Take two.
Note that the processors on a JS20 are noticably slower to handshake
than those on a JS21. I had to rid of the hard-coded 1024 timebase
ticks and replace it with calculating five seconds from the timebase
frequency, as the timeout logic was firing on my JS20 blade.
Note that the SLOF image I have for JS20 blades seems to have a bug
wherein string passed to the last of_printf() call before quiescing is
never output to the serial port. This will cause you to waste a lot of
time when debugging with printfs, not to mention that it appears to the
user that cpu #1 was never spun up. So this patch makes us print one
extra line before quiescing OF.
Signed-off-by: Amos Waterland <apw@xxxxxxxxxx>
---
boot_of.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++---
powerpc64/exceptions.S | 8 +++++++
2 files changed, 57 insertions(+), 3 deletions(-)
diff -r 058f2e27476d xen/arch/powerpc/boot_of.c
--- a/xen/arch/powerpc/boot_of.c Mon Aug 07 17:49:16 2006 -0500
+++ b/xen/arch/powerpc/boot_of.c Thu Aug 10 21:56:18 2006 -0400
@@ -30,6 +30,9 @@
#include <asm/io.h>
#include "exceptions.h"
#include "of-devtree.h"
+
+/* Secondary processors use this for handshaking with main processor. */
+volatile unsigned int __spin_ack;
static ulong of_vec;
static ulong of_msr;
@@ -928,7 +931,7 @@ static int __init boot_of_cpus(void)
static int __init boot_of_cpus(void)
{
int cpus;
- int cpu;
+ int cpu, bootcpu;
int result;
u32 cpu_clock[2];
@@ -953,10 +956,52 @@ static int __init boot_of_cpus(void)
cpu_khz /= 1000;
of_printf("OF: clock-frequency = %ld KHz\n", cpu_khz);
- /* FIXME: should not depend on the boot CPU bring the first child */
+ /* Look up which CPU we are running on right now. */
+ result = of_getprop(bof_chosen, "cpu", &bootcpu, sizeof (bootcpu));
+ if (result == OF_FAILURE)
+ of_panic("Failed to look up boot cpu\n");
+
cpu = of_getpeer(cpu);
while (cpu > 0) {
- of_start_cpu(cpu, (ulong)spin_start, 0);
+ unsigned int cpuid, ping, pong;
+ unsigned long now, then, timeout;
+ unsigned int *ack = (unsigned int *)&__spin_ack;
+
+ if (cpu == bootcpu) {
+ of_printf("skipping boot cpu!\n");
+ continue;
+ }
+
+ result = of_getprop(cpu, "reg", &cpuid, sizeof(cpuid));
+ if (result == OF_FAILURE)
+ of_panic("cpuid lookup failed\n");
+
+ of_printf("spinning up secondary processor #%d: ", cpuid);
+
+ *ack = ~0x0;
+ ping = *ack;
+ of_printf("ping = 0x%x: ", ping);
+
+ mb();
+ of_start_cpu(cpu, (ulong)spin_start, cpuid);
+
+ /* We will give the secondary processor five seconds to reply. */
+ then = mftb();
+ timeout = then + (5 * timebase_freq);
+
+ do {
+ now = mftb();
+ if (now >= timeout) {
+ of_printf("BROKEN: ");
+ pong = 0x0;
+ break;
+ }
+
+ mb();
+ pong = *ack;
+ } while (pong == ping);
+ of_printf("pong = 0x%x\n", pong);
+
cpu = of_getpeer(cpu);
}
return 1;
@@ -1004,6 +1049,7 @@ multiboot_info_t __init *boot_of_init(
boot_of_rtas();
/* end of OF */
+ of_printf("Quiescing Open Firmware ...\n");
of_call("quiesce", 0, 0, NULL);
return &mbi;
diff -r 058f2e27476d xen/arch/powerpc/powerpc64/exceptions.S
--- a/xen/arch/powerpc/powerpc64/exceptions.S Mon Aug 07 17:49:16 2006 -0500
+++ b/xen/arch/powerpc/powerpc64/exceptions.S Thu Aug 10 22:03:15 2006 -0400
@@ -514,6 +514,14 @@ _GLOBAL(sleep)
mtmsrd r3
blr
+/* Firmware is told to spin up secondary processors at this address. We
+ * only need a function entry point instead of a descriptor since this is
+ * never called from C code.
+ */
.globl spin_start
spin_start:
+ /* Our physical cpu number is passed in r3. */
+ LOADADDR(r4, __spin_ack)
+ stw r3, 0(r4)
+ sync
b .
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