On Fri, May 22, 2015 at 11:22:40AM +0300, Mika Kahola wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Implement support for changing the cdclk frequency during runtime on
> HSW. VLV/CHV already have support for this, so we can follow their
> example for the most part. Only the actual hardware programming differs,
> the rest is pretty much the same.
>
> The pipe pixel rate stuff is handled a bit differently for now due to
> the difference in pch vs. gmch pfit handling. Eventually we should unify
> that part to eliminate what is essentially duplicated code.
>
> v2: Grab rps.hw_lock around sandybridge_pcode_write()
> v3: Rebase due to power well vs. .global_resources() reordering
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> v3: Rebased to the latest
> v4: Reformatting 'haswell_modeset_global_pipes' function to
> support atomic state
>
> Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx>
>
> Author: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
Apart from the small remark below, it looks like it does what the spec
tell us to do.
However there are a few extra comments:
- I remember someone saying changing CDCLK hasn't been validated on
HSW, that's usually a red flag. Even if it seems like it's working,
I've no idea what the pcode does with the notification on ULX for
instance
- Changing CDCLK means we have to bring whole display down and up
again, which will make the current display flicker when hotplugging
a screen that needs a CDCLK bump for instance.
- it'd be nice to have some idea of the power gain running at a lower
frequency
--
Damien
> drivers/gpu/drm/i915/i915_reg.h | 3 +
> drivers/gpu/drm/i915/intel_display.c | 161 +++++++++++++++++++++++++++++++++--
> 2 files changed, 159 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 14366c8..015fe12 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6701,6 +6701,7 @@ enum skl_disp_power_wells {
> #define GEN6_PCODE_READ_RC6VIDS 0x5
> #define GEN6_ENCODE_RC6_VID(mv) (((mv) - 245) / 5)
> #define GEN6_DECODE_RC6_VID(vids) (((vids) * 5) + 245)
> +#define HSW_PCODE_DE_WRITE_FREQ_REQ 0x17
> #define GEN9_PCODE_READ_MEM_LATENCY 0x6
> #define GEN9_MEM_LATENCY_LEVEL_MASK 0xFF
> #define GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT 8
> @@ -7159,10 +7160,12 @@ enum skl_disp_power_wells {
> #define LCPLL_PLL_LOCK (1<<30)
> #define LCPLL_CLK_FREQ_MASK (3<<26)
> #define LCPLL_CLK_FREQ_450 (0<<26)
> +#define LCPLL_CLK_FREQ_ALT_HSW (1<<26) /* 337.5 (ULX) or 540 */
> #define LCPLL_CLK_FREQ_54O_BDW (1<<26)
> #define LCPLL_CLK_FREQ_337_5_BDW (2<<26)
> #define LCPLL_CLK_FREQ_675_BDW (3<<26)
> #define LCPLL_CD_CLOCK_DISABLE (1<<25)
> +#define LCPLL_ROOT_CD_CLOCK_DISABLE (1<<24)
> #define LCPLL_CD2X_CLOCK_DISABLE (1<<23)
> #define LCPLL_POWER_DOWN_ALLOW (1<<22)
> #define LCPLL_CD_SOURCE_FCLK (1<<21)
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index febf993..556d0ec7 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5545,7 +5545,16 @@ static void intel_update_max_cdclk(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> - if (IS_VALLEYVIEW(dev)) {
> + if (IS_HASWELL(dev)) {
> + if (I915_READ(FUSE_STRAP) & HSW_CDCLK_LIMIT)
> + dev_priv->max_cdclk_freq = 450000;
> + else if (IS_HSW_ULX(dev))
> + dev_priv->max_cdclk_freq = 337500;
> + else if (IS_HSW_ULT(dev))
> + dev_priv->max_cdclk_freq = 450000;
> + else
> + dev_priv->max_cdclk_freq = 540000;
> + } else if (IS_VALLEYVIEW(dev)) {
> dev_priv->max_cdclk_freq = 400000;
> } else {
> /* otherwise assume cdclk is fixed */
> @@ -9404,6 +9413,139 @@ static void broxton_modeset_global_resources(struct drm_atomic_state *old_state)
> broxton_set_cdclk(dev, req_cdclk);
> }
>
> +/* compute the max rate for new configuration */
> +static int ilk_max_pixel_rate(struct drm_i915_private *dev_priv)
> +{
> + struct drm_device *dev = dev_priv->dev;
> + struct intel_crtc *crtc;
> + int max_pixel_rate = 0;
> +
> + for_each_intel_crtc(dev, crtc) {
> + if (crtc->new_enabled)
> + max_pixel_rate = max((int)max_pixel_rate,
> + (int)ilk_pipe_pixel_rate(crtc->config));
> + }
> +
> + return max_pixel_rate;
> +}
new_enabled doesn't look like what we want to look at, it looks like a
temporary field we shouldn't be using in new code. Maybe
crtc->state->enable instead?
> +
> +static int haswell_calc_cdclk(struct drm_i915_private *dev_priv,
> + int max_pixel_rate)
> +{
> + int cdclk;
> +
> + /*
> + * FIXME should also account for plane ratio
> + * once 64bpp pixel formats are supported.
