From 734796f12351f9a0f38c47b981414f82d852f222 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 8 Mar 2011 13:54:50 +1100 Subject: [PATCH] powerpc/pmac/smp: Fix CPU hotplug crashes on some machines On some machines that use i2c to synchronize the timebases (such as PowerMac7,2/7,3 G5 machines), hotplug CPU would crash when putting back a new CPU online due to the underlying i2c bus being closed. This uses the newly added bringup_done() callback to move the close along with other housekeeping calls, and adds a CPU notifier to re-open the i2c bus around subsequent hotplug operations Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/powermac/smp.c | 71 +++++++++++++++++++++++++++-------- 1 file changed, 55 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c index 837989e..74a43c6 100644 --- a/arch/powerpc/platforms/powermac/smp.c +++ b/arch/powerpc/platforms/powermac/smp.c @@ -840,30 +840,68 @@ static void __devinit smp_core99_setup_cpu(int cpu_nr) /* Setup openpic */ mpic_setup_this_cpu(); +} - if (cpu_nr == 0) { -#ifdef CONFIG_PPC64 - extern void g5_phy_disable_cpu1(void); +#ifdef CONFIG_HOTPLUG_CPU +static int smp_core99_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + int rc; - /* Close i2c bus if it was used for tb sync */ + switch(action) { + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: + /* Open i2c bus if it was used for tb sync */ if (pmac_tb_clock_chip_host) { - pmac_i2c_close(pmac_tb_clock_chip_host); - pmac_tb_clock_chip_host = NULL; + rc = pmac_i2c_open(pmac_tb_clock_chip_host, 1); + if (rc) { + pr_err("Failed to open i2c bus for time sync\n"); + return notifier_from_errno(rc); + } } + break; + case CPU_ONLINE: + case CPU_UP_CANCELED: + /* Close i2c bus if it was used for tb sync */ + if (pmac_tb_clock_chip_host) + pmac_i2c_close(pmac_tb_clock_chip_host); + break; + default: + break; + } + return NOTIFY_OK; +} - /* If we didn't start the second CPU, we must take - * it off the bus - */ - if (of_machine_is_compatible("MacRISC4") && - num_online_cpus() < 2) - g5_phy_disable_cpu1(); -#endif /* CONFIG_PPC64 */ +static struct notifier_block __cpuinitdata smp_core99_cpu_nb = { + .notifier_call = smp_core99_cpu_notify, +}; +#endif /* CONFIG_HOTPLUG_CPU */ - if (ppc_md.progress) - ppc_md.progress("core99_setup_cpu 0 done", 0x349); +static void __init smp_core99_bringup_done(void) +{ +#ifdef CONFIG_PPC64 + extern void g5_phy_disable_cpu1(void); + + /* Close i2c bus if it was used for tb sync */ + if (pmac_tb_clock_chip_host) + pmac_i2c_close(pmac_tb_clock_chip_host); + + /* If we didn't start the second CPU, we must take + * it off the bus. + */ + if (of_machine_is_compatible("MacRISC4") && + num_online_cpus() < 2) { + set_cpu_present(1, false); + g5_phy_disable_cpu1(); } -} +#endif /* CONFIG_PPC64 */ +#ifdef CONFIG_HOTPLUG_CPU + register_cpu_notifier(&smp_core99_cpu_nb); +#endif + if (ppc_md.progress) + ppc_md.progress("smp_core99_bringup_done", 0x349); +} #ifdef CONFIG_HOTPLUG_CPU @@ -940,6 +978,7 @@ static void pmac_cpu_die(void) struct smp_ops_t core99_smp_ops = { .message_pass = smp_mpic_message_pass, .probe = smp_core99_probe, + .bringup_done = smp_core99_bringup_done, .kick_cpu = smp_core99_kick_cpu, .setup_cpu = smp_core99_setup_cpu, .give_timebase = smp_core99_give_timebase, -- 2.7.4