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Message-ID: <a349b22e-c76b-f30f-d258-830e9c7b50ba@tuxon.dev>
Date:   Mon, 18 Sep 2023 07:30:11 +0300
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Subject: Re: [PATCH v4 5/8] drm: atmel_hlcdc: Add support for XLCDC in atmel
 LCD driver
Content-Language: en-US
To:     Manikandan.M@microchip.com, sam@ravnborg.org,
        bbrezillon@kernel.org, airlied@gmail.com, daniel@ffwll.ch,
        Nicolas.Ferre@microchip.com, alexandre.belloni@bootlin.com,
        lee@kernel.org, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Hari.PrasathGE@microchip.com,
        Balamanikandan.Gunasundar@microchip.com,
        Durai.ManickamKR@microchip.com, Nayabbasha.Sayed@microchip.com,
        Dharma.B@microchip.com, Varshini.Rajendran@microchip.com,
        Balakrishnan.S@microchip.com
References: <20230825125444.93222-1-manikandan.m@microchip.com>
 <20230825125444.93222-6-manikandan.m@microchip.com>
 <1a3154b5-e849-dc60-8434-892b38cec87e@tuxon.dev>
 <f8aa53f9-a9e5-baf9-a683-c7c14b924863@microchip.com>
From:   claudiu beznea <claudiu.beznea@tuxon.dev>
In-Reply-To: <f8aa53f9-a9e5-baf9-a683-c7c14b924863@microchip.com>
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Precedence: bulk


On 12.09.2023 13:44, Manikandan.M@microchip.com wrote:
> On 09/09/23 9:50 pm, claudiu beznea wrote:
>> [You don't often get email from claudiu.beznea@tuxon.dev. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> Hi, Manikandan,
>>
>> On 8/25/23 15:54, Manikandan Muralidharan wrote:
>>> - XLCDC in SAM9X7 has different sets of registers and additional
>>> configuration bits when compared to previous HLCDC IP. Read/write
>>> operation on the controller registers is now separated using the
>>> XLCDC status flag.
>>>        - HEO scaling, window resampling, Alpha blending, YUV-to-RGB
>>> conversion in XLCDC is derived and handled using additional
>>> configuration bits and registers.
>>>        - Writing one to the Enable fields of each layer in LCD_ATTRE
>>> is required to reflect the values set in Configuration, FBA, Enable
>>> registers of each layer
>>>
>>> Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
>>> Co-developed-by: Hari Prasath Gujulan Elango <Hari.PrasathGE@microchip.com>
>>> Signed-off-by: Hari Prasath Gujulan Elango <Hari.PrasathGE@microchip.com>
>>> Co-developed-by: Durai Manickam KR <durai.manickamkr@microchip.com>
>>> Signed-off-by: Durai Manickam KR <durai.manickamkr@microchip.com>
>>> ---
>>>   .../gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c    |  25 +-
>>>   .../gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c   | 333 +++++++++++++++---
>>>   2 files changed, 299 insertions(+), 59 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>>> index cc5cf4c2faf7..4b11a1de8af4 100644
>>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>>> @@ -79,6 +79,7 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
>>>        unsigned int mask = ATMEL_HLCDC_CLKDIV_MASK | ATMEL_HLCDC_CLKPOL;
>>>        unsigned int cfg = 0;
>>>        int div, ret;
>>> +     bool is_xlcdc = crtc->dc->desc->is_xlcdc;
>>>
>>>        /* get encoder from crtc */
>>>        drm_for_each_encoder(en_iter, ddev) {
>>> @@ -164,10 +165,10 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
>>>        state = drm_crtc_state_to_atmel_hlcdc_crtc_state(c->state);
>>>        cfg = state->output_mode << 8;
>>>
>>> -     if (adj->flags & DRM_MODE_FLAG_NVSYNC)
>>> +     if (!is_xlcdc && (adj->flags & DRM_MODE_FLAG_NVSYNC))
>>>                cfg |= ATMEL_HLCDC_VSPOL;
>>>
>>> -     if (adj->flags & DRM_MODE_FLAG_NHSYNC)
>>> +     if (!is_xlcdc && (adj->flags & DRM_MODE_FLAG_NHSYNC))
>>>                cfg |= ATMEL_HLCDC_HSPOL;
>>>
>>>        regmap_update_bits(regmap, ATMEL_HLCDC_CFG(5),
>>> @@ -202,6 +203,16 @@ static void atmel_hlcdc_crtc_atomic_disable(struct drm_crtc *c,
>>>
>>>        pm_runtime_get_sync(dev->dev);
>>>
>>> +     if (crtc->dc->desc->is_xlcdc) {
>>> +             regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_XLCDC_CM);
>>> +             regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
>>> +                                      !(status & ATMEL_XLCDC_CM), 10, 0);
>>
>> You may want to check the return value of regmap_read_poll_timeout().
