Re: [PATCH drm-dp 2/4] drm/hisilicon/hibmc: add dp link moduel in hibmc drivers
From: Jani Nikula
Date: Wed Oct 09 2024 - 04:20:40 EST
On Mon, 30 Sep 2024, shiyongbang <shiyongbang@xxxxxxxxxx> wrote:
> From: baihan li <libaihan@xxxxxxxxxx>
>
> Add link training process functions in this moduel.
Lots of duplication of drm_dp_helper.[ch] stuff here too. I'll mention a
few inline, but there's more.
BR,
Jani.
>
> Signed-off-by: baihan li <libaihan@xxxxxxxxxx>
> ---
> drivers/gpu/drm/hisilicon/hibmc/Makefile | 2 +-
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_kapi.c | 258 ++++++++++++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c | 390 +++++++++++++++++++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.h | 24 ++
> 4 files changed, 673 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_kapi.c
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.h
>
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/Makefile b/drivers/gpu/drm/hisilicon/hibmc/Makefile
> index 8770ec6dfffd..94d77da88bbf 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/Makefile
> +++ b/drivers/gpu/drm/hisilicon/hibmc/Makefile
> @@ -1,5 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> hibmc-drm-y := hibmc_drm_drv.o hibmc_drm_de.o hibmc_drm_vdac.o hibmc_drm_i2c.o \
> - dp/dp_aux.o
> + dp/dp_aux.o dp/dp_link.o
>
> obj-$(CONFIG_DRM_HISI_HIBMC) += hibmc-drm.o
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_kapi.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_kapi.c
> new file mode 100644
> index 000000000000..4091723473ad
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_kapi.c
> @@ -0,0 +1,258 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// Copyright (c) 2024 Hisilicon Limited.
> +
> +#include <linux/io.h>
> +#include <linux/delay.h>
> +#include "dp_config.h"
> +#include "dp_comm.h"
> +#include "dp_reg.h"
> +#include "dp_kapi.h"
> +#include "dp_link.h"
> +
> +#define DP_LINK_RATE_HBR 0xa
> +
> +static int hibmc_dp_link_init(struct hibmc_dp_dev *dp)
> +{
> + dp->link.cap.lanes = 2;
> + dp->link.train_set = devm_kzalloc(dp->dev->dev,
> + dp->link.cap.lanes * sizeof(u8), GFP_KERNEL);
> + if (!dp->link.train_set)
> + return -ENOMEM;
> +
> + dp->link.cap.link_rate = DP_LINK_RATE_HBR;
> +
> + return 0;
> +}
> +
> +static void hibmc_dp_aux_init(struct hibmc_dp_dev *dp)
> +{
> + struct hibmc_dp_aux *aux = &dp->aux;
> +
> + aux->addr = dp->base;
> + /* aux read/write lock */
> + mutex_init(&aux->lock);
> + dp_write_bits(aux->addr + DP_AUX_REQ, DP_CFG_AUX_SYNC_LEN_SEL, 0x0);
> + dp_write_bits(aux->addr + DP_AUX_REQ, DP_CFG_AUX_TIMER_TIMEOUT, 0x1);
> + dp_write_bits(aux->addr + DP_AUX_REQ, DP_CFG_AUX_MIN_PULSE_NUM, DP_MIN_PULSE_NUM);
> +}
> +
> +static void hibmc_dp_aux_uninit(struct hibmc_dp_dev *dp)
> +{
> + struct hibmc_dp_aux *aux = &dp->aux;
> +
> + mutex_destroy(&aux->lock);
> +}
> +
> +static void hibmc_dp_set_tu(struct hibmc_dp_dev *dp, struct dp_mode *mode)
> +{
> + u32 tu_symbol_frac_size;
> + u32 tu_symbol_size;
> + u64 pixel_clock;
> + u64 rate_ks;
> + u8 lane_num;
> + u32 value;
> + u32 bpp;
> +
> + pixel_clock = mode->pixel_clock;
> + lane_num = dp->link.cap.lanes;
> + if (lane_num == 0) {
> + drm_err(dp->dev, "set tu failed, lane num cannot be 0!\n");
> + return;
> + }
> +
> + bpp = DP_BPP;
> + rate_ks = dp->link.cap.link_rate * DP_LINK_RATE_CAL;
