[PATCH v6 6/7] drm/mediatek: change the dsi phytiming calculate method

From: Jitao Shi
Date: Sun Aug 11 2019 - 06:41:15 EST


Change the method of frame rate calc which can get more accurate
frame rate.

data rate = pixel_clock * bit_per_pixel / lanes
Adjust hfp_wc to adapt the additional phy_data

if MIPI_DSI_MODE_VIDEO_BURST
hfp_wc = hfp * bpp - data_phy_cycles * lanes - 12 - 6;
else
hfp_wc = hfp * bpp - data_phy_cycles * lanes - 12;

Note:
//(2: 1 for sync, 1 for phy idle)
data_phy_cycles = T_hs_exit + T_lpx + T_hs_prepare + T_hs_zero + 2;

bpp: bit per pixel

Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
Tested-by: Ryan Case <ryandcase@xxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 118 ++++++++++++++++++++---------
1 file changed, 81 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index b3676426aeb5..4d98ea08635a 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -136,12 +136,6 @@
#define DATA_0 (0xff << 16)
#define DATA_1 (0xff << 24)

-#define T_LPX 5
-#define T_HS_PREP 6
-#define T_HS_TRAIL 8
-#define T_HS_EXIT 7
-#define T_HS_ZERO 10
-
#define NS_TO_CYCLE(n, c) ((n) / (c) + (((n) % (c)) ? 1 : 0))

#define MTK_DSI_HOST_IS_READ(type) \
@@ -150,6 +144,25 @@
(type == MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM) || \
(type == MIPI_DSI_DCS_READ))

+struct mtk_phy_timing {
+ u32 lpx;
+ u32 da_hs_prepare;
+ u32 da_hs_zero;
+ u32 da_hs_trail;
+
+ u32 ta_go;
+ u32 ta_sure;
+ u32 ta_get;
+ u32 da_hs_exit;
+
+ u32 clk_hs_zero;
+ u32 clk_hs_trail;
+
+ u32 clk_hs_prepare;
+ u32 clk_hs_post;
+ u32 clk_hs_exit;
+};
+
struct phy;

struct mtk_dsi_driver_data {
@@ -180,6 +193,7 @@ struct mtk_dsi {
enum mipi_dsi_pixel_format format;
unsigned int lanes;
struct videomode vm;
+ struct mtk_phy_timing phy_timing;
int refcount;
bool enabled;
u32 irq_data;
@@ -213,17 +227,36 @@ static void mtk_dsi_phy_timconfig(struct mtk_dsi *dsi)
{
u32 timcon0, timcon1, timcon2, timcon3;
u32 ui, cycle_time;
+ struct mtk_phy_timing *timing = &dsi->phy_timing;
+
+ ui = DIV_ROUND_UP(1000000000, dsi->data_rate);
+ cycle_time = div_u64(8000000000ULL, dsi->data_rate);
+
+ timing->lpx = NS_TO_CYCLE(60, cycle_time);
+ timing->da_hs_prepare = NS_TO_CYCLE(50 + 5 * ui, cycle_time);
+ timing->da_hs_zero = NS_TO_CYCLE(110 + 6 * ui, cycle_time);
+ timing->da_hs_trail = NS_TO_CYCLE(90 + 4 * ui, cycle_time);

- ui = 1000 / dsi->data_rate + 0x01;
- cycle_time = 8000 / dsi->data_rate + 0x01;
+ timing->ta_go = 4 * timing->lpx;
+ timing->ta_sure = 3 * timing->lpx / 2;
+ timing->ta_get = 5 * timing->lpx;
+ timing->da_hs_exit = 2 * timing->lpx;

- timcon0 = T_LPX | T_HS_PREP << 8 | T_HS_ZERO << 16 | T_HS_TRAIL << 24;
- timcon1 = 4 * T_LPX | (3 * T_LPX / 2) << 8 | 5 * T_LPX << 16 |
- T_HS_EXIT << 24;
- timcon2 = ((NS_TO_CYCLE(0x64, cycle_time) + 0xa) << 24) |
- (NS_TO_CYCLE(0x150, cycle_time) << 16);
- timcon3 = NS_TO_CYCLE(0x40, cycle_time) | (2 * T_LPX) << 16 |
- NS_TO_CYCLE(80 + 52 * ui, cycle_time) << 8;
+ timing->clk_hs_zero = NS_TO_CYCLE(336, cycle_time);
+ timing->clk_hs_trail = NS_TO_CYCLE(100, cycle_time) + 10;
+
+ timing->clk_hs_prepare = NS_TO_CYCLE(64, cycle_time);
+ timing->clk_hs_post = NS_TO_CYCLE(80 + 52 * ui, cycle_time);
+ timing->clk_hs_exit = 2 * timing->lpx;
+
+ timcon0 = timing->lpx | timing->da_hs_prepare << 8 |
+ timing->da_hs_zero << 16 | timing->da_hs_trail << 24;
+ timcon1 = timing->ta_go | timing->ta_sure << 8 |
+ timing->ta_get << 16 | timing->da_hs_exit << 24;
+ timcon2 = 1 << 8 | timing->clk_hs_zero << 16 |
+ timing->clk_hs_trail << 24;
+ timcon3 = timing->clk_hs_prepare | timing->clk_hs_post << 8 |
+ timing->clk_hs_exit << 16;

