diff options
author | Mike Leach <mike.leach@linaro.org> | 2020-07-01 19:08:52 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-01 19:45:34 +0300 |
commit | 9b6a3f3633a5cc928b78627764793b60cb62e0f6 (patch) | |
tree | 53c6f285cb8b67184857fa2bbdaac7079dc509a5 /drivers/hwtracing/coresight/coresight-etm4x.c | |
parent | 6740de9433556d5e3f94c4901dce120d27677be1 (diff) | |
download | linux-9b6a3f3633a5cc928b78627764793b60cb62e0f6.tar.xz |
coresight: etmv4: Fix CPU power management setup in probe() function
The current probe() function calls a pair of cpuhp_xxx API functions to
setup CPU hotplug handling. The hotplug lock is held for the duration of
the two calls and other CPU related code using cpus_read_lock() /
cpus_read_unlock() calls.
The problem is that on error states, goto: statements bypass the
cpus_read_unlock() call. This code has increased in complexity as the
driver has developed.
This patch introduces a pair of helper functions etm4_pm_setup_cpuslocked()
and etm4_pm_clear() which correct the issues above and group the PM code a
little better.
The two functions etm4_cpu_pm_register() and etm4_cpu_pm_unregister() are
dropped as these call cpu_pm_register_notifier() / ..unregister_notifier()
dependent on CONFIG_CPU_PM - but this define is used to nop these functions
out in the pm headers - so the wrapper functions are superfluous.
Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states")
Fixes: e9f5d63f84fe ("hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()")
Fixes: 58eb457be028 ("hwtracing/coresight-etm4x: Convert to hotplug state machine")
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200701160852.2782823-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etm4x.c')
-rw-r--r-- | drivers/hwtracing/coresight/coresight-etm4x.c | 82 |
1 files changed, 53 insertions, 29 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index 747afc875f91..0c35cd5e0d1d 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -1388,18 +1388,57 @@ static struct notifier_block etm4_cpu_pm_nb = { .notifier_call = etm4_cpu_pm_notify, }; -static int etm4_cpu_pm_register(void) +/* Setup PM. Called with cpus locked. Deals with error conditions and counts */ +static int etm4_pm_setup_cpuslocked(void) { - if (IS_ENABLED(CONFIG_CPU_PM)) - return cpu_pm_register_notifier(&etm4_cpu_pm_nb); + int ret; - return 0; + if (etm4_count++) + return 0; + + ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb); + if (ret) + goto reduce_count; + + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING, + "arm/coresight4:starting", + etm4_starting_cpu, etm4_dying_cpu); + + if (ret) + goto unregister_notifier; + + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, + "arm/coresight4:online", + etm4_online_cpu, NULL); + + /* HP dyn state ID returned in ret on success */ + if (ret > 0) { + hp_online = ret; + return 0; + } + + /* failed dyn state - remove others */ + cpuhp_remove_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING); + +unregister_notifier: + cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); + +reduce_count: + --etm4_count; + return ret; } -static void etm4_cpu_pm_unregister(void) +static void etm4_pm_clear(void) { - if (IS_ENABLED(CONFIG_CPU_PM)) - cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); + if (--etm4_count != 0) + return; + + cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); + if (hp_online) { + cpuhp_remove_state_nocalls(hp_online); + hp_online = 0; + } } static int etm4_probe(struct amba_device *adev, const struct amba_id *id) @@ -1453,24 +1492,15 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) etm4_init_arch_data, drvdata, 1)) dev_err(dev, "ETM arch init failed\n"); - if (!etm4_count++) { - cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING, - "arm/coresight4:starting", - etm4_starting_cpu, etm4_dying_cpu); - ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, - "arm/coresight4:online", - etm4_online_cpu, NULL); - if (ret < 0) - goto err_arch_supported; - hp_online = ret; + ret = etm4_pm_setup_cpuslocked(); + cpus_read_unlock(); - ret = etm4_cpu_pm_register(); - if (ret) - goto err_arch_supported; + /* etm4_pm_setup_cpuslocked() does its own cleanup - exit on error */ + if (ret) { + etmdrvdata[drvdata->cpu] = NULL; + return ret; } - cpus_read_unlock(); - if (etm4_arch_supported(drvdata->arch) == false) { ret = -EINVAL; goto err_arch_supported; @@ -1517,13 +1547,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) err_arch_supported: etmdrvdata[drvdata->cpu] = NULL; - if (--etm4_count == 0) { - etm4_cpu_pm_unregister(); - - cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); - if (hp_online) - cpuhp_remove_state_nocalls(hp_online); - } + etm4_pm_clear(); return ret; } |