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[PATCH] ppc64: Fix g5 hw timebase sync

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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>
This commit is contained in:
Benjamin Herrenschmidt 2005-05-23 16:54:14 +10:00 committed by Linus Torvalds
parent e16fa6b9d2
commit f10d20c1f1
1 changed files with 21 additions and 7 deletions
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28
arch/ppc64/kernel/pmac_smp.c
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@ -68,6 +68,7 @@ extern struct smp_ops_t *smp_ops;
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 @@ static void smp_core99_pulsar_tb_freeze(int freeze)
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 @@ static void smp_core99_pulsar_tb_freeze(int freeze)
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 @@ static int __init smp_core99_probe(void)
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 @@ static int __init smp_core99_probe(void)
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 @@ static int __init smp_core99_probe(void)
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;