From: Randy Vinson <rvinson@mvista•com>
To: "linuxppc-dev@ozlabs•org" <linuxppc-dev@ozlabs•org>
Subject: [PATCH v2] 85xxCDS: Make sure restart resets the PCI bus.
Date: Mon, 11 Jun 2007 15:18:23 -0700 [thread overview]
Message-ID: <466DCA2F.9010306@mvista.com> (raw)
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>
---
Updated to incorporate feedback from M. Greer.
arch/powerpc/platforms/85xx/mpc85xx_cds.c | 35 +++++++++++++++++++++++++++++
1 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_cds.c b/arch/powerpc/platforms/85xx/mpc85xx_cds.c
index bc01364..a8720bf 100644
--- a/arch/powerpc/platforms/85xx/mpc85xx_cds.c
+++ b/arch/powerpc/platforms/85xx/mpc85xx_cds.c
@@ -63,6 +63,37 @@ static volatile u8 *cadmus;
extern int mpc85xx_pci2_busno;
+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 int mpc85xx_exclude_device(u_char bus, u_char devfn)
{
if (bus == 0 && PCI_SLOT(devfn) == 0)
@@ -320,7 +351,11 @@ 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,
};
--
1.5.0.GIT
reply other threads:[~2007-06-11 22:18 UTC|newest]
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