Re:[PATCH v5] rockchip/drm: vop2: add support for gamma LUT

From: Andy Yan
Date: Mon Oct 14 2024 - 23:40:47 EST

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In reply to: Piotr Zalewski: "[PATCH v5] rockchip/drm: vop2: add support for gamma LUT"
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Hi Piotr,

At 2024-10-15 06:30:27, "Piotr Zalewski" <pZ010001011111@xxxxxxxxx> wrote:
>Add support for gamma LUT in VOP2 driver. The implementation was inspired
>by one found in VOP1 driver. Blue and red channels in gamma LUT register
>write were swapped with respect to how gamma LUT values are written in
>VOP1. Gamma LUT port selection was added before the write of new gamma LUT
>table. If the current SoC is RK3588, "seamless" gamma lut update is
>performed similarly to how it was done in the case of RK3399 in VOP1[1]. In
>seamless update gamma LUT disable before the write isn't necessary,
>different register is being used to select gamma LUT port[2] and after
>setting DSP_LUT_EN bit, GAMMA_UPDATE_EN bit is set[3]. Gamma size is set
>and drm color management is enabled for each video port's CRTC except ones
>which have no associated device.
>
>Solution was tested on RK3566 (Pinetab2). When using userspace tools
>which set eg. constant color temperature no issues were noticed. When
>using userspace tools which adjust eg. color temperature the slight screen
>flicker is visible probably because of gamma LUT disable.
>
>Compare behaviour of eg.:
>```
>gammastep -O 3000
>```
>
>To eg.:
>```
>gammastep -l 53:23 -t 6000:3000
>```
>
>In latter case color temperature is slowly adjusted at the beginning which
>causes screen to slighly flicker. Then it adjusts every few seconds which
>also causes slight screen flicker.
>
>[1] https://lists.infradead.org/pipermail/linux-rockchip/2021-October/028132.html
>[2] https://lore.kernel.org/linux-rockchip/48249708-8c05-40d2-a5d8-23de960c5a77@xxxxxxxxxxxxxx/
>[3] https://github.com/radxa/kernel/blob/linux-6.1-stan-rkr1/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c#L3437
>
>Helped-by: Daniel Stone <daniel@xxxxxxxxxxxxx>
>Helped-by: Dragan Simic <dsimic@xxxxxxxxxxx>
>Helped-by: Diederik de Haas <didi.debian@xxxxxxxxx>
>Helped-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
>Signed-off-by: Piotr Zalewski <pZ010001011111@xxxxxxxxx>
>---
>
>Notes:
> Changes in v5:
> - Do not trigger full modeset in case seamless gamma lut update
> isn't possible (eg. rk356x case). It was discovered that with
> full modeset, userspace tools which adjust color temperature with
> high frequency cause screen to go black and reduce overall
> performance. Instead, revert to previous behaviour of lut update
> happening in atomic_begin or (in case there is a modeset) in
> atomic_enable. Also, add unrelated to modeset trigger
> changes/improvements from v4 on top. Improve code readability
> too.
>
> Changes in v4:
> - rework the implementation to better utilize DRM atomic updates[2]
> - handle the RK3588 case[2][3]
>
> Changes in v3:
> - v3 is patch v2 "resend", by mistake the incremental patch was
> sent in v2
>
> Changes in v2:
> - Apply code styling corrections[1]
> - Move gamma LUT write inside the vop2 lock
>
> Link to v4: https://lore.kernel.org/linux-rockchip/20240815124306.189282-2-pZ010001011111@xxxxxxxxx/
> Link to v3: https://lore.kernel.org/linux-rockchip/TkgKVivuaLFLILPY-n3iZo_8KF-daKdqdu-0_e0HP-5Ar_8DALDeNWog2suwWKjX7eomcbGET0KZe7DlzdhK2YM6CbLbeKeFZr-MJzJMtw0=@proton.me/
> Link to v2: https://lore.kernel.org/linux-rockchip/Hk03HDb6wSSHWtEFZHUye06HR0-9YzP5nCHx9A8_kHzWSZawDrU1o1pjEGkCOJFoRg0nTB4BWEv6V0XBOjF4-0Mj44lp2TrjaQfnytzp-Pk=@proton.me/T/#u
