Re: [PATCH v4 6/9] drm: rcar-du: crtc: Enable and disable CMMs

From: Kieran Bingham
Date: Wed Sep 11 2019 - 14:40:34 EST


Hi Jacopo,

On 06/09/2019 14:54, Jacopo Mondi wrote:
> Enable/disable the CMM associated with a CRTC at CRTC start and stop
> time and enable the CMM unit through the Display Extensional Functions
> register at group setup time.
>
> Reviewed-by: Ulrich Hecht <uli+renesas@xxxxxxxx>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> ---
> drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 7 +++++++
> drivers/gpu/drm/rcar-du/rcar_du_group.c | 8 ++++++++
> drivers/gpu/drm/rcar-du/rcar_du_regs.h | 5 +++++
> 3 files changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> index 23f1d6cc1719..3dac605c3a67 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> @@ -21,6 +21,7 @@
> #include <drm/drm_plane_helper.h>
> #include <drm/drm_vblank.h>
>
> +#include "rcar_cmm.h"
> #include "rcar_du_crtc.h"
> #include "rcar_du_drv.h"
> #include "rcar_du_encoder.h"
> @@ -619,6 +620,9 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
> if (rcar_du_has(rcrtc->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
> rcar_du_vsp_disable(rcrtc);
>
> + if (rcrtc->cmm)
> + rcar_cmm_disable(rcrtc->cmm);
> +
> /*
> * Select switch sync mode. This stops display operation and configures
> * the HSYNC and VSYNC signals as inputs.
> @@ -686,6 +690,9 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
> }
>
> rcar_du_crtc_start(rcrtc);
> +
> + if (rcrtc->cmm)
> + rcar_cmm_enable(rcrtc->cmm);
> }
>
> static void rcar_du_crtc_atomic_disable(struct drm_crtc *crtc,
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
> index 9eee47969e77..25d0fc125d7a 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
> @@ -147,6 +147,14 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
>
> rcar_du_group_setup_pins(rgrp);
>
> + if (rcar_du_has(rcdu, RCAR_DU_FEATURE_CMM)) {
> + u32 defr7 = DEFR7_CODE
> + | (rgrp->cmms_mask & BIT(1) ? DEFR7_CMME1 : 0)
> + | (rgrp->cmms_mask & BIT(0) ? DEFR7_CMME0 : 0);
> +
> + rcar_du_group_write(rgrp, DEFR7, defr7);
> + }
> +

What's the effect here on platforms with a CMM, but with
CONFIG_DRM_RCAR_CMM unset?

Will this incorrectly configure the DU ?

Will it stall the display if the DU tries to interact with another
module which is not enabled?


> if (rcdu->info->gen >= 2) {
> rcar_du_group_setup_defr8(rgrp);
> rcar_du_group_setup_didsr(rgrp);
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_regs.h b/drivers/gpu/drm/rcar-du/rcar_du_regs.h
> index bc87f080b170..fb9964949368 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_regs.h
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_regs.h
> @@ -197,6 +197,11 @@
> #define DEFR6_MLOS1 (1 << 2)
> #define DEFR6_DEFAULT (DEFR6_CODE | DEFR6_TCNE1)
>
> +#define DEFR7 0x000ec
> +#define DEFR7_CODE (0x7779 << 16)
> +#define DEFR7_CMME1 BIT(6)
> +#define DEFR7_CMME0 BIT(4)
> +
> /* -----------------------------------------------------------------------------
> * R8A7790-only Control Registers
> */
>