drm/nv50: rework PGPIO IRQ handling and hotplug detection

Allows callers to install their own handlers for when a GPIO line
changes state (such as for hotplug detect).

This also fixes a bug where we weren't acknowledging the GPIO IRQ
until after the bottom half had run, causing a severe IRQ storm
in some cases.
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -37,6 +37,8 @@
 #include "nouveau_connector.h"
 #include "nouveau_hw.h"
 
+static void nouveau_connector_hotplug(void *, int);
+
 static struct nouveau_encoder *
 find_encoder_by_type(struct drm_connector *connector, int type)
 {
@@ -94,22 +96,30 @@ nouveau_connector_bpp(struct drm_connector *connector)
 }
 
 static void
-nouveau_connector_destroy(struct drm_connector *drm_connector)
+nouveau_connector_destroy(struct drm_connector *connector)
 {
-	struct nouveau_connector *nv_connector =
-		nouveau_connector(drm_connector);
+	struct nouveau_connector *nv_connector = nouveau_connector(connector);
+	struct drm_nouveau_private *dev_priv;
+	struct nouveau_gpio_engine *pgpio;
 	struct drm_device *dev;
 
 	if (!nv_connector)
 		return;
 
 	dev = nv_connector->base.dev;
+	dev_priv = dev->dev_private;
 	NV_DEBUG_KMS(dev, "\n");
 
+	pgpio = &dev_priv->engine.gpio;
+	if (pgpio->irq_unregister) {
+		pgpio->irq_unregister(dev, nv_connector->dcb->gpio_tag,
+				      nouveau_connector_hotplug, connector);
+	}
+
 	kfree(nv_connector->edid);
-	drm_sysfs_connector_remove(drm_connector);
-	drm_connector_cleanup(drm_connector);
-	kfree(drm_connector);
+	drm_sysfs_connector_remove(connector);
+	drm_connector_cleanup(connector);
+	kfree(connector);
 }
 
 static struct nouveau_i2c_chan *
@@ -760,6 +770,7 @@ nouveau_connector_create(struct drm_device *dev, int index)
 {
 	const struct drm_connector_funcs *funcs = &nouveau_connector_funcs;
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
 	struct nouveau_connector *nv_connector = NULL;
 	struct dcb_connector_table_entry *dcb = NULL;
 	struct drm_connector *connector;
@@ -876,6 +887,11 @@ nouveau_connector_create(struct drm_device *dev, int index)
 		break;
 	}
 
+	if (pgpio->irq_register) {
+		pgpio->irq_register(dev, nv_connector->dcb->gpio_tag,
+				    nouveau_connector_hotplug, connector);
+	}
+
 	drm_sysfs_connector_add(connector);
 	dcb->drm = connector;
 	return dcb->drm;
@@ -886,3 +902,29 @@ nouveau_connector_create(struct drm_device *dev, int index)
 	return ERR_PTR(ret);
 
 }
+
+static void
+nouveau_connector_hotplug(void *data, int plugged)
+{
+	struct drm_connector *connector = data;
+	struct drm_device *dev = connector->dev;
+
+	NV_INFO(dev, "%splugged %s\n", plugged ? "" : "un",
+		drm_get_connector_name(connector));
+
+	if (connector->encoder && connector->encoder->crtc &&
+	    connector->encoder->crtc->enabled) {
+		struct nouveau_encoder *nv_encoder = nouveau_encoder(connector->encoder);
+		struct drm_encoder_helper_funcs *helper =
+			connector->encoder->helper_private;
+
+		if (nv_encoder->dcb->type == OUTPUT_DP) {
+			if (plugged)
+				helper->dpms(connector->encoder, DRM_MODE_DPMS_ON);
+			else
+				helper->dpms(connector->encoder, DRM_MODE_DPMS_OFF);
+		}
+	}
+
+	drm_helper_hpd_irq_event(dev);
+}

drivers/gpu/drm/nouveau/nouveau_dp.c

@@ -279,7 +279,7 @@ nouveau_dp_link_train(struct drm_encoder *encoder)
 	struct bit_displayport_encoder_table *dpe;
 	int dpe_headerlen;
 	uint8_t config[4], status[3];
-	bool cr_done, cr_max_vs, eq_done;
+	bool cr_done, cr_max_vs, eq_done, hpd_state;
 	int ret = 0, i, tries, voltage;
 
