diff options
author | Yi Li <yi.li@analog.com> | 2009-12-02 10:58:12 +0300 |
---|---|---|
committer | Mike Frysinger <vapier@gentoo.org> | 2009-12-15 08:16:09 +0300 |
commit | 578d36f5e160208821e8f51037ac1038e065ecaf (patch) | |
tree | 6b1da0d6e7108c0bd217b132e165f2d06007fef8 /arch/blackfin/mach-bf561/smp.c | |
parent | ad774b7cb0604d02c3596b79921fcb812df4dc71 (diff) | |
download | linux-578d36f5e160208821e8f51037ac1038e065ecaf.tar.xz |
Blackfin: SMP: don't start up core b until its state has been completely onlined
When testing PREEMPT_RT kernel on BF561-EZKit, the kernel blocks while
booting. When the kernel initializes the ethernet driver, it sleeps and
never wakes up.
The issue happens when the kernel waits for a timer for Core B to timeout
(the timers are per-cpu based: static DEFINE_PER_CPU(struct tvec_base *,
tvec_bases) = &boot_tvec_bases).
However, the ksoftirqd thread for Core B (note, the ksoftirqd thread is
also per-cpu based) cannot work properly, and the timers for Core B never
times out.
When ksoftirqd() for the first time runs on core B, it is possible core A
is still initializing core B (see smp_init() -> cpu_up() -> __cpu_up()).
So the "cpu_is_offline()" check may return true and ksoftirqd moves to
"wait_to_die".
So delay the core b start up until the per-cpu timers have been set up
fully.
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/mach-bf561/smp.c')
-rw-r--r-- | arch/blackfin/mach-bf561/smp.c | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/arch/blackfin/mach-bf561/smp.c b/arch/blackfin/mach-bf561/smp.c index 510f57641495..0192532e96a2 100644 --- a/arch/blackfin/mach-bf561/smp.c +++ b/arch/blackfin/mach-bf561/smp.c @@ -52,8 +52,6 @@ int __init setup_profiling_timer(unsigned int multiplier) /* not supported */ void __cpuinit platform_secondary_init(unsigned int cpu) { - local_irq_disable(); - /* Clone setup for peripheral interrupt sources from CoreA. */ bfin_write_SICB_IMASK0(bfin_read_SICA_IMASK0()); bfin_write_SICB_IMASK1(bfin_read_SICA_IMASK1()); @@ -70,11 +68,6 @@ void __cpuinit platform_secondary_init(unsigned int cpu) bfin_write_SICB_IAR7(bfin_read_SICA_IAR7()); SSYNC(); - local_irq_enable(); - - /* Calibrate loops per jiffy value. */ - calibrate_delay(); - /* Store CPU-private information to the cpu_data array. */ bfin_setup_cpudata(cpu); @@ -108,9 +101,13 @@ int __cpuinit platform_boot_secondary(unsigned int cpu, struct task_struct *idle barrier(); } - spin_unlock(&boot_lock); - - return cpu_isset(cpu, cpu_callin_map) ? 0 : -ENOSYS; + if (cpu_isset(cpu, cpu_callin_map)) { + cpu_set(cpu, cpu_online_map); + /* release the lock and let coreb run */ + spin_unlock(&boot_lock); + return 0; + } else + panic("CPU%u: processor failed to boot\n", cpu); } void __init platform_request_ipi(irq_handler_t handler) |