[PATCH] cciss: adds MSI and MSI-X support

This creates a new function, cciss_interrupt_mode called from
cciss_pci_init.  This function determines what type of interrupt vector to
use, i.e., MSI, MSI-X, or IO-APIC.

One noticeable difference is changing the interrupt field of the controller
struct to an array of 4 unsigned ints.  The Smart Array HW is capable of
generating 4 distinct interrupts depending on the transport method in use
during operation.  These are:

#define DOORBELL_INT 0
Used to notify the contoller of configuration updates. We only use
this feature when in polling mode.

#define PERF_MODE_INT 0
Used when the controller is in Performant Mode.

#define SIMPLE_MODE_INT 2
Used when the controller is in Simple Mode (current Linux implementation).

#define MEMQ_INT_MODE 3
Not used.

When using IO-APIC interrupts these 4 lines are OR'ed together so when any
one fires an interrupt an is generated.  In MSI or MSI-X mode this hardware
OR'ing is ignored.  We must register for our interrupt depending on what
mode the controller is running.  For Linux we use SIMPLE_MODE_INT
exclusively at this time.  Please consider this for inclusion.

Signed-off-by: Mike Miller <mike.miller@hp.com>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/block/cciss.c

@@ -1,6 +1,6 @@
 /*
  *    Disk Array driver for HP SA 5xxx and 6xxx Controllers
- *    Copyright 2000, 2005 Hewlett-Packard Development Company, L.P.
+ *    Copyright 2000, 2006 Hewlett-Packard Development Company, L.P.
  *
  *    This program is free software; you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
@@ -47,12 +47,12 @@
 #include <linux/completion.h>
 
 #define CCISS_DRIVER_VERSION(maj,min,submin) ((maj<<16)|(min<<8)|(submin))
-#define DRIVER_NAME "HP CISS Driver (v 2.6.8)"
+#define DRIVER_NAME "HP CISS Driver (v 2.6.10)"
-#define DRIVER_VERSION CCISS_DRIVER_VERSION(2,6,8)
+#define DRIVER_VERSION CCISS_DRIVER_VERSION(2,6,10)
 
 /* Embedded module documentation macros - see modules.h */
 MODULE_AUTHOR("Hewlett-Packard Company");
-MODULE_DESCRIPTION("Driver for HP Controller SA5xxx SA6xxx version 2.6.8");
+MODULE_DESCRIPTION("Driver for HP Controller SA5xxx SA6xxx version 2.6.10");
 MODULE_SUPPORTED_DEVICE("HP SA5i SA5i+ SA532 SA5300 SA5312 SA641 SA642 SA6400"
 			" SA6i P600 P800 P400 P400i E200 E200i");
 MODULE_LICENSE("GPL");
@@ -167,7 +167,7 @@ static void cciss_geometry_inquiry(int ctlr, int logvol,
 			unsigned int block_size, InquiryData_struct *inq_buff,
 			drive_info_struct *drv);
 static void cciss_getgeometry(int cntl_num);
-
+static void __devinit cciss_interrupt_mode(ctlr_info_t *, struct pci_dev *, __u32);
 static void start_io( ctlr_info_t *h);
 static int sendcmd( __u8 cmd, int ctlr, void *buff, size_t size,
 	unsigned int use_unit_num, unsigned int log_unit, __u8 page_code,
@@ -284,7 +284,7 @@ static int cciss_proc_get_info(char *buffer, char **start, off_t offset,
                 h->product_name,
                 (unsigned long)h->board_id,
 		h->firm_ver[0], h->firm_ver[1], h->firm_ver[2], h->firm_ver[3],
-                (unsigned int)h->intr,
+                (unsigned int)h->intr[SIMPLE_MODE_INT],
                 h->num_luns, 
 		h->Qdepth, h->commands_outstanding,
 		h->maxQsinceinit, h->max_outstanding, h->maxSG);
@@ -2662,6 +2662,60 @@ static int find_PCI_BAR_index(struct pci_dev *pdev,
 	return -1;
 }
 
+/* If MSI/MSI-X is supported by the kernel we will try to enable it on
+ * controllers that are capable. If not, we use IO-APIC mode.
+ */
+
+static void __devinit cciss_interrupt_mode(ctlr_info_t *c, struct pci_dev *pdev, __u32 board_id)
+{
+#ifdef CONFIG_PCI_MSI
+        int err;
+        struct msix_entry cciss_msix_entries[4] = {{0,0}, {0,1},
+						   {0,2}, {0,3}};
+
+	/* Some boards advertise MSI but don't really support it */
+	if ((board_id == 0x40700E11) ||
+		(board_id == 0x40800E11) ||
+		(board_id == 0x40820E11) ||
+		(board_id == 0x40830E11))
+		goto default_int_mode;
+
+        if (pci_find_capability(pdev, PCI_CAP_ID_MSIX)) {
+                err = pci_enable_msix(pdev, cciss_msix_entries, 4);
+                if (!err) {
+                        c->intr[0] = cciss_msix_entries[0].vector;
+                        c->intr[1] = cciss_msix_entries[1].vector;
+                        c->intr[2] = cciss_msix_entries[2].vector;
+                        c->intr[3] = cciss_msix_entries[3].vector;
+                        c->msix_vector = 1;
+                        return;
+                }
+                if (err > 0) {
+                        printk(KERN_WARNING "cciss: only %d MSI-X vectors "
+                                        "available\n", err);
+                } else {
+                        printk(KERN_WARNING "cciss: MSI-X init failed %d\n",
+						err);
+                }
+        }
+        if (pci_find_capability(pdev, PCI_CAP_ID_MSI)) {
+                if (!pci_enable_msi(pdev)) {
+                        c->intr[SIMPLE_MODE_INT] = pdev->irq;
+                        c->msi_vector = 1;
+                        return;
+                } else {
+                        printk(KERN_WARNING "cciss: MSI init failed\n");
+        		c->intr[SIMPLE_MODE_INT] = pdev->irq;
+                        return;
+                }
+        }
+#endif /* CONFIG_PCI_MSI */
+	/* if we get here we're going to use the default interrupt mode */
+default_int_mode:
+        c->intr[SIMPLE_MODE_INT] = pdev->irq;
+	return;
+}
+
 static int cciss_pci_init(ctlr_info_t *c, struct pci_dev *pdev)
 {
 	ushort subsystem_vendor_id, subsystem_device_id, command;
@@ -2722,7 +2776,10 @@ static int cciss_pci_init(ctlr_info_t *c, struct pci_dev *pdev)
 	printk("board_id = %x\n", board_id);
 #endif /* CCISS_DEBUG */ 
 
