From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
For now there are no callers, but these functions are going to be
needed for the code that allows Package C8+. Other future features may
also require this code.
v2: - Rebase.
- Fix D_COMP wait timeout.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 7 +++
drivers/gpu/drm/i915/intel_display.c | 92 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_drv.h | 3 ++
3 files changed, 102 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index bfa6f7f..b57d564 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5007,7 +5007,14 @@
#define LCPLL_CLK_FREQ_450 (0<<26)
#define LCPLL_CD_CLOCK_DISABLE (1<<25)
#define LCPLL_CD2X_CLOCK_DISABLE (1<<23)
+#define LCPLL_POWER_DOWN_ALLOW (1<<22)
#define LCPLL_CD_SOURCE_FCLK (1<<21)
+#define LCPLL_CD_SOURCE_FCLK_DONE (1<<19)
+
+#define D_COMP (MCHBAR_MIRROR_BASE_SNB + 0x5F0C)
+#define D_COMP_RCOMP_IN_PROGRESS (1<<9)
+#define D_COMP_COMP_FORCE (1<<8)
+#define D_COMP_COMP_DISABLE (1<<0)
/* Pipe WM_LINETIME - watermark line time */
#define PIPE_WM_LINETIME_A 0x45270
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0741e1f..915da2d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5924,6 +5924,98 @@ static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
return true;
}
+/*
+ * This function implements pieces of two sequences from BSpec:
+ * - Sequence for display software to disable LCPLL
+ * - Sequence for display software to allow package C8+
+ * The steps implemented here are just the steps that actually touch the LCPLL
+ * register. Callers should take care of disabling all the display engine
+ * functions, doing the mode unset, fixing interrupts, etc.
+ */
+void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
+ bool switch_to_fclk, bool allow_power_down)
+{
+ uint32_t val;
+
+ val = I915_READ(LCPLL_CTL);
+
+ if (switch_to_fclk) {
+ val |= LCPLL_CD_SOURCE_FCLK;
+ I915_WRITE(LCPLL_CTL, val);
+ POSTING_READ(LCPLL_CTL);
+
+ udelay(1);
+
+ val = I915_READ(LCPLL_CTL);
+ if (!(val & LCPLL_CD_SOURCE_FCLK_DONE))
+ DRM_ERROR("Switching to FCLK failed\n");
+ }
+
+ val |= LCPLL_PLL_DISABLE;
+ I915_WRITE(LCPLL_CTL, val);
+ POSTING_READ(LCPLL_CTL);
+
+ if (wait_for((I915_READ(LCPLL_CTL) & LCPLL_PLL_LOCK) == 0, 1))
+ DRM_ERROR("LCPLL still locked\n");
+
+ val = I915_READ(D_COMP);
+ val |= D_COMP_COMP_DISABLE;
+ I915_WRITE(D_COMP, val);
+ POSTING_READ(D_COMP);
+
+ if (wait_for((I915_READ(D_COMP) & D_COMP_RCOMP_IN_PROGRESS) == 0, 1))
+ DRM_ERROR("D_COMP RCOMP still in progress\n");
+
+ if (allow_power_down) {
+ val = I915_READ(LCPLL_CTL);
+ val |= LCPLL_POWER_DOWN_ALLOW;
+ I915_WRITE(LCPLL_CTL, val);
+ POSTING_READ(LCPLL_CTL);
+ }
+}
+
+/*
+ * Fully restores LCPLL, disallowing power down and switching back to LCPLL
+ * source.
+ */
+void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
+{
+ uint32_t val;
+
+ val = I915_READ(LCPLL_CTL);
+
+ if (val & LCPLL_POWER_DOWN_ALLOW) {
+ val &= ~LCPLL_POWER_DOWN_ALLOW;
+ I915_WRITE(LCPLL_CTL, val);
+ }
+
+ val = I915_READ(D_COMP);
+ val |= D_COMP_COMP_FORCE;
+ val &= ~D_COMP_COMP_DISABLE;
+ I915_WRITE(D_COMP, val);
+
+ val = I915_READ(LCPLL_CTL);
+ val &= ~LCPLL_PLL_DISABLE;
+ I915_WRITE(LCPLL_CTL, val);
+ POSTING_READ(LCPLL_CTL);
+
+ if (wait_for(I915_READ(LCPLL_CTL) & LCPLL_PLL_LOCK, 5))
+ DRM_ERROR("LCPLL not locked yet\n");
+
+ if (val & LCPLL_CD_SOURCE_FCLK) {
+ val = I915_READ(LCPLL_CTL);
+ val &= ~LCPLL_CD_SOURCE_FCLK;
+ I915_WRITE(LCPLL_CTL, val);
+ POSTING_READ(LCPLL_CTL);
+
+ udelay(1);
+
+ val = I915_READ(LCPLL_CTL);
+ if (val & LCPLL_CD_SOURCE_FCLK_DONE)
+ DRM_ERROR("Switching back to LCPLL failed\n");
+ }
+}
+
static void haswell_modeset_global_resources(struct drm_device *dev)
{
bool enable = false;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 31087ff..3fbe80b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -838,5 +838,8 @@ extern bool intel_set_pch_fifo_underrun_reporting(struct drm_device *dev,
extern void intel_edp_psr_enable(struct intel_dp *intel_dp);
extern void intel_edp_psr_disable(struct intel_dp *intel_dp);
extern void intel_edp_psr_update(struct drm_device *dev);
+extern void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
+ bool switch_to_fclk, bool allow_power_down);
+extern void hsw_restore_lcpll(struct drm_i915_private *dev_priv);
#endif /* __INTEL_DRV_H__ */
--
1.8.1.2
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