 	NV_DEBUG_KMS(dev, "link training!!\n");
@@ -297,7 +297,7 @@ nouveau_dp_link_train(struct drm_encoder *encoder)
 	/* disable hotplug detect, this flips around on some panels during
 	 * link training.
 	 */
-	pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, false);
+	hpd_state = pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, false);
 
 	if (dpe->script0) {
 		NV_DEBUG_KMS(dev, "SOR-%d: running DP script 0\n", nv_encoder->or);
@@ -439,7 +439,7 @@ nouveau_dp_link_train(struct drm_encoder *encoder)
 	}
 
 	/* re-enable hotplug detect */
-	pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, true);
+	pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, hpd_state);
 
 	return eq_done;
 }

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -376,13 +376,19 @@ struct nouveau_display_engine {
 };
 
 struct nouveau_gpio_engine {
+	void *priv;
+
 	int  (*init)(struct drm_device *);
 	void (*takedown)(struct drm_device *);
 
 	int  (*get)(struct drm_device *, enum dcb_gpio_tag);
 	int  (*set)(struct drm_device *, enum dcb_gpio_tag, int state);
 
-	void (*irq_enable)(struct drm_device *, enum dcb_gpio_tag, bool on);
+	int  (*irq_register)(struct drm_device *, enum dcb_gpio_tag,
+			     void (*)(void *, int), void *);
+	void (*irq_unregister)(struct drm_device *, enum dcb_gpio_tag,
+			       void (*)(void *, int), void *);
+	bool (*irq_enable)(struct drm_device *, enum dcb_gpio_tag, bool on);
 };
 
 struct nouveau_pm_voltage_level {
@@ -619,13 +625,6 @@ struct drm_nouveau_private {
 	bool msi_enabled;
 	struct workqueue_struct *wq;
 	struct work_struct irq_work;
-	struct work_struct hpd_work;
-
-	struct {
-		spinlock_t lock;
-		uint32_t hpd0_bits;
-		uint32_t hpd1_bits;
-	} hpd_state;
 
 	struct list_head vbl_waiting;
 
@@ -1366,7 +1365,11 @@ int nv50_gpio_init(struct drm_device *dev);
 void nv50_gpio_fini(struct drm_device *dev);
 int nv50_gpio_get(struct drm_device *dev, enum dcb_gpio_tag tag);
 int nv50_gpio_set(struct drm_device *dev, enum dcb_gpio_tag tag, int state);
-void nv50_gpio_irq_enable(struct drm_device *, enum dcb_gpio_tag, bool on);
+int  nv50_gpio_irq_register(struct drm_device *, enum dcb_gpio_tag,
+			    void (*)(void *, int), void *);
+void nv50_gpio_irq_unregister(struct drm_device *, enum dcb_gpio_tag,
+			      void (*)(void *, int), void *);
+bool nv50_gpio_irq_enable(struct drm_device *, enum dcb_gpio_tag, bool on);
 
 /* nv50_calc. */
 int nv50_calc_pll(struct drm_device *, struct pll_lims *, int clk,

