Re: [PATCH] mediatek: dsi: Add dsi per-frame lp code for mt8188

From: Shuijing Li (李水静)
Date: Wed Apr 24 2024 - 05:15:32 EST

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Dear Angelo,

> Please document those "magic numbers": why is this 12 + 2 + 4 ?
> What is 12? what is 2? what is 4?
==>
This is several packets, as specified in chapter 8.11 of the DSI
specification. Taking this as an example, 12 = 4 (HSS) + 4 (HSA_PH) + 4
(HSE), 2 = HSA_PF, and 4 = HBP_PH.

> Is this supported only on MT8188? Are you sure that MT8195 doesn't
> support that?
==>
MT8195 does not have this plan.

Based on the feedback you provided, I have made the necessary changes
and would like to submit a version 2 for your consideration at a later
date.

Thank you for your time and attention to this matter.

Best regards,
Shuijing

On Thu, 2024-03-14 at 11:10 +0100, AngeloGioacchino Del Regno wrote:
> Il 14/03/24 10:41, Shuijing Li ha scritto:
> > Adding the per-frame lp function of mt8188, which can keep HFP in
> > HS and
> > reduce the time required for each line to enter and exit low power.
> > Per Frame LP:
> > |<----------One Active Frame-------->|
> > --______________________________________----___________________
> > ^HSA+HBP^^RGB^^HFP^^HSA+HBP^^RGB^^HFP^ ^HSA+HBP^^RGB^^HFP^
> >
> > Per Line LP:
> > |<---------------One Active Frame----------->|
> > --______________--______________--______________----______________
> > ^HSA+HBP^^RGB^ ^HSA+HBP^^RGB^ ^HSA+HBP^^RGB^ ^HSA+HBP^^RGB^
> >
> > Signed-off-by: Shuijing Li <shuijing.li@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/mediatek/mtk_dsi.c | 100
> > +++++++++++++++++++++++++++++
> > 1 file changed, 100 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index a2fdfc8ddb15..e6f4807c8711 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -83,6 +83,7 @@
> > #define DSI_HSA_WC 0x50
> > #define DSI_HBP_WC 0x54
> > #define DSI_HFP_WC 0x58
> > +#define DSI_BLLP_WC 0x5C
> >
> > #define DSI_CMDQ_SIZE 0x60
> > #define CMDQ_SIZE 0x3f
> > @@ -180,6 +181,7 @@ struct mtk_dsi_driver_data {
> > bool has_shadow_ctl;
> > bool has_size_ctl;
> > bool cmdq_long_packet_ctl;
> > + bool support_per_frame_lp;
> > };
> >
> > struct mtk_dsi {
> > @@ -516,6 +518,103 @@ static void mtk_dsi_config_vdo_timing(struct
> > mtk_dsi *dsi)
> > (vm->hactive * dsi_tmp_buf_bpp + 2) % dsi-
> > >lanes;
> > }
> >
> > + if (dsi->driver_data->support_per_frame_lp) {
>
> This really looks like a good candidate to fit in a function on its
> own...
>
> > + unsigned int lpx = 0, da_hs_exit = 0, da_hs_prep = 0,
> > da_hs_trail = 0;
> > + unsigned int da_hs_zero = 0, ps_wc = 0, hs_vb_ps_wc =
> > 0;
> > + u32 bllp_wc, bllp_en, v_active_roundup, hstx_cklp_wc;
> > + u32 hstx_cklp_wc_max, hstx_cklp_wc_min;
