Re: [PATCH 2/3] drm/rockchip: Add optional support for CRTC gamma LUT

Jacopo Mondi
2019-06-21T08:21:19Z

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Hi Ezequiel,
just a few minor comments. Thanks for this new iteration.

On Tue, Jun 18, 2019 at 06:34:05PM -0300, Ezequiel Garcia wrote:
> Add an optional CRTC gamma LUT support, and enable it on RK3288.
> This is currently enabled via a separate address resource,
> which needs to be specified in the devicetree.
>
> The address resource is required because on some SoCs, such as
> RK3288, the LUT address is after the MMU address, and the latter
> is supported by a different driver. This prevents the DRM driver
> from requesting an entire register space.
>
> The current implementation works for RGB 10-bit tables, as that
> is what seems to work on RK3288.
>
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> ---
> Changes from RFC:
> * Request (an optional) address resource for the LUT.
> * Drop support for RK3399, which doesn't seem to work
> out of the box and needs more research.
> * Support pass-thru setting when GAMMA_LUT is NULL.
> * Add a check for the gamma size, as suggested by Ilia.
> * Move gamma setting to atomic_commit_tail, as pointed
> out by Jacopo/Laurent, is the correct way.
> ---
> drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 3 +
> drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 106 ++++++++++++++++++++
> drivers/gpu/drm/rockchip/rockchip_drm_vop.h | 7 ++
> drivers/gpu/drm/rockchip/rockchip_vop_reg.c | 2 +
> 4 files changed, 118 insertions(+)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> index 1c69066b6894..bf9ad6240971 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
> @@ -16,6 +16,7 @@
> #include "rockchip_drm_fb.h"
> #include "rockchip_drm_gem.h"
> #include "rockchip_drm_psr.h"
> +#include "rockchip_drm_vop.h"
>
> static int rockchip_drm_fb_dirty(struct drm_framebuffer *fb,
> struct drm_file *file,
> @@ -128,6 +129,8 @@ rockchip_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state)
>
> drm_atomic_helper_commit_modeset_disables(dev, old_state);
>
> + rockchip_drm_vop_gamma_set(old_state);
> +
> drm_atomic_helper_commit_modeset_enables(dev, old_state);
>
> drm_atomic_helper_commit_planes(dev, old_state,
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> index 12ed5265a90b..5b6edbe2673f 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> @@ -137,6 +137,7 @@ struct vop {
>
> uint32_t *regsbak;
> void __iomem *regs;
> + void __iomem *lut_regs;
>
> /* physical map length of vop register */
> uint32_t len;
> @@ -1153,6 +1154,94 @@ static void vop_wait_for_irq_handler(struct vop *vop)
> synchronize_irq(vop->irq);
> }
>
> +static bool vop_dsp_lut_is_enable(struct vop *vop)
> +{
> + return vop_read_reg(vop, 0, &vop->data->common->dsp_lut_en);
> +}
> +
> +static void vop_crtc_write_gamma_lut(struct vop *vop, struct drm_crtc *crtc)
> +{
> + struct drm_color_lut *lut = crtc->state->gamma_lut->data;
> + int i;

unsigned i

> +
> + for (i = 0; i < crtc->gamma_size; i++) {
> + u32 word;

here and below you could declare and initialize in one line. Matter of
tastes, up to you.

