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@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_engine_cs.c | 12 ---
drivers/gpu/drm/i915/intel_lrc.c | 110 ++++++++++--------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 23 +++--
3 files changed, 62 insertions(+), 83 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index b1a1ca0758ce..ad6508e991f3 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 0c7108249244..6701778c7dc1 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"
@@ -963,13 +964,8 @@ 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];
+ const u32 * const buf = execlists->csb_status;
unsigned int head, tail;
- bool fw = false;
/*
* We must never release our device wakeref until after we have
@@ -981,32 +977,16 @@ static void process_csb(struct intel_engine_cs *engine)
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)));
-
- 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;
+ /* 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 = 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 ? "" : "?");
+ rmb(); /* Hopefully paired with a wmb() in HW */
- while (head != tail) {
+ do {
struct i915_request *rq;
unsigned int status;
unsigned int count;
@@ -1119,16 +1099,11 @@ 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;
}
/*
@@ -2365,28 +2340,11 @@ 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);
@@ -2394,34 +2352,56 @@ 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 =
+ i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0));
+
+ execlists->csb_write = 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 4ad9c5842575..0a96088f522f 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 *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
--
2.17.0
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