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>

1 files changed, 167 insertions, 19 deletions

diff --git a/drivers/gpu/drm/nouveau/nv50_gpio.c b/drivers/gpu/drm/nouveau/nv50_gpio.c
index 87266d1b5de..6b149c0cc06 100644
--- a/drivers/gpu/drm/nouveau/nv50_gpio.c
+++ b/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);
 }