> + value = (pixel_clock * bpp * 5000) / (61 * lane_num * rate_ks);
> +
> + if (value % 10 == 9) { /* 10: div, 9: carry */
> + tu_symbol_size = value / 10 + 1; /* 10: div */
> + tu_symbol_frac_size = 0;
> + } else {
> + tu_symbol_size = value / 10; /* 10: div */
> + tu_symbol_frac_size = value % 10 + 1; /* 10: div */
> + }
> +
> + drm_info(dp->dev, "tu value: %u.%u value: %u\n",
> + tu_symbol_size, tu_symbol_frac_size, value);
> +
> + dp_write_bits(dp->base + DP_VIDEO_PACKET,
> + DP_CFG_STREAM_TU_SYMBOL_SIZE, tu_symbol_size);
> + dp_write_bits(dp->base + DP_VIDEO_PACKET,
> + DP_CFG_STREAM_TU_SYMBOL_FRAC_SIZE, tu_symbol_frac_size);
> +}
> +
> +static void hibmc_dp_set_sst(struct hibmc_dp_dev *dp, struct dp_mode *mode)
> +{
> + u32 hblank_size;
> + u32 htotal_size;
> + u32 htotal_int;
> + u32 hblank_int;
> + u32 fclk; /* flink_clock */
> +
> + fclk = dp->link.cap.link_rate * DP_LINK_RATE_CAL;
> +
> + /* ssc: 9947 / 10000 = 0.9947 */
> + htotal_int = mode->h_total * 9947 / 10000;
> + htotal_size = (u32)((u64)htotal_int * fclk / (DP_SYMBOL_PER_FCLK * mode->pixel_clock));
> +
> + /* ssc: max effect bandwidth 53 / 10000 = 0.53% */
> + hblank_int = mode->h_blank - mode->h_active * 53 / 10000;
> + hblank_size = (u64)hblank_int * fclk * 9947 /
> + ((u64)mode->pixel_clock * 10000 * DP_SYMBOL_PER_FCLK);
> +
> + drm_info(dp->dev, "h_active %u v_active %u htotal_size %u hblank_size %u",
> + mode->h_active, mode->v_active, htotal_size, hblank_size);
> + drm_info(dp->dev, "flink_clock %u pixel_clock %u", fclk, mode->pixel_clock);
> +
> + dp_write_bits(dp->base + DP_VIDEO_HORIZONTAL_SIZE, DP_CFG_STREAM_HTOTAL_SIZE, htotal_size);
> + dp_write_bits(dp->base + DP_VIDEO_HORIZONTAL_SIZE, DP_CFG_STREAM_HBLANK_SIZE, hblank_size);
> +}
> +
> +static void hibmc_dp_link_cfg(struct hibmc_dp_dev *dp, struct dp_mode *mode)
> +{
> + u32 timing_delay;
> + u32 vblank;
> + u32 hstart;
> + u32 vstart;
> +
> + vblank = mode->v_total - mode->v_active;
> + timing_delay = mode->h_sync + mode->h_back;
> + hstart = mode->h_sync + mode->h_back;
> + vstart = mode->v_sync + mode->v_back;
> +
> + dp_write_bits(dp->base + DP_TIMING_GEN_CONFIG0,
> + DP_CFG_TIMING_GEN0_HBLANK, mode->h_blank);
> + dp_write_bits(dp->base + DP_TIMING_GEN_CONFIG0,
> + DP_CFG_TIMING_GEN0_HACTIVE, mode->h_active);
> +
> + dp_write_bits(dp->base + DP_TIMING_GEN_CONFIG2,
> + DP_CFG_TIMING_GEN0_VBLANK, vblank);
> + dp_write_bits(dp->base + DP_TIMING_GEN_CONFIG2,
> + DP_CFG_TIMING_GEN0_VACTIVE, mode->v_active);
> + dp_write_bits(dp->base + DP_TIMING_GEN_CONFIG3,
> + DP_CFG_TIMING_GEN0_VFRONT_PORCH, mode->v_front);
> +
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG0,
> + DP_CFG_STREAM_HACTIVE, mode->h_active);
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG0,
> + DP_CFG_STREAM_HBLANK, mode->h_blank);
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG2,
> + DP_CFG_STREAM_HSYNC_WIDTH, mode->h_sync);
> +
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG1,
> + DP_CFG_STREAM_VACTIVE, mode->v_active);
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG1,
> + DP_CFG_STREAM_VBLANK, vblank);
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG3,
> + DP_CFG_STREAM_VFRONT_PORCH, mode->v_front);
> + dp_write_bits(dp->base + DP_VIDEO_CONFIG3,
> + DP_CFG_STREAM_VSYNC_WIDTH, mode->v_sync);
> +
> + dp_write_bits(dp->base + DP_VIDEO_MSA0,
> + DP_CFG_STREAM_VSTART, vstart);
> + dp_write_bits(dp->base + DP_VIDEO_MSA0,
> + DP_CFG_STREAM_HSTART, hstart);
> +
> + dp_write_bits(dp->base + DP_VIDEO_CTRL,
> + DP_CFG_STREAM_VSYNC_POLARITY, mode->v_pol);
> + dp_write_bits(dp->base + DP_VIDEO_CTRL,
> + DP_CFG_STREAM_HSYNC_POLARITY, mode->h_pol);
> +
> + /* MSA mic 0 and 1*/
> + writel(DP_MSA1, dp->base + DP_VIDEO_MSA1);
> + writel(DP_MSA2, dp->base + DP_VIDEO_MSA2);
> +
> + hibmc_dp_set_tu(dp, mode);
> +
> + dp_write_bits(dp->base + DP_VIDEO_CTRL, DP_CFG_STREAM_RGB_ENABLE, 0x1);
> + dp_write_bits(dp->base + DP_VIDEO_CTRL, DP_CFG_STREAM_VIDEO_MAPPING, 0);
> +
> + /*divide 2: up even */
> + if (timing_delay % 2)
> + timing_delay++;
> +
> + dp_write_bits(dp->base + DP_TIMING_MODEL_CTRL,
> + DP_CFG_PIXEL_NUM_TIMING_MODE_SEL1, timing_delay);
> +
> + hibmc_dp_set_sst(dp, mode);
> +}
> +
> +int hibmc_dp_kapi_init(struct hibmc_dp *dp)
> +{
> + struct drm_device *drm_dev = dp->drm_dev;
> + struct hibmc_dp_dev *dp_dev;
> + int ret;
> +
> + dp_dev = devm_kzalloc(drm_dev->dev, sizeof(struct hibmc_dp_dev), GFP_KERNEL);
> + if (!dp_dev)
> + return -ENOMEM;
> +
> + dp->dp_dev = dp_dev;
> +
> + dp_dev->dev = drm_dev;
> + dp_dev->base = dp->mmio + DP_OFFSET;
> +
> + hibmc_dp_aux_init(dp_dev);
> +
> + ret = hibmc_dp_link_init(dp_dev);
> + if (ret) {
> + drm_err(drm_dev, "dp link init failed\n");
> + hibmc_dp_aux_uninit(dp_dev);
> + return ret;
> + }
> +
> + /* hdcp data */
> + writel(DP_HDCP, dp_dev->base + DP_HDCP_CFG);
> + /* int init */
> + writel(0, dp_dev->base + DP_INTR_ENABLE);
> + writel(DP_INT_RST, dp_dev->base + DP_INTR_ORIGINAL_STATUS);
> + /* rst */
> + writel(DP_DPTX_RST, dp_dev->base + DP_DPTX_RST_CTRL);
> + /* clock enable */
> + writel(DP_CLK_EN, dp_dev->base + DP_DPTX_CLK_CTRL);
> +
> + return 0;
> +}
> +
> +void hibmc_dp_kapi_uninit(struct hibmc_dp *dp)
> +{
> + hibmc_dp_aux_uninit(dp->dp_dev);
> +}
> +
> +void hibmc_dp_display_en(struct hibmc_dp *dp, bool enable)
> +{
> + struct hibmc_dp_dev *dp_dev = dp->dp_dev;
> +
> + if (enable) {
> + dp_write_bits(dp_dev->base + DP_VIDEO_CTRL, BIT(0), 0x1);
> + writel(DP_SYNC_EN_MASK, dp_dev->base + DP_TIMING_SYNC_CTRL);
> + dp_write_bits(dp_dev->base + DP_DPTX_GCTL0, BIT(10), 0x1);
> + writel(DP_SYNC_EN_MASK, dp_dev->base + DP_TIMING_SYNC_CTRL);
> + } else {
> + dp_write_bits(dp_dev->base + DP_DPTX_GCTL0, BIT(10), 0);
> + writel(DP_SYNC_EN_MASK, dp_dev->base + DP_TIMING_SYNC_CTRL);
> + dp_write_bits(dp_dev->base + DP_VIDEO_CTRL, BIT(0), 0);
> + writel(DP_SYNC_EN_MASK, dp_dev->base + DP_TIMING_SYNC_CTRL);
> + }
> +
> + msleep(50);
> +}
> +
> +int hibmc_dp_mode_set(struct hibmc_dp *dp, struct dp_mode *mode)
> +{
> + struct hibmc_dp_dev *dp_dev = dp->dp_dev;
> + int ret;
> +
> + if (!dp_dev->link.status.channel_equalized) {
> + ret = dp_link_training(dp_dev);
> + if (ret) {
> + drm_err(dp->drm_dev, "dp link training failed, ret: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + hibmc_dp_display_en(dp, false);
> + hibmc_dp_link_cfg(dp_dev, mode);
> +
> + return 0;
> +}
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c
> new file mode 100644
> index 000000000000..0a10cae1d8a4
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c
> @@ -0,0 +1,390 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// Copyright (c) 2024 Hisilicon Limited.