writel(timcon0, dsi->regs + DSI_PHY_TIMECON0);
writel(timcon1, dsi->regs + DSI_PHY_TIMECON1);
@@ -410,7 +443,8 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
u32 horizontal_sync_active_byte;
u32 horizontal_backporch_byte;
u32 horizontal_frontporch_byte;
- u32 dsi_tmp_buf_bpp;
+ u32 dsi_tmp_buf_bpp, data_phy_cycles;
+ struct mtk_phy_timing *timing = &dsi->phy_timing;

struct videomode *vm = &dsi->vm;

@@ -437,7 +471,34 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
dsi_tmp_buf_bpp - 10);

- horizontal_frontporch_byte = (vm->hfront_porch * dsi_tmp_buf_bpp - 12);
+ data_phy_cycles = timing->lpx + timing->da_hs_prepare +
+ timing->da_hs_zero + timing->da_hs_exit + 2;
+
+ if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
+ if (vm->hfront_porch * dsi_tmp_buf_bpp >
+ data_phy_cycles * dsi->lanes + 18) {
+ horizontal_frontporch_byte = vm->hfront_porch *
+ dsi_tmp_buf_bpp -
+ data_phy_cycles *
+ dsi->lanes - 18;
+ } else {
+ DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
+ horizontal_frontporch_byte = vm->hfront_porch *
+ dsi_tmp_buf_bpp;
+ }
+ } else {
+ if (vm->hfront_porch * dsi_tmp_buf_bpp >
+ data_phy_cycles * dsi->lanes + 12) {
+ horizontal_frontporch_byte = vm->hfront_porch *
+ dsi_tmp_buf_bpp -
+ data_phy_cycles *
+ dsi->lanes - 12;
+ } else {
+ DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
+ horizontal_frontporch_byte = vm->hfront_porch *
+ dsi_tmp_buf_bpp;
+ }
+ }

writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
writel(horizontal_backporch_byte, dsi->regs + DSI_HBP_WC);
@@ -537,8 +598,7 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
{
struct device *dev = dsi->host.dev;
int ret;
- u64 pixel_clock, total_bits;
- u32 htotal, htotal_bits, bit_per_pixel, overhead_cycles, overhead_bits;
+ u32 bit_per_pixel;

if (++dsi->refcount != 1)
return 0;
@@ -557,24 +617,8 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
break;
}

- /**
- * htotal_time = htotal * byte_per_pixel / num_lanes
- * overhead_time = lpx + hs_prepare + hs_zero + hs_trail + hs_exit
- * mipi_ratio = (htotal_time + overhead_time) / htotal_time
- * data_rate = pixel_clock * bit_per_pixel * mipi_ratio / num_lanes;
- */
- pixel_clock = dsi->vm.pixelclock;
- htotal = dsi->vm.hactive + dsi->vm.hback_porch + dsi->vm.hfront_porch +
- dsi->vm.hsync_len;
- htotal_bits = htotal * bit_per_pixel;
-
- overhead_cycles = T_LPX + T_HS_PREP + T_HS_ZERO + T_HS_TRAIL +
- T_HS_EXIT;
- overhead_bits = overhead_cycles * dsi->lanes * 8;
- total_bits = htotal_bits + overhead_bits;
-
- dsi->data_rate = DIV_ROUND_UP_ULL(pixel_clock * total_bits,
- htotal * dsi->lanes);
+ dsi->data_rate = DIV_ROUND_UP_ULL(dsi->vm.pixelclock * bit_per_pixel,
+ dsi->lanes);

ret = clk_set_rate(dsi->hs_clk, dsi->data_rate);
if (ret < 0) {
--
2.21.0