> > +
> > + da_hs_trail = (readl(dsi->regs + DSI_PHY_TIMECON0) >>
> > 24) & 0xff;
> > + bllp_en = (readl(dsi->regs + DSI_TXRX_CTRL) >> 7) &
> > 0x1;
>
> (somewhere: #define HSTX_BLLP_EN BIT(7))
>
> u32 timecon0, txrx_ctrl;
>
> timecon0 = readl(....DSI_PHY_TIMECON0);
> txrx_ctrl = readl(.....);
>
> da_hs_trail = FIELD_GET(HS_TRAIL, timecon0);
> bllp_en = FIELD_GET(HSTX_BLLP_EN, txrx_ctrl);
>
> > + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) {
> > + horizontal_sync_active_byte =
> > + (vm->hsync_len * dsi_tmp_buf_bpp - 10);
> > + horizontal_backporch_byte =
> > + (vm->hback_porch * dsi_tmp_buf_bpp -
> > 10);
> > + horizontal_frontporch_byte =
> > + (vm->hfront_porch * dsi_tmp_buf_bpp -
> > 12);
> > +
> > + ps_wc = readl(dsi->regs + DSI_PSCTRL) & 0x7fff;
> > + v_active_roundup = (32 +
> > horizontal_sync_active_byte +
> > + horizontal_backporch_byte + ps_wc +
> > + horizontal_frontporch_byte) % dsi-
> > >lanes;
> > + if (v_active_roundup)
> > + horizontal_backporch_byte =
> > horizontal_backporch_byte +
> > + dsi->lanes - v_active_roundup;
> > + hstx_cklp_wc_min = (DIV_ROUND_UP((12 + 2 + 4 +
>
> Please document those "magic numbers": why is this 12 + 2 + 4 ?
> What is 12? what is 2? what is 4?
>
> > + horizontal_sync_active_byte), dsi-
> > >lanes) + da_hs_trail + 1)
> > + * dsi->lanes / 6 - 1;
> > + hstx_cklp_wc_max = (DIV_ROUND_UP((20 + 6 + 4 +
> > + horizontal_sync_active_byte +
> > horizontal_backporch_byte +
> > + ps_wc), dsi->lanes) + da_hs_trail + 1)
> > * dsi->lanes / 6 - 1;
> > + } else {
> > + horizontal_sync_active_byte = vm->hsync_len *
> > dsi_tmp_buf_bpp - 4;
> > +
> > + horizontal_backporch_byte = (vm->hback_porch +
> > vm->hsync_len) *
> > + dsi_tmp_buf_bpp - 10;
> > + hstx_cklp_wc_min = (DIV_ROUND_UP(4, dsi->lanes)
> > + da_hs_trail + 1)
> > + * dsi->lanes / 6 - 1;
> > +
> > + if (dsi->mode_flags &
> > MIPI_DSI_MODE_VIDEO_BURST) {
> > + ps_wc = readl(dsi->regs + DSI_PSCTRL) &
> > 0x7fff;
> > + bllp_wc = readl(dsi->regs +
> > DSI_BLLP_WC) & 0xfff;
>
> Please use bitfield macros here as well.
>
> > + horizontal_frontporch_byte = (vm-
> > >hfront_porch *
> > + dsi_tmp_buf_bpp - 18);
> > +
> > + v_active_roundup = (28 +
> > horizontal_backporch_byte + ps_wc +
> > + horizontal_frontporch_byte +
> > bllp_wc) % dsi->lanes;
> > + if (v_active_roundup)
> > + horizontal_backporch_byte =
> > horizontal_backporch_byte +
> > + dsi->lanes - v_active_roundup;
> > + if (bllp_en) {
> > + hstx_cklp_wc_max =
> > (DIV_ROUND_UP((16 + 6 + 4 +
> > + horizontal_backporch_by
> > te + bllp_wc + ps_wc),
> > + dsi->lanes) +
> > da_hs_trail + 1) * dsi->lanes / 6 - 1;
> > + } else {
> > + hstx_cklp_wc_max =
> > (DIV_ROUND_UP((12 + 4 + 4 +
> > + horizontal_backporch_by