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -396,6 +396,8 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->gpio.takedown		= nv50_gpio_fini;
 		engine->gpio.get		= nv50_gpio_get;
 		engine->gpio.set		= nv50_gpio_set;
+		engine->gpio.irq_register	= nv50_gpio_irq_register;
+		engine->gpio.irq_unregister	= nv50_gpio_irq_unregister;
 		engine->gpio.irq_enable		= nv50_gpio_irq_enable;
 		switch (dev_priv->chipset) {
 		case 0x84:
@@ -487,6 +489,8 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->gpio.takedown		= nouveau_stub_takedown;
 		engine->gpio.get		= nv50_gpio_get;
 		engine->gpio.set		= nv50_gpio_set;
+		engine->gpio.irq_register	= nv50_gpio_irq_register;
+		engine->gpio.irq_unregister	= nv50_gpio_irq_unregister;
 		engine->gpio.irq_enable		= nv50_gpio_irq_enable;
 		engine->crypt.init		= nouveau_stub_init;
 		engine->crypt.takedown		= nouveau_stub_takedown;

drivers/gpu/drm/nouveau/nv50_display.c

@@ -804,71 +804,6 @@ nv50_display_error_handler(struct drm_device *dev)
 	}
 }
 
-void
-nv50_display_irq_hotplug_bh(struct work_struct *work)
-{
-	struct drm_nouveau_private *dev_priv =
-		container_of(work, struct drm_nouveau_private, hpd_work);
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_connector *connector;
-	const uint32_t gpio_reg[4] = { 0xe104, 0xe108, 0xe280, 0xe284 };
-	uint32_t unplug_mask, plug_mask, change_mask;
-	uint32_t hpd0, hpd1;
-
-	spin_lock_irq(&dev_priv->hpd_state.lock);
-	hpd0 = dev_priv->hpd_state.hpd0_bits;
-	dev_priv->hpd_state.hpd0_bits = 0;
-	hpd1 = dev_priv->hpd_state.hpd1_bits;
-	dev_priv->hpd_state.hpd1_bits = 0;
-	spin_unlock_irq(&dev_priv->hpd_state.lock);
-
-	hpd0 &= nv_rd32(dev, 0xe050);
-	if (dev_priv->chipset >= 0x90)
-		hpd1 &= nv_rd32(dev, 0xe070);
-
-	plug_mask   = (hpd0 & 0x0000ffff) | (hpd1 << 16);
-	unplug_mask = (hpd0 >> 16) | (hpd1 & 0xffff0000);
-	change_mask = plug_mask | unplug_mask;
-
-	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
-		struct drm_encoder_helper_funcs *helper;
-		struct nouveau_connector *nv_connector =
-			nouveau_connector(connector);
-		struct nouveau_encoder *nv_encoder;
-		struct dcb_gpio_entry *gpio;
-		uint32_t reg;
-		bool plugged;
-
-		if (!nv_connector->dcb)
-			continue;
-
-		gpio = nouveau_bios_gpio_entry(dev, nv_connector->dcb->gpio_tag);
-		if (!gpio || !(change_mask & (1 << gpio->line)))
-			continue;
-
-		reg = nv_rd32(dev, gpio_reg[gpio->line >> 3]);
-		plugged = !!(reg & (4 << ((gpio->line & 7) << 2)));
-		NV_INFO(dev, "%splugged %s\n", plugged ? "" : "un",
-			drm_get_connector_name(connector)) ;
-
-		if (!connector->encoder || !connector->encoder->crtc ||
-		    !connector->encoder->crtc->enabled)
-			continue;
-		nv_encoder = nouveau_encoder(connector->encoder);
-		helper = connector->encoder->helper_private;
-
-		if (nv_encoder->dcb->type != OUTPUT_DP)
-			continue;
-
-		if (plugged)
-			helper->dpms(connector->encoder, DRM_MODE_DPMS_ON);
-		else
-			helper->dpms(connector->encoder, DRM_MODE_DPMS_OFF);
-	}
-
-	drm_helper_hpd_irq_event(dev);
-}
-
 static void
 nv50_display_isr(struct drm_device *dev)
 {
@@ -918,4 +853,3 @@ nv50_display_isr(struct drm_device *dev)
 		}
 	}
 }
-

drivers/gpu/drm/nouveau/nv50_display.h

@@ -36,7 +36,6 @@
 #include "nv50_evo.h"
 
 void nv50_display_irq_handler_bh(struct work_struct *work);
-void nv50_display_irq_hotplug_bh(struct work_struct *work);
 int nv50_display_early_init(struct drm_device *dev);
 void nv50_display_late_takedown(struct drm_device *dev);
 int nv50_display_create(struct drm_device *dev);

