Re: [PATCH v3 drm-dp 7/8] drm/hisilicon/hibmc: Enable this hot plug detect of irq feature

[Yongbang Shi <shiyongbang@huawei.com>]

> On Sat, Feb 22, 2025 at 10:51:00AM +0800, Yongbang Shi wrote:
>> From: Baihan Li <libaihan@huawei.com>
>>
>> Enable HPD feature and add its isr and event function. Add a drm client
>> dev and realized the hotplug callback in it.
> What for? There should be no need to add a separate drm client just for
> the hotplug.
>
>> Signed-off-by: Baihan Li <libaihan@huawei.com>
>> Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
>> ---
>> ChangeLog:
>> v2 -> v3:
>>    - remove mdelay(100) hpd function in ISR, suggested by Dmitry Baryshkov.
>>    - remove enble_display in ISR, suggested by Dmitry Baryshkov.
>>    - change drm_kms_helper_connector_hotplug_event() to
>>      drm_connector_helper_hpd_irq_event(), suggested by Dmitry Baryshkov.
>>    - move macros to dp_reg.h, suggested by Dmitry Baryshkov.
>>    - remove struct irqs, suggested by Dmitry Baryshkov.
>>    - split this patch into two parts, suggested by Dmitry Baryshkov.
>>    - add a drm client dev to handle HPD event.
>> v1 -> v2:
>>    - optimizing the description in commit message, suggested by Dmitry Baryshkov.
>>    - add mdelay(100) comments, suggested by Dmitry Baryshkov.
>>    - deleting display enable in hpd event, suggested by Dmitry Baryshkov.
>> ---
>>   .../gpu/drm/hisilicon/hibmc/dp/dp_config.h    |  1 +
>>   drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c    | 22 +++++++
>>   drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h    |  6 ++
>>   .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c    | 61 +++++++++++++++++++
>>   .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h   |  2 +
>>   5 files changed, 92 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h
>> index c5feef8dc27d..08f9e1caf7fc 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h
>> @@ -16,5 +16,6 @@
>>   #define HIBMC_DP_SYNC_EN_MASK		0x3
>>   #define HIBMC_DP_LINK_RATE_CAL		27
>>   #define HIBMC_DP_SYNC_DELAY(lanes)	((lanes) == 0x2 ? 86 : 46)
>> +#define HIBMC_DP_INT_ENABLE		0xc
>>   
>>   #endif
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
>> index a921b98dbf50..b2116395b8dd 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
>> @@ -182,6 +182,7 @@ int hibmc_dp_hw_init(struct hibmc_dp *dp)
>>   	/* int init */
>>   	writel(0, dp_dev->base + HIBMC_DP_INTR_ENABLE);
>>   	writel(HIBMC_DP_INT_RST, dp_dev->base + HIBMC_DP_INTR_ORIGINAL_STATUS);
>> +	writel(HIBMC_DP_INT_ENABLE, dp_dev->base + HIBMC_DP_INTR_ENABLE);
>>   	/* rst */
>>   	writel(HIBMC_DP_DPTX_RST, dp_dev->base + HIBMC_DP_DPTX_RST_CTRL);
>>   	/* clock enable */
>> @@ -190,6 +191,21 @@ int hibmc_dp_hw_init(struct hibmc_dp *dp)
>>   	return 0;
>>   }
>>   
>> +void hibmc_dp_hpd_cfg(struct hibmc_dp *dp)
>> +{
>> +	struct hibmc_dp_dev *dp_dev = dp->dp_dev;
>> +
>> +	hibmc_dp_reg_write_field(dp_dev, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_SYNC_LEN_SEL, 0x0);
>> +	hibmc_dp_reg_write_field(dp_dev, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_TIMER_TIMEOUT, 0x1);
>> +	hibmc_dp_reg_write_field(dp->dp_dev, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_MIN_PULSE_NUM, 0x9);
>> +	writel(HIBMC_DP_HDCP, dp_dev->base + HIBMC_DP_HDCP_CFG);
>> +	writel(0, dp_dev->base + HIBMC_DP_INTR_ENABLE);
>> +	writel(HIBMC_DP_INT_RST, dp_dev->base + HIBMC_DP_INTR_ORIGINAL_STATUS);
>> +	writel(HIBMC_DP_INT_ENABLE, dp_dev->base + HIBMC_DP_INTR_ENABLE);
>> +	writel(HIBMC_DP_DPTX_RST, dp_dev->base + HIBMC_DP_DPTX_RST_CTRL);
>> +	writel(HIBMC_DP_CLK_EN, dp_dev->base + HIBMC_DP_DPTX_CLK_CTRL);
>> +}
>> +
>>   void hibmc_dp_display_en(struct hibmc_dp *dp, bool enable)
>>   {
>>   	struct hibmc_dp_dev *dp_dev = dp->dp_dev;
>> @@ -228,6 +244,12 @@ int hibmc_dp_mode_set(struct hibmc_dp *dp, struct drm_display_mode *mode)
>>   	return 0;
>>   }
>>   
>> +void hibmc_dp_reset_link(struct hibmc_dp *dp)
>> +{
>> +	dp->dp_dev->link.status.clock_recovered = false;
>> +	dp->dp_dev->link.status.channel_equalized = false;
> Could you please point out, where the link rate and number of lanes are
> reset?

Thanks for your reminder, I will reset link rate and lanes here too.


>> +}
>> +
>>   static const struct hibmc_dp_color_raw g_rgb_raw[] = {
>>   	{CBAR_COLOR_BAR, 0x000, 0x000, 0x000},
>>   	{CBAR_WHITE,     0xfff, 0xfff, 0xfff},
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
>> index 83a53dae8012..a55d66d53966 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
>> @@ -11,6 +11,7 @@
>>   #include <drm/drm_connector.h>
>>   #include <drm/drm_print.h>
>>   #include <drm/display/drm_dp_helper.h>
>> +#include <drm/drm_client.h>
>>   
>>   struct hibmc_dp_dev;
>>   
>> @@ -49,11 +50,16 @@ struct hibmc_dp {
>>   	void __iomem *mmio;
>>   	struct drm_dp_aux aux;
>>   	struct hibmc_dp_cbar_cfg cfg;
>> +	u32 irq_status;
>> +	u32 hpd_status;
>> +	struct drm_client_dev client;
>>   };
>>   
>>   int hibmc_dp_hw_init(struct hibmc_dp *dp);
>>   int hibmc_dp_mode_set(struct hibmc_dp *dp, struct drm_display_mode *mode);
>>   void hibmc_dp_display_en(struct hibmc_dp *dp, bool enable);
>>   void hibmc_dp_set_cbar(struct hibmc_dp *dp, const struct hibmc_dp_cbar_cfg *cfg);
>> +void hibmc_dp_reset_link(struct hibmc_dp *dp);
>> +void hibmc_dp_hpd_cfg(struct hibmc_dp *dp);
>>   
>>   #endif
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>> index a7f611e82f73..40a3ebb8ac4b 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>> @@ -9,10 +9,13 @@
>>   #include <drm/drm_modes.h>
>>   #include <drm/drm_drv.h>
>>   #include <drm/drm_edid.h>
>> +#include <drm/drm_client.h>
>>   
>>   #include "hibmc_drm_drv.h"
>>   #include "dp/dp_hw.h"
>>   
>> +#define DP_MASKED_SINK_HPD_PLUG_INT	BIT(2)
>> +
>>   static int hibmc_dp_connector_get_modes(struct drm_connector *connector)
>>   {
>>   	struct hibmc_dp *dp = to_hibmc_dp(connector);
>> @@ -98,6 +101,58 @@ static const struct drm_encoder_helper_funcs hibmc_dp_encoder_helper_funcs = {
>>   	.atomic_disable = hibmc_dp_encoder_disable,
>>   };
>>   
>> +irqreturn_t hibmc_dp_hpd_isr(int irq, void *arg)
>> +{
>> +	struct drm_device *dev = (struct drm_device *)arg;
>> +	struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
>> +	int idx;
>> +
>> +	if (!drm_dev_enter(dev, &idx))
>> +		return -ENODEV;
>> +
>> +	if (priv->dp.irq_status & DP_MASKED_SINK_HPD_PLUG_INT) {
>> +		drm_dbg_dp(&priv->dev, "HPD IN isr occur!\n");
>> +		priv->dp.hpd_status = 1;
>> +	} else {
>> +		drm_dbg_dp(&priv->dev, "HPD OUT isr occur!\n");
>> +		priv->dp.hpd_status = 0;
>> +	}
>> +
>> +	if (dev->registered)
>> +		drm_connector_helper_hpd_irq_event(&priv->dp.connector);
>> +
>> +	drm_dev_exit(idx);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int hibmc_dp_hpd_event(struct drm_client_dev *client)
>> +{
>> +	struct hibmc_dp *dp = container_of(client, struct hibmc_dp, client);
>> +	struct hibmc_drm_private *priv = to_hibmc_drm_private(dp->drm_dev);
>> +	struct drm_display_mode *mode = &priv->crtc.state->adjusted_mode;
>> +	int ret;
>> +
>> +	if (dp->hpd_status) {
>> +		hibmc_dp_hpd_cfg(&priv->dp);
>> +		ret = hibmc_dp_prepare(dp, mode);
>> +		if (ret)
>> +			return ret;
>> +
>> +		hibmc_dp_display_en(dp, true);
>> +	} else {
>> +		hibmc_dp_display_en(dp, false);
>> +		hibmc_dp_reset_link(&priv->dp);
>> +	}
> If I understand this correctly, you are using a separate drm_client to
> enable and disable the link & display. Why is it necessary? Existing
> drm_clients and userspace compositors use drm framework, they should be
> able to turn the display on and off as required.
>
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct drm_client_funcs hibmc_dp_client_funcs = {
>> +	.hotplug = hibmc_dp_hpd_event,
>> +	.unregister = drm_client_release,
>> +};
>> +
>>   int hibmc_dp_init(struct hibmc_drm_private *priv)
>>   {
>>   	struct drm_device *dev = &priv->dev;
>> @@ -138,5 +193,11 @@ int hibmc_dp_init(struct hibmc_drm_private *priv)
>>   
>>   	drm_connector_attach_encoder(connector, encoder);
>>   
>> +	ret = drm_client_init(dev, &dp->client, "hibmc-DP-HPD", &hibmc_dp_client_funcs);
>> +	if (ret)
>> +		return ret;
>> +
>> +	drm_client_register(&dp->client);
>> +
>>   	return 0;
>>   }
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>> index bc89e4b9f4e3..daed1330b961 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>> @@ -71,4 +71,6 @@ int hibmc_dp_init(struct hibmc_drm_private *priv);
>>   
>>   void hibmc_debugfs_init(struct drm_connector *connector, struct dentry *root);
>>   
>> +irqreturn_t hibmc_dp_hpd_isr(int irq, void *arg);
>> +
>>   #endif
>> -- 
>> 2.33.0
>>