[PATCH v5 drm-dp 2/5] drm/hisilicon/hibmc: add dp link moduel in hibmc
Yongbang Shi
shiyongbang at huawei.com
Mon Nov 18 14:28:02 UTC 2024
From: baihan li <libaihan at huawei.com>
Add link training process functions in this moduel.
Signed-off-by: Baihan Li <libaihan at huawei.com>
Signed-off-by: Yongbang Shi <shiyongbang at huawei.com>
---
Changelog:
v3 -> v4:
- optimizing hibmc_dp_link_get_adjust_train() to delete for loop, suggested by Dmitry Baryshkov.
- changing ELNRNG to EIO error code, suggested by Dmitry Baryshkov.
- deleting meaningless macro, suggested by Dmitry Baryshkov.
- fixing build errors reported by kernel test robot <lkp at intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411041559.WIfxRN6n-lkp@intel.com/
v2 -> v3:
- using switchcase in dp_link_reduce_lane, suggested by Dmitry Baryshkov.
- deleting dp_link_pattern2dpcd function and using macros directly, suggested by Dmitry Baryshkov.
- deleting EFAULT error codes, suggested by Dmitry Baryshkov.
v1 -> v2:
- using drm_dp_* functions implement dp link training process, suggested by Jani Nikula.
- fix build errors reported by kernel test robot <lkp at intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410031735.8iRZZR6T-lkp@intel.com/
v1:https://lore.kernel.org/all/20240930100610.782363-1-shiyongbang@huawei.com/
---
drivers/gpu/drm/hisilicon/hibmc/Makefile | 2 +-
drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h | 24 ++
drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c | 339 +++++++++++++++++++
drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h | 8 +
4 files changed, 372 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c
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_comm.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
index ce3b6fa4ea9e..8553e531ba67 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
@@ -13,11 +13,34 @@
#include <linux/io.h>
#include <drm/display/drm_dp_helper.h>
+#define HIBMC_DP_LANE_NUM_MAX 2
+
+struct hibmc_link_status {
+ bool clock_recovered;
+ bool channel_equalized;
+};
+
+struct hibmc_link_cap {
+ int rx_dpcd_revision;
+ u8 link_rate;
+ u8 lanes;
+ bool is_tps3;
+ bool is_tps4;
+};
+
+struct hibmc_dp_link {
+ struct hibmc_link_status status;
+ u8 train_set[HIBMC_DP_LANE_NUM_MAX];
+ struct hibmc_link_cap cap;
+};
+
struct hibmc_dp_dev {
struct drm_dp_aux aux;
struct drm_device *dev;
void __iomem *base;
struct mutex lock; /* protects concurrent RW in hibmc_dp_reg_write_field() */
+ struct hibmc_dp_link link;
+ u8 dpcd[DP_RECEIVER_CAP_SIZE];
};
#define dp_field_modify(reg_value, mask, val) ({ \
@@ -34,5 +57,6 @@ struct hibmc_dp_dev {
mutex_unlock(&_dp->lock); })
void hibmc_dp_aux_init(struct hibmc_dp_dev *dp);
+int hibmc_dp_link_training(struct hibmc_dp_dev *dp);
#endif
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..b7ae9e54126c
--- /dev/null
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c
@@ -0,0 +1,339 @@
+// 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"
+
