Re: [PATCH v11 09/24] coresight: etm3x: allow etm3x to be built as a module

Tingwei Zhang
2020-09-23T00:23:26Z

On Wed, Sep 23, 2020 at 05:42:08AM +0800, Mathieu Poirier wrote:
> On Tue, Sep 15, 2020 at 12:09:18PM -0600, Mathieu Poirier wrote:
> > On Tue, Sep 15, 2020 at 06:41:01PM +0800, Tingwei Zhang wrote:
> > > From: Kim Phillips <kim.phillips@arm.com>
> > >
> > > Allow to build coresight-etm3x as a module, for ease of development.
> > >
> > > - Kconfig becomes a tristate, to allow =m
> > > - append -core to source file name to allow module to
> > > be called coresight-etm3x by the Makefile
> > > - add an etm_remove function, for module unload
> > > - add a MODULE_DEVICE_TABLE for autoloading on boot
> > > - delay advertising the per-cpu etmdrvdata
> > > - protect etmdrvdata[] by modifying it on relevant CPU
> > >
> > > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> > > Cc: Leo Yan <leo.yan@linaro.org>
> > > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> > > Cc: Randy Dunlap <rdunlap@infradead.org>
> > > Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Cc: Russell King <linux@armlinux.org.uk>
> > > Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> > > Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
> > > Reviewed-by: Mike Leach <mike.leach@linaro.org>
> > > ---
> > > drivers/hwtracing/coresight/Kconfig | 5 +-
> > > drivers/hwtracing/coresight/Makefile | 5 +-
> > > ...resight-etm3x.c => coresight-etm3x-core.c} | 148
> ++++++++++++++----
> > > 3 files changed, 122 insertions(+), 36 deletions(-)
> > > rename drivers/hwtracing/coresight/{coresight-etm3x.c =>
> coresight-etm3x-core.c} (90%)
> > >
>
> I got tired of waiting for a V12 and Mike has based his work on complex
> configuration on your patchset. So I did the corrections and applied
> this set to my tree. With a little luck Greg won't mind the late
> submission and
> things will work out fine.
>
> You owe me a beer. If Greg accepts my pull request, you owe him one too.
>
> Mathieu
>

Really appreciated it, Mathieu. I definitely owe you and Greg one.

I was waiting for other comments.

Thanks
Tingwei

> > > diff --git a/drivers/hwtracing/coresight/Kconfig
> b/drivers/hwtracing/coresight/Kconfig
> > > index 6433f835fc97..8fd9fd139cf3 100644
> > > --- a/drivers/hwtracing/coresight/Kconfig
> > > +++ b/drivers/hwtracing/