[PATCH 2/3] hpilo: add interrupt handler

[David Altobelli <david.altobelli@hp.com>]

Add interrupt handler to hpilo.  This is enablement for poll handler, and
it also simplifies the logic for handling an iLO reset, because now 
only the interrupt handler needs to look for reset, the file system interfaces
only need to return failure when a reset has happened.

Please CC me on any replies.

Signed-off-by: David Altobelli <david.altobelli@hp.com>
---
 hpilo.c |  138 +++++++++++++++++++++++++++++++++++++++++++---------------------
 hpilo.h |    8 +++
 2 files changed, 101 insertions(+), 45 deletions(-)
diff -uprN -X linux-2.6.30.3-orig/Documentation/dontdiff linux-2.6.30.3-orig/drivers/misc/hpilo.c linux-2.6.30.3/drivers/misc/hpilo.c
--- linux-2.6.30.3-orig/drivers/misc/hpilo.c	2009-08-07 09:26:45.000000000 -0500
+++ linux-2.6.30.3/drivers/misc/hpilo.c	2009-08-07 09:26:24.000000000 -0500
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/pci.h>
+#include <linux/interrupt.h>
 #include <linux/ioport.h>
 #include <linux/device.h>
 #include <linux/file.h>
@@ -21,6 +22,7 @@
 #include <linux/delay.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/wait.h>
 #include "hpilo.h"
 
 static struct class *ilo_class;
@@ -61,9 +63,10 @@ static inline int desc_mem_sz(int nr_ent
 static int fifo_enqueue(struct ilo_hwinfo *hw, char *fifobar, int entry)
 {
 	struct fifo *fifo_q = FIFOBARTOHANDLE(fifobar);
+	unsigned long flags;
 	int ret = 0;
 
-	spin_lock(&hw->fifo_lock);
+	spin_lock_irqsave(&hw->fifo_lock, flags);
 	if (!(fifo_q->fifobar[(fifo_q->tail + 1) & fifo_q->imask]
 	      & ENTRY_MASK_O)) {
 		fifo_q->fifobar[fifo_q->tail & fifo_q->imask] |=
@@ -71,7 +74,7 @@ static int fifo_enqueue(struct ilo_hwinf
 		fifo_q->tail += 1;
 		ret = 1;
 	}
-	spin_unlock(&hw->fifo_lock);
+	spin_unlock_irqrestore(&hw->fifo_lock, flags);
 
 	return ret;
 }
@@ -79,10 +82,11 @@ static int fifo_enqueue(struct ilo_hwinf
 static int fifo_dequeue(struct ilo_hwinfo *hw, char *fifobar, int *entry)
 {
 	struct fifo *fifo_q = FIFOBARTOHANDLE(fifobar);
+	unsigned long flags;
 	int ret = 0;
 	u64 c;
 
-	spin_lock(&hw->fifo_lock);
+	spin_lock_irqsave(&hw->fifo_lock, flags);
 	c = fifo_q->fifobar[fifo_q->head & fifo_q->imask];
 	if (c & ENTRY_MASK_C) {
 		if (entry)
@@ -93,7 +97,7 @@ static int fifo_dequeue(struct ilo_hwinf
 		fifo_q->head += 1;
 		ret = 1;
 	}
-	spin_unlock(&hw->fifo_lock);
+	spin_unlock_irqrestore(&hw->fifo_lock, flags);
 
 	return ret;
 }
@@ -374,7 +378,18 @@ static inline void clear_device(struct i
 	clear_pending_db(hw, -1);
 }
 
-static void ilo_locked_reset(struct ilo_hwinfo *hw)
+static inline void ilo_enable_interrupts(struct ilo_hwinfo *hw)
+{
+	iowrite8(ioread8(&hw->mmio_vaddr[DB_IRQ]) | 1, &hw->mmio_vaddr[DB_IRQ]);
+}
+
+static inline void ilo_disable_interrupts(struct ilo_hwinfo *hw)
+{
+	iowrite8(ioread8(&hw->mmio_vaddr[DB_IRQ]) & ~1,
+		 &hw->mmio_vaddr[DB_IRQ]);
+}
+
+static void ilo_set_reset(struct ilo_hwinfo *hw)
 {
 	int slot;
 
@@ -387,19 +402,6 @@ static void ilo_locked_reset(struct ilo_
 			continue;
 		set_channel_reset(&hw->ccb_alloc[slot]->driver_ccb);
 	}
-
-	clear_device(hw);
-}
-
-static void ilo_reset(struct ilo_hwinfo *hw)
-{
-	spin_lock(&hw->alloc_lock);
-
-	/* reset might have been handled after lock was taken */
-	if (is_device_reset(hw))
-		ilo_locked_reset(hw);
-
-	spin_unlock(&hw->alloc_lock);
 }
 
 static ssize_t ilo_read(struct file *fp, char __user *buf,
@@ -411,12 +413,11 @@ static ssize_t ilo_read(struct file *fp,
 	struct ilo_hwinfo *hw = data->ilo_hw;
 	void *pkt;
 
