[PATCH] ata: pata_hpt37x: disable primary channel on HPT371

[Sergey Shtylyov <s.shtylyov@omp.ru>]

HPT371 chips physically have only one channel, the secondary one, however
the primary channel registers do exist!  Thus we have to manually disable
the non-existing channel (if the BIOS hasn't done this already).  Alan Cox
has only added such code to the 'pata_hpt3x2n' driver, forgetting about
this one... :-/

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>

---
This patch is against the 'for-next' branch of Damien Le Moal's 'libata.git'
repo.

 drivers/ata/pata_hpt37x.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

Index: libata/drivers/ata/pata_hpt37x.c
===================================================================
--- libata.orig/drivers/ata/pata_hpt37x.c
+++ libata/drivers/ata/pata_hpt37x.c
@@ -867,6 +867,20 @@ static int hpt37x_init_one(struct pci_de
 	pci_write_config_byte(dev, 0x5a, irqmask);
 
 	/*
+	 * HPT371 chips physically have only one channel, the secondary one,
+	 * but the primary channel registers do exist!  Go figure...
+	 * So,  we manually disable the non-existing channel here
+	 * (if the BIOS hasn't done this already).
+	 */
+	if (dev->device == PCI_DEVICE_ID_TTI_HPT371) {
+		u8 mcr1;
+
+		pci_read_config_byte(dev, 0x50, &mcr1);
+		mcr1 &= ~0x04;
+		pci_write_config_byte(dev, 0x50, mcr1);
+	}
+
+	/*
 	 * default to pci clock. make sure MA15/16 are set to output
 	 * to prevent drives having problems with 40-pin cables. Needed
 	 * for some drives such as IBM-DTLA which will not enter ready