> Link to v1: https://lore.kernel.org/linux-rockchip/9736eadf6a9d8e97eef919c6b3d88828@xxxxxxxxxxx/T/#t
>
> [1] https://lore.kernel.org/linux-rockchip/d019761504b540600d9fc7a585d6f95f@xxxxxxxxxxx
> [2] https://lore.kernel.org/linux-rockchip/CAPj87rOM=j0zmuWL9frGKV1xzPbJrk=Q9ip7F_HAPYnbCqPouw@xxxxxxxxxxxxxx
> [3] https://lore.kernel.org/linux-rockchip/7d998e4c-e1d3-4e8b-af76-c5bc83b43647@xxxxxxxxxxxxxx
>
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 161 +++++++++++++++++++
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.h | 5 +
> 2 files changed, 166 insertions(+)
>
>diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>index 9873172e3fd3..a6a2d7df5ecc 100644
>--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>@@ -278,6 +278,15 @@ static u32 vop2_readl(struct vop2 *vop2, u32 offset)
> return val;
> }
>
>+static u32 vop2_vp_read(struct vop2_video_port *vp, u32 offset)
>+{
>+ u32 val;
>+
>+ regmap_read(vp->vop2->map, vp->data->offset + offset, &val);
>+
>+ return val;
>+}
>+
> static void vop2_win_write(const struct vop2_win *win, unsigned int reg, u32 v)
> {
> regmap_field_write(win->reg[reg], v);
>@@ -998,6 +1007,55 @@ static void vop2_disable(struct vop2 *vop2)
> clk_disable_unprepare(vop2->hclk);
> }
>
>+static bool vop2_vp_dsp_lut_is_enabled(struct vop2_video_port *vp)
>+{
>+ return (u32) (vop2_vp_read(vp, RK3568_VP_DSP_CTRL) & RK3568_VP_DSP_CTRL__DSP_LUT_EN) >
>+ 0;
>+}
>+
>+static void vop2_vp_dsp_lut_disable(struct vop2_video_port *vp)
>+{
>+ u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
>+
>+ dsp_ctrl &= ~RK3568_VP_DSP_CTRL__DSP_LUT_EN;
>+ vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
>+}
>+
>+static bool vop2_vp_dsp_lut_poll_disable(struct vop2_video_port *vp)
>+{
>+ u32 dsp_ctrl;
>+ int ret = readx_poll_timeout(vop2_vp_dsp_lut_is_enabled, vp, dsp_ctrl,
>+ !dsp_ctrl, 5, 30 * 1000);
>+ if (ret) {
>+ drm_err(vp->vop2->drm, "display LUT RAM enable timeout!\n");
>+ return false;
>+ }
>+
>+ return true;
>+}
>+
>+static void vop2_vp_dsp_lut_enable(struct vop2_video_port *vp)
>+{
>+ u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
>+
>+ dsp_ctrl |= RK3568_VP_DSP_CTRL__DSP_LUT_EN;
>+ vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
>+}
>+
>+static void vop2_vp_dsp_lut_update_enable(struct vop2_video_port *vp)
>+{
>+ u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
>+
>+ dsp_ctrl |= RK3588_VP_DSP_CTRL__GAMMA_UPDATE_EN;
>+ vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
>+}
>+
>+static inline bool vop2_supports_seamless_gamma_lut_update(struct vop2 *vop2)
>+{
>+ return (vop2->data->soc_id == 3588);
>+}
>+
>+
> static void vop2_crtc_atomic_disable(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
>@@ -1482,6 +1540,66 @@ static bool vop2_crtc_mode_fixup(struct drm_crtc *crtc,
> return true;
> }
>
>+static void vop2_crtc_write_gamma_lut(struct vop2 *vop2, struct drm_crtc *crtc)
>+{
>+ const struct vop2_video_port *vp = to_vop2_video_port(crtc);
>+ const struct vop2_video_port_data *vp_data = &vop2->data->vp[vp->id];
>+
>+ struct drm_color_lut *lut = crtc->state->gamma_lut->data;
>+ unsigned int i, bpc = ilog2(vp_data->gamma_lut_len);
>+ u32 word;
>+
>+ for (i = 0; i < crtc->gamma_size; i++) {
>+ word = (drm_color_lut_extract(lut[i].blue, bpc) << (2 * bpc)) |
>+ (drm_color_lut_extract(lut[i].green, bpc) << bpc) |
>+ drm_color_lut_extract(lut[i].red, bpc);
>+
>+ writel(word, vop2->lut_regs + i * 4);
>+ }
>+}
>+
>+static void vop2_crtc_atomic_try_set_gamma(struct vop2 *vop2,

Why we need a _try_ in the function name ?

