Re: [PATCH v2 drm-dp 7/7] drm/hisilicon/hibmc: Enable this hot plug detect of irq feature

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On Mon, Feb 10, 2025 at 10:49:59PM +0800, Yongbang Shi wrote:
From: Baihan Li <libaihan@xxxxxxxxxx>

To realize HPD feature, we have getting hpd status function, registering
irq function, interrupt handler function, and hpd event process function.
And also we use pci_alloc_irq_vectors() to get our msi irq, because we have
two interrupts now.

Signed-off-by: Baihan Li <libaihan@xxxxxxxxxx>
Signed-off-by: Yongbang Shi <shiyongbang@xxxxxxxxxx>
---
ChangeLog:
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    | 33 ++++++++
  drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h    | 13 ++++
  drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h   |  2 +
  .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c    | 57 +++++++++++++-
  .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c   | 78 +++++++++++++++----
  .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h   | 14 ++++
  7 files changed, 181 insertions(+), 17 deletions(-)

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 5e889c377117..0b6ce48c5d8f 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
@@ -181,6 +181,7 @@ 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 */
@@ -284,3 +285,35 @@ void hibmc_dp_set_cbar(struct hibmc_dp *dp, const struct hibmc_dp_cbar_cfg *cfg)
  	hibmc_dp_reg_write_field(dp_dev, HIBMC_DP_COLOR_BAR_CTRL, BIT(0), cfg->enable);
  	writel(HIBMC_DP_SYNC_EN_MASK, dp_dev->base + HIBMC_DP_TIMING_SYNC_CTRL);
  }
+
+enum hibmc_dp_hpd_status hibmc_dp_get_hpd_status(const struct hibmc_dp *dp)
+{
+	enum hibmc_dp_hpd_status status;
+	u32 val;
+
+	/* spec said the HPD signal needs to be pulled up for
+	 * more than 100 ms to enter the plug status
+	 */
+	mdelay(100);
Please check that your code doesn't break with CONFIG_DEBUG_ATOMIC_SLEEP=y

Having a 100msec delay in the ISR handler is a really sad idea. Don't
you have HPD debouncing handled in the hardware?

+
+	val = readl(dp->dp_dev->base + HIBMC_DP_HPD_STATUS);
+	val = (val & HIBMC_DP_CFG_SINK_HPD_STATE_MACHINE) >> 4;
+
+	switch (val) {
+	case 0: /* 0: IDLE */
+	case 3: /* 3: DONE */
+		status = HIBMC_DP_HPD_OUT;
+		break;
+	case 1: /* 1: PLUG */
+		status = HIBMC_DP_HPD_IN;
+		break;
+	case 4: /* 4: ASSERT_LENGHT */
+		status = HIBMC_DP_HPD_DETECTING;
+		break;
+	default: /* unknown status */
+		status = HIBMC_DP_HPD_DET_FAIL;
+		break;
+	}
Is there a way to detect a short pulse on the HPD line aka attention?
You have defined HIBMC_DP_HPD_SHORT below, but it is not being assigned
at all.

Okay, I'll fix this funciton.