>> Otherwise your setup may fail.
>>
>> Also, regmap_read_poll_timeout() may sleep, the other settings in this
>> functions are done with bussy looping, is there a reason for that?
>> Hi Claudiu
> 
> Not sure if a non-zero timeout_us coud be sufficient for this operation, 
> considering the next power-up and power-down sequence following the 
> current step.
> Any suggestion on the value of timeout_us is appreciable.

Ok, haven't noticed that the timeout is zero.

>>> +
>>> +             regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_XLCDC_SD);
>>> +             regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
>>> +                                      status & ATMEL_XLCDC_SD, 10, 0);
>>
>> Same here.
>>
>>> +     }
>>> +
>>>        regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_DISP);
>>>        while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
>>>               (status & ATMEL_HLCDC_DISP))
>>> @@ -256,6 +267,16 @@ static void atmel_hlcdc_crtc_atomic_enable(struct drm_crtc *c,
>>>               !(status & ATMEL_HLCDC_DISP))
>>>                cpu_relax();
>>>
>>> +     if (crtc->dc->desc->is_xlcdc) {
>>> +             regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_XLCDC_CM);
>>> +             regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
>>> +                                      status & ATMEL_XLCDC_CM, 10, 0);
>>> +
>>> +             regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_XLCDC_SD);
>>> +             regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
>>> +                                      !(status & ATMEL_XLCDC_SD), 10, 0);
>>> +     }
>>> +
>>>        pm_runtime_put_sync(dev->dev);
>>>
>>>   }
>>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> index daa508504f47..26caf4cddfa4 100644
>>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> @@ -330,11 +330,59 @@ static void atmel_hlcdc_plane_setup_scaler(struct atmel_hlcdc_plane *plane,
>>>                                                                     yfactor));
>>>   }
>>>
>>> +static void atmel_xlcdc_plane_setup_scaler(struct atmel_hlcdc_plane *plane,
>>> +                                        struct atmel_hlcdc_plane_state *state)
>>> +{
>>> +     const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     u32 xfactor, yfactor;
>>> +
>>> +     if (!desc->layout.scaler_config)
>>> +             return;
>>> +
>>> +     if (state->crtc_w == state->src_w && state->crtc_h == state->src_h) {
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> +                                         desc->layout.scaler_config, 0);
>>> +             return;
>>> +     }
>>> +
>>> +     /* xfactor = round[(2^20 * XMEMSIZE)/XSIZE)] */
>>> +     xfactor = (u32)(((1 << 20) * state->src_w) / state->crtc_w);
>>
>> Could ((1 << 20) * state->src_w) overflow?
> It is within the limits, state->src_w will contain a 11bit reg value at max.
>>
>>> +
>>> +     /* yfactor = round[(2^20 * YMEMSIZE)/YSIZE)] */
>>> +     yfactor = (u32)(((1 << 20) * state->src_h) / state->crtc_h);
>>
>> Same here.