-	c->intr = pdev->irq;
+/* If the kernel supports MSI/MSI-X we will try to enable that functionality,
+ * else we use the IO-APIC interrupt assigned to us by system ROM.
+ */
+	cciss_interrupt_mode(c, pdev, board_id);
 
 	/*
 	 * Memory base addr is first addr , the second points to the config
@@ -3076,11 +3133,11 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 
 	/* make sure the board interrupts are off */
 	hba[i]->access.set_intr_mask(hba[i], CCISS_INTR_OFF);
-	if( request_irq(hba[i]->intr, do_cciss_intr, 
+	if( request_irq(hba[i]->intr[SIMPLE_MODE_INT], do_cciss_intr,
 		SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, 
 			hba[i]->devname, hba[i])) {
 		printk(KERN_ERR "cciss: Unable to get irq %d for %s\n",
-			hba[i]->intr, hba[i]->devname);
+			hba[i]->intr[SIMPLE_MODE_INT], hba[i]->devname);
 		goto clean2;
 	}
 	hba[i]->cmd_pool_bits = kmalloc(((NR_CMDS+BITS_PER_LONG-1)/BITS_PER_LONG)*sizeof(unsigned long), GFP_KERNEL);
@@ -3186,7 +3243,7 @@ clean4:
 			NR_CMDS * sizeof( ErrorInfo_struct),
 			hba[i]->errinfo_pool,
 			hba[i]->errinfo_pool_dhandle);
-	free_irq(hba[i]->intr, hba[i]);
+	free_irq(hba[i]->intr[SIMPLE_MODE_INT], hba[i]);
 clean2:
 	unregister_blkdev(hba[i]->major, hba[i]->devname);
 clean1:
@@ -3227,7 +3284,15 @@ static void __devexit cciss_remove_one (struct pci_dev *pdev)
 		printk(KERN_WARNING "Error Flushing cache on controller %d\n", 
 			i);
 	}
-	free_irq(hba[i]->intr, hba[i]);
+	free_irq(hba[i]->intr[2], hba[i]);
+
+#ifdef CONFIG_PCI_MSI
+        if (hba[i]->msix_vector)
+                pci_disable_msix(hba[i]->pdev);
+        else if (hba[i]->msi_vector)
+                pci_disable_msi(hba[i]->pdev);
+#endif /* CONFIG_PCI_MSI */
+
 	pci_set_drvdata(pdev, NULL);
 	iounmap(hba[i]->vaddr);
 	cciss_unregister_scsi(i);  /* unhook from SCSI subsystem */

drivers/block/cciss.h

@@ -65,7 +65,6 @@ struct ctlr_info
 	unsigned long io_mem_addr;
 	unsigned long io_mem_length;
 	CfgTable_struct __iomem *cfgtable;
-	unsigned int intr;
 	int	interrupts_enabled;
 	int	major;
 	int 	max_commands;
@@ -74,6 +73,13 @@ struct ctlr_info
 	int	num_luns;
 	int 	highest_lun;
 	int	usage_count;  /* number of opens all all minor devices */
+#	define DOORBELL_INT	0
+#	define PERF_MODE_INT	1
+#	define SIMPLE_MODE_INT	2
+#	define MEMQ_MODE_INT	3
+	unsigned int intr[4];
+	unsigned int msix_vector;
+	unsigned int msi_vector;
 
 	// information about each logical volume
 	drive_info_struct drv[CISS_MAX_LUN];

drivers/block/cciss_scsi.c

@@ -714,7 +714,7 @@ cciss_scsi_detect(int ctlr)
 	((struct cciss_scsi_adapter_data_t *) 
 		hba[ctlr]->scsi_ctlr)->scsi_host = (void *) sh;
 	sh->hostdata[0] = (unsigned long) hba[ctlr];
-	sh->irq = hba[ctlr]->intr;
+	sh->irq = hba[ctlr]->intr[SIMPLE_MODE_INT];
 	sh->unique_id = sh->irq;
 	error = scsi_add_host(sh, &hba[ctlr]->pdev->dev);
 	if (error)