From: Aaron Sierra <asie...@xes-inc.com>
Some OSes require that secondary cores not be initialized when they
are booted (eg VxWorks). By default when U-Boot is compiled with the
CONFIG_MP option all secondary cores are brought out of reset and held
in spinloops. Setting the "mp_holdoff" environment variable to a
non-null value will cause U-Boot to leave secondary cores in their
default state.
Signed-off-by: Aaron Sierra <asie...@xes-inc.com>
Signed-off-by: Peter Tyser <pty...@xes-inc.com>
---
arch/powerpc/cpu/mpc85xx/mp.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/cpu/mpc85xx/mp.c b/arch/powerpc/cpu/mpc85xx/mp.c
index 603baef..7ad5efb 100644
--- a/arch/powerpc/cpu/mpc85xx/mp.c
+++ b/arch/powerpc/cpu/mpc85xx/mp.c
@@ -51,6 +51,11 @@ int cpu_status(int nr)
{
u32 *table, id = get_my_id();
+ if (getenv("mp_holdoff")) {
+ printf("Secondary cores are disabled; mp_holdoff is set\n");
+ return 0;
+ }
+
if (nr == id) {
table = (u32 *)get_spin_virt_addr();
printf("table base @ 0x%p\n", table);
@@ -133,6 +138,11 @@ int cpu_release(int nr, int argc, char * const argv[])
u32 i, val, *table = (u32 *)get_spin_virt_addr() + nr * NUM_BOOT_ENTRY;
u64 boot_addr;
+ if (getenv("mp_holdoff")) {
+ printf("Secondary cores are disabled; mp_holdoff is set\n");
+ return 0;
+ }
+
if (nr == get_my_id()) {
printf("Invalid to release the boot core.\n\n");
return 1;
@@ -353,6 +363,14 @@ void setup_mp(void)
ulong fixup = (ulong)&__secondary_start_page;
u32 bootpg = determine_mp_bootpg();
+ /*
+ * Some OSes expect the secondary cores to be held in reset when the OS
+ * boots. Use the optional 'mp_holdoff' environment variable to allow
+ * users to disable the bring up of secondary cores.
+ */
+ if (getenv("mp_holdoff"))
+ return;
+
/* Store the bootpg's SDRAM address for use by secondary CPU cores */
__bootpg_addr = bootpg;
--
1.7.0.4
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