[POWERPC] 85xxCDS: Make sure restart resets the PCI bus.
authorRandy Vinson <rvinson@linuxbox.(none)>
Fri, 23 Mar 2007 22:43:37 +0000 (15:43 -0700)
committerKumar Gala <galak@kernel.crashing.org>
Tue, 24 Jul 2007 03:35:12 +0000 (22:35 -0500)
The current 85xxCDS restart code fails to reset the PCI bus which can
lead to odd behavior after the restart. This patch uses the VIA Super
Southbridge to perform a PCI reset which will reset the entire system.
NOTE: Since the VIA chip is behind a PCI-to-PCI bridge which can be
disabled with a switch setting, it may not be possible to perform the
PCI bus reset. In this case, the code defaults to the previous restart
mechanism.

Signed-off-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
arch/powerpc/platforms/85xx/mpc85xx_cds.c

index 81b70628df75c8c287689c67d093058e8619f34b..e77c869d391621f727a3fb53d61d5eea9cd02095 100644 (file)
@@ -69,6 +69,37 @@ static int mpc85xx_exclude_device(struct pci_controller *hose,
                return PCIBIOS_SUCCESSFUL;
 }
 
+static void mpc85xx_cds_restart(char *cmd)
+{
+       struct pci_dev *dev;
+       u_char tmp;
+
+       if ((dev = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686,
+                                       NULL))) {
+
+               /* Use the VIA Super Southbridge to force a PCI reset */
+               pci_read_config_byte(dev, 0x47, &tmp);
+               pci_write_config_byte(dev, 0x47, tmp | 1);
+
+               /* Flush the outbound PCI write queues */
+               pci_read_config_byte(dev, 0x47, &tmp);
+
+               /*
+                *  At this point, the harware reset should have triggered.
+                *  However, if it doesn't work for some mysterious reason,
+                *  just fall through to the default reset below.
+                */
+
+               pci_dev_put(dev);
+       }
+
+       /*
+        *  If we can't find the VIA chip (maybe the P2P bridge is disabled)
+        *  or the VIA chip reset didn't work, just use the default reset.
+        */
+       mpc85xx_restart(NULL);
+}
+
 static void __init mpc85xx_cds_pci_irq_fixup(struct pci_dev *dev)
 {
        u_char c;
@@ -304,7 +335,11 @@ define_machine(mpc85xx_cds) {
        .init_IRQ       = mpc85xx_cds_pic_init,
        .show_cpuinfo   = mpc85xx_cds_show_cpuinfo,
        .get_irq        = mpic_get_irq,
+#ifdef CONFIG_PCI
+       .restart        = mpc85xx_cds_restart,
+#else
        .restart        = mpc85xx_restart,
+#endif
        .calibrate_decr = generic_calibrate_decr,
        .progress       = udbg_progress,
        .pcibios_fixup_bus      = fsl_pcibios_fixup_bus,