Re: [PATCH v1 drm-dp 4/4] drm/hisilicon/hibmc: Enable this hot plug detect of irq feature

From: Yongbang Shi
Date: Wed Feb 05 2025 - 03:56:40 EST

On Mon, Jan 27, 2025 at 11:20:24AM +0800, Yongbang Shi wrote:
From: Baihan Li <libaihan@xxxxxxxxxx>

This is a series of functions about getting dp connector status
function, registering irq function, interrupt handler function, and
hpd event process function to realize DP HPD feature.
Please follow the Documentation/process/submit-checklist.rst. Start with
the problem description, then describe what is being done.

Also, does it make sense to implement the enable_hpd() and disable_hpd()
callbacks for your connector?

Hi Dmitry,

Thanks for your advising! I will check and fix this description problem in all the patches.

I think our chip comes with this hpd feature, and I can't find a reason why we need to disable it,
or is there some place that is useful?


Signed-off-by: Baihan Li <libaihan@xxxxxxxxxx>
Signed-off-by: Yongbang Shi <shiyongbang@xxxxxxxxxx>
---
.../gpu/drm/hisilicon/hibmc/dp/dp_config.h | 1 +
drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 30 +++++++
drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h | 2 +
drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h | 2 +
.../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c | 61 ++++++++++++++-
.../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 78 +++++++++++++++----
.../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h | 14 ++++
7 files changed, 171 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 9c8b91ff0e3b..1797b40e54fc 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 +285,32 @@ 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;
+
+ mdelay(100);

why?

Because the spec says the HPD signal needs to be pulled up for more than 100 ms to enter the plug from the ilde.

I will add comment here.


+
+ 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;
+ }
+
+ 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 f2f59f2feb3c..6f1da7a0b9e7 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
@@ -61,6 +61,7 @@ struct hibmc_dp {
struct drm_dp_aux aux;
struct hibmc_dp_cbar_cfg cfg;
bool is_inited;
+ u32 hpd_status;
};
int hibmc_dp_hw_init(struct hibmc_dp *dp);
@@ -70,5 +71,6 @@ 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 cc1f9ee0656f..e4aee75e12e8 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 int hibmc_dp_connector_get_modes(struct drm_connector *connector)
{
struct hibmc_dp *dp = to_hibmc_dp(connector);
@@ -106,6 +110,57 @@ 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);
+
+ 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;
+ struct drm_display_mode *mode;
+ 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);
+ mode = &priv->crtc.state->adjusted_mode;
+ hibmc_dp_prepare(&priv->dp, mode);
+ hibmc_dp_display_en(&priv->dp, true);
No, please don't enable the display without the framework telling you to
do so.

Okay, I got it, but I can't find a callback to process these set_mode and enable functions after the interrupt
triggered. How can I let the framework know the irq process is done, and it's ready to enable display again?


+ } 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");
+ hibmc_dp_display_en(&priv->dp, false);
+ } 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;
@@ -118,14 +173,12 @@ 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 3d4d5185c523..42323ff89309 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
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);
+ 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);
+ 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 */
@@ -375,7 +427,7 @@ 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 ff61efb8a2ab..3bc4194689cb 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_register(struct hibmc_drm_private *priv);
+irqreturn_t hibmc_dp_hpd_event_isr(int irq, void *arg);
+
#endif
--
2.33.0