diff options
| -rw-r--r-- | arch/mips/kernel/pm-cps.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c index 421e06dfee72..55c3fbeb2df6 100644 --- a/arch/mips/kernel/pm-cps.c +++ b/arch/mips/kernel/pm-cps.c @@ -12,6 +12,7 @@ #include <linux/init.h> #include <linux/percpu.h> #include <linux/slab.h> +#include <linux/suspend.h> #include <asm/asm-offsets.h> #include <asm/cacheflush.h> @@ -670,6 +671,34 @@ static int cps_pm_online_cpu(unsigned int cpu) return 0; } +static int cps_pm_power_notifier(struct notifier_block *this, + unsigned long event, void *ptr) +{ + unsigned int stat; + + switch (event) { + case PM_SUSPEND_PREPARE: + stat = read_cpc_cl_stat_conf(); + /* + * If we're attempting to suspend the system and power down all + * of the cores, the JTAG detect bit indicates that the CPC will + * instead put the cores into clock-off state. In this state + * a connected debugger can cause the CPU to attempt + * interactions with the powered down system. At best this will + * fail. At worst, it can hang the NoC, requiring a hard reset. + * To avoid this, just block system suspend if a JTAG probe + * is detected. + */ + if (stat & CPC_Cx_STAT_CONF_EJTAG_PROBE) { + pr_warn("JTAG probe is connected - abort suspend\n"); + return NOTIFY_BAD; + } + return NOTIFY_DONE; + default: + return NOTIFY_DONE; + } +} + static int __init cps_pm_init(void) { /* A CM is required for all non-coherent states */ @@ -705,6 +734,8 @@ static int __init cps_pm_init(void) pr_warn("pm-cps: no CPC, clock & power gating unavailable\n"); } + pm_notifier(cps_pm_power_notifier, 0); + return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mips/cps_pm:online", cps_pm_online_cpu, NULL); } |