Re: [PATCH] drm/i915: clock readout support for DDI v3

Ville Syrjälä
2014-01-22T08:56:40Z

On Tue, Jan 21, 2014 at 12:42:10PM -0800, Jesse Barnes wrote:
> Read out and calculate the port and pixel clocks on DDI configs as well.
> This means we have to grab the DP divider values and look at the port
> mapping to figure out which clock select reg to read out.
>
> v2: do the work from ddi_get_config (Ville)
> v3: check WRPLL reference clock (Ville)
> add additional SPLL freqs (Ville)
> clean up port/crtc clock calc (Ville)
> fix up crtc_clock conditionals (Ville)
> drop superfluous dp_get_m_n from get_config (Ville)
>
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Look good.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
> drivers/gpu/drm/i915/i915_reg.h | 10 +++++
> drivers/gpu/drm/i915/intel_ddi.c | 92 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 102 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index a699efd..7bfc710 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5306,8 +5306,12 @@
> #define SPLL_PLL_ENABLE (1<<31)
> #define SPLL_PLL_SSC (1<<28)
> #define SPLL_PLL_NON_SSC (2<<28)
> +#define SPLL_PLL_LCPLL (3<<28)
> +#define SPLL_PLL_REF_MASK (3<<28)
> #define SPLL_PLL_FREQ_810MHz (0<<26)
> #define SPLL_PLL_FREQ_1350MHz (1<<26)
> +#define SPLL_PLL_FREQ_2700MHz (2<<26)
> +#define SPLL_PLL_FREQ_MASK (3<<26)
>
> /* WRPLL */
> #define WRPLL_CTL1 0x46040
> @@ -5318,8 +5322,13 @@
> #define WRPLL_PLL_SELECT_LCPLL_2700 (0x03<<28)
> /* WRPLL divider programming */
> #define WRPLL_DIVIDER_REFERENCE(x) ((x)<<0)
> +#define WRPLL_DIVIDER_REF_MASK (0xff)
> #define WRPLL_DIVIDER_POST(x) ((x)<<8)
> +#define WRPLL_DIVIDER_POST_MASK (0x3f<<8)
> +#define WRPLL_DIVIDER_POST_SHIFT 8
> #define WRPLL_DIVIDER_FEEDBACK(x) ((x)<<16)
> +#define WRPLL_DIVIDER_FB_SHIFT 16
> +#define WRPLL_DIVIDER_FB_MASK (0xff<<16)
>
> /* Port clock selection */
> #define PORT_CLK_SEL_A 0x46100
> @@ -5332,6 +5341,7 @@
> #define PORT_CLK_SEL_WRPLL1 (4<<29)
> #define PORT_CLK_SEL_WRPLL2 (5<<29)
> #define PORT_CLK_SEL_NONE (7<<29)
> +#define PORT_CLK_SEL_MASK (7<<29)
>
> /* Transcoder clock selection */
> #define TRANS_CLK_SEL_A 0x46140
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 1488b28..b6171cf 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -633,6 +633,96 @@ static void wrpll_update_rnp(uint64_t freq2k, unsigned budget,
> /* Otherwise a < c && b >= d, do nothing */
> }
>
> +static int intel_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
> + int reg)
> +{
> + int refclk = LC_FREQ;
> + int n, p, r;
> + u32 wrpll;
> +
> + wrpll = I915_READ(reg);
> + switch (wrpll & SPLL_PLL_REF_MASK) {
> + case SPLL_PLL_SSC:
> + case SPLL_PLL_NON_SSC:
> + /*
> + * We could calculate spread here, but our checking
> + * code only cares about 5% accuracy, and spread is a max of
> + * 0.5% downspread.
> + */
> + refclk = 135;
> + break;
> + case SPLL_PLL_LCPLL:
> + refclk = LC_FREQ;
> + break;
> + default:
> + WARN(1, "bad wrpll refclk\n");
> + return 0;
> + }
> +
> + r = wrpll & WRPLL_DIVIDER_REF_MASK;
> + p = (wrpll & WRPLL_DIVIDER_POST_MASK) >> WRPLL_DIVIDER_POST_SHIFT;
> + n = (wrpll & WRPLL_DIVIDER_FB_MASK) >> WRPLL_DIVIDER_FB_SHIFT;
> +
> + return (LC_FREQ * n) / (p * r);
> +}
> +
> +static void intel_ddi_clock_get(struct intel_encoder *encoder,
> + struct intel_crtc_config *pipe_config)
> +{
> + struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> + enum port port = intel_ddi_get_encoder_port(encoder);
> + int link_clock = 0;
> + u32 val, pll;
> +
> + val = I915_READ(PORT_CLK_SEL(port));
> + switch (val & PORT_CLK_SEL_MASK) {
> + case PORT_CLK_SEL_LCPLL_810:
> + link_clock = 81000;
> + break;
> + case PORT_CLK_SEL_LCPLL_1350:
> + link_clock = 135000;
> + break;
> + case PORT_CLK_SEL_LCPLL_2700:
> + link_clock = 270000;
> + break;
> + case PORT_CLK_SEL_WRPLL1:
> + link_clock = intel_ddi_calc_wrpll_link(dev_priv, WRPLL_CTL1);
> + break;
> + case PORT_CLK_SEL_WRPLL2:
> + link_clock = intel_ddi_calc_wrpll_link(dev_priv, WRPLL_CTL2);
> + break;
> + case PORT_CLK_SEL_SPLL:
> + pll = I915_READ(SPLL_CTL) & SPLL_PLL_FREQ_MASK;
> + if (pll == SPLL_PLL_FREQ_810MHz)
> + link_clock = 81000;
> + else if (pll == SPLL_PLL_FREQ_1350MHz)
> + link_clock = 135000;
> + else if (pll == SPLL_PLL_FREQ_2700MHz)
> + link_clock = 270000;
> + else {
> + WARN(1, "bad spll freq\n");
> + return;
> + }
> + break;
> + default:
> + WARN(1, "bad port clock sel\n");
> + return;
> + }
> +
> + pipe_config->port_clock = link_clock * 2;
> +
> + if (pipe_config->has_pch_encoder)
> + pipe_config->adjusted_mode.crtc_clock =
> + intel_dotclock_calculate(pipe_config->port_clock,
> + &pipe_config->fdi_m_n);
> + else if (pipe_config->has_dp_encoder)
> + pipe_config->adjusted_mode.crtc_clock =
> + intel_dotclock_calculate(pipe_config->port_clock,
> + &pipe_config->dp_m_n);
> + else
> + pipe_config->adjusted_mode.crtc_clock = pipe_config->port_clock;
> +}
> +
> static void
> intel_ddi_calculate_wrpll(int clock /* in Hz */,
> unsigned *r2_out, unsigned *n2_out, unsigned *p_out)
> @@ -1504,6 +1594,8 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
> pipe_config->pipe_bpp, dev_priv->vbt.edp_bpp);
> dev_priv->vbt.edp_bpp = pipe_config->pipe_bpp;
> }
> +
> + intel_ddi_clock_get(encoder, pipe_config);
> }
>
> static void intel_ddi_destroy(struct drm_encoder *encoder)
> --
> 1.8.3.2
>
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--
Ville Syrjälä
Intel OTC