> +
> +#include <linux/delay.h>
> +#include <drm/drm_device.h>
> +#include <drm/drm_print.h>
> +#include "dp_comm.h"
> +#include "dp_reg.h"
> +#include "dp_link.h"
> +#include "dp_aux.h"
> +
> +static int dp_link_training_configure(struct hibmc_dp_dev *dp)
> +{
> + u8 buf[2];
> + int ret;
> +
> + /* DP 2 lane */
> + dp_write_bits(dp->base + DP_PHYIF_CTRL0, DP_CFG_LANE_DATA_EN,
> + dp->link.cap.lanes == DP_LANE_NUM_2 ? 0x3 : 0x1);
> + dp_write_bits(dp->base + DP_DPTX_GCTL0, DP_CFG_PHY_LANE_NUM,
> + dp->link.cap.lanes == DP_LANE_NUM_2 ? 0x1 : 0);
> +
> + /* enhanced frame */
> + dp_write_bits(dp->base + DP_VIDEO_CTRL, DP_CFG_STREAM_FRAME_MODE, 0x1);
> +
> + /* set rate and lane count */
> + buf[0] = dp->link.cap.link_rate;
> + buf[1] = DPCD_ENHANCED_FRAME_EN | dp->link.cap.lanes;
> + ret = dp_aux_write(dp, DPCD_LINK_BW_SET, buf, sizeof(buf));
> + if (ret) {
> + drm_err(dp->dev, "dp aux write link rate and lanes failed, ret: %d\n", ret);
> + return ret;
> + }
> +
> + /* set 8b/10b and downspread */
> + buf[0] = 0x10;
> + buf[1] = 0x1;
> + ret = dp_aux_write(dp, DPCD_DOWNSPREAD_CTRL, buf, sizeof(buf));
> + if (ret)
> + drm_err(dp->dev, "dp aux write 8b/10b and downspread failed, ret: %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int dp_link_pattern2dpcd(struct hibmc_dp_dev *dp, enum dp_pattern_e pattern)
> +{
> + switch (pattern) {
> + case DP_PATTERN_NO:
> + return DPCD_TRAINING_PATTERN_DISABLE;
> + case DP_PATTERN_TPS1:
> + return DPCD_TRAINING_PATTERN_1;
> + case DP_PATTERN_TPS2:
> + return DPCD_TRAINING_PATTERN_2;
> + case DP_PATTERN_TPS3:
> + return DPCD_TRAINING_PATTERN_3;
> + case DP_PATTERN_TPS4:
> + return DPCD_TRAINING_PATTERN_4;
> + default:
> + drm_err(dp->dev, "dp link unknown pattern %d\n", pattern);
> + return -EINVAL;
> + }
> +}
> +
> +static int dp_link_set_pattern(struct hibmc_dp_dev *dp, enum dp_pattern_e pattern)
> +{
> + int ret;
> + u8 buf;
> +
> + ret = dp_link_pattern2dpcd(dp, pattern);
> + if (ret < 0)
> + return ret;
> +
> + buf = (u8)ret;
> + if (pattern != DPCD_TRAINING_PATTERN_DISABLE && pattern != DPCD_TRAINING_PATTERN_4) {
> + buf |= DPCD_SCRAMBLING_DISABLE;
> + dp_write_bits(dp->base + DP_PHYIF_CTRL0, DP_CFG_SCRAMBLE_EN, 0x1);
> + } else {
> + dp_write_bits(dp->base + DP_PHYIF_CTRL0, DP_CFG_SCRAMBLE_EN, 0);
> + }
> +
> + dp_write_bits(dp->base + DP_PHYIF_CTRL0, DP_CFG_PAT_SEL, pattern);
> +
> + ret = dp_aux_write(dp, DPCD_TRAINING_PATTERN_SET, &buf, sizeof(buf));
> + if (ret)
> + drm_err(dp->dev, "dp aux write training pattern set failed\n");
> +
> + return ret;
> +}
> +
> +static int dp_link_training_cr_pre(struct hibmc_dp_dev *dp)
> +{
> + u8 *train_set = dp->link.train_set;
> + int ret;
> + u8 i;
> +
> + ret = dp_link_training_configure(dp);
> + if (ret)
> + return ret;
> +
