pata_cm64x: fix boot crash on parisc

The old IDE cmd64x checks the status of the CNTRL register to see if
the ports are enabled before probing them.  pata_cmd64x doesn't do
this, which causes a HPMC on parisc when it tries to poke at the
secondary port because apparently the BAR isn't wired up (and a
non-responding piece of memory causes a HPMC).

Fix this by porting the CNTRL register port detection logic from IDE
cmd64x.  In addition, following converns from Alan Cox, add a check to
see if a mobility electronics bridge is the immediate parent and forgo
the check if it is (prevents problems on hotplug controllers).

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 38 insertions, 4 deletions

diff --git a/drivers/ata/pata_cmd64x.c b/drivers/ata/pata_cmd64x.c
index 905ff76d3cbb..7bafc16cf5e0 100644
--- a/drivers/ata/pata_cmd64x.c
+++ b/drivers/ata/pata_cmd64x.c
@@ -41,6 +41,9 @@
 enum {
         CFR             = 0x50,
                 CFR_INTR_CH0  = 0x04,
+        CNTRL           = 0x51,
+                CNTRL_CH0     = 0x04,
+                CNTRL_CH1     = 0x08,
         CMDTIM          = 0x52,
         ARTTIM0         = 0x53,
         DRWTIM0         = 0x54,
@@ -328,9 +331,19 @@ static int cmd64x_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
                         .port_ops = &cmd648_port_ops
                 }
         };
-        const struct ata_port_info *ppi[] = { &cmd_info[id->driver_data], NULL };
-        u8 mrdmode;
+        const struct ata_port_info *ppi[] = { 
+                &cmd_info[id->driver_data],
+                &cmd_info[id->driver_data],
+                NULL
+        };
+        u8 mrdmode, reg;
         int rc;
+        struct pci_dev *bridge = pdev->bus->self;
+        /* mobility split bridges don't report enabled ports correctly */
+        int port_ok = !(bridge && bridge->vendor ==
+                        PCI_VENDOR_ID_MOBILITY_ELECTRONICS);
+        /* all (with exceptions below) apart from 643 have CNTRL_CH0 bit */
+        int cntrl_ch0_ok = (id->driver_data != 0);
 
         rc = pcim_enable_device(pdev);
         if (rc)
@@ -341,11 +354,18 @@ static int cmd64x_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 
         if (pdev->device == PCI_DEVICE_ID_CMD_646) {
                 /* Does UDMA work ? */
-                if (pdev->revision > 4)
+                if (pdev->revision > 4) {
                         ppi[0] = &cmd_info[2];
+                        ppi[1] = &cmd_info[2];
+                }
                 /* Early rev with other problems ? */
-                else if (pdev->revision == 1)
+                else if (pdev->revision == 1) {
                         ppi[0] = &cmd_info[3];
+                        ppi[1] = &cmd_info[3];
+                }
+                /* revs 1,2 have no CNTRL_CH0 */
+                if (pdev->revision < 3)
+                        cntrl_ch0_ok = 0;
         }
 
         pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 64);
@@ -354,6 +374,20 @@ static int cmd64x_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
         mrdmode |= 0x02;        /* Memory read line enable */
         pci_write_config_byte(pdev, MRDMODE, mrdmode);
 
+        /* check for enabled ports */
+        pci_read_config_byte(pdev, CNTRL, &reg);
+        if (!port_ok)
+                dev_printk(KERN_NOTICE, &pdev->dev, "Mobility Bridge detected, ignoring CNTRL port enable/disable\n");
+        if (port_ok && cntrl_ch0_ok && !(reg & CNTRL_CH0)) {
+                dev_printk(KERN_NOTICE, &pdev->dev, "Primary port is disabled\n");
+                ppi[0] = &ata_dummy_port_info;
+                
+        }
+        if (port_ok && !(reg & CNTRL_CH1)) {
+                dev_printk(KERN_NOTICE, &pdev->dev, "Secondary port is disabled\n");
+                ppi[1] = &ata_dummy_port_info;
+        }
+
         /* Force PIO 0 here.. */
 
         /* PPC specific fixup copied from old driver */