+#define HIBMC_EQ_MAX_RETRY 5
+
+static int hibmc_dp_link_training_configure(struct hibmc_dp_dev *dp)
+{
+ u8 buf[2];
+ int ret;
+
+ /* DP 2 lane */
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_PHYIF_CTRL0, HIBMC_DP_CFG_LANE_DATA_EN,
+ dp->link.cap.lanes == 0x2 ? 0x3 : 0x1);
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_DPTX_GCTL0, HIBMC_DP_CFG_PHY_LANE_NUM,
+ dp->link.cap.lanes == 0x2 ? 0x1 : 0);
+
+ /* enhanced frame */
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_VIDEO_CTRL, HIBMC_DP_CFG_STREAM_FRAME_MODE, 0x1);
+
+ /* set rate and lane count */
+ buf[0] = dp->link.cap.link_rate;
+ buf[1] = DP_LANE_COUNT_ENHANCED_FRAME_EN | dp->link.cap.lanes;
+ ret = drm_dp_dpcd_write(&dp->aux, DP_LINK_BW_SET, buf, sizeof(buf));
+ if (ret != sizeof(buf)) {
+ drm_dbg_dp(dp->dev, "dp aux write link rate and lanes failed, ret: %d\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+
+ /* set 8b/10b and downspread */
+ buf[0] = 0x10;
+ buf[1] = 0x1;
+ ret = drm_dp_dpcd_write(&dp->aux, DP_DOWNSPREAD_CTRL, buf, sizeof(buf));
+ if (ret != sizeof(buf)) {
+ drm_dbg_dp(dp->dev, "dp aux write 8b/10b and downspread failed, ret: %d\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+
+ ret = drm_dp_read_dpcd_caps(&dp->aux, dp->dpcd);
+ if (ret)
+ drm_err(dp->dev, "dp aux read dpcd failed, ret: %d\n", ret);
+
+ return ret;
+}
+
+static int hibmc_dp_link_set_pattern(struct hibmc_dp_dev *dp, int pattern)
+{
+ int ret;
+ u8 val;
+ u8 buf;
+
+ buf = (u8)pattern;
+ if (pattern != DP_TRAINING_PATTERN_DISABLE && pattern != DP_TRAINING_PATTERN_4) {
+ buf |= DP_LINK_SCRAMBLING_DISABLE;
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_PHYIF_CTRL0, HIBMC_DP_CFG_SCRAMBLE_EN, 0x1);
+ } else {
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_PHYIF_CTRL0, HIBMC_DP_CFG_SCRAMBLE_EN, 0);
+ }
+
+ switch (pattern) {
+ case DP_TRAINING_PATTERN_1:
+ val = 1;
+ break;
+ case DP_TRAINING_PATTERN_2:
+ val = 2;
+ break;
+ case DP_TRAINING_PATTERN_3:
+ val = 3;
+ break;
+ case DP_TRAINING_PATTERN_4:
+ val = 4;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ hibmc_dp_reg_write_field(dp, HIBMC_DP_PHYIF_CTRL0, HIBMC_DP_CFG_PAT_SEL, val);
+
+ ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_PATTERN_SET, &buf, sizeof(buf));
+ if (ret != sizeof(buf)) {
+ drm_dbg_dp(dp->dev, "dp aux write training pattern set failed\n");
+ return ret >= 0 ? -EIO : ret;
+ }
+
+ return 0;
+}
+
+static int hibmc_dp_link_training_cr_pre(struct hibmc_dp_dev *dp)
+{
+ u8 *train_set = dp->link.train_set;
+ int ret;
+ u8 i;
+
+ ret = hibmc_dp_link_training_configure(dp);
+ if (ret)
+ return ret;
+
+ ret = hibmc_dp_link_set_pattern(dp, DP_TRAINING_PATTERN_1);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < dp->link.cap.lanes; i++)
+ train_set[i] = DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
+
+ ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, train_set, dp->link.cap.lanes);
+ if (ret != dp->link.cap.lanes) {
+ drm_dbg_dp(dp->dev, "dp aux write training lane set failed\n");