-	if (is_device_reset(hw) || is_channel_reset(driver_ccb)) {
+	if (is_channel_reset(driver_ccb)) {
 		/*
 		 * If the device has been reset, applications
 		 * need to close and reopen all ccbs.
 		 */
-		ilo_reset(hw);
 		return -ENODEV;
 	}
 
@@ -462,14 +463,8 @@ static ssize_t ilo_write(struct file *fp
 	struct ilo_hwinfo *hw = data->ilo_hw;
 	void *pkt;
 
-	if (is_device_reset(hw) || is_channel_reset(driver_ccb)) {
-		/*
-		 * If the device has been reset, applications
-		 * need to close and reopen all ccbs.
-		 */
-		ilo_reset(hw);
+	if (is_channel_reset(driver_ccb))
 		return -ENODEV;
-	}
 
 	/* get a packet to send the user command */
 	if (!ilo_pkt_dequeue(hw, driver_ccb, SENDQ, &pkt_id, &pkt_len, &pkt))
@@ -496,27 +491,28 @@ static int ilo_close(struct inode *ip, s
 	int slot;
 	struct ccb_data *data;
 	struct ilo_hwinfo *hw;
+	unsigned long flags;
 
 	slot = iminor(ip) % MAX_CCB;
 	hw = container_of(ip->i_cdev, struct ilo_hwinfo, cdev);
 
-	spin_lock(&hw->alloc_lock);
-
-	if (is_device_reset(hw))
-		ilo_locked_reset(hw);
+	spin_lock(&hw->open_lock);
 
 	if (hw->ccb_alloc[slot]->ccb_cnt == 1) {
 
 		data = fp->private_data;
 
+		spin_lock_irqsave(&hw->alloc_lock, flags);
+		hw->ccb_alloc[slot] = NULL;
+		spin_unlock_irqrestore(&hw->alloc_lock, flags);
+
 		ilo_ccb_close(hw->ilo_dev, data);
 
 		kfree(data);
-		hw->ccb_alloc[slot] = NULL;
 	} else
 		hw->ccb_alloc[slot]->ccb_cnt--;
 
-	spin_unlock(&hw->alloc_lock);
+	spin_unlock(&hw->open_lock);
 
 	return 0;
 }
@@ -526,6 +522,7 @@ static int ilo_open(struct inode *ip, st
 	int slot, error;
 	struct ccb_data *data;
 	struct ilo_hwinfo *hw;
+	unsigned long flags;
 
 	slot = iminor(ip) % MAX_CCB;
 	hw = container_of(ip->i_cdev, struct ilo_hwinfo, cdev);
@@ -535,10 +532,7 @@ static int ilo_open(struct inode *ip, st
 	if (!data)
 		return -ENOMEM;
 
-	spin_lock(&hw->alloc_lock);
-
-	if (is_device_reset(hw))
-		ilo_locked_reset(hw);
+	spin_lock(&hw->open_lock);
 
 	/* each fd private_data holds sw/hw view of ccb */
 	if (hw->ccb_alloc[slot] == NULL) {
@@ -549,22 +543,31 @@ static int ilo_open(struct inode *ip, st
 			goto out;
 		}
 
+		data->ccb_cnt = 1;
+		data->ccb_excl = fp->f_flags & O_EXCL;
+		data->ilo_hw = hw;
+		init_waitqueue_head(&data->ccb_waitq);
+
 		/* write the ccb to hw */
+		spin_lock_irqsave(&hw->alloc_lock, flags);
 		ilo_ccb_open(hw, data, slot);
+		hw->ccb_alloc[slot] = data;
+		spin_unlock_irqrestore(&hw->alloc_lock, flags);
 
 		/* make sure the channel is functional */
 		error = ilo_ccb_verify(hw, data);
 		if (error) {
+
+			spin_lock_irqsave(&hw->alloc_lock, flags);
+			hw->ccb_alloc[slot] = NULL;
+			spin_unlock_irqrestore(&hw->alloc_lock, flags);
+
 			ilo_ccb_close(hw->ilo_dev, data);
+
 			kfree(data);
 			goto out;
 		}
 
-		data->ccb_cnt = 1;
-		data->ccb_excl = fp->f_flags & O_EXCL;
-		data->ilo_hw = hw;
-		hw->ccb_alloc[slot] = data;
-
 	} else {
 		kfree(data);
 		if (fp->f_flags & O_EXCL || hw->ccb_alloc[slot]->ccb_excl) {
@@ -580,7 +583,7 @@ static int ilo_open(struct inode *ip, st
 		}
 	}
 out:
-	spin_unlock(&hw->alloc_lock);
+	spin_unlock(&hw->open_lock);
 
 	if (!error)
 		fp->private_data = hw->ccb_alloc[slot];
@@ -596,6 +599,41 @@ static const struct file_operations ilo_
 	.release 	= ilo_close,
 };
 