> + ret = dp_link_set_pattern(dp, DP_PATTERN_TPS1);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < dp->link.cap.lanes; i++)
> + train_set[i] = DPCD_VOLTAGE_SWING_LEVEL_2 | DPCD_PRE_EMPHASIS_LEVEL_0;
> +
> + ret = dp_aux_write(dp, DPCD_TRAINING_LANE0_SET, train_set, dp->link.cap.lanes);
> + if (ret)
> + drm_err(dp->dev, "dp aux write training lane set failed\n");
> +
> + return ret;
> +}
> +
> +static bool dp_dpcd_cr_done_check_and_update(u8 lane_status, u8 lane_count,
> + u8 *cr_done_lanes)
drm_dp_clock_recovery_ok().
> +{
> + bool is_ok = true;
> + u8 val;
> +
> + *cr_done_lanes = GENMASK(lane_count - 1, 0);
> +
> + for (u8 lane = 0; lane < lane_count; lane++) {
> + val = lane_status >> (lane * AUX_4_BIT);
> + if ((val & DPCD_CR_DONE_BITS) == 0) {
> + *cr_done_lanes &= ~(BIT(lane));
> + is_ok = false;
> + }
> + }
> +
> + return is_ok;
> +}
> +
> +static bool dp_dpcd_eq_is_ok(u8 lane_status, u8 lane_count)
drm_dp_channel_eq_ok().
> +{
> + u8 val;
> +
> + for (u8 lane = 0; lane < lane_count; lane++) {
> + val = (lane_status >> (lane * AUX_4_BIT));
> + if ((val & DPCD_EQ_DONE_BITS) != DPCD_EQ_DONE_BITS)
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static bool dp_link_get_adjust_train(struct hibmc_dp_dev *dp, u8 lane_status)
drm_dp_get_adjust_request_voltage()
drm_dp_get_adjust_request_pre_emphasis()
> +{
> + u8 pre_emph[DP_LANE_NUM_MAX] = {0};
> + u8 voltage[DP_LANE_NUM_MAX] = {0};
> + bool changed = false;
> + u8 train_set;
> + u8 lane;
> +
> + /* not support level 3 */
> + for (lane = 0; lane < dp->link.cap.lanes; lane++) {
> + voltage[lane] = (lane_status & (DPCD_VOLTAGE_SWING_LANE_0 << (AUX_4_BIT * lane)))
> + << DPCD_VOLTAGE_SWING_SET_S;
> + pre_emph[lane] = (lane_status & (DPCD_PRE_EMPHASIS_LANE_0 << (AUX_4_BIT * lane)))
> + << DPCD_PRE_EMPHASIS_SET_S;
> + }
> +
> + for (lane = 0; lane < dp->link.cap.lanes; lane++) {
> + train_set = voltage[lane] | pre_emph[lane];
> + if (dp->link.train_set[lane] != train_set) {
> + changed = true;
> + dp->link.train_set[lane] = train_set;
> + }
> + }
> +
> + return changed;
> +}
> +
> +static int dp_link_reduce_rate(struct hibmc_dp_dev *dp)
> +{
> + u8 link_rate_map[DP_LINK_RATE_NUM] = {DP_LINK_RATE_0, DP_LINK_RATE_1,
> + DP_LINK_RATE_2, DP_LINK_RATE_3};
> +
> + for (u8 i = 0; i < DP_LINK_RATE_NUM; i++) {
> + if (link_rate_map[i] == dp->link.cap.link_rate) {
> + if (i == 0) {
> + drm_err(dp->dev, "dp link training reduce rate failed, already lowest rate\n");
> + return -EFAULT;
> + }
> + dp->link.cap.link_rate = link_rate_map[i - 1];
> + return 0;
> + }
> + }
> +
> + drm_err(dp->dev, "dp link training reduce rate failed, rate match failed\n");
> + return -EFAULT;
> +}
> +
> +static int dp_link_reduce_lane(struct hibmc_dp_dev *dp)
> +{
> + /* currently only 1 lane */