+ return ret >= 0 ? -EIO : ret;
+ }
+
+ return 0;
+}
+
+static bool hibmc_dp_link_get_adjust_train(struct hibmc_dp_dev *dp,
+ u8 lane_status[DP_LINK_STATUS_SIZE])
+{
+ u8 train_set[HIBMC_DP_LANE_NUM_MAX] = {0};
+ u8 lane;
+
+ for (lane = 0; lane < dp->link.cap.lanes; lane++)
+ train_set[lane] = drm_dp_get_adjust_request_voltage(lane_status, lane) |
+ drm_dp_get_adjust_request_pre_emphasis(lane_status, lane);
+
+ if (memcmp(dp->link.train_set, train_set, HIBMC_DP_LANE_NUM_MAX)) {
+ memcpy(dp->link.train_set, train_set, HIBMC_DP_LANE_NUM_MAX);
+ return true;
+ }
+
+ return false;
+}
+
+static inline int hibmc_dp_link_reduce_rate(struct hibmc_dp_dev *dp)
+{
+ switch (dp->link.cap.link_rate) {
+ case DP_LINK_BW_2_7:
+ dp->link.cap.link_rate = DP_LINK_BW_1_62;
+ return 0;
+ case DP_LINK_BW_5_4:
+ dp->link.cap.link_rate = DP_LINK_BW_2_7;
+ return 0;
+ case DP_LINK_BW_8_1:
+ dp->link.cap.link_rate = DP_LINK_BW_5_4;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static inline int hibmc_dp_link_reduce_lane(struct hibmc_dp_dev *dp)
+{
+ switch (dp->link.cap.lanes) {
+ case 0x2:
+ dp->link.cap.lanes--;
+ break;
+ case 0x1:
+ drm_err(dp->dev, "dp link training reduce lane failed, already reach minimum\n");
+ return -EIO;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int hibmc_dp_link_training_cr(struct hibmc_dp_dev *dp)
+{
+ u8 lane_status[DP_LINK_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 >= DP_DPCD_REV_14 ? 10 : 80;
+
+ voltage_tries = 1;
+ for (cr_tries = 0; cr_tries < max_cr; cr_tries++) {
+ drm_dp_link_train_clock_recovery_delay(&dp->aux, dp->dpcd);
+
+ ret = drm_dp_dpcd_read_link_status(&dp->aux, lane_status);
+ if (ret != DP_LINK_STATUS_SIZE) {
+ drm_err(dp->dev, "Get lane status failed\n");
+ return ret;
+ }
+
+ if (drm_dp_clock_recovery_ok(lane_status, dp->link.cap.lanes)) {
+ 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;
+ }
+
+ level_changed = hibmc_dp_link_get_adjust_train(dp, lane_status);
+ ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, dp->link.train_set,
+ dp->link.cap.lanes);
+ if (ret != dp->link.cap.lanes) {
+ drm_dbg_dp(dp->dev, "Update link training failed\n");
+ return ret >= 0 ? -EIO : 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 hibmc_dp_link_training_channel_eq(struct hibmc_dp_dev *dp)
+{
+ u8 lane_status[DP_LINK_STATUS_SIZE] = {0};
+ u8 eq_tries;
+ int tps;
+ int ret;
+
+ if (dp->link.cap.is_tps4)
+ tps = DP_TRAINING_PATTERN_4;
+ else if (dp->link.cap.is_tps3)
+ tps = DP_TRAINING_PATTERN_3;
+ else
+ tps = DP_TRAINING_PATTERN_2;
+
+ ret = hibmc_dp_link_set_pattern(dp, tps);
+ if (ret)
+ return ret;
+
+ for (eq_tries = 0; eq_tries < HIBMC_EQ_MAX_RETRY; eq_tries++) {
+ drm_dp_link_train_channel_eq_delay(&dp->aux, dp->dpcd);
+
+ ret = drm_dp_dpcd_read_link_status(&dp->aux, lane_status);
+ if (ret != DP_LINK_STATUS_SIZE) {
+ drm_err(dp->dev, "get lane status failed\n");
+ break;
+ }
+
+ if (!drm_dp_clock_recovery_ok(lane_status, dp->link.cap.lanes)) {