drivers/gpu/drm/nouveau/nv50_gpio.c

@@ -29,6 +29,24 @@
 #include "nv50_display.h"
 
 static void nv50_gpio_isr(struct drm_device *dev);
+static void nv50_gpio_isr_bh(struct work_struct *work);
+
+struct nv50_gpio_priv {
+	struct list_head handlers;
+	spinlock_t lock;
+};
+
+struct nv50_gpio_handler {
+	struct drm_device *dev;
+	struct list_head head;
+	struct work_struct work;
+	bool inhibit;
+
+	struct dcb_gpio_entry *gpio;
+
+	void (*handler)(void *data, int state);
+	void *data;
+};
 
 static int
 nv50_gpio_location(struct dcb_gpio_entry *gpio, uint32_t *reg, uint32_t *shift)
@@ -79,29 +97,123 @@ nv50_gpio_set(struct drm_device *dev, enum dcb_gpio_tag tag, int state)
 	return 0;
 }
 
+int
+nv50_gpio_irq_register(struct drm_device *dev, enum dcb_gpio_tag tag,
+		       void (*handler)(void *, int), void *data)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv = pgpio->priv;
+	struct nv50_gpio_handler *gpioh;
+	struct dcb_gpio_entry *gpio;
+	unsigned long flags;
+
+	gpio = nouveau_bios_gpio_entry(dev, tag);
+	if (!gpio)
+		return -ENOENT;
+
+	gpioh = kzalloc(sizeof(*gpioh), GFP_KERNEL);
+	if (!gpioh)
+		return -ENOMEM;
+
+	INIT_WORK(&gpioh->work, nv50_gpio_isr_bh);
+	gpioh->dev  = dev;
+	gpioh->gpio = gpio;
+	gpioh->handler = handler;
+	gpioh->data = data;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	list_add(&gpioh->head, &priv->handlers);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return 0;
+}
+
 void
-nv50_gpio_irq_enable(struct drm_device *dev, enum dcb_gpio_tag tag, bool on)
+nv50_gpio_irq_unregister(struct drm_device *dev, enum dcb_gpio_tag tag,
+			 void (*handler)(void *, int), void *data)
 {
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv = pgpio->priv;
+	struct nv50_gpio_handler *gpioh, *tmp;
 	struct dcb_gpio_entry *gpio;
-	u32 reg, mask;
+	unsigned long flags;
 
 	gpio = nouveau_bios_gpio_entry(dev, tag);
-	if (!gpio) {
-		NV_ERROR(dev, "gpio tag 0x%02x not found\n", tag);
+	if (!gpio)
 		return;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	list_for_each_entry_safe(gpioh, tmp, &priv->handlers, head) {
+		if (gpioh->gpio != gpio ||
+		    gpioh->handler != handler ||
+		    gpioh->data != data)
+			continue;
+		list_del(&gpioh->head);
+		kfree(gpioh);
 	}
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+bool
+nv50_gpio_irq_enable(struct drm_device *dev, enum dcb_gpio_tag tag, bool on)
+{
+	struct dcb_gpio_entry *gpio;
+	u32 reg, mask;
+
+	gpio = nouveau_bios_gpio_entry(dev, tag);
+	if (!gpio)
+		return false;
 
 	reg  = gpio->line < 16 ? 0xe050 : 0xe070;
 	mask = 0x00010001 << (gpio->line & 0xf);
 
 	nv_wr32(dev, reg + 4, mask);
-	nv_mask(dev, reg + 0, mask, on ? mask : 0);
+	reg = nv_mask(dev, reg + 0, mask, on ? mask : 0);
+	return (reg & mask) == mask;
+}
+
+static int
+nv50_gpio_create(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&priv->handlers);
+	spin_lock_init(&priv->lock);
+	pgpio->priv = priv;
+	return 0;
+}
+
+static void
+nv50_gpio_destroy(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+
+	kfree(pgpio->priv);
+	pgpio->priv = NULL;
 }
 
 int
 nv50_gpio_init(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv;
+	int ret;
+
+	if (!pgpio->priv) {
+		ret = nv50_gpio_create(dev);
+		if (ret)
+			return ret;
+	}
+	priv = pgpio->priv;
 
