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Message-Id: <20240315230916.1759060-4-sean.anderson@linux.dev>
Date: Fri, 15 Mar 2024 19:09:13 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
dri-devel@...ts.freedesktop.org
Cc: David Airlie <airlied@...il.com>,
linux-kernel@...r.kernel.org,
Michal Simek <michal.simek@....com>,
linux-arm-kernel@...ts.infradead.org,
Daniel Vetter <daniel@...ll.ch>,
Sean Anderson <sean.anderson@...ux.dev>
Subject: [PATCH 3/6] drm: zynqmp_dp: Add locking
Add some locking, since none is provided by the drm subsystem. This will
prevent the IRQ/workers/bridge API calls from stepping on each other's
toes.
Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
---
drivers/gpu/drm/xlnx/zynqmp_dp.c | 59 +++++++++++++++++++++++---------
1 file changed, 42 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 8635b5673386..d2dee58e7bf2 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -279,6 +279,7 @@ struct zynqmp_dp_config {
* @dpsub: Display subsystem
* @iomem: device I/O memory for register access
* @reset: reset controller
+ * @lock: Mutex protecting this struct and register access (but not AUX)
* @irq: irq
* @bridge: DRM bridge for the DP encoder
* @next_bridge: The downstream bridge
@@ -299,6 +300,7 @@ struct zynqmp_dp {
struct zynqmp_dpsub *dpsub;
void __iomem *iomem;
struct reset_control *reset;
+ struct mutex lock;
int irq;
struct drm_bridge bridge;
@@ -308,7 +310,7 @@ struct zynqmp_dp {
struct drm_dp_aux aux;
struct phy *phy[ZYNQMP_DP_MAX_LANES];
u8 num_lanes;
- struct delayed_work hpd_work;
+ struct delayed_work hpd_work, hpd_irq_work;
enum drm_connector_status status;
bool enabled;
@@ -1371,8 +1373,10 @@ zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
}
/* Check with link rate and lane count */
+ mutex_lock(&dp->lock);
rate = zynqmp_dp_max_rate(dp->link_config.max_rate,
dp->link_config.max_lanes, dp->config.bpp);
+ mutex_unlock(&dp->lock);
if (mode->clock > rate) {
dev_dbg(dp->dev, "filtered mode %s for high pixel rate\n",
mode->name);
@@ -1399,6 +1403,7 @@ static void zynqmp_dp_bridge_atomic_enable(struct drm_bridge *bridge,
pm_runtime_get_sync(dp->dev);
+ mutex_lock(&dp->lock);
zynqmp_dp_disp_enable(dp, old_bridge_state);
/*
@@ -1459,6 +1464,7 @@ static void zynqmp_dp_bridge_atomic_enable(struct drm_bridge *bridge,
zynqmp_dp_write(dp, ZYNQMP_DP_SOFTWARE_RESET,
ZYNQMP_DP_SOFTWARE_RESET_ALL);
zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 1);
+ mutex_unlock(&dp->lock);
}
static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
@@ -1466,6 +1472,7 @@ static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
{
struct zynqmp_dp *dp = bridge_to_dp(bridge);
+ mutex_lock(&dp->lock);
dp->enabled = false;
cancel_delayed_work(&dp->hpd_work);
zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 0);
@@ -1476,6 +1483,7 @@ static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CONTROL, 0);
zynqmp_dp_disp_disable(dp, old_bridge_state);
+ mutex_unlock(&dp->lock);
pm_runtime_put_sync(dp->dev);
}
@@ -1518,6 +1526,8 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid
u32 state, i;
int ret;
+ mutex_lock(&dp->lock);
+
/*
* This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to
* get the HPD signal with some monitors.
@@ -1545,11 +1555,13 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid
dp->num_lanes);
dp->status = connector_status_connected;
+ mutex_unlock(&dp->lock);
return connector_status_connected;
}
disconnected:
dp->status = connector_status_disconnected;
+ mutex_unlock(&dp->lock);
return connector_status_disconnected;
}
@@ -1611,6 +1623,29 @@ static void zynqmp_dp_hpd_work_func(struct work_struct *work)
drm_bridge_hpd_notify(&dp->bridge, status);
}
+static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work)
+{
+ struct zynqmp_dp *dp = container_of(work, struct zynqmp_dp,
+ hpd_irq_work.work);
+ u8 status[DP_LINK_STATUS_SIZE + 2];
+ int err;
+
+ mutex_lock(&dp->lock);
+ err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
+ DP_LINK_STATUS_SIZE + 2);
+ if (err < 0) {
+ dev_dbg_ratelimited(dp->dev,
+ "could not read sink status: %d\n", err);
+ } else {
+ if (status[4] & DP_LINK_STATUS_UPDATED ||
+ !drm_dp_clock_recovery_ok(&status[2], dp->mode.lane_cnt) ||
+ !drm_dp_channel_eq_ok(&status[2], dp->mode.lane_cnt)) {
+ zynqmp_dp_train_loop(dp);
+ }
+ }
+ mutex_unlock(&dp->lock);
+}
+
static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
{
struct zynqmp_dp *dp = (struct zynqmp_dp *)data;
@@ -1635,23 +1670,9 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
if (status & ZYNQMP_DP_INT_HPD_EVENT)
schedule_delayed_work(&dp->hpd_work, 0);
- if (status & ZYNQMP_DP_INT_HPD_IRQ) {
- int ret;
- u8 status[DP_LINK_STATUS_SIZE + 2];
+ if (status & ZYNQMP_DP_INT_HPD_IRQ)
+ schedule_delayed_work(&dp->hpd_irq_work, 0);
- ret = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
- DP_LINK_STATUS_SIZE + 2);
- if (ret < 0)
- goto handled;
-
- if (status[4] & DP_LINK_STATUS_UPDATED ||
- !drm_dp_clock_recovery_ok(&status[2], dp->mode.lane_cnt) ||
- !drm_dp_channel_eq_ok(&status[2], dp->mode.lane_cnt)) {
- zynqmp_dp_train_loop(dp);
- }
- }
-
-handled:
return IRQ_HANDLED;
}
@@ -1674,8 +1695,10 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub)
dp->dev = &pdev->dev;
dp->dpsub = dpsub;
dp->status = connector_status_disconnected;
+ mutex_init(&dp->lock);
INIT_DELAYED_WORK(&dp->hpd_work, zynqmp_dp_hpd_work_func);
+ INIT_DELAYED_WORK(&dp->hpd_irq_work, zynqmp_dp_hpd_irq_work_func);
/* Acquire all resources (IOMEM, IRQ and PHYs). */
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dp");
@@ -1775,6 +1798,7 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub)
zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, ZYNQMP_DP_INT_ALL);
disable_irq(dp->irq);
+ cancel_delayed_work_sync(&dp->hpd_irq_work);
cancel_delayed_work_sync(&dp->hpd_work);
zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 0);
@@ -1782,4 +1806,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub)
zynqmp_dp_phy_exit(dp);
zynqmp_dp_reset(dp, true);
+ mutex_destroy(&dp->lock);
}
--
2.35.1.1320.gc452695387.dirty
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