>>
>>> +
>>> +     atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config,
>>> +                                 ATMEL_XLCDC_LAYER_VSCALER_LUMA_ENABLE |
>>> +                                 ATMEL_XLCDC_LAYER_VSCALER_CHROMA_ENABLE |
>>> +                                 ATMEL_XLCDC_LAYER_HSCALER_LUMA_ENABLE |
>>> +                                 ATMEL_XLCDC_LAYER_HSCALER_CHROMA_ENABLE);
>>> +
>>> +     atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 1,
>>> +                                 yfactor);
>>> +     atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 3,
>>> +                                 xfactor);
>>> +
>>> +     /* As per YCbCr window resampling configuration */
>>> +     if (state->base.fb->format->format == DRM_FORMAT_YUV420) {
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 2,
>>> +                                         yfactor / 2);
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 4,
>>> +                                         xfactor / 2);
>>> +     } else {
>>> +             /* As per ARGB window resampling configuration */
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 2,
>>> +                                         yfactor);
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 4,
>>> +                                         xfactor);
>>> +     }
>>
>> This can be written as follows:
>> if (state->base.fb->format->format == DRM_FORMAT_YUV420) {
>>          yfactor /= 2);
>>          xfactor /= 2);
>> }
>> atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 2,
>>                              yfactor);
>> atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.scaler_config + 4,
>>                              xfactor);
>>
>>
>>
>>> +}
>>> +
>>>   static void
>>>   atmel_hlcdc_plane_update_pos_and_size(struct atmel_hlcdc_plane *plane,
>>>                                      struct atmel_hlcdc_plane_state *state)
>>>   {
>>>        const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     struct atmel_hlcdc_dc *dc = plane->base.dev->dev_private;
>>>
>>>        if (desc->layout.size)
>>>                atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.size,
>>> @@ -352,7 +400,10 @@ atmel_hlcdc_plane_update_pos_and_size(struct atmel_hlcdc_plane *plane,
>>>                                        ATMEL_HLCDC_LAYER_POS(state->crtc_x,
>>>                                                              state->crtc_y));
>>>
>>> -     atmel_hlcdc_plane_setup_scaler(plane, state);
>>> +     if (dc->desc->is_xlcdc)
>>> +             atmel_xlcdc_plane_setup_scaler(plane, state);
>>> +     else
>>> +             atmel_hlcdc_plane_setup_scaler(plane, state);
>>
>> What if you embedd the plane_setup_scaller function in struct
>> atmel_hlcdc_dc_desc and define per lcdc variant the proper function you can
>> have here something like:
>>          dc->desc->plane_setup_scaler();
>>
>> This is valid for other places in this patch (see below).
> Sure, I will try to incoperate this change.
>>
>>>   }
>>>
>>>   static void
>>> @@ -393,6 +444,40 @@ atmel_hlcdc_plane_update_general_settings(struct atmel_hlcdc_plane *plane,
>>>                                    cfg);
>>>   }
>>>
>>> +static void
>>> +atmel_xlcdc_plane_update_general_settings(struct atmel_hlcdc_plane *plane,
>>> +                                       struct atmel_hlcdc_plane_state *state)
>>> +{
>>> +     unsigned int cfg;
>>> +     const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     const struct drm_format_info *format = state->base.fb->format;
>>> +
>>> +     atmel_hlcdc_layer_write_cfg(&plane->layer, ATMEL_XLCDC_LAYER_DMA_CFG,
>>> +                                 ATMEL_HLCDC_LAYER_DMA_BLEN_INCR16 | state->ahb_id);
>>> +
>>> +     cfg = ATMEL_XLCDC_LAYER_DMA | ATMEL_XLCDC_LAYER_REP;
>>> +
>>> +     if (plane->base.type != DRM_PLANE_TYPE_PRIMARY) {
>>> +             /*
>>> +              * Alpha Blending bits specific to SAM9X7 SoC
>>> +              */
>>> +             cfg |= ATMEL_XLCDC_LAYER_SFACTC_A0_MULT_AS |
>>> +                    ATMEL_XLCDC_LAYER_SFACTA_ONE |
>>> +                    ATMEL_XLCDC_LAYER_DFACTC_M_A0_MULT_AS |