> + dp->link.cap.lanes = DP_LANE_NUM_1;
> +
> + return 0;
> +}
> +
> +static int dp_link_training_cr(struct hibmc_dp_dev *dp)
> +{
> + u8 lane_status[DP_LANE_STATUS_SIZE] = {0};
> + bool level_changed;
> + u32 voltage_tries;
> + u32 cr_tries;
> + u32 max_cr;
> + int ret;
> +
> + /*
> + * DP 1.4 spec define 10 for maxtries value, for pre DP 1.4 version set a limit of 80
> + * (4 voltage levels x 4 preemphasis levels x 5 identical voltage retries)
> + */
> + max_cr = dp->link.cap.rx_dpcd_revision >= DPCD_REVISION_14 ? 10 : 80;
> +
> + voltage_tries = 1;
> + for (cr_tries = 0; cr_tries < max_cr; cr_tries++) {
> + msleep(50);
> +
> + ret = dp_aux_read(dp, DPCD_LANE0_1_STATUS, lane_status, DP_LANE_STATUS_SIZE);
> + if (ret) {
> + drm_err(dp->dev, "Get lane status failed\n");
> + return ret;
> + }
> +
> + ret = dp_dpcd_cr_done_check_and_update(lane_status[0], dp->link.cap.lanes,
> + &dp->link.status.cr_done_lanes);
> + if (ret) {
> + drm_info(dp->dev, "dp link training cr done\n");
> + dp->link.status.clock_recovered = true;
> + return 0;
> + }
> +
> + if (voltage_tries == 5) {
> + drm_info(dp->dev, "same voltage tries 5 times\n");
> + dp->link.status.clock_recovered = false;
> + return 0;
> + }
> +
> + ret = dp_aux_read(dp, DPCD_ADJUST_REQUEST_LANE0_1, lane_status,
> + DP_LANE_STATUS_SIZE);
> + if (ret) {
> + drm_err(dp->dev, "Get adjust status failed\n");
> + return ret;
> + }
> +
> + level_changed = dp_link_get_adjust_train(dp, lane_status[0]);
> + ret = dp_aux_write(dp, DPCD_TRAINING_LANE0_SET, dp->link.train_set,
> + dp->link.cap.lanes);
> + if (ret) {
> + drm_err(dp->dev, "Update link training failed\n");
> + return ret;
> + }
> +
> + voltage_tries = level_changed ? 1 : voltage_tries + 1;
> + }
> +
> + drm_err(dp->dev, "dp link training clock recovery %u timers failed\n", max_cr);
> + dp->link.status.clock_recovered = false;
> +
> + return 0;
> +}
> +
> +static int dp_link_training_channel_eq(struct hibmc_dp_dev *dp)
> +{
> + u8 lane_status[DP_LANE_STATUS_SIZE] = {0};
> + enum dp_pattern_e tps;
> + u8 eq_tries;
> + int ret;
> +
> + if (dp->link.cap.is_tps4)
> + tps = DP_PATTERN_TPS4;
> + else if (dp->link.cap.is_tps3)
> + tps = DP_PATTERN_TPS3;
> + else
> + tps = DP_PATTERN_TPS2;
> +
> + ret = dp_link_set_pattern(dp, tps);
> + if (ret)
> + return ret;
> +
> + for (eq_tries = 0; eq_tries < EQ_MAX_RETRY; eq_tries++) {
> + msleep(50);
> +
> + ret = dp_aux_read(dp, DPCD_LANE0_1_STATUS, lane_status, DP_LANE_STATUS_SIZE);
> + if (ret) {
> + drm_err(dp->dev, "get lane status failed\n");
> + break;
> + }
> +
> + ret = dp_dpcd_cr_done_check_and_update(lane_status[0], dp->link.cap.lanes,
> + &dp->link.status.cr_done_lanes);
> + if (!ret) {
> + drm_info(dp->dev, "clock recovery check failed\n");
> + drm_info(dp->dev, "cannot continue channel equalization\n");
