[PATCH] aic7xxx: move to dma_get_required_mask() and correct 39 bit assumptions

[James Bottomley <James.Bottomley@SteelEye.com>]

This patch moves aic7xxx over to the dma_get_required_mask() API and
dumps its open coded memory check.

It also appears from this bug:

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=167049

That 39 bit addressing doesn't work on older cards.  I surmise that the
AHC_LARGE_SCBS flag is the one that marks cards capable of using 39 bit
addressing, so I also folded that check into the code.

Luben, since you have access to the docs, could you confirm this guess.

Dave, could you see if this fixes the problem for the bug reporter.

James

diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -1036,15 +1036,6 @@ ahc_linux_register_host(struct ahc_softc
 	return (0);
 }
 
-uint64_t
-ahc_linux_get_memsize(void)
-{
-	struct sysinfo si;
-
-	si_meminfo(&si);
-	return ((uint64_t)si.totalram << PAGE_SHIFT);
-}
-
 /*
  * Place the SCSI bus into a known state by either resetting it,
  * or forcing transfer negotiations on the next command to any
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.h b/drivers/scsi/aic7xxx/aic7xxx_osm.h
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.h
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.h
@@ -494,8 +494,6 @@ ahc_insb(struct ahc_softc * ahc, long po
 int		ahc_linux_register_host(struct ahc_softc *,
 					struct scsi_host_template *);
 
-uint64_t	ahc_linux_get_memsize(void);
-
 /*************************** Pretty Printing **********************************/
 struct info_str {
 	char *buffer;
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c b/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c
--- a/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c
@@ -180,6 +180,7 @@ ahc_linux_pci_dev_probe(struct pci_dev *
 	struct		 ahc_pci_identity *entry;
 	char		*name;
 	int		 error;
+	struct device	*dev = &pdev->dev;
 
 	pci = pdev;
 	entry = ahc_find_pci_device(pci);
@@ -209,11 +210,12 @@ ahc_linux_pci_dev_probe(struct pci_dev *
 	pci_set_master(pdev);
 
 	if (sizeof(dma_addr_t) > 4
-	 && ahc_linux_get_memsize() > 0x80000000
-	 && pci_set_dma_mask(pdev, mask_39bit) == 0) {
+	    && ahc->features & AHC_LARGE_SCBS
+	    && dma_set_mask(dev, mask_39bit) == 0
+	    && dma_get_required_mask(dev) > DMA_32BIT_MASK) {
 		ahc->flags |= AHC_39BIT_ADDRESSING;
 	} else {
-		if (pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+		if (dma_set_mask(dev, DMA_32BIT_MASK)) {
 			printk(KERN_WARNING "aic7xxx: No suitable DMA available.\n");
                 	return (-ENODEV);
 		}