ const u32 * const buf = execlists->csb_status;
+ u8 head, tail;
/* Clear before reading to catch new interrupts */
clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
smp_mb__after_atomic();
- if (unlikely(execlists->csb_use_mmio)) {
- intel_uncore_forcewake_get(i915, execlists->fw_domains);
- fw = true;
-
- buf = (u32 * __force)
- (i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0)));
+ /* Note that csb_write, csb_status may be either in HWSP or mmio */
+ head = execlists->csb_head;
+ tail = READ_ONCE(*execlists->csb_write);
+ GEM_TRACE("%s cs-irq head=%d, tail=%d\n", engine->name, head, tail);
+ if (unlikely(head == tail))
+ return;
- head = readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)));
- tail = GEN8_CSB_WRITE_PTR(head);
- head = GEN8_CSB_READ_PTR(head);
- execlists->csb_head = head;
- } else {
- const int write_idx =
- intel_hws_csb_write_index(i915) -
- I915_HWS_CSB_BUF0_INDEX;
+ rmb(); /* Hopefully paired with a wmb() in HW */
- head = execlists->csb_head;
- tail = READ_ONCE(buf[write_idx]);
- rmb(); /* Hopefully paired with a wmb() in HW */
- }
- GEM_TRACE("%s cs-irq head=%d [%d%s], tail=%d [%d%s]\n",
- engine->name,
- head, GEN8_CSB_READ_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?",
- tail, GEN8_CSB_WRITE_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?");
-
- while (head != tail) {
+ do {
struct i915_request *rq;
unsigned int status;
unsigned int count;
@@ -1015,12 +995,12 @@ static void process_csb(struct intel_engine_cs *engine)
* status notifier.
*/
- status = READ_ONCE(buf[2 * head]); /* maybe mmio! */
GEM_TRACE("%s csb[%d]: status=0x%08x:0x%08x, active=0x%x\n",
engine->name, head,
- status, buf[2*head + 1],
+ buf[2 * head + 0], buf[2 * head + 1],
execlists->active);
+ status = buf[2 * head];
if (status & (GEN8_CTX_STATUS_IDLE_ACTIVE |
GEN8_CTX_STATUS_PREEMPTED))
execlists_set_active(execlists,
@@ -1102,16 +1082,11 @@ static void process_csb(struct intel_engine_cs *engine)
} else {
port_set(port, port_pack(rq, count));
}
- }
-
- if (head != execlists->csb_head) {
- execlists->csb_head = head;
- writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK, head << 8),
- i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)));
- }
+ } while (head != tail);
- if (unlikely(fw))
- intel_uncore_forcewake_put(i915, execlists->fw_domains);
+ writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK, head << 8),
+ execlists->csb_read);
+ execlists->csb_head = head;
}
/*
@@ -2394,28 +2369,11 @@ logical_ring_default_irqs(struct intel_engine_cs *engine)
static void
logical_ring_setup(struct intel_engine_cs *engine)
{
- struct drm_i915_private *dev_priv = engine->i915;
- enum forcewake_domains fw_domains;
-
intel_engine_setup_common(engine);
/* Intentionally left blank. */
engine->buffer = NULL;
- fw_domains = intel_uncore_forcewake_for_reg(dev_priv,
- RING_ELSP(engine),
- FW_REG_WRITE);
-
- fw_domains |= intel_uncore_forcewake_for_reg(dev_priv,
- RING_CONTEXT_STATUS_PTR(engine),
- FW_REG_READ | FW_REG_WRITE);
-
- fw_domains |= intel_uncore_forcewake_for_reg(dev_priv,
- RING_CONTEXT_STATUS_BUF_BASE(engine),
- FW_REG_READ);
-
- engine->execlists.fw_domains = fw_domains;
-
tasklet_init(&engine->execlists.tasklet,
execlists_submission_tasklet, (unsigned long)engine);
@@ -2423,34 +2381,56 @@ logical_ring_setup(struct intel_engine_cs *engine)
logical_ring_default_irqs(engine);
}
+static bool csb_force_mmio(struct drm_i915_private *i915)
+{
+ /* Older GVT emulation depends upon intercepting CSB mmio */
+ return intel_vgpu_active(i915) && !intel_vgpu_has_hwsp_emulation(i915);
+}
+
static int logical_ring_init(struct intel_engine_cs *engine)
{
+ struct drm_i915_private *i915 = engine->i915;
+ struct intel_engine_execlists * const execlists = &engine->execlists;
int ret;
ret = intel_engine_init_common(engine);
if (ret)
goto error;
- if (HAS_LOGICAL_RING_ELSQ(engine->i915)) {
- engine->execlists.submit_reg = engine->i915->regs +
+ if (HAS_LOGICAL_RING_ELSQ(i915)) {
+ execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(engine));
- engine->execlists.ctrl_reg = engine->i915->regs +
+ execlists->ctrl_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_CONTROL(engine));
} else {
- engine->execlists.submit_reg = engine->i915->regs +
+ execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_ELSP(engine));
}
- engine->execlists.preempt_complete_status = ~0u;
- if (engine->i915->preempt_context) {
+ execlists->preempt_complete_status = ~0u;
+ if (i915->preempt_context) {
struct intel_context *ce =
- to_intel_context(engine->i915->preempt_context, engine);
+ to_intel_context(i915->preempt_context, engine);
- engine->execlists.preempt_complete_status =
+ execlists->preempt_complete_status =
upper_32_bits(ce->lrc_desc);
}
- engine->execlists.csb_head = GEN8_CSB_ENTRIES - 1;
+ execlists->csb_head = GEN8_CSB_ENTRIES - 1;
+ execlists->csb_read =
+ i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine));
+ if (csb_force_mmio(i915)) {
+ execlists->csb_status = (u32 __force *)
+ (i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0)));
+
+ execlists->csb_write = (u32 __force *)execlists->csb_read;
+ } else {
+ execlists->csb_status =
+ &engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX];
+
+ execlists->csb_write =
+ &engine->status_page.page_addr[intel_hws_csb_write_index(i915)];
+ }
return 0;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index acef385c4c80..88418477f9ab 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -299,19 +299,30 @@ struct intel_engine_execlists {
struct rb_node *first;
/**
- * @fw_domains: forcewake domains for irq tasklet
+ * @csb_head: context status buffer head
*/
- unsigned int fw_domains;
+ unsigned int csb_head;
/**
- * @csb_head: context status buffer head
+ * @csb_read: control register for Context Switch buffer
+ *
+ * Note this register is always in mmio.
*/
- unsigned int csb_head;
+ u32 __iomem *csb_read;
/**
- * @csb_use_mmio: access csb through mmio, instead of hwsp
+ * @csb_write: control register for Context Switch buffer
+ *
+ * Note this register may be either mmio or HWSP shadow.
+ */
+ u32 *csb_write;
+
+ /**
+ * @csb_status: status array for Context Switch buffer
+ *
+ * Note these register may be either mmio or HWSP shadow.
*/
- bool csb_use_mmio;
+ u32 *csb_status;
/**
* @preempt_complete_status: expected CSB upon completing preemption
--
2.17.1
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