>>> +                    ATMEL_XLCDC_LAYER_DFACTA_ONE;
>>> +             if (format->has_alpha)
>>> +                     cfg |= ATMEL_XLCDC_LAYER_A0(0xff);
>>> +             else
>>> +                     cfg |= ATMEL_XLCDC_LAYER_A0(state->base.alpha);
>>> +     }
>>> +
>>> +     if (state->disc_h && state->disc_w)
>>> +             cfg |= ATMEL_XLCDC_LAYER_DISCEN;
>>> +
>>> +     atmel_hlcdc_layer_write_cfg(&plane->layer, desc->layout.general_config,
>>> +                                 cfg);
>>> +}
>>> +
>>>   static void atmel_hlcdc_plane_update_format(struct atmel_hlcdc_plane *plane,
>>>                                        struct atmel_hlcdc_plane_state *state)
>>>   {
>>> @@ -437,36 +522,55 @@ static void atmel_hlcdc_plane_update_clut(struct atmel_hlcdc_plane *plane,
>>>        }
>>>   }
>>>
>>> +static void update_hlcdc_buffers(struct atmel_hlcdc_plane *plane,
>>> +                              struct atmel_hlcdc_plane_state *state, u32 sr, int i)
>>> +{
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                 ATMEL_HLCDC_LAYER_PLANE_HEAD(i),
>>> +                                 state->dscrs[i]->self);
>>> +
>>> +     if (!(sr & ATMEL_HLCDC_LAYER_EN)) {
>>
>> To avoid extra indenting:
>>          if (sr & ATMEL_HLCDC_LAYER_EN)
>>                  return;
>>
>>> +             atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                         ATMEL_HLCDC_LAYER_PLANE_ADDR(i),
>>> +                                         state->dscrs[i]->addr);
>>> +             atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                         ATMEL_HLCDC_LAYER_PLANE_CTRL(i),
>>> +                                         state->dscrs[i]->ctrl);
>>> +             atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                         ATMEL_HLCDC_LAYER_PLANE_NEXT(i),
>>> +                                         state->dscrs[i]->self);
>>> +     }
>>> +}
>>> +
>>> +static void update_xlcdc_buffers(struct atmel_hlcdc_plane *plane,
>>> +                              struct atmel_hlcdc_plane_state *state, int i)
>>> +{
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                 ATMEL_XLCDC_LAYER_PLANE_ADDR(i),
>>> +                                 state->dscrs[i]->addr);
>>> +}
>>> +
>>>   static void atmel_hlcdc_plane_update_buffers(struct atmel_hlcdc_plane *plane,
>>> -                                     struct atmel_hlcdc_plane_state *state)
>>> +                                          struct atmel_hlcdc_plane_state *state)
>>
>> update_hlcdc_buffers() and update_xlcdc_buffers() could also be members in
>> the struct atmel_hlcdc_dc_desc and called accordingly where needed w/o
>> checking is_xlcdc.
>>
>>>   {
>>>        const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     struct atmel_hlcdc_dc *dc = plane->base.dev->dev_private;
>>>        struct drm_framebuffer *fb = state->base.fb;
>>>        u32 sr;
>>>        int i;
>>>
>>> -     sr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHSR);
>>> +     if (!dc->desc->is_xlcdc)
>>> +             sr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHSR);
>>>
>>>        for (i = 0; i < state->nplanes; i++) {
>>>                struct drm_gem_dma_object *gem = drm_fb_dma_get_gem_obj(fb, i);
>>>
>>>                state->dscrs[i]->addr = gem->dma_addr + state->offsets[i];
>>>
>>> -             atmel_hlcdc_layer_write_reg(&plane->layer,
>>> -                                         ATMEL_HLCDC_LAYER_PLANE_HEAD(i),
>>> -                                         state->dscrs[i]->self);
>>> -
>>> -             if (!(sr & ATMEL_HLCDC_LAYER_EN)) {
>>> -                     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> -                                     ATMEL_HLCDC_LAYER_PLANE_ADDR(i),
>>> -                                     state->dscrs[i]->addr);
>>> -                     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> -                                     ATMEL_HLCDC_LAYER_PLANE_CTRL(i),
>>> -                                     state->dscrs[i]->ctrl);
