On Thu, May 21, 2015 at 04:37:48PM +0100, Damien Lespiau wrote:
> 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)
>
> v3:
> - Restore dev_priv->skl_boot_cdclk, leaving unification with
> dev_priv->cdclk_freq for a later patch (Daniel, Ville)
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Damien Lespiau <damien.lespiau@xxxxxxxxx>
Queued for -next, thanks for the patch.
-Daniel
> ---
> drivers/gpu/drm/i915/i915_drv.c | 3 +
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/i915_reg.h | 3 +
> drivers/gpu/drm/i915/intel_ddi.c | 8 +-
> drivers/gpu/drm/i915/intel_display.c | 208 +++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_drv.h | 2 +
> 6 files changed, 223 insertions(+), 2 deletions(-)
>
> 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_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index b4eebd0..44d592f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1705,6 +1705,7 @@ struct drm_i915_private {
> int num_fence_regs; /* 8 on pre-965, 16 otherwise */
>
> unsigned int fsb_freq, mem_freq, is_ddr3;
> + unsigned int skl_boot_cdclk;
> unsigned int cdclk_freq;
> unsigned int hpll_freq;
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 5afff3a..4d7282e 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6699,6 +6699,9 @@ 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 d602db2..cacb07b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -2510,6 +2510,7 @@ void intel_ddi_pll_init(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> uint32_t val = I915_READ(LCPLL_CTL);
> + int cdclk_freq;
>
> if (IS_SKYLAKE(dev))
> skl_shared_dplls_init(dev_priv);
> @@ -2518,12 +2519,15 @@ void intel_ddi_pll_init(struct drm_device *dev)
> else
> hsw_shared_dplls_init(dev_priv);
>
> - DRM_DEBUG_KMS("CDCLK running at %dKHz\n",
> - dev_priv->display.get_display_clock_speed(dev));
> + cdclk_freq = dev_priv->display.get_display_clock_speed(dev);
> + DRM_DEBUG_KMS("CDCLK running at %dKHz\n", cdclk_freq);
>
> if (IS_SKYLAKE(dev)) {
> + dev_priv->skl_boot_cdclk = cdclk_freq;
> 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 0485655..268043f 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5527,6 +5527,214 @@ 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);
> +}
> +
> +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->skl_boot_cdclk);
> + skl_dpll0_enable(dev_priv, required_vco);
> +
> + /* set CDCLK to the frequency the BIOS chose */
> + skl_set_cdclk(dev_priv, dev_priv->skl_boot_cdclk);
> +
> + /* 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 e94cb6e..02d8317 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1118,6 +1118,8 @@ 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
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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