 	/* disable, and ack any pending gpio interrupts */
 	nv_wr32(dev, 0xe050, 0x00000000);
@@ -111,8 +223,6 @@ nv50_gpio_init(struct drm_device *dev)
 		nv_wr32(dev, 0xe074, 0xffffffff);
 	}
 
-	INIT_WORK(&dev_priv->hpd_work, nv50_display_irq_hotplug_bh);
-	spin_lock_init(&dev_priv->hpd_state.lock);
 	nouveau_irq_register(dev, 21, nv50_gpio_isr);
 	return 0;
 }
@@ -126,26 +236,64 @@ nv50_gpio_fini(struct drm_device *dev)
 	if (dev_priv->chipset >= 0x90)
 		nv_wr32(dev, 0xe070, 0x00000000);
 	nouveau_irq_unregister(dev, 21);
+
+	nv50_gpio_destroy(dev);
+}
+
+static void
+nv50_gpio_isr_bh(struct work_struct *work)
+{
+	struct nv50_gpio_handler *gpioh =
+		container_of(work, struct nv50_gpio_handler, work);
+	struct drm_nouveau_private *dev_priv = gpioh->dev->dev_private;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv = pgpio->priv;
+	unsigned long flags;
+	int state;
+
+	state = pgpio->get(gpioh->dev, gpioh->gpio->tag);
+	if (state < 0)
+		return;
+
+	gpioh->handler(gpioh->data, state);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	gpioh->inhibit = false;
+	spin_unlock_irqrestore(&priv->lock, flags);
 }
 
 static void
 nv50_gpio_isr(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
-	uint32_t hpd0_bits, hpd1_bits = 0;
+	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
+	struct nv50_gpio_priv *priv = pgpio->priv;
+	struct nv50_gpio_handler *gpioh;
+	u32 intr0, intr1 = 0;
+	u32 hi, lo, ch;
 
-	hpd0_bits = nv_rd32(dev, 0xe054);
-	nv_wr32(dev, 0xe054, hpd0_bits);
+	intr0 = nv_rd32(dev, 0xe054) & nv_rd32(dev, 0xe050);
+	if (dev_priv->chipset >= 0x90)
+		intr1 = nv_rd32(dev, 0xe074) & nv_rd32(dev, 0xe070);
 
-	if (dev_priv->chipset >= 0x90) {
-		hpd1_bits = nv_rd32(dev, 0xe074);
-		nv_wr32(dev, 0xe074, hpd1_bits);
-	}
+	hi = (intr0 & 0x0000ffff) | (intr1 << 16);
+	lo = (intr0 >> 16) | (intr1 & 0xffff0000);
+	ch = hi | lo;
 
-	spin_lock(&dev_priv->hpd_state.lock);
-	dev_priv->hpd_state.hpd0_bits |= hpd0_bits;
-	dev_priv->hpd_state.hpd1_bits |= hpd1_bits;
-	spin_unlock(&dev_priv->hpd_state.lock);
+	nv_wr32(dev, 0xe054, intr0);
+	if (dev_priv->chipset >= 0x90)
+		nv_wr32(dev, 0xe074, intr1);
+
+	spin_lock(&priv->lock);
+	list_for_each_entry(gpioh, &priv->handlers, head) {
+		if (!(ch & (1 << gpioh->gpio->line)))
+			continue;
 
-	queue_work(dev_priv->wq, &dev_priv->hpd_work);
+		if (gpioh->inhibit)
+			continue;
+		gpioh->inhibit = true;
+
+		queue_work(dev_priv->wq, &gpioh->work);
+	}
+	spin_unlock(&priv->lock);
 }