>>> -                     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> -                                     ATMEL_HLCDC_LAYER_PLANE_NEXT(i),
>>> -                                     state->dscrs[i]->self);
>>> -             }
>>> +             if (dc->desc->is_xlcdc)
>>> +                     update_xlcdc_buffers(plane, state, i);
>>> +             else
>>> +                     update_hlcdc_buffers(plane, state, sr, i);
>>
>> And here you can have something like:
>>                  dc->desc->update_lcdc_buffers();
>>>
>>>                if (desc->layout.xstride[i])
>>>                        atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> @@ -712,11 +816,8 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
>>>        return 0;
>>>   }
>>>
>>> -static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>>> -                                          struct drm_atomic_state *state)
>>> +static void hlcdc_atomic_disable(struct atmel_hlcdc_plane *plane)
>>>   {
>>> -     struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
>>> -
>>>        /* Disable interrupts */
>>>        atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_IDR,
>>>                                    0xffffffff);
>>> @@ -731,6 +832,72 @@ static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>>>        atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
>>>   }
>>>
>>> +static void xlcdc_atomic_disable(struct atmel_hlcdc_plane *plane)
>>> +{
>>> +     /* Disable interrupts */
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_XLCDC_LAYER_IDR,
>>> +                                 0xffffffff);
>>> +
>>> +     /* Disable the layer */
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer,
>>> +                                 ATMEL_XLCDC_LAYER_ENR, 0);
>>> +
>>> +     /* Clear all pending interrupts */
>>> +     atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_XLCDC_LAYER_ISR);
>>> +}
>>> +
>>> +static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>>> +                                          struct drm_atomic_state *state)
>>> +{
>>> +     struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
>>> +     struct atmel_hlcdc_dc *dc = plane->base.dev->dev_private;
>>> +
>>> +     if (dc->desc->is_xlcdc)
>>> +             xlcdc_atomic_disable(plane);
>>> +     else
>>> +             hlcdc_atomic_disable(plane);
>>
>>          dc->desc->lcdc_atomic_disable();
>>
>>> +}
>>> +
>>> +static void hlcdc_atomic_update(struct atmel_hlcdc_plane *plane)
>>> +{
>>> +     u32 sr;
>>> +
>>> +     /* Enable the overrun interrupts. */
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_IER,
>>> +                                 ATMEL_HLCDC_LAYER_OVR_IRQ(0) |
>>> +                                 ATMEL_HLCDC_LAYER_OVR_IRQ(1) |
>>> +                                 ATMEL_HLCDC_LAYER_OVR_IRQ(2));
>>> +
>>> +     /* Apply the new config at the next SOF event. */
>>> +     sr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHSR);
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHER,
>>> +                                 ATMEL_HLCDC_LAYER_UPDATE |
>>> +                                 (sr & ATMEL_HLCDC_LAYER_EN ?
>>> +                                 ATMEL_HLCDC_LAYER_A2Q : ATMEL_HLCDC_LAYER_EN));
>>> +}
>>> +
>>> +static void xlcdc_atomic_update(struct atmel_hlcdc_plane *plane,
>>> +                             struct atmel_hlcdc_dc *dc)
>>> +{
>>> +     /* Enable the overrun interrupts. */
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_XLCDC_LAYER_IER,
>>> +                                 ATMEL_XLCDC_LAYER_OVR_IRQ(0) |
>>> +                                 ATMEL_XLCDC_LAYER_OVR_IRQ(1) |
>>> +                                 ATMEL_XLCDC_LAYER_OVR_IRQ(2));
>>> +
>>> +     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_XLCDC_LAYER_ENR,
>>> +                                 ATMEL_XLCDC_LAYER_EN);
>>> +
>>> +     /*
>>> +      * Updating XLCDC_xxxCFGx, XLCDC_xxxFBA and XLCDC_xxxEN,
>>> +      * (where xxx indicates each layer) requires writing one to the
>>> +      * Update Attribute field for each layer in LCDC_ATTRE register for SAM9X7.