> +
> + word = (drm_color_lut_extract(lut[i].red, 10) << 20) |
> + (drm_color_lut_extract(lut[i].green, 10) << 10) |
> + drm_color_lut_extract(lut[i].blue, 10);
> + writel(word, vop->lut_regs + i * 4);
> + }
> +}
> +
> +static void vop_crtc_gamma_set(struct vop *vop, struct drm_crtc *crtc,
> + struct drm_crtc_state *old_state)
> +{
> + int idle, ret, i;

idle and i could be unsigned

> +
> + spin_lock(&vop->reg_lock);
> + VOP_REG_SET(vop, common, dsp_lut_en, 0);
> + vop_cfg_done(vop);
> + spin_unlock(&vop->reg_lock);
> +
> + ret = readx_poll_timeout(vop_dsp_lut_is_enable, vop,
> + idle, !idle, 5, 30 * 1000);
> + if (ret)
> + return;
> +
> + spin_lock(&vop->reg_lock);
> +
> + if (crtc->state->gamma_lut) {
> + if (!old_state->gamma_lut || (crtc->state->gamma_lut->base.id !=
> + old_state->gamma_lut->base.id))
> + vop_crtc_write_gamma_lut(vop, crtc);
> + } else {

i could also be declared here...

> + for (i = 0; i < crtc->gamma_size; i++) {
> + u32 word;
> +
> + word = (i << 20) | (i << 10) | i;
> + writel(word, vop->lut_regs + i * 4);
> + }

I might be confused, but are you here configuring a linear LUT table?
Isn't this equivalent to have it disabled?

> + }
> +
> + VOP_REG_SET(vop, common, dsp_lut_en, 1);
> + vop_cfg_done(vop);
> + spin_unlock(&vop->reg_lock);
> +}
> +
> +static int vop_crtc_atomic_check(struct drm_crtc *crtc,
> + struct drm_crtc_state *crtc_state)
> +{
> + struct vop *vop = to_vop(crtc);
> +
> + if (vop->lut_regs && crtc_state->color_mgmt_changed &&
> + crtc_state->gamma_lut) {
> + int len;
> +
> + len = drm_color_lut_size(crtc_state->gamma_lut);
> + if (len != crtc->gamma_size) {

Don't you accept LUT tables whose size is < that the maximum
crtc->gamma_size ?

> + DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n",
> + len, crtc->gamma_size);
> + return -EINVAL;
> + }
> + }

Most (but not all) functions in this file have an empty line before the
return closing the function.

> + return 0;
> +}
> +
> +void rockchip_drm_vop_gamma_set(struct drm_atomic_state *state)
> +{
> + struct drm_crtc_state *old_crtc_state;
> + struct drm_crtc *crtc;
> + int i;

unsigned i ?

I'm glad you've been able to verify atomic_flush was not the right
place where to update the LUT tables, as my testing is limited to
run kms++ tests and I didn't notice any particular artifact. Thanks
for checking!

> +
> + for_each_old_crtc_in_state(state, crtc, old_crtc_state, i) {
> + struct vop *vop = to_vop(crtc);
> +
> + if (vop->lut_regs && crtc->state->color_mgmt_changed)
> + vop_crtc_gamma_set(vop, crtc, old_crtc_state);
> + }
> +}
> +
> static void vop_crtc_atomic_flush(struct drm_crtc *crtc,
> struct drm_crtc_state *old_crtc_state)
> {
> @@ -1205,6 +1294,7 @@ static void vop_crtc_atomic_flush(struct drm_crtc *crtc,
>
> static const struct drm_crtc_helper_funcs vop_crtc_helper_funcs = {
> .mode_fixup = vop_crtc_mode_fixup,
> + .atomic_check = vop_crtc_atomic_check,
> .atomic_flush = vop_crtc_atomic_flush,
> .atomic_enable = vop_crtc_atomic_enable,
> .atomic_disable = vop_crtc_atomic_disable,
> @@ -1323,6 +1413,7 @@ static const struct drm_crtc_funcs vop_crtc_funcs = {
> .disable_vblank = vop_crtc_disable_vblank,
> .set_crc_source = vop_crtc_set_crc_source,
> .verify_crc_source = vop_crtc_verify_crc_source,
> + .gamma_set = drm_atomic_helper_legacy_gamma_set,
> };
>
> static void vop_fb_unref_worker(struct drm_flip_work *work, void *val)
> @@ -1480,6 +1571,10 @@ static int vop_create_crtc(struct vop *vop)
> goto err_cleanup_planes;
>
> drm_crtc_helper_add(crtc, &vop_crtc_helper_funcs);
> + if (vop_data->lut_size) {
> + drm_mode_crtc_set_gamma_size(crtc, vop_data->lut_size);
> + drm_crtc_enable_color_mgmt(crtc, 0, false, vop_data->lut_size);
> + }
>
> /*
> * Create drm_planes for overlay windows with possible_crtcs restricted
> @@ -1776,6 +1871,17 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
> if (IS_ERR(vop->regs))
> return PTR_ERR(vop->regs);
>
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "lut");
> + if (res) {
> + if (!vop_data->lut_size) {
> + DRM_DEV_ERROR(dev, "no gamma LUT size defined\n");
> + return -EINVAL;
> + }
> + vop->lut_regs = devm_ioremap_resource(dev, res);
> + if (IS_ERR(vop->lut_regs))
> + return PTR_ERR(vop->lut_regs);
> + }
> +
> vop->regsbak = devm_kzalloc(dev, vop->len, GFP_KERNEL);
> if (!vop->regsbak)
> return -ENOMEM;
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
> index 2149a889c29d..bd1bcd5a14e9 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
> @@ -7,6 +7,8 @@
> #ifndef _ROCKCHIP_DRM_VOP_H
> #define _ROCKCHIP_DRM_VOP_H
>
> +#include <drm/drm_atomic.h>
> +
> /*
> * major: IP major version, used for IP structure
> * minor: big feature change under same structure
> @@ -67,6 +69,7 @@ struct vop_common {
> struct vop_reg dither_down_mode;
> struct vop_reg dither_down_en;
> struct vop_reg dither_up;
> + struct vop_reg dsp_lut_en;
> struct vop_reg gate_en;
> struct vop_reg mmu_en;
> struct vop_reg out_mode;
> @@ -170,6 +173,7 @@ struct vop_data {
> const struct vop_win_yuv2yuv_data *win_yuv2yuv;
> const struct vop_win_data *win;
> unsigned int win_size;
> + unsigned int lut_size;
>
> #define VOP_FEATURE_OUTPUT_RGB10 BIT(0)
> #define VOP_FEATURE_INTERNAL_RGB BIT(1)
> @@ -373,4 +377,7 @@ static inline int scl_vop_cal_lb_mode(int width, bool is_yuv)
> }
>
> extern const struct component_ops vop_component_ops;
> +
> +void rockchip_drm_vop_gamma_set(struct drm_atomic_state *state);
> +
> #endif /* _ROCKCHIP_DRM_VOP_H */
> diff --git a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
> index 7b9c74750f6d..30d49eff3670 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
> @@ -593,6 +593,7 @@ static const struct vop_common rk3288_common = {
> .dither_down_en = VOP_REG(RK3288_DSP_CTRL1, 0x1, 2),
> .pre_dither_down = VOP_REG(RK3288_DSP_CTRL1, 0x1, 1),
> .dither_up = VOP_REG(RK3288_DSP_CTRL1, 0x1, 6),
> + .dsp_lut_en = VOP_REG(RK3288_DSP_CTRL1, 0x1, 0),
> .data_blank = VOP_REG(RK3288_DSP_CTRL0, 0x1, 19),
> .dsp_blank = VOP_REG(RK3288_DSP_CTRL0, 0x3, 18),
> .out_mode = VOP_REG(RK3288_DSP_CTRL0, 0xf, 0),
> @@ -641,6 +642,7 @@ static const struct vop_data rk3288_vop = {
> .output = &rk3288_output,
> .win = rk3288_vop_win_data,
> .win_size = ARRAY_SIZE(rk3288_vop_win_data),
> + .lut_size = 1024,
> };
>
> static const int rk3368_vop_intrs[] = {
> --
> 2.20.1
>

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