+ 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;
+ }
+
+ if (drm_dp_channel_eq_ok(lane_status, dp->link.cap.lanes)) {
+ dp->link.status.channel_equalized = true;
+ drm_info(dp->dev, "dp link training eq done\n");
+ break;
+ }
+
+ hibmc_dp_link_get_adjust_train(dp, lane_status);
+ ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET,
+ dp->link.train_set, dp->link.cap.lanes);
+ if (ret != dp->link.cap.lanes) {
+ drm_dbg_dp(dp->dev, "Update link training failed\n");
+ ret = (ret >= 0) ? -EIO : ret;
+ break;
+ }
+ }
+
+ if (eq_tries == HIBMC_EQ_MAX_RETRY)
+ drm_err(dp->dev, "channel equalization failed %u times\n", eq_tries);
+
+ hibmc_dp_link_set_pattern(dp, DP_TRAINING_PATTERN_DISABLE);
+
+ return ret < 0 ? ret : 0;
+}
+
+static int hibmc_dp_link_downgrade_training_cr(struct hibmc_dp_dev *dp)
+{
+ if (hibmc_dp_link_reduce_rate(dp))
+ return hibmc_dp_link_reduce_lane(dp);
+
+ return 0;
+}
+
+static int hibmc_dp_link_downgrade_training_eq(struct hibmc_dp_dev *dp)
+{
+ if ((dp->link.status.clock_recovered && !dp->link.status.channel_equalized)) {
+ if (!hibmc_dp_link_reduce_lane(dp))
+ return 0;
+ }
+
+ return hibmc_dp_link_reduce_rate(dp);
+}
+
+int hibmc_dp_link_training(struct hibmc_dp_dev *dp)
+{
+ struct hibmc_dp_link *link = &dp->link;
+ int ret;
+
+ while (true) {
+ ret = hibmc_dp_link_training_cr_pre(dp);
+ if (ret)
+ goto err;
+
+ ret = hibmc_dp_link_training_cr(dp);
+ if (ret)
+ goto err;
+
+ if (!link->status.clock_recovered) {
+ ret = hibmc_dp_link_downgrade_training_cr(dp);
+ if (ret)
+ goto err;
+ continue;
+ }
+
+ ret = hibmc_dp_link_training_channel_eq(dp);
+ if (ret)
+ goto err;
+
+ if (!link->status.channel_equalized) {
+ ret = hibmc_dp_link_downgrade_training_eq(dp);
+ if (ret)
+ goto err;
+ continue;
+ }
+
+ return 0;
+ }
+
+err:
+ hibmc_dp_link_set_pattern(dp, DP_TRAINING_PATTERN_DISABLE);
+
+ return ret;
+}
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
index f3e6781e111a..0bd308eccdc5 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
@@ -12,16 +12,24 @@
#define HIBMC_DP_AUX_RD_DATA0 0x64
#define HIBMC_DP_AUX_REQ 0x74
#define HIBMC_DP_AUX_STATUS 0x78
+#define HIBMC_DP_PHYIF_CTRL0 0xa0
+#define HIBMC_DP_VIDEO_CTRL 0x100
#define HIBMC_DP_DPTX_RST_CTRL 0x700
+#define HIBMC_DP_DPTX_GCTL0 0x708
#define HIBMC_DP_CFG_AUX_SYNC_LEN_SEL BIT(1)
#define HIBMC_DP_CFG_AUX_TIMER_TIMEOUT BIT(2)
+#define HIBMC_DP_CFG_STREAM_FRAME_MODE BIT(6)
#define HIBMC_DP_CFG_AUX_MIN_PULSE_NUM GENMASK(13, 9)
+#define HIBMC_DP_CFG_LANE_DATA_EN GENMASK(11, 8)
+#define HIBMC_DP_CFG_PHY_LANE_NUM GENMASK(2, 1)
#define HIBMC_DP_CFG_AUX_REQ BIT(0)
#define HIBMC_DP_CFG_AUX_RST_N BIT(4)
#define HIBMC_DP_CFG_AUX_TIMEOUT BIT(0)
#define HIBMC_DP_CFG_AUX_READY_DATA_BYTE GENMASK(16, 12)
#define HIBMC_DP_CFG_AUX GENMASK(24, 17)
#define HIBMC_DP_CFG_AUX_STATUS GENMASK(11, 4)
+#define HIBMC_DP_CFG_SCRAMBLE_EN BIT(0)
+#define HIBMC_DP_CFG_PAT_SEL GENMASK(7, 4)
#endif
--
2.33.0
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