ETE registers are always system registers so it's highly unlikely there will be an implementation that preserves them on CPU power down. Also the ETE DT binding never documented "arm,coresight-loses-context-with-cpu" so nobody would have legitimately been able to use that binding to fix it.
Fix it by hard coding the setting for ETE and add a warning if the user tried to use the module parameter. Don't add a warning if loses-context-with-cpu is present in the DT as it's not a documented binding anyway. etm4_init_pm_save() needs to happen after drvdata is initialised so etm4x_is_ete() can be called.
This fixes the following error when using Coresight with ACPI on the FVP which supports CPU PM:
coresight ete0: External agent took claim tag WARNING: drivers/hwtracing/coresight/coresight-core.c:248 at coresight_disclaim_device_unlocked+0xe0/0xe8, CPU#0: perf/117
Fixes: 35e1c9163e02 ("coresight: ete: Add support for ETE tracing") Signed-off-by: James Clark james.clark@linaro.org --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 41 +++++++++++++++------- 1 file changed, 29 insertions(+), 12 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d565a73f0042..a7fb680dd383 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -56,10 +56,11 @@ MODULE_PARM_DESC(boot_enable, "Enable tracing on boot"); #define PARAM_PM_SAVE_NEVER 1 /* never save any state */ #define PARAM_PM_SAVE_SELF_HOSTED 2 /* save self-hosted state only */
+/* Save option for ETM4. ETE ignores this option and always saves */ static int pm_save_enable = PARAM_PM_SAVE_FIRMWARE; module_param(pm_save_enable, int, 0444); MODULE_PARM_DESC(pm_save_enable, - "Save/restore state on power down: 1 = never, 2 = self-hosted"); + "Save/restore state on power down: 1 = never, 2 = self-hosted. ETM4 only.");
static struct etmv4_drvdata *etmdrvdata[NR_CPUS]; static void etm4_set_default_config(struct etmv4_config *config); @@ -1365,6 +1366,30 @@ static void etm4_fixup_wrong_ccitmin(struct etmv4_drvdata *drvdata) } }
+static int etm4_init_pm_save(struct device *dev, struct etmv4_drvdata *drvdata) +{ + if (etm4x_is_ete(drvdata)) { + /* + * Always do PM save for ETE. It always uses system registers + * which will be lost on CPU power down. + */ + pm_save_enable = PARAM_PM_SAVE_SELF_HOSTED; + } else if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE) { + pm_save_enable = coresight_loses_context_with_cpu(dev) ? + PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER; + } + + if (pm_save_enable != PARAM_PM_SAVE_NEVER) { + drvdata->save_state = devm_kmalloc(dev, + sizeof(struct etmv4_save_state), + GFP_KERNEL); + if (!drvdata->save_state) + return -ENOMEM; + } + + return 0; +} + static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -2247,6 +2272,9 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg) return -ENOMEM;
etm4_set_default(&drvdata->config); + ret = etm4_init_pm_save(dev, drvdata); + if (ret) + return ret;
pdata = coresight_get_platform_data(dev); if (IS_ERR(pdata)) @@ -2305,17 +2333,6 @@ static int etm4_probe(struct device *dev) if (ret) return ret;
- if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE) - pm_save_enable = coresight_loses_context_with_cpu(dev) ? - PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER; - - if (pm_save_enable != PARAM_PM_SAVE_NEVER) { - drvdata->save_state = devm_kmalloc(dev, - sizeof(struct etmv4_save_state), GFP_KERNEL); - if (!drvdata->save_state) - return -ENOMEM; - } - raw_spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev);