On Thu, 04 Dec 2014, Gaurav K Singh <gaurav.k.singh@xxxxxxxxx> wrote:
> For dual link MIPI Panels, each port needs half of pixel clock. Pixel overlap
> can be enabled if needed by panel, then in that case, pixel clock will be
> increased for extra pixels.
>
> v2 : Address review comments by Jani
> - Removed the bit mask used for ->dual_link
> - Used DSI instead of MIPI for #define variables
>
> Signed-off-by: Gaurav K Singh <gaurav.k.singh@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 4 ++++
> drivers/gpu/drm/i915/intel_bios.h | 3 ++-
> drivers/gpu/drm/i915/intel_dsi.c | 8 ++++++++
> drivers/gpu/drm/i915/intel_dsi.h | 6 ++++++
> drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 21 +++++++++++++++++++++
> 5 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c981f5d..87149ba 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6029,6 +6029,10 @@ enum punit_power_well {
> #define GEN8_PMINTR_REDIRECT_TO_NON_DISP (1<<31)
> #define VLV_PWRDWNUPCTL 0xA294
>
> +#define VLV_CHICKEN_3 0x7040C
> +#define PIXEL_OVERLAP_CNT_MASK (3 << 30)
> +#define PIXEL_OVERLAP_CNT_SHIFT 30
I didn't find this register, but does it not need + VLV_DISPLAY_BASE?
Given that I can't find the register my review is pretty shallow, but I
don't spot anything obviously wrong either. With these caveats,
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> +
> #define GEN6_PMISR 0x44020
> #define GEN6_PMIMR 0x44024 /* rps_lock */
> #define GEN6_PMIIR 0x44028
> diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
> index de01167..a6a8710 100644
> --- a/drivers/gpu/drm/i915/intel_bios.h
> +++ b/drivers/gpu/drm/i915/intel_bios.h
> @@ -818,7 +818,8 @@ struct mipi_config {
> #define DUAL_LINK_PIXEL_ALT 2
> u16 dual_link:2;
> u16 lane_cnt:2;
> - u16 rsvd3:12;
> + u16 pixel_overlap:3;
> + u16 rsvd3:9;
>
> u16 rsvd4;
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index dbe52e9..4e18abd 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -111,6 +111,14 @@ static void intel_dsi_port_enable(struct intel_encoder *encoder)
> enum port port;
> u32 temp;
>
> + if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
> + temp = I915_READ(VLV_CHICKEN_3);
> + temp &= ~PIXEL_OVERLAP_CNT_MASK |
> + intel_dsi->pixel_overlap <<
> + PIXEL_OVERLAP_CNT_SHIFT;
> + I915_WRITE(VLV_CHICKEN_3, temp);
> + }
> +
> for_each_dsi_port(port, intel_dsi->ports) {
> temp = I915_READ(MIPI_PORT_CTRL(port));
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
> index f2cc2fc..8fe2064 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -28,6 +28,11 @@
> #include <drm/drm_crtc.h>
> #include "intel_drv.h"
>
> +/* Dual Link support */
> +#define DSI_DUAL_LINK_NONE 0
> +#define DSI_DUAL_LINK_FRONT_BACK 1
> +#define DSI_DUAL_LINK_PIXEL_ALT 2
> +
> struct intel_dsi_device {
> unsigned int panel_id;
> const char *name;
> @@ -105,6 +110,7 @@ struct intel_dsi {
>
> u8 escape_clk_div;
> u8 dual_link;
> + u8 pixel_overlap;
> u32 port_bits;
> u32 bw_timer;
> u32 dphy_reg;
> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> index f60146f..f8c2269 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> @@ -288,6 +288,7 @@ static bool generic_init(struct intel_dsi_device *dsi)
> intel_dsi->lane_count = mipi_config->lane_cnt + 1;
> intel_dsi->pixel_format = mipi_config->videomode_color_format << 7;
> intel_dsi->dual_link = mipi_config->dual_link;
> + intel_dsi->pixel_overlap = mipi_config->pixel_overlap;
>
> if (intel_dsi->dual_link)
> intel_dsi->ports = ((1 << PORT_A) | (1 << PORT_C));
> @@ -310,6 +311,20 @@ static bool generic_init(struct intel_dsi_device *dsi)
>
> pclk = mode->clock;
>
> + /* In dual link mode each port needs half of pixel clock */
> + if (intel_dsi->dual_link) {
> + pclk = pclk / 2;
> +
> + /* we can enable pixel_overlap if needed by panel. In this
> + * case we need to increase the pixelclock for extra pixels
> + */
> + if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
> + pclk += DIV_ROUND_UP(mode->vtotal *
> + intel_dsi->pixel_overlap *
> + 60, 1000);
> + }
> + }
> +
> /* Burst Mode Ratio
> * Target ddr frequency from VBT / non burst ddr freq
> * multiply by 100 to preserve remainder
> @@ -504,6 +519,12 @@ static bool generic_init(struct intel_dsi_device *dsi)
> DRM_DEBUG_KMS("Clockstop %s\n", intel_dsi->clock_stop ?
> "disabled" : "enabled");
> DRM_DEBUG_KMS("Mode %s\n", intel_dsi->operation_mode ? "command" : "video");
> + if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)
> + DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_FRONT_BACK\n");
> + else if (intel_dsi->dual_link == DSI_DUAL_LINK_PIXEL_ALT)
> + DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_PIXEL_ALT\n");
> + else
> + DRM_DEBUG_KMS("Dual link: NONE\n");
> DRM_DEBUG_KMS("Pixel Format %d\n", intel_dsi->pixel_format);
> DRM_DEBUG_KMS("TLPX %d\n", intel_dsi->escape_clk_div);
> DRM_DEBUG_KMS("LP RX Timeout 0x%x\n", intel_dsi->lp_rx_timeout);
> --
> 1.7.9.5
>
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--
Jani Nikula, Intel Open Source Technology Center
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