>>> +      */
>>> +     regmap_write(dc->hlcdc->regmap, ATMEL_XLCDC_ATTRE, ATMEL_XLCDC_BASE_UPDATE |
>>> +                  ATMEL_XLCDC_OVR1_UPDATE | ATMEL_XLCDC_OVR3_UPDATE |
>>> +                  ATMEL_XLCDC_HEO_UPDATE);
>>> +}
>>> +
>>>   static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
>>>                                            struct drm_atomic_state *state)
>>>   {
>>> @@ -739,7 +906,7 @@ static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
>>>        struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
>>>        struct atmel_hlcdc_plane_state *hstate =
>>>                        drm_plane_state_to_atmel_hlcdc_plane_state(new_s);
>>> -     u32 sr;
>>> +     struct atmel_hlcdc_dc *dc = p->dev->dev_private;
>>>
>>>        if (!new_s->crtc || !new_s->fb)
>>>                return;
>>> @@ -750,29 +917,67 @@ static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
>>>        }
>>>
>>>        atmel_hlcdc_plane_update_pos_and_size(plane, hstate);
>>> -     atmel_hlcdc_plane_update_general_settings(plane, hstate);
>>> +     if (dc->desc->is_xlcdc)
>>> +             atmel_xlcdc_plane_update_general_settings(plane, hstate);
>>> +     else
>>> +             atmel_hlcdc_plane_update_general_settings(plane, hstate);
>>
>>          dc->desc->lcdc_plane_update_general_settigns();
>>
>>>        atmel_hlcdc_plane_update_format(plane, hstate);
>>>        atmel_hlcdc_plane_update_clut(plane, hstate);
>>>        atmel_hlcdc_plane_update_buffers(plane, hstate);
>>>        atmel_hlcdc_plane_update_disc_area(plane, hstate);
>>>
>>> -     /* Enable the overrun interrupts. */
>>> -     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_IER,
>>> -                                 ATMEL_HLCDC_LAYER_OVR_IRQ(0) |
>>> -                                 ATMEL_HLCDC_LAYER_OVR_IRQ(1) |
>>> -                                 ATMEL_HLCDC_LAYER_OVR_IRQ(2));
>>> +     if (dc->desc->is_xlcdc)
>>> +             xlcdc_atomic_update(plane, dc);
>>> +     else
>>> +             hlcdc_atomic_update(plane);
>>
>>          dc->desc->lcdc_atomic_update();
>>
>>> +}
>>>
>>> -     /* Apply the new config at the next SOF event. */
>>> -     sr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHSR);
>>> -     atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHER,
>>> -                     ATMEL_HLCDC_LAYER_UPDATE |
>>> -                     (sr & ATMEL_HLCDC_LAYER_EN ?
>>> -                      ATMEL_HLCDC_LAYER_A2Q : ATMEL_HLCDC_LAYER_EN));
>>> +u32 hlcdc_csc_coeffs[] = {
>>> +     0x4c900091,
>>> +     0x7a5f5090,
>>> +     0x40040890
>>> +};
>>
>> You can move this in function where it is used and declare it static.
>>
>>> +
>>> +u32 xlcdc_csc_coeffs[] = {
>>> +     0x00000488,
>>> +     0x00000648,
>>> +     0x1EA00480,
>>> +     0x00001D28,
>>> +     0x08100480,
>>> +     0x00000000,
>>> +     0x00000007
>>> +};
>>
>> Same here.
>>
>>> +
>>> +static void hlcdc_csc_init(struct atmel_hlcdc_plane *plane,
>>> +                        const struct atmel_hlcdc_layer_desc *desc)
>>> +{
>>> +     /*
>>> +      * TODO: declare a "yuv-to-rgb-conv-factors" property to let
>>> +      * userspace modify these factors (using a BLOB property ?).
>>> +      */
>>> +     for (int i = 0; i < ARRAY_SIZE(hlcdc_csc_coeffs); i++)
>>
>> { at the end of for statement.
>>
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> +                                         desc->layout.csc + i,
>>> +                                         hlcdc_csc_coeffs[i]);
>>
>> } here
>>
>>> +}
>>> +
>>> +static void xlcdc_csc_init(struct atmel_hlcdc_plane *plane,
>>> +                        const struct atmel_hlcdc_layer_desc *desc)
>>> +{
>>> +     /*
>>> +      * yuv-to-rgb-conv-factors are now defined from LCDC_HEOCFG16 to
>>> +      * LCDC_HEOCFG21 registers in SAM9X7.
>>> +      */
>>> +     for (int i = 0; i < ARRAY_SIZE(xlcdc_csc_coeffs); i++)
>>> +             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> +                                         desc->layout.csc + i,
>>> +                                         xlcdc_csc_coeffs[i]);
>>
>> Ditto
>>
>>>   }
>>>
>>>   static int atmel_hlcdc_plane_init_properties(struct atmel_hlcdc_plane *plane)
>>>   {
>>>        const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     struct atmel_hlcdc_dc *dc = plane->base.dev->dev_private;
>>>
>>>        if (desc->type == ATMEL_HLCDC_OVERLAY_LAYER ||
>>>            desc->type == ATMEL_HLCDC_CURSOR_LAYER) {
>>> @@ -796,31 +1001,19 @@ static int atmel_hlcdc_plane_init_properties(struct atmel_hlcdc_plane *plane)
>>>                        return ret;
>>>        }
>>>
>>> -     if (desc->layout.csc) {
>>> -             /*
>>> -              * TODO: decare a "yuv-to-rgb-conv-factors" property to let
>>> -              * userspace modify these factors (using a BLOB property ?).