> + */
> + if (max_pixel_rate > 450000)
> + cdclk = 540000;
> + else if (max_pixel_rate > 337500 || !IS_HSW_ULX(dev_priv))
> + cdclk = 450000;
> + else
> + cdclk = 337500;
> +
> + /*
> + * FIXME move the cdclk caclulation to
> + * compute_config() so we can fail gracegully.
> + */
> + if (cdclk > dev_priv->max_cdclk_freq) {
> + DRM_ERROR("requested cdclk (%d kHz) exceeds max (%d kHz)\n",
> + cdclk, dev_priv->max_cdclk_freq);
> + cdclk = dev_priv->max_cdclk_freq;
> + }
> +
> + return cdclk;
> +}
> +
> +static void haswell_set_cdclk(struct drm_device *dev, int cdclk)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + uint32_t val;
> +
> + if (WARN((I915_READ(LCPLL_CTL) &
> + (LCPLL_PLL_DISABLE | LCPLL_PLL_LOCK |
> + LCPLL_CD_CLOCK_DISABLE | LCPLL_ROOT_CD_CLOCK_DISABLE |
> + LCPLL_CD2X_CLOCK_DISABLE | LCPLL_POWER_DOWN_ALLOW |
> + LCPLL_CD_SOURCE_FCLK)) != LCPLL_PLL_LOCK,
> + "trying to change cdclk frequency with cdclk not enabled\n"))
> + return;
> +
> + val = I915_READ(LCPLL_CTL);
> + val &= ~LCPLL_CLK_FREQ_MASK;
> +
> + switch (cdclk) {
> + case 450000:
> + val |= LCPLL_CLK_FREQ_450;
> + break;
> + case 337500:
> + case 540000:
> + val |= LCPLL_CLK_FREQ_ALT_HSW;
> + break;
> + default:
> + WARN(1, "invalid cdclk frequency\n");
> + return;
> + }
> +
> + I915_WRITE(LCPLL_CTL, val);
> +
> + if (IS_HSW_ULX(dev)) {
> + mutex_lock(&dev_priv->rps.hw_lock);
> + sandybridge_pcode_write(dev_priv, HSW_PCODE_DE_WRITE_FREQ_REQ,
> + cdclk == 337500);
> + mutex_unlock(&dev_priv->rps.hw_lock);
> + }
> +
> + intel_update_cdclk(dev);
> +
> + WARN(cdclk != dev_priv->cdclk_freq,
> + "cdclk requested %d kHz but got %d kHz\n",
> + cdclk, dev_priv->cdclk_freq);
> +}
> +
> +static int haswell_modeset_global_pipes(struct drm_atomic_state *state)
> +{
> + struct drm_i915_private *dev_priv = to_i915(state->dev);
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *crtc_state;
> + int max_pixclk = ilk_max_pixel_rate(dev_priv);
> + int cdclk, i;
> +
> + cdclk = haswell_calc_cdclk(dev_priv, max_pixclk);
> +
> + if (cdclk == dev_priv->cdclk_freq)
> + return 0;
> +
> + /* add all active pipes to the state */
> + for_each_crtc(state->dev, crtc) {
> + if (!crtc->state->enable)
> + continue;
> +
> + crtc_state = drm_atomic_get_crtc_state(state, crtc);
> + if (IS_ERR(crtc_state))
> + return PTR_ERR(crtc_state);
> + }
> +
> + /* disable/enable all currently active pipes while we change cdclk */
> + for_each_crtc_in_state(state, crtc, crtc_state, i)
> + if (crtc_state->enable)
> + crtc_state->mode_changed = true;
> +
> + return 0;
> +}
> +
> +static void haswell_modeset_global_resources(struct drm_atomic_state *state)
> +{
> + struct drm_device *dev = state->dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + int max_pixel_rate = ilk_max_pixel_rate(dev_priv);
> + int req_cdclk = haswell_calc_cdclk(dev_priv, max_pixel_rate);
> +
> + if (req_cdclk != dev_priv->cdclk_freq) {
> + haswell_set_cdclk(dev, req_cdclk);
> + }
> +}
> +
> static int haswell_crtc_compute_clock(struct intel_crtc *crtc,
> struct intel_crtc_state *crtc_state)
> {
> @@ -12582,10 +12724,16 @@ static int __intel_set_mode_checks(struct drm_atomic_state *state)
> * mode set on this crtc. For other crtcs we need to use the
> * adjusted_mode bits in the crtc directly.
> */
> - if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev)) {
> - ret = valleyview_modeset_global_pipes(state);
> - if (ret)
> - return ret;
> + if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev) || IS_HASWELL(dev)) {
> + if (IS_VALLEYVIEW(dev) || IS_BROXTON(dev)) {
> + ret = valleyview_modeset_global_pipes(state);
> + if (ret)
> + return ret;
> + } else {
> + ret = haswell_modeset_global_pipes(state);
> + if (ret)
> + return ret;
> + }
> }
>
> ret = __intel_set_mode_setup_plls(state);
> @@ -14468,6 +14616,9 @@ static void intel_init_display(struct drm_device *dev)
> dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
> } else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
> dev_priv->display.fdi_link_train = hsw_fdi_link_train;
> + if (IS_HASWELL(dev))
> + dev_priv->display.modeset_global_resources =
> + haswell_modeset_global_resources;
> } else if (IS_VALLEYVIEW(dev)) {
> dev_priv->display.modeset_global_resources =
> valleyview_modeset_global_resources;
> --
> 1.9.1
>
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