>+ struct vop2_video_port *vp,
>+ struct drm_crtc *crtc,
>+ struct drm_crtc_state *crtc_state)
>+{
>+
>+ if (vop2->lut_regs && crtc_state->color_mgmt_changed) {
>+ if (!crtc_state->gamma_lut) {
>+ vop2_vp_dsp_lut_disable(vp);
>+ return;
>+ }
>+
>+ if (vop2_supports_seamless_gamma_lut_update(vop2)) {
I think it's bettery to check for rk3568/rk3566 here, the newer soc will all follow
rk3588 support seamless gamma lut update.

>+ vop2_writel(vop2, RK3568_LUT_PORT_SEL, FIELD_PREP(
>+ RK3588_LUT_PORT_SEL__GAMMA_AHB_WRITE_SEL,
>+ vp->id));
>+ vop2_crtc_write_gamma_lut(vop2, crtc);
>+ vop2_vp_dsp_lut_enable(vp);
>+ vop2_vp_dsp_lut_update_enable(vp);
>+ } else {

As for rk3566/68, we should do exclusive check here, because there is only
one gamma , only one VP can use it at a time. See my comments in V3:

https://patchwork.kernel.org/project/linux-rockchip/patch/TkgKVivuaLFLILPY-n3iZo_8KF-daKdqdu-0_e0HP-5Ar_8DALDeNWog2suwWKjX7eomcbGET0KZe7DlzdhK2YM6CbLbeKeFZr-MJzJMtw0=@proton.me/

>+ vop2_vp_dsp_lut_disable(vp);
>+ vop2_cfg_done(vp);
>+ if (!vop2_vp_dsp_lut_poll_disable(vp))
>+ return;
>+
>+ vop2_writel(vop2, RK3568_LUT_PORT_SEL, vp->id);
>+ vop2_crtc_write_gamma_lut(vop2, crtc);
>+ vop2_vp_dsp_lut_enable(vp);
>+ }
>+ }
>+}
>+
>+static inline void vop2_crtc_atomic_try_set_gamma_locked(struct vop2 *vop2,
>+ struct vop2_video_port *vp,
>+ struct drm_crtc *crtc,
>+ struct drm_crtc_state *crtc_state)
>+{
>+ vop2_lock(vop2);
>+ vop2_crtc_atomic_try_set_gamma(vop2, vp, crtc, crtc_state);
>+ vop2_unlock(vop2);
>+}
>+
> static void vop2_dither_setup(struct drm_crtc *crtc, u32 *dsp_ctrl)
> {
> struct rockchip_crtc_state *vcstate = to_rockchip_crtc_state(crtc->state);
>@@ -2057,11 +2175,35 @@ static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
>
> vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
>
>+ vop2_crtc_atomic_try_set_gamma(vop2, vp, crtc, crtc_state);
>+
> drm_crtc_vblank_on(crtc);
>
> vop2_unlock(vop2);
> }
>
>+static int vop2_crtc_atomic_check_gamma(struct vop2_video_port *vp,
>+ struct drm_crtc *crtc,
>+ struct drm_atomic_state *state,
>+ struct drm_crtc_state *crtc_state)
>+{
>+ struct vop2 *vop2 = vp->vop2;
>+ unsigned int len;
>+
>+ if (!vp->vop2->lut_regs || !crtc_state->color_mgmt_changed ||
>+ !crtc_state->gamma_lut)
>+ return 0;
>+
>+ len = drm_color_lut_size(crtc_state->gamma_lut);
>+ if (len != crtc->gamma_size) {
>+ drm_dbg(vop2->drm, "Invalid LUT size; got %d, expected %d\n",
>+ len, crtc->gamma_size);
>+ return -EINVAL;
>+ }
>+
>+ return 0;
>+}
>+
> static int vop2_crtc_atomic_check(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
>@@ -2069,6 +2211,11 @@ static int vop2_crtc_atomic_check(struct drm_crtc *crtc,
> struct drm_plane *plane;
> int nplanes = 0;
> struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
>+ int ret;
>+
>+ ret = vop2_crtc_atomic_check_gamma(vp, crtc, state, crtc_state);
>+ if (ret)
>+ return ret;
>
> drm_atomic_crtc_state_for_each_plane(plane, crtc_state)
> nplanes++;
>@@ -2456,9 +2603,12 @@ static void vop2_setup_dly_for_windows(struct vop2 *vop2)
> vop2_writel(vop2, RK3568_SMART_DLY_NUM, sdly);
> }
>
>+
> static void vop2_crtc_atomic_begin(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
>+ struct drm_crtc_state *crtc_state =
>+ drm_atomic_get_new_crtc_state(state, crtc);
> struct vop2_video_port *vp = to_vop2_video_port(crtc);
> struct vop2 *vop2 = vp->vop2;
> struct drm_plane *plane;
>@@ -2482,6 +2632,11 @@ static void vop2_crtc_atomic_begin(struct drm_crtc *crtc,
> vop2_setup_layer_mixer(vp);
> vop2_setup_alpha(vp);
> vop2_setup_dly_for_windows(vop2);
>+
>+ // NOTE: in case of modeset gamma lut update
>+ // already happened in atomic enable
>+ if (!drm_atomic_crtc_needs_modeset(crtc_state))
>+ vop2_crtc_atomic_try_set_gamma_locked(vop2, vp, crtc, crtc_state);