> + dp->link.status.clock_recovered = false;
> + break;
> + }
> +
> + ret = dp_dpcd_eq_is_ok(lane_status[0], dp->link.cap.lanes);
> + if (ret) {
> + dp->link.status.channel_equalized = true;
> + drm_info(dp->dev, "dp link training eq done\n");
> + break;
> + }
> +
> + ret = dp_aux_read(dp, DPCD_ADJUST_REQUEST_LANE0_1,
> + lane_status, DP_LANE_STATUS_SIZE);
> + if (ret) {
> + drm_err(dp->dev, "Get adjust status failed\n");
> + return ret;
> + }
> +
> + dp_link_get_adjust_train(dp, lane_status[0]);
> +
> + ret = dp_aux_write(dp, DPCD_TRAINING_LANE0_SET,
> + dp->link.train_set, dp->link.cap.lanes);
> + if (ret) {
> + drm_err(dp->dev, "Update link training failed\n");
> + break;
> + }
> + }
> +
> + if (eq_tries == EQ_MAX_RETRY)
> + drm_err(dp->dev, "channel equalization failed %u times\n", eq_tries);
> +
> + dp_link_set_pattern(dp, DP_PATTERN_NO);
> +
> + return ret;
> +}
> +
> +static int dp_link_downgrade_training_cr(struct hibmc_dp_dev *dp)
> +{
> + if (dp_link_reduce_rate(dp))
> + return dp_link_reduce_lane(dp);
> +
> + return 0;
> +}
> +
> +static int dp_link_downgrade_training_eq(struct hibmc_dp_dev *dp)
> +{
> + if ((!dp->link.status.clock_recovered && dp->link.status.cr_done_lanes != 0) ||
> + (dp->link.status.clock_recovered && !dp->link.status.channel_equalized)) {
> + if (!dp_link_reduce_lane(dp))
> + return 0;
> + }
> +
> + return dp_link_reduce_rate(dp);
> +}
> +
> +int dp_link_training(struct hibmc_dp_dev *dp)
> +{
> + struct hibmc_dp_link *link = &dp->link;
> + int ret;
> +
> + while (true) {
> + ret = dp_link_training_cr_pre(dp);
> + if (ret)
> + goto err;
> +
> + ret = dp_link_training_cr(dp);
> + if (ret)
> + goto err;
> +
> + if (!link->status.clock_recovered) {
> + ret = dp_link_downgrade_training_cr(dp);
> + if (ret)
> + goto err;
> + continue;
> + }
> +
> + ret = dp_link_training_channel_eq(dp);
> + if (ret)
> + goto err;
> +
> + if (!link->status.channel_equalized) {
> + ret = dp_link_downgrade_training_eq(dp);
> + if (ret)
> + goto err;
> + continue;
> + }
> +
> + return 0;
> + }
> +
> +err:
> + dp_link_set_pattern(dp, DP_PATTERN_NO);
> +
> + return ret;
> +}
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.h
> new file mode 100644
> index 000000000000..3271cdc4550c
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) 2024 Hisilicon Limited. */
> +
> +#ifndef DP_LINK_H
> +#define DP_LINK_H
> +
> +#include "dp_comm.h"
> +
> +#define DP_LANE_NUM_MAX 2
> +#define DP_LANE_STATUS_SIZE 1
> +#define DP_LANE_NUM_1 0x1
> +#define DP_LANE_NUM_2 0x2
> +
> +enum dp_pattern_e {
> + DP_PATTERN_NO = 0,
> + DP_PATTERN_TPS1,
> + DP_PATTERN_TPS2,
> + DP_PATTERN_TPS3,
> + DP_PATTERN_TPS4,
> +};
> +
> +int dp_link_training(struct hibmc_dp_dev *dp);
> +
> +#endif
--
Jani Nikula, Intel