[PATCH] libata-sff: Allow for wacky systems

There are some Linux supported platforms that simply cannot hit the low
I/O addresses used by ATA legacy mode PCI mappings. These platforms have
a window for PCI space that is fixed by the board logic and doesn't
include the neccessary locations.

Provide a config option so that such platforms faced with a controller
that they cannot support simply error it and punt

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-sff.c

@@ -981,6 +981,15 @@ int ata_pci_init_one (struct pci_dev *pdev, struct ata_port_info **port_info,
 		mask = (1 << 2) | (1 << 0);
 		if ((tmp8 & mask) != mask)
 			legacy_mode = (1 << 3);
+#if defined(CONFIG_NO_ATA_LEGACY)
+		/* Some platforms with PCI limits cannot address compat
+		   port space. In that case we punt if their firmware has
+		   left a device in compatibility mode */
+		if (legacy_mode) {
+			printk(KERN_ERR "ata: Compatibility mode ATA is not supported on this platform, skipping.\n");
+			return -EOPNOTSUPP;
+		}
+#endif
 	}
 
 	rc = pci_request_regions(pdev, DRV_NAME);