> > te + bllp_wc + ps_wc),
> > + dsi->lanes) +
> > da_hs_trail + 1) * dsi->lanes / 6 - 1;
> > + }
> > + } else {
> > + ps_wc = readl(dsi->regs + DSI_PSCTRL) &
> > 0x7fff;
> > + horizontal_frontporch_byte = (vm-
> > >hfront_porch *
> > + dsi_tmp_buf_bpp - 12);
> > +
> > + v_active_roundup = (22 +
> > horizontal_backporch_byte + ps_wc +
> > + horizontal_frontporch_byte) %
> > dsi->lanes;
> > + if (v_active_roundup)
> > + horizontal_backporch_byte =
> > horizontal_backporch_byte +
> > + dsi->lanes - v_active_roundup;
> > +
> > + hstx_cklp_wc_max = (DIV_ROUND_UP((12 +
> > 4 + 4 +
> > + horizontal_backporch_byte +
> > ps_wc),
> > + dsi->lanes) + da_hs_trail + 1)
> > * dsi->lanes / 6 - 1;
> > + }
> > + }
> > + hstx_cklp_wc = (readl(dsi->regs + DSI_HSTX_CKL_WC) >>
> > 2) & 0x3fff;
>
> same here
>
> > + if (hstx_cklp_wc <= hstx_cklp_wc_min ||
> > + hstx_cklp_wc >= hstx_cklp_wc_max) {
> > + hstx_cklp_wc = (hstx_cklp_wc_max / 2) << 2;
>
> and same here... and everywhere else.
>
> > + writel(hstx_cklp_wc, dsi->regs +
> > DSI_HSTX_CKL_WC);
> > + }
> > + hstx_cklp_wc = hstx_cklp_wc >> 2;
> > + if (hstx_cklp_wc <= hstx_cklp_wc_min ||
> > + hstx_cklp_wc >= hstx_cklp_wc_max) {
> > + DRM_WARN("Wrong setting of hstx_ckl_wc\n");
> > + }
> > +
> > + lpx = readl(dsi->regs + DSI_PHY_TIMECON0) & 0xff;
> > + da_hs_exit = (readl(dsi->regs + DSI_PHY_TIMECON1) >>
> > 24) & 0xff;
> > + da_hs_prep = (readl(dsi->regs + DSI_PHY_TIMECON0) >> 8)
> > & 0xff;
> > + da_hs_zero = (readl(dsi->regs + DSI_PHY_TIMECON0) >>
> > 16) & 0xff;
> > + ps_wc = readl(dsi->regs + DSI_PSCTRL) & 0x7fff;
> > + hs_vb_ps_wc = ps_wc -
> > + (lpx + da_hs_exit + da_hs_prep + da_hs_zero +
> > 2)
> > + * dsi->lanes;
> > + horizontal_frontporch_byte = (1 << 31)
> > + | (hs_vb_ps_wc << 16)
> > + | (horizontal_frontporch_byte);
> > + }
> > writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
> > writel(horizontal_backporch_byte, dsi->regs + DSI_HBP_WC);
> > writel(horizontal_frontporch_byte, dsi->regs + DSI_HFP_WC);
> > @@ -1246,6 +1345,7 @@ static const struct mtk_dsi_driver_data
> > mt8188_dsi_driver_data = {
> > .has_shadow_ctl = true,
> > .has_size_ctl = true,
> > .cmdq_long_packet_ctl = true,
> > + .support_per_frame_lp = true,
>
> Is this supported only on MT8188? Are you sure that MT8195 doesn't
> support that?
>
> Regards,
> Angelo
>
> > };
> >
> > static const struct of_device_id mtk_dsi_of_match[] = {
>
>

Next message: Marc Kleine-Budde: "Re: [PATCH 3/4] can: mcp251xfd: add gpio functionality"
Previous message: Shuijing Li (李水静): "Re: [PATCH] mediatek: dsi: Add dsi per-frame lp code for mt8188"
In reply to: Shuijing Li (李水静): "Re: [PATCH] mediatek: dsi: Add dsi per-frame lp code for mt8188"
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