>>> -              */
>>> -             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> -                                         desc->layout.csc,
>>> -                                         0x4c900091);
>>> -             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> -                                         desc->layout.csc + 1,
>>> -                                         0x7a5f5090);
>>> -             atmel_hlcdc_layer_write_cfg(&plane->layer,
>>> -                                         desc->layout.csc + 2,
>>> -                                         0x40040890);
>>> -     }
>>> +     if (dc->desc->is_xlcdc && desc->layout.csc)
>>> +             xlcdc_csc_init(plane, desc);
>>> +     else
>>> +             if (desc->layout.csc)
>>> +                     hlcdc_csc_init(plane, desc);
>>
>>          if (desc->layout.csc)
>>                  dc->desc->lcdc_csc_init();
>>
>>>
>>>        return 0;
>>>   }
>>>
>>> -void atmel_hlcdc_plane_irq(struct atmel_hlcdc_plane *plane)
>>> +static void hlcdc_irq_dbg(struct atmel_hlcdc_plane *plane,
>>> +                       const struct atmel_hlcdc_layer_desc *desc)
>>>   {
>>> -     const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> -     u32 isr;
>>> -
>>> -     isr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
>>> +     u32 isr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
>>>
>>>        /*
>>>         * There's not much we can do in case of overrun except informing
>>> @@ -830,8 +1023,34 @@ void atmel_hlcdc_plane_irq(struct atmel_hlcdc_plane *plane)
>>>        if (isr &
>>>            (ATMEL_HLCDC_LAYER_OVR_IRQ(0) | ATMEL_HLCDC_LAYER_OVR_IRQ(1) |
>>>             ATMEL_HLCDC_LAYER_OVR_IRQ(2)))
>>> -             dev_dbg(plane->base.dev->dev, "overrun on plane %s\n",
>>> -                     desc->name);
>>> +             pr_warn("%s: overrun on plane %s\n", __func__, desc->name);
>>
>> Why changing to pr_warn? why not dev_warn, if any?
>>
>>> +}
>>> +
>>> +static void xlcdc_irq_dbg(struct atmel_hlcdc_plane *plane,
>>> +                       const struct atmel_hlcdc_layer_desc *desc)
>>> +{
>>> +     u32 isr = atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_XLCDC_LAYER_ISR);
>>> +
>>> +     /*
>>> +      * There's not much we can do in case of overrun except informing
>>> +      * the user. However, we are in interrupt context here, hence the
>>> +      * use of dev_dbg().
>>> +      */
>>> +     if (isr &
>>> +         (ATMEL_XLCDC_LAYER_OVR_IRQ(0) | ATMEL_XLCDC_LAYER_OVR_IRQ(1) |
>>> +          ATMEL_XLCDC_LAYER_OVR_IRQ(2)))
>>> +             pr_warn("%s: overrun on plane %s\n", __func__, desc->name);
>>
>> dev_warn() ?
>>
>>> +}
>>> +
>>> +void atmel_hlcdc_plane_irq(struct atmel_hlcdc_plane *plane)
>>> +{
>>> +     const struct atmel_hlcdc_layer_desc *desc = plane->layer.desc;
>>> +     struct atmel_hlcdc_dc *dc = plane->base.dev->dev_private;
>>> +
>>> +     if (dc->desc->is_xlcdc)
>>> +             xlcdc_irq_dbg(plane, desc);
>>> +     else
>>> +             hlcdc_irq_dbg(plane, desc);
>>
>>          dc->desc->lcdc_irq_dbg() ?
>>
>>>   }
>>>
>>>   static const struct drm_plane_helper_funcs atmel_hlcdc_layer_plane_helper_funcs = {
>