I would like update gamma at crtc_atomic_flush callback like mediateck, tidss, ast, and
we also following these in our bsp code.

> }
>
> static void vop2_crtc_atomic_flush(struct drm_crtc *crtc,
>@@ -2790,7 +2945,13 @@ static int vop2_create_crtcs(struct vop2 *vop2)
> }
>
> drm_crtc_helper_add(&vp->crtc, &vop2_crtc_helper_funcs);
>+ if (vop2->lut_regs && vp->crtc.dev != NULL) {
>+ const struct vop2_video_port_data *vp_data = &vop2_data->vp[vp->id];
>
>+ drm_mode_crtc_set_gamma_size(&vp->crtc, vp_data->gamma_lut_len);
>+ drm_crtc_enable_color_mgmt(&vp->crtc, 0, false,
>+ vp_data->gamma_lut_len);

It seems that we can keep it in one line, the default limit of linux kernel coding style is 100 characters now.

>+ }
> init_completion(&vp->dsp_hold_completion);
> }
>
>diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
>index 615a16196aff..510dda6f9092 100644
>--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
>+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
>@@ -394,6 +394,7 @@ enum dst_factor_mode {
> #define RK3568_REG_CFG_DONE__GLB_CFG_DONE_EN BIT(15)
>
> #define RK3568_VP_DSP_CTRL__STANDBY BIT(31)
>+#define RK3568_VP_DSP_CTRL__DSP_LUT_EN BIT(28)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_MODE BIT(20)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_SEL GENMASK(19, 18)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_EN BIT(17)
>@@ -408,6 +409,8 @@ enum dst_factor_mode {
> #define RK3568_VP_DSP_CTRL__CORE_DCLK_DIV BIT(4)
> #define RK3568_VP_DSP_CTRL__OUT_MODE GENMASK(3, 0)
>
>+#define RK3588_VP_DSP_CTRL__GAMMA_UPDATE_EN BIT(22)
>+
> #define RK3588_VP_CLK_CTRL__DCLK_OUT_DIV GENMASK(3, 2)
> #define RK3588_VP_CLK_CTRL__DCLK_CORE_DIV GENMASK(1, 0)
>
>@@ -460,6 +463,8 @@ enum dst_factor_mode {
> #define RK3588_DSP_IF_POL__DP1_PIN_POL GENMASK(14, 12)
> #define RK3588_DSP_IF_POL__DP0_PIN_POL GENMASK(10, 8)
>
>+#define RK3588_LUT_PORT_SEL__GAMMA_AHB_WRITE_SEL GENMASK(13, 12)
>+
> #define RK3568_VP0_MIPI_CTRL__DCLK_DIV2_PHASE_LOCK BIT(5)
> #define RK3568_VP0_MIPI_CTRL__DCLK_DIV2 BIT(4)
>
>--
>2.47.0
>
>
>
>_______________________________________________
>Linux-rockchip mailing list
>Linux-rockchip@xxxxxxxxxxxxxxxxxxx
>http://lists.infradead.org/mailman/listinfo/linux-rockchip

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Previous message: sergeh: "Re: [PATCH v2 1/6] LSM: Ensure the correct LSM context releaser"
In reply to: Piotr Zalewski: "[PATCH v5] rockchip/drm: vop2: add support for gamma LUT"
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