+static irqreturn_t ilo_isr(int irq, void *data)
+{
+	struct ilo_hwinfo *hw = data;
+	int pending, i;
+
+	spin_lock(&hw->alloc_lock);
+
+	/* check for ccbs which have data */
+	pending = get_device_outbound(hw);
+	if (!pending) {
+		spin_unlock(&hw->alloc_lock);
+		return IRQ_NONE;
+	}
+
+	if (is_db_reset(pending)) {
+		/* wake up all ccbs if the device was reset */
+		pending = -1;
+		ilo_set_reset(hw);
+	}
+
+	for (i = 0; i < MAX_CCB; i++) {
+		if (!hw->ccb_alloc[i])
+			continue;
+		if (pending & (1 << i))
+			wake_up_interruptible(&hw->ccb_alloc[i]->ccb_waitq);
+	}
+
+	/* clear the device of the channels that have been handled */
+	clear_pending_db(hw, pending);
+
+	spin_unlock(&hw->alloc_lock);
+
+	return IRQ_HANDLED;
+}
+
 static void ilo_unmap_device(struct pci_dev *pdev, struct ilo_hwinfo *hw)
 {
 	pci_iounmap(pdev, hw->db_vaddr);
@@ -649,6 +687,8 @@ static void ilo_remove(struct pci_dev *p
 		device_destroy(ilo_class, MKDEV(ilo_major, i));
 
 	cdev_del(&ilo_hw->cdev);
+	ilo_disable_interrupts(ilo_hw);
+	free_irq(pdev->irq, ilo_hw);
 	ilo_unmap_device(pdev, ilo_hw);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
@@ -684,6 +724,7 @@ static int __devinit ilo_probe(struct pc
 	ilo_hw->ilo_dev = pdev;
 	spin_lock_init(&ilo_hw->alloc_lock);
 	spin_lock_init(&ilo_hw->fifo_lock);
+	spin_lock_init(&ilo_hw->open_lock);
 
 	error = pci_enable_device(pdev);
 	if (error)
@@ -702,13 +743,19 @@ static int __devinit ilo_probe(struct pc
 	pci_set_drvdata(pdev, ilo_hw);
 	clear_device(ilo_hw);
 
+	error = request_irq(pdev->irq, ilo_isr, IRQF_SHARED, "hpilo", ilo_hw);
+	if (error)
+		goto unmap;
+
+	ilo_enable_interrupts(ilo_hw);
+
 	cdev_init(&ilo_hw->cdev, &ilo_fops);
 	ilo_hw->cdev.owner = THIS_MODULE;
 	start = devnum * MAX_CCB;
 	error = cdev_add(&ilo_hw->cdev, MKDEV(ilo_major, start), MAX_CCB);
 	if (error) {
 		dev_err(&pdev->dev, "Could not add cdev\n");
-		goto unmap;
+		goto remove_isr;
 	}
 
 	for (minor = 0 ; minor < MAX_CCB; minor++) {
@@ -721,6 +768,9 @@ static int __devinit ilo_probe(struct pc
 	}
 
 	return 0;
+remove_isr:
+	ilo_disable_interrupts(ilo_hw);
+	free_irq(pdev->irq, ilo_hw);
 unmap:
 	ilo_unmap_device(pdev, ilo_hw);
 free_regions:
diff -uprN -X linux-2.6.30.3-orig/Documentation/dontdiff linux-2.6.30.3-orig/drivers/misc/hpilo.h linux-2.6.30.3/drivers/misc/hpilo.h
--- linux-2.6.30.3-orig/drivers/misc/hpilo.h	2009-08-07 09:05:09.000000000 -0500
+++ linux-2.6.30.3/drivers/misc/hpilo.h	2009-07-28 16:27:46.000000000 -0500
@@ -46,11 +46,14 @@ struct ilo_hwinfo {
 
 	spinlock_t alloc_lock;
 	spinlock_t fifo_lock;
+	spinlock_t open_lock;
 
 	struct cdev cdev;
 };
 
-/* offset from mmio_vaddr */
+/* offset from mmio_vaddr for enabling doorbell interrupts */
+#define DB_IRQ		0xB2
+/* offset from mmio_vaddr for outbound communications */
 #define DB_OUT		0xD4
 /* DB_OUT reset bit */
 #define DB_RESET	26
@@ -131,6 +134,9 @@ struct ccb_data {
 	/* pointer to hardware device info */
 	struct ilo_hwinfo *ilo_hw;
 
+	/* queue for this ccb to wait for recv data */
+	wait_queue_head_t ccb_waitq;
+
 	/* usage count, to allow for shared ccb's */
 	int	    ccb_cnt;