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85xx: Add support for not releasing secondary cores via 'mp_holdoff'

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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 'yes'
or '1' will cause U-Boot to leave secondary cores in their default
state.

Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Aaron Sierra
2010-09-30 12:22:16 -05:00
committed by Kumar Gala
parent 58edbc9caa
commit 9d64c6bb4a
3 changed files with 51 additions and 3 deletions
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31
arch/powerpc/cpu/mpc85xx/mp.c
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@@ -36,6 +36,27 @@ u32 get_my_id()
return mfspr(SPRN_PIR);
}
/*
* Determine if U-Boot should keep secondary cores in reset, or let them out
* of reset and hold them in a spinloop
*/
int hold_cores_in_reset(int verbose)
{
const char *s = getenv("mp_holdoff");
/* Default to no, overriden by 'y', 'yes', 'Y', 'Yes', or '1' */
if (s && (*s == 'y' || *s == 'Y' || *s == '1')) {
if (verbose) {
puts("Secondary cores are being held in reset.\n");
puts("See 'mp_holdoff' environment variable\n");
}
return 1;
}
return 0;
}
int cpu_reset(int nr)
{
volatile ccsr_pic_t *pic = (void *)(CONFIG_SYS_MPC8xxx_PIC_ADDR);
@@ -51,6 +72,9 @@ int cpu_status(int nr)
{
u32 *table, id = get_my_id();
if (hold_cores_in_reset(1))
return 0;
if (nr == id) {
table = (u32 *)get_spin_virt_addr();
printf("table base @ 0x%p\n", table);
@@ -133,6 +157,9 @@ 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 (hold_cores_in_reset(1))
return 0;
if (nr == get_my_id()) {
printf("Invalid to release the boot core.\n\n");
return 1;
@@ -353,6 +380,10 @@ void setup_mp(void)
ulong fixup = (ulong)&__secondary_start_page;
u32 bootpg = determine_mp_bootpg();
/* Some OSes expect secondary cores to be held in reset */
if (hold_cores_in_reset(0))
return;
/* Store the bootpg's SDRAM address for use by secondary CPU cores */
__bootpg_addr = bootpg;