+
+	return status;
+}
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
index 823544b8008b..df7b692b1998 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
@@ -41,6 +41,17 @@ struct hibmc_dp_cbar_cfg {
  	enum hibmc_dp_cbar_pattern pattern;
  };
+enum hibmc_dp_hpd_status {
+	HIBMC_DP_HPD_DETECTING,
+	HIBMC_DP_HPD_IN,
+	HIBMC_DP_HPD_OUT,
+	HIBMC_DP_HPD_SHORT, /* Short hpd (irq_hpd) */
+	HIBMC_DP_HPD_DET_FAIL,
+	HIBMC_DP_HPD_IN_SIMULATE,
+	HIBMC_DP_HPD_OUT_SIMULATE,
+	HIBMC_DP_HPD_SHORT_SIMULATE,
+};
+
  struct hibmc_dp {
  	struct hibmc_dp_dev *dp_dev;
  	struct drm_device *drm_dev;
@@ -49,6 +60,7 @@ struct hibmc_dp {
  	void __iomem *mmio;
  	struct drm_dp_aux aux;
  	struct hibmc_dp_cbar_cfg cfg;
+	u32 hpd_status;
  };
int hibmc_dp_hw_init(struct hibmc_dp *dp);
@@ -58,5 +70,6 @@ int hibmc_dp_get_dpcd(struct hibmc_dp *dp);
  u8 hibmc_dp_get_link_rate(struct hibmc_dp *dp);
  u8 hibmc_dp_get_lanes(struct hibmc_dp *dp);
  void hibmc_dp_set_cbar(struct hibmc_dp *dp, const struct hibmc_dp_cbar_cfg *cfg);
+enum hibmc_dp_hpd_status hibmc_dp_get_hpd_status(const struct hibmc_dp *dp);
#endif
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
index c43ad6b30c2c..6c4ba0412b15 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
@@ -12,6 +12,7 @@
  #define HIBMC_DP_AUX_RD_DATA0			0x64
  #define HIBMC_DP_AUX_REQ			0x74
  #define HIBMC_DP_AUX_STATUS			0x78
+#define HIBMC_DP_HPD_STATUS			0x98
  #define HIBMC_DP_PHYIF_CTRL0			0xa0
  #define HIBMC_DP_VIDEO_CTRL			0x100
  #define HIBMC_DP_VIDEO_CONFIG0			0x104
@@ -75,5 +76,6 @@
  #define HIBMC_DP_CFG_STREAM_HTOTAL_SIZE		GENMASK(31, 16)
  #define HIBMC_DP_CFG_STREAM_HBLANK_SIZE		GENMASK(15, 0)
  #define HIBMC_DP_CFG_STREAM_SYNC_CALIBRATION	GENMASK(31, 20)
+#define HIBMC_DP_CFG_SINK_HPD_STATE_MACHINE	GENMASK(7, 4)
#endif
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
index 1f8f7b74f5b4..057dd3caa043 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
@@ -11,8 +11,12 @@
  #include <drm/drm_edid.h>
#include "hibmc_drm_drv.h"
+#include "hibmc_drm_regs.h"
  #include "dp/dp_hw.h"
+#define DP_MASKED_SINK_HPD_UNPLUG_INT BIT(3)
+#define DP_MASKED_SINK_HPD_PLUG_INT	BIT(2)
+
  static const struct drm_connector_helper_funcs hibmc_dp_conn_helper_funcs = {
  	.get_modes = drm_connector_helper_get_modes,
  	.detect_ctx = drm_connector_helper_detect_from_ddc,
@@ -81,6 +85,53 @@ static const struct drm_encoder_helper_funcs hibmc_dp_encoder_helper_funcs = {
  	.atomic_disable = hibmc_dp_encoder_disable,
  };
+static int hibmc_dp_cfg(struct hibmc_dp *dp)
+{
+	int ret;
+
+	ret = hibmc_dp_hw_init(dp);
+	if (ret)
+		return ret;
+
+	hibmc_dp_display_en(dp, false);
Does this enable video signal? You should only enable AUX and perform
link training at this point.

It's a switch function, the parameter false.
Also I can change the function name.


+
+	return 0;
+}
+
+irqreturn_t hibmc_dp_hpd_event_isr(int irq, void *arg)
+{
+	struct drm_device *dev = (struct drm_device *)arg;
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
+	enum hibmc_dp_hpd_status status;
+	int idx;
+
+	if (!drm_dev_enter(dev, &idx))
+		return -ENODEV;
+
+	status  = hibmc_dp_get_hpd_status(&priv->dp);
+	if (status == HIBMC_DP_HPD_IN) {
+		if (!(priv->dp.hpd_status & DP_MASKED_SINK_HPD_PLUG_INT))
+			goto err;
+		drm_dbg_dp(&priv->dev, "HPD IN isr occur!\n");
+		hibmc_dp_cfg(&priv->dp);
+		drm_kms_helper_connector_hotplug_event(&priv->dp.connector);
+	} else if (status == HIBMC_DP_HPD_OUT) {
+		if (!(priv->dp.hpd_status & DP_MASKED_SINK_HPD_UNPLUG_INT))
+			goto err;
+		drm_dbg_dp(&priv->dev, "HPD OUT isr occur!\n");
+		drm_kms_helper_connector_hotplug_event(&priv->dp.connector);
This looks like a hand-coded drm_connector_helper_hpd_irq_event()

Ok. I will change to it.


