linux-kernel - Re: [PATCH v6 drm-dp 2/5] drm/hisilicon/hibmc: add dp link moduel in hibmc

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Message-ID: <bca38499-5479-4edc-9cea-217f3164258b@huawei.com>
Date: Mon, 9 Dec 2024 22:24:41 +0800
From: Yongbang Shi <shiyongbang@...wei.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC: <xinliang.liu@...aro.org>, <tiantao6@...ilicon.com>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <daniel@...ll.ch>,
	<kong.kongxinwei@...ilicon.com>, <liangjian010@...wei.com>,
	<chenjianmin@...wei.com>, <lidongming5@...wei.com>, <libaihan@...wei.com>,
	<shenjian15@...wei.com>, <shaojijie@...wei.com>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
	<shiyongbang@...wei.com>
Subject: Re: [PATCH v6 drm-dp 2/5] drm/hisilicon/hibmc: add dp link moduel in
 hibmc

> On Mon, Dec 02, 2024 at 09:13:19PM +0800, Yongbang Shi wrote:
>> From: baihan li <libaihan@...wei.com>
>>
>> Add link training process functions in this moduel.
>>
>> Signed-off-by: Baihan Li <libaihan@...wei.com>
>> Signed-off-by: Yongbang Shi <shiyongbang@...wei.com>
>> ---
>> Changelog:
>> v5 -> v6:
>>    - using drm_dbg_dp() to print debug info instead of drm_info(), suggested by Dmitry Baryshkov.
>> 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@...el.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@...el.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 7d3cd32393c0..8422999acbf0 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;
> These two fields are set neither in this patch nor in any of the
> following patches.

Hi Dmitry,
Thanks for your carefully and patiently reviewing. These two will be assigned when edid is acquired,
so I accept and delete them in this patch, and I will add them in next series.

Sincerely，
Baihan Li


>> +};
>> +
> [...]
>
>> +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;
> DP_SPREAD_AMP_0_5
>
>> +	buf[1] = 0x1;
> DP_SET_ANSI_8B10B
>
>> +	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;
>> +}
>> +