Re: [PATCH v2] drm/i915: Add intel_dotclock_calculate()

Jani Nikula
2013-09-16T11:12:38Z

On Fri, 13 Sep 2013, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Extract the code to calculate the dotclock from the link clock and M/N
> values into a new function from ironlake_crtc_clock_get().
>
> The new function can be used to calculate the dotclock for both FDI and
> DP cases.
>
> Also simplify the code a bit along the way.
>
> v2: Don't forget about non-pch encoders in ironlake_crtc_clock_get()
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
> drivers/gpu/drm/i915/intel_display.c | 43 ++++++++++++++++++------------------
> drivers/gpu/drm/i915/intel_drv.h | 2 ++
> 2 files changed, 24 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index c0ee41c..13dea9b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7405,16 +7405,9 @@ static void i9xx_crtc_clock_get(struct intel_crtc *crtc,
> pipe_config->adjusted_mode.clock = clock.dot;
> }
>
> -static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> - struct intel_crtc_config *pipe_config)
> +int intel_dotclock_calculate(int link_freq,
> + const struct intel_link_m_n *m_n)
> {
> - struct drm_device *dev = crtc->base.dev;
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
> - int link_freq;
> - u64 clock;
> - u32 link_m, link_n;
> -
> /*
> * The calculation for the data clock is:
> * pixel_clock = ((m/n)*(link_clock * nr_lanes))/bpp
> @@ -7425,6 +7418,18 @@ static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> * link_clock = (m * link_clock) / n
> */
>
> + if (!m_n->link_n)
> + return 0;
> +
> + return div_u64((u64)m_n->link_m * link_freq, m_n->link_n);
> +}
> +
> +static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> + struct intel_crtc_config *pipe_config)
> +{
> + struct drm_device *dev = crtc->base.dev;
> + int link_freq;
> +
> /*
> * We need to get the FDI or DP link clock here to derive
> * the M/N dividers.
> @@ -7433,21 +7438,17 @@ static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> * For DP, it's either 1.62GHz or 2.7GHz.
> * We do our calculations in 10*MHz since we don't need much precison.
> */
> - if (pipe_config->has_pch_encoder)
> + if (pipe_config->has_pch_encoder) {
> link_freq = intel_fdi_link_freq(dev) * 10000;
> - else
> - link_freq = pipe_config->port_clock;
>
> - link_m = I915_READ(PIPE_LINK_M1(cpu_transcoder));
> - link_n = I915_READ(PIPE_LINK_N1(cpu_transcoder));
> -
> - if (!link_m || !link_n)
> - return;
> -
> - clock = ((u64)link_m * (u64)link_freq);
> - do_div(clock, link_n);
> + pipe_config->adjusted_mode.clock =
> + intel_dotclock_calculate(link_freq, &pipe_config->fdi_m_n);
> + } else {
> + link_freq = pipe_config->port_clock;
>
> - pipe_config->adjusted_mode.clock = clock;
> + pipe_config->adjusted_mode.clock =
> + intel_dotclock_calculate(link_freq, &pipe_config->dp_m_n);
> + }
> }
>
> /** Returns the currently programmed mode of the given pipe. */
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index c058f1b..6b97ac1 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -805,5 +805,7 @@ extern void intel_aux_display_runtime_put(struct drm_i915_private *dev_priv);
> extern void i915_disable_vga_mem(struct drm_device *dev);
> extern void intel_dp_get_m_n(struct intel_crtc *crtc,
> struct intel_crtc_config *pipe_config);
> +extern int intel_dotclock_calculate(int link_freq,
> + const struct intel_link_m_n *m_n);
>
> #endif /* __INTEL_DRV_H__ */
> --
> 1.8.1.5
>

--
Jani Nikula, Intel Open Source Technology Center