[PATCH] ppc64: Fix g5 hw timebase sync
The hardware sync of the timebase on SMP G5s uses a black magic
incantation to the i2c clock chip that was inspired from what Darwin
does.
However, this was an earlier version of Darwin that was ... buggy !
heh. This causes the latest models to break though when starting SMP,
so it's worth fixing.
Here's a new version of the incantation based on careful transcription
of the said incantations as found in the latest version of apple's
temple.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/ppc64/kernel/pmac_smp.c b/arch/ppc64/kernel/pmac_smp.c
index c27588e..a23de37 100644
--- a/arch/ppc64/kernel/pmac_smp.c
+++ b/arch/ppc64/kernel/pmac_smp.c
@@ -68,6 +68,7 @@
static void (*pmac_tb_freeze)(int freeze);
static struct device_node *pmac_tb_clock_chip_host;
+static u8 pmac_tb_pulsar_addr;
static DEFINE_SPINLOCK(timebase_lock);
static unsigned long timebase;
@@ -106,12 +107,9 @@
u8 data;
int rc;
- /* Strangely, the device-tree says address is 0xd2, but darwin
- * accesses 0xd0 ...
- */
pmac_low_i2c_setmode(pmac_tb_clock_chip_host, pmac_low_i2c_mode_combined);
rc = pmac_low_i2c_xfer(pmac_tb_clock_chip_host,
- 0xd4 | pmac_low_i2c_read,
+ pmac_tb_pulsar_addr | pmac_low_i2c_read,
0x2e, &data, 1);
if (rc != 0)
goto bail;
@@ -120,7 +118,7 @@
pmac_low_i2c_setmode(pmac_tb_clock_chip_host, pmac_low_i2c_mode_stdsub);
rc = pmac_low_i2c_xfer(pmac_tb_clock_chip_host,
- 0xd4 | pmac_low_i2c_write,
+ pmac_tb_pulsar_addr | pmac_low_i2c_write,
0x2e, &data, 1);
bail:
if (rc != 0) {
@@ -185,6 +183,12 @@
if (ncpus <= 1)
return 1;
+ /* HW sync only on these platforms */
+ if (!machine_is_compatible("PowerMac7,2") &&
+ !machine_is_compatible("PowerMac7,3") &&
+ !machine_is_compatible("RackMac3,1"))
+ goto nohwsync;
+
/* Look for the clock chip */
for (cc = NULL; (cc = of_find_node_by_name(cc, "i2c-hwclock")) != NULL;) {
struct device_node *p = of_get_parent(cc);
@@ -198,11 +202,18 @@
goto next;
switch (*reg) {
case 0xd2:
- pmac_tb_freeze = smp_core99_cypress_tb_freeze;
- printk(KERN_INFO "Timebase clock is Cypress chip\n");
+ if (device_is_compatible(cc, "pulsar-legacy-slewing")) {
+ pmac_tb_freeze = smp_core99_pulsar_tb_freeze;
+ pmac_tb_pulsar_addr = 0xd2;
+ printk(KERN_INFO "Timebase clock is Pulsar chip\n");
+ } else if (device_is_compatible(cc, "cy28508")) {
+ pmac_tb_freeze = smp_core99_cypress_tb_freeze;
+ printk(KERN_INFO "Timebase clock is Cypress chip\n");
+ }
break;
case 0xd4:
pmac_tb_freeze = smp_core99_pulsar_tb_freeze;
+ pmac_tb_pulsar_addr = 0xd4;
printk(KERN_INFO "Timebase clock is Pulsar chip\n");
break;
}
@@ -210,12 +221,15 @@
pmac_tb_clock_chip_host = p;
smp_ops->give_timebase = smp_core99_give_timebase;
smp_ops->take_timebase = smp_core99_take_timebase;
+ of_node_put(cc);
+ of_node_put(p);
break;
}
next:
of_node_put(p);
}
+ nohwsync:
mpic_request_ipis();
return ncpus;