+	} else {
+		drm_warn(&priv->dev, "HPD unknown isr occur, status: %d\n", status);
+	}
+
+err:
+	priv->dp.hpd_status = 0;
+
+	drm_dev_exit(idx);
+
+	return IRQ_HANDLED;
+}
+
  int hibmc_dp_init(struct hibmc_drm_private *priv)
  {
  	struct drm_device *dev = &priv->dev;
@@ -93,14 +144,12 @@ int hibmc_dp_init(struct hibmc_drm_private *priv)
  	dp->mmio = priv->mmio;
  	dp->drm_dev = dev;
- ret = hibmc_dp_hw_init(&priv->dp);
+	ret = hibmc_dp_cfg(dp);
  	if (ret) {
-		drm_err(dev, "hibmc dp hw init failed: %d\n", ret);
+		drm_err(dev, "hibmc dp cfg failed: %d\n", ret);
  		return ret;
  	}
- hibmc_dp_display_en(&priv->dp, false);
-
  	encoder->possible_crtcs = drm_crtc_mask(crtc);
  	ret = drmm_encoder_init(dev, encoder, NULL, DRM_MODE_ENCODER_TMDS, NULL);
  	if (ret) {
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index bade693d9730..199acb3e7a73 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -29,9 +29,13 @@
  #include "hibmc_drm_regs.h"
#define HIBMC_DP_HOST_SERDES_CTRL 0x1f001c
+#define HIBMC_DP_INTSTAT		0x1e0724
+#define HIBMC_DP_INTCLR			0x1e0728
Why are those defined outside of hibmc_drm_regs.h?

Ok, I will fix it.


DEFINE_DRM_GEM_FOPS(hibmc_fops); +static const char *g_irqs_names_map[HIBMC_MAX_VECTORS] = { "vblank", "hpd" };
+
  static irqreturn_t hibmc_interrupt(int irq, void *arg)
  {
  	struct drm_device *dev = (struct drm_device *)arg;
@@ -49,6 +53,22 @@ static irqreturn_t hibmc_interrupt(int irq, void *arg)
  	return IRQ_HANDLED;
  }
+static irqreturn_t hibmc_dp_interrupt(int irq, void *arg)
+{
+	struct drm_device *dev = (struct drm_device *)arg;
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
+	u32 status;
+
+	status = readl(priv->mmio + HIBMC_DP_INTSTAT);
+	if (status) {
+		priv->dp.hpd_status = status;
+		writel(status, priv->mmio + HIBMC_DP_INTCLR);
+		return IRQ_WAKE_THREAD;
+	}
+
+	return IRQ_HANDLED;
+}
+
  static int hibmc_dumb_create(struct drm_file *file, struct drm_device *dev,
  			     struct drm_mode_create_dumb *args)
  {
@@ -248,15 +268,52 @@ static int hibmc_hw_init(struct hibmc_drm_private *priv)
  	return 0;
  }
-static int hibmc_unload(struct drm_device *dev)
+static void hibmc_unload(struct drm_device *dev)
+{
+	drm_atomic_helper_shutdown(dev);
+
+	pci_disable_msi(to_pci_dev(dev->dev));
+}
+
+static int hibmc_msi_init(struct drm_device *dev)
  {
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
  	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	int ret;
- drm_atomic_helper_shutdown(dev);
+	ret = pci_alloc_irq_vectors(pdev, HIBMC_MIN_VECTORS,
+				    HIBMC_MAX_VECTORS, PCI_IRQ_MSI);
+	if (ret < 0) {
+		drm_err(dev, "enabling MSI failed: %d\n", ret);
+		return ret;
+	}
- free_irq(pdev->irq, dev);
+	priv->valid_irq_num = ret;
- pci_disable_msi(to_pci_dev(dev->dev));
+	priv->irqs = drmm_kcalloc(dev, priv->valid_irq_num,
+				  sizeof(struct hibmc_irq), GFP_KERNEL);
Why do you need an extra pointer?  You know that there are no more than
HIBMC_MAX_VECTORS, so you can have this data as a part of your private
structure.

