[Intel-gfx] [PATCH 5/5] drm/i915/skl: Deinit/init the display at suspend/resume
Damien Lespiau
damien.lespiau at intel.com
Wed May 20 06:45:18 PDT 2015
We need to re-init the display hardware when going out of suspend. This
includes:
- Hooking the PCH to the reset logic
- Restoring CDCDLK
- Enabling the DDB power
Among those, only the CDCDLK one is a bit tricky. There's some
complexity in that:
- DPLL0 (which is the source for CDCLK) has two VCOs, each with a set
of supported frequencies. As eDP also uses DPLL0 for its link rate,
once DPLL0 is on, we restrict the possible eDP link rates the chosen
VCO.
- CDCLK also limits the bandwidth available to push pixels.
So, as a first step, this commit restore what the BIOS set, until I can
do more testing.
In case that's of interest for the reviewer, I've unit tested the
function that derives the decimal frequency field:
#include <stdio.h>
#include <stdint.h>
#include <assert.h>
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
static const struct dpll_freq {
unsigned int freq;
unsigned int decimal;
} freqs[] = {
{ .freq = 308570, .decimal = 0b01001100111},
{ .freq = 337500, .decimal = 0b01010100001},
{ .freq = 432000, .decimal = 0b01101011110},
{ .freq = 450000, .decimal = 0b01110000010},
{ .freq = 540000, .decimal = 0b10000110110},
{ .freq = 617140, .decimal = 0b10011010000},
{ .freq = 675000, .decimal = 0b10101000100},
};
static void intbits(unsigned int v)
{
int i;
for(i = 10; i >= 0; i--)
putchar('0' + ((v >> i) & 1));
}
static unsigned int freq_decimal(unsigned int freq /* in kHz */)
{
return (freq - 1000) / 500;
}
static void test_freq(const struct dpll_freq *entry)
{
unsigned int decimal = freq_decimal(entry->freq);
printf("freq: %d, expected: ", entry->freq);
intbits(entry->decimal);
printf(", got: ");
intbits(decimal);
putchar('\n');
assert(decimal == entry->decimal);
}
int main(int argc, char **argv)
{
int i;
for (i = 0; i < ARRAY_SIZE(freqs); i++)
test_freq(&freqs[i]);
return 0;
}
v2:
- Rebase on top of -nightly
- Use (freq - 1000) / 500 for the decimal frequency (Ville)
- Fix setting the enable bit of HSW_NDE_RSTWRN_OPT (Ville)
- Rename skl_display_{resume,suspend} to skl_{init,uninit}_cdclk to
be consistent with the BXT code (Ville)
- Store boot CDCLK in ddi_pll_init (Ville)
- Merge dev_priv's skl_boot_cdclk into cdclk_freq
- Use LCPLL_PLL_LOCK instead of (1 << 30) (Ville)
- Replace various '0' by SKL_DPLL0 to be a bit more explicit that
we're programming DPLL0
- Busy poll the PCU before doing the frequency change. It takes about
3/4 cycles, each separated by 10us, to get the ACK from the CPU
(Ville)
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
drivers/gpu/drm/i915/i915_drv.c | 3 +
drivers/gpu/drm/i915/i915_reg.h | 3 +
drivers/gpu/drm/i915/intel_ddi.c | 2 +
drivers/gpu/drm/i915/intel_display.c | 210 +++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_drv.h | 2 +
5 files changed, 220 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 93191c1..884b4f9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1047,6 +1047,8 @@ static int skl_suspend_complete(struct drm_i915_private *dev_priv)
*/
intel_csr_load_status_set(dev_priv, FW_UNINITIALIZED);
+ skl_uninit_cdclk(dev_priv);
+
return 0;
}
@@ -1093,6 +1095,7 @@ static int skl_resume_prepare(struct drm_i915_private *dev_priv)
{
struct drm_device *dev = dev_priv->dev;
+ skl_init_cdclk(dev_priv);
intel_csr_load_program(dev);
return 0;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 84af255..4df5cdd 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6698,6 +6698,9 @@ enum skl_disp_power_wells {
#define GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT 8
#define GEN9_MEM_LATENCY_LEVEL_2_6_SHIFT 16
#define GEN9_MEM_LATENCY_LEVEL_3_7_SHIFT 24
+#define SKL_PCODE_CDCLK_CONTROL 0x7
+#define SKL_CDCLK_PREPARE_FOR_CHANGE 0x3
+#define SKL_CDCLK_READY_FOR_CHANGE 0x1
#define GEN6_PCODE_WRITE_MIN_FREQ_TABLE 0x8
#define GEN6_PCODE_READ_MIN_FREQ_TABLE 0x9
#define GEN6_READ_OC_PARAMS 0xc
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index b57f156..bc6b899 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2524,6 +2524,8 @@ void intel_ddi_pll_init(struct drm_device *dev)
if (IS_SKYLAKE(dev)) {
if (!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE))
DRM_ERROR("LCPLL1 is disabled\n");
+ else
+ intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
} else if (IS_BROXTON(dev)) {
broxton_init_cdclk(dev);
broxton_ddi_phy_init(dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c97b496..1f2f4f9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5527,6 +5527,216 @@ void broxton_uninit_cdclk(struct drm_device *dev)
intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
}
+static const struct skl_cdclk_entry {
+ unsigned int freq;
+ unsigned int vco;
+} skl_cdclk_frequencies[] = {
+ { .freq = 308570, .vco = 8640 },
+ { .freq = 337500, .vco = 8100 },
+ { .freq = 432000, .vco = 8640 },
+ { .freq = 450000, .vco = 8100 },
+ { .freq = 540000, .vco = 8100 },
+ { .freq = 617140, .vco = 8640 },
+ { .freq = 675000, .vco = 8100 },
+};
+
+static unsigned int skl_cdclk_decimal(unsigned int freq)
+{
+ return (freq - 1000) / 500;
+}
+
+static unsigned int skl_cdclk_get_vco(unsigned int freq)
+{
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(skl_cdclk_frequencies); i++) {
+ const struct skl_cdclk_entry *e = &skl_cdclk_frequencies[i];
+
+ if (e->freq == freq)
+ return e->vco;
+ }
+
+ return 8100;
+}
+
+static void
+skl_dpll0_enable(struct drm_i915_private *dev_priv, unsigned int required_vco)
+{
+ unsigned int min_freq;
+ u32 val;
+
+ /* select the minimum CDCLK before enabling DPLL 0 */
+ val = I915_READ(CDCLK_CTL);
+ val &= ~CDCLK_FREQ_SEL_MASK | ~CDCLK_FREQ_DECIMAL_MASK;
+ val |= CDCLK_FREQ_337_308;
+
+ if (required_vco == 8640)
+ min_freq = 308570;
+ else
+ min_freq = 337500;
+
+ val = CDCLK_FREQ_337_308 | skl_cdclk_decimal(min_freq);
+
+ I915_WRITE(CDCLK_CTL, val);
+ POSTING_READ(CDCLK_CTL);
+
+ /*
+ * We always enable DPLL0 with the lowest link rate possible, but still
+ * taking into account the VCO required to operate the eDP panel at the
+ * desired frequency. The usual DP link rates operate with a VCO of
+ * 8100 while the eDP 1.4 alternate link rates need a VCO of 8640.
+ * The modeset code is responsible for the selection of the exact link
+ * rate later on, with the constraint of choosing a frequency that
+ * works with required_vco.
+ */
+ val = I915_READ(DPLL_CTRL1);
+
+ val &= ~(DPLL_CTRL1_HDMI_MODE(SKL_DPLL0) | DPLL_CTRL1_SSC(SKL_DPLL0) |
+ DPLL_CTRL1_LINK_RATE_MASK(SKL_DPLL0));
+ val |= DPLL_CTRL1_OVERRIDE(SKL_DPLL0);
+ if (required_vco == 8640)
+ val |= DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_1080,
+ SKL_DPLL0);
+ else
+ val |= DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_810,
+ SKL_DPLL0);
+
+ I915_WRITE(DPLL_CTRL1, val);
+ POSTING_READ(DPLL_CTRL1);
+
+ I915_WRITE(LCPLL1_CTL, I915_READ(LCPLL1_CTL) | LCPLL_PLL_ENABLE);
+
+ if (wait_for(I915_READ(LCPLL1_CTL) & LCPLL_PLL_LOCK, 5))
+ DRM_ERROR("DPLL0 not locked\n");
+}
+
+static bool skl_cdclk_pcu_ready(struct drm_i915_private *dev_priv)
+{
+ int ret;
+ u32 val;
+
+ /* inform PCU we want to change CDCLK */
+ val = SKL_CDCLK_PREPARE_FOR_CHANGE;
+ mutex_lock(&dev_priv->rps.hw_lock);
+ ret = sandybridge_pcode_read(dev_priv, SKL_PCODE_CDCLK_CONTROL, &val);
+ mutex_unlock(&dev_priv->rps.hw_lock);
+
+ return ret == 0 && (val & SKL_CDCLK_READY_FOR_CHANGE);
+}
+
+static bool skl_cdclk_wait_for_pcu_ready(struct drm_i915_private *dev_priv)
+{
+ unsigned int i;
+
+ for (i = 0; i < 15; i++) {
+ if (skl_cdclk_pcu_ready(dev_priv))
+ return true;
+ udelay(10);
+ }
+
+ return false;
+}
+
+static void skl_set_cdclk(struct drm_i915_private *dev_priv, unsigned int freq)
+{
+ u32 freq_select, pcu_ack;
+
+ DRM_DEBUG_DRIVER("Changing CDCLK to %dKHz\n", freq);
+
+ if (!skl_cdclk_wait_for_pcu_ready(dev_priv)) {
+ DRM_ERROR("failed to inform PCU about cdclk change\n");
+ return;
+ }
+
+ /* set CDCLK_CTL */
+ switch(freq) {
+ case 450000:
+ case 432000:
+ freq_select = CDCLK_FREQ_450_432;
+ pcu_ack = 1;
+ break;
+ case 540000:
+ freq_select = CDCLK_FREQ_540;
+ pcu_ack = 2;
+ break;
+ case 308570:
+ case 337500:
+ default:
+ freq_select = CDCLK_FREQ_337_308;
+ pcu_ack = 0;
+ break;
+ case 617140:
+ case 675000:
+ freq_select = CDCLK_FREQ_675_617;
+ pcu_ack = 3;
+ break;
+ }
+
+ I915_WRITE(CDCLK_CTL, freq_select | skl_cdclk_decimal(freq));
+ POSTING_READ(CDCLK_CTL);
+
+ /* inform PCU of the change */
+ mutex_lock(&dev_priv->rps.hw_lock);
+ sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL, pcu_ack);
+ mutex_unlock(&dev_priv->rps.hw_lock);
+
+ dev_priv->cdclk_freq = freq;
+}
+
+void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
+{
+ /* disable DBUF power */
+ I915_WRITE(DBUF_CTL, I915_READ(DBUF_CTL) & ~DBUF_POWER_REQUEST);
+ POSTING_READ(DBUF_CTL);
+
+ udelay(10);
+
+ if (I915_READ(DBUF_CTL) & DBUF_POWER_STATE)
+ DRM_ERROR("DBuf power disable timeout\n");
+
+ /* disable DPLL0 */
+ I915_WRITE(LCPLL1_CTL, I915_READ(LCPLL1_CTL) & ~LCPLL_PLL_ENABLE);
+ if (wait_for(!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_LOCK), 1))
+ DRM_ERROR("Couldn't disable DPLL0\n");
+
+ intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
+}
+
+void skl_init_cdclk(struct drm_i915_private *dev_priv)
+{
+ u32 val;
+ unsigned int required_vco;
+
+ /* enable PCH reset handshake */
+ val = I915_READ(HSW_NDE_RSTWRN_OPT);
+ I915_WRITE(HSW_NDE_RSTWRN_OPT, val | RESET_PCH_HANDSHAKE_ENABLE);
+
+ /* enable PG1 and Misc I/O */
+ intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
+
+ /* DPLL0 already enabed !? */
+ if (I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE) {
+ DRM_DEBUG_DRIVER("DPLL0 already running\n");
+ return;
+ }
+
+ /* enable DPLL0 */
+ required_vco = skl_cdclk_get_vco(dev_priv->cdclk_freq);
+ skl_dpll0_enable(dev_priv, required_vco);
+
+ /* set CDCLK to the frequency the BIOS chose */
+ skl_set_cdclk(dev_priv, dev_priv->cdclk_freq);
+
+ /* enable DBUF power */
+ I915_WRITE(DBUF_CTL, I915_READ(DBUF_CTL) | DBUF_POWER_REQUEST);
+ POSTING_READ(DBUF_CTL);
+
+ udelay(10);
+
+ if (!(I915_READ(DBUF_CTL) & DBUF_POWER_STATE))
+ DRM_ERROR("DBuf power enable timeout\n");
+}
+
/* returns HPLL frequency in kHz */
static int valleyview_get_vco(struct drm_i915_private *dev_priv)
{
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 47bc729..4640fb6 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1117,6 +1117,8 @@ void broxton_ddi_phy_init(struct drm_device *dev);
void broxton_ddi_phy_uninit(struct drm_device *dev);
void bxt_enable_dc9(struct drm_i915_private *dev_priv);
void bxt_disable_dc9(struct drm_i915_private *dev_priv);
+void skl_init_cdclk(struct drm_i915_private *dev_priv);
+void skl_uninit_cdclk(struct drm_i915_private *dev_priv);
void intel_dp_get_m_n(struct intel_crtc *crtc,
struct intel_crtc_state *pipe_config);
void intel_dp_set_m_n(struct intel_crtc *crtc, enum link_m_n_set m_n);
--
2.1.0
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