Decoupled MMIO is an alternative way to access forcewake domain
registers, which requires less cycles and avoids frequent software
forcewake.
v2:
- Moved platform check out of the function and got rid of duplicate
functions to find out decoupled power domain.
- Added a check for forcewake already held and skipped decoupled access
- Skipped writing 64 bit register through decoupled MMIO
Signed-off-by: Zhe Wang <zhe1.wang@xxxxxxxxx>
Signed-off-by: Damien Lespiau <damien.lespiau@xxxxxxxxx>
Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
Signed-off-by: Praveen Paneri <praveen.paneri@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 11 ++++
drivers/gpu/drm/i915/i915_reg.h | 7 +++
drivers/gpu/drm/i915/intel_uncore.c | 118 +++++++++++++++++++++++++++++++++++-
3 files changed, 134 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4dd307e..065247b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -558,6 +558,16 @@ enum forcewake_domains {
#define FW_REG_READ (1)
#define FW_REG_WRITE (2)
+enum power_domains {
+ GEN9_DECOUPLED_PD_BLITTER = 0,
+ GEN9_DECOUPLED_PD_RENDER,
+ GEN9_DECOUPLED_PD_MEDIA,
+ GEN9_DECOUPLED_PD_ALL
+};
+
+#define GEN9_DECOUPLED_OP_WRITE (0)
+#define GEN9_DECOUPLED_OP_READ (1)
+
enum forcewake_domains
intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
i915_reg_t reg, unsigned int op);
@@ -2854,6 +2864,7 @@ struct drm_i915_cmd_table {
#define GT_FREQUENCY_MULTIPLIER 50
#define GEN9_FREQ_SCALER 3
+#define HAS_DECOUPLED_MMIO(dev_priv) (IS_BROXTON(dev_priv) && IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
#include "i915_trace.h"
static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 70d9616..be59803 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7394,6 +7394,13 @@ enum {
#define SKL_FUSE_PG1_DIST_STATUS (1<<26)
#define SKL_FUSE_PG2_DIST_STATUS (1<<25)
+/* Decoupled MMIO register pair for kernel driver */
+#define GEN9_DECOUPLED_REG0_DW0 _MMIO(0xF00)
+#define GEN9_DECOUPLED_REG0_DW1 _MMIO(0xF04)
+#define GEN9_DECOUPLED_DW1_GO (1<<31)
+#define GEN9_DECOUPLED_PD_SHIFT 28
+#define GEN9_DECOUPLED_OP_SHIFT 24
+
/* Per-pipe DDI Function Control */
#define _TRANS_DDI_FUNC_CTL_A 0x60400
#define _TRANS_DDI_FUNC_CTL_B 0x61400
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index a9b6c93..06fffba 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -816,6 +816,42 @@ unclaimed_reg_debug(struct drm_i915_private *dev_priv,
__unclaimed_reg_debug(dev_priv, reg, read, before);
}
+/*
+ * Decoupled MMIO access for only 1 DWORD
+ */
+static void __gen9_decoupled_mmio_access(struct drm_i915_private *dev_priv,
+ uint32_t reg, u32 *ptr_data,
+ enum forcewake_domains fw_engine, int operation)
+{
+ enum power_domains pd_engine;
+ u32 ctrl_reg_data = 0;
+
+ if (operation == GEN9_DECOUPLED_OP_WRITE)
+ __raw_i915_write32(dev_priv,
+ GEN9_DECOUPLED_REG0_DW0,
+ *ptr_data);
+
+ pd_engine = (fw_engine == (FORCEWAKE_RENDER || FORCEWAKE_BLITTER)) ? \
+ !(fw_engine >> 1) : (fw_engine >> 1); \
+
+ ctrl_reg_data |= reg;
+ ctrl_reg_data |= (operation << GEN9_DECOUPLED_OP_SHIFT);
+ ctrl_reg_data |= (pd_engine << GEN9_DECOUPLED_PD_SHIFT);
+ __raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW1, ctrl_reg_data);
+
+ ctrl_reg_data |= GEN9_DECOUPLED_DW1_GO;
+ __raw_i915_write32(dev_priv, GEN9_DECOUPLED_REG0_DW1, ctrl_reg_data);
+
+ if (wait_for_atomic((__raw_i915_read32(dev_priv,
+ GEN9_DECOUPLED_REG0_DW1) & GEN9_DECOUPLED_DW1_GO) == 0,
+ FORCEWAKE_ACK_TIMEOUT_MS))
+ DRM_ERROR("Decoupled MMIO wait timed out\n");
+
+ if (operation == GEN9_DECOUPLED_OP_READ)
+ *ptr_data = __raw_i915_read32(dev_priv,
+ GEN9_DECOUPLED_REG0_DW0);
+}
+
#define GEN2_READ_HEADER(x) \
u##x val = 0; \
assert_rpm_wakelock_held(dev_priv);
@@ -892,6 +928,20 @@ static inline void __force_wake_auto(struct drm_i915_private *dev_priv,
dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains);
}
+static inline bool __is_forcewake_active(struct drm_i915_private *dev_priv,
+ enum forcewake_domains fw_domains)
+{
+ struct intel_uncore_forcewake_domain *domain;
+
+ /* Ideally GCC would be constant-fold and eliminate this loop */
+ for_each_fw_domain_masked(domain, fw_domains, dev_priv) {
+ if (domain->wake_count)
+ fw_domains &= ~domain->mask;
+ }
+
+ return fw_domains ? 0 : 1;
+}
+
#define __gen6_read(x) \
static u##x \
gen6_read##x(struct drm_i915_private *dev_priv, i915_reg_t reg, bool trace) { \
@@ -940,6 +990,37 @@ gen9_read##x(struct drm_i915_private *dev_priv, i915_reg_t reg, bool trace) { \
GEN6_READ_FOOTER; \
}
+#define __gen9_decoupled_read(x) \
+static u##x \
+gen9_decoupled_read##x(struct drm_i915_private *dev_priv, i915_reg_t reg, bool trace) { \
+ enum forcewake_domains fw_engine; \
+ GEN6_READ_HEADER(x); \
+ fw_engine = __gen9_reg_read_fw_domains(offset); \
+ if (fw_engine && x%32 == 0) { \
+ if (__is_forcewake_active(dev_priv, fw_engine)) \
+ __raw_i915_write##x(dev_priv, reg, val); \
+ else { \
+ unsigned i; \
+ u32 *ptr_data = (u32 *) &val; \
+ for (i = 0; i < x/32; i++) \
+ __gen9_decoupled_mmio_access(dev_priv, \
+ (offset + i*4), \
+ ptr_data + i, \
+ fw_engine, \
+ GEN9_DECOUPLED_OP_READ); \
+ } \
+ } else { \
+ if (fw_engine) \
+ __force_wake_auto(dev_priv, fw_engine); \
+ val = __raw_i915_read##x(dev_priv, reg); \
+ } \
+ GEN6_READ_FOOTER; \
+}
+
+__gen9_decoupled_read(8)
+__gen9_decoupled_read(16)
+__gen9_decoupled_read(32)
+__gen9_decoupled_read(64)
__gen9_read(8)
__gen9_read(16)
__gen9_read(32)
@@ -1107,6 +1188,34 @@ gen9_write##x(struct drm_i915_private *dev_priv, i915_reg_t reg, u##x val, \
GEN6_WRITE_FOOTER; \
}
+#define __gen9_decoupled_write(x) \
+static void \
+gen9_decoupled_write##x(struct drm_i915_private *dev_priv, i915_reg_t reg, u##x val, \
+ bool trace) { \
+ enum forcewake_domains fw_engine; \
+ GEN6_WRITE_HEADER; \
+ fw_engine = __gen9_reg_write_fw_domains(offset); \
+ if (fw_engine && x == 32) { \
+ u32 *ptr_data = (u32 *) &val; \
+ if (__is_forcewake_active(dev_priv, fw_engine)) \
+ __raw_i915_write##x(dev_priv, reg, val); \
+ else \
+ __gen9_decoupled_mmio_access(dev_priv, \
+ offset, \
+ ptr_data, \
+ fw_engine, \
+ GEN9_DECOUPLED_OP_WRITE); \
+ } else { \
+ if (fw_engine) \
+ __force_wake_auto(dev_priv, fw_engine); \
+ __raw_i915_write##x(dev_priv, reg, val); \
+ } \
+ GEN6_WRITE_FOOTER; \
+}
+
+__gen9_decoupled_write(8)
+__gen9_decoupled_write(16)
+__gen9_decoupled_write(32)
__gen9_write(8)
__gen9_write(16)
__gen9_write(32)
@@ -1328,8 +1437,13 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
switch (INTEL_INFO(dev_priv)->gen) {
default:
case 9:
- ASSIGN_WRITE_MMIO_VFUNCS(gen9);
- ASSIGN_READ_MMIO_VFUNCS(gen9);
+ if (HAS_DECOUPLED_MMIO(dev_priv)) {
+ ASSIGN_WRITE_MMIO_VFUNCS(gen9_decoupled);
+ ASSIGN_READ_MMIO_VFUNCS(gen9_decoupled);
+ } else {
+ ASSIGN_WRITE_MMIO_VFUNCS(gen9);
+ ASSIGN_READ_MMIO_VFUNCS(gen9);
+ }
break;
case 8:
if (IS_CHERRYVIEW(dev_priv)) {
--
1.9.1
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