Ok.


+	if (!priv->irqs)
+		return -ENOMEM;
+
+	for (int i = 0; i < priv->valid_irq_num; i++) {
+		snprintf(priv->irqs[i].name, sizeof(priv->irqs[i].name) - 1, "%s-%s-%s",
+			 dev->driver->name, pci_name(pdev), g_irqs_names_map[i]);
+
+		priv->irqs[i].irq_num = pci_irq_vector(pdev, i);
+
+		if (i)
+			/* PCI devices require shared interrupts. */
+			ret = devm_request_threaded_irq(&pdev->dev, priv->irqs[i].irq_num,
+							hibmc_dp_interrupt, hibmc_dp_hpd_event_isr,
+							IRQF_SHARED, priv->irqs[i].name, dev);
+		else
+			ret = devm_request_irq(&pdev->dev, priv->irqs[i].irq_num, hibmc_interrupt,
+					       IRQF_SHARED, priv->irqs[i].name, dev);
This feels like "too many changes". You have MSI-related changes, devm_,
your HPD interrupt. Please split this patch into logical parts.

Alright, I'll fix them and split it, thanks.


+		if (ret) {
+			drm_err(dev, "install irq failed: %d\n", ret);
+			return ret;
+		}
+	}
return 0;
  }
@@ -288,15 +345,10 @@ static int hibmc_load(struct drm_device *dev)
  		goto err;
  	}
- ret = pci_enable_msi(pdev);
+	ret = hibmc_msi_init(dev);
  	if (ret) {
-		drm_warn(dev, "enabling MSI failed: %d\n", ret);
-	} else {
-		/* PCI devices require shared interrupts. */
-		ret = request_irq(pdev->irq, hibmc_interrupt, IRQF_SHARED,
-				  dev->driver->name, dev);
-		if (ret)
-			drm_warn(dev, "install irq failed: %d\n", ret);
+		drm_err(dev, "hibmc msi init failed, ret:%d\n", ret);
+		goto err;
  	}
/* reset all the states of crtc/plane/encoder/connector */
@@ -372,7 +424,7 @@ static void hibmc_pci_remove(struct pci_dev *pdev)
static void hibmc_pci_shutdown(struct pci_dev *pdev)
  {
-	drm_atomic_helper_shutdown(pci_get_drvdata(pdev));
+	hibmc_pci_remove(pdev);
  }
static const struct pci_device_id hibmc_pci_table[] = {
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
index bc89e4b9f4e3..764e211a8779 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
@@ -22,6 +22,14 @@
#include "dp/dp_hw.h" +#define HIBMC_MIN_VECTORS 1
+#define HIBMC_MAX_VECTORS	2
+
+struct hibmc_irq {
+	s32 irq_num;
+	char name[32];
+};
+
  struct hibmc_vdac {
  	struct drm_device *dev;
  	struct drm_encoder encoder;
@@ -40,6 +48,10 @@ struct hibmc_drm_private {
  	struct drm_crtc crtc;
  	struct hibmc_vdac vdac;
  	struct hibmc_dp dp;
+
+	/* irqs */
+	struct hibmc_irq *irqs;
+	u32 valid_irq_num;
  };
static inline struct hibmc_vdac *to_hibmc_vdac(struct drm_connector *connector)
@@ -71,4 +83,6 @@ 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_event_isr(int irq, void *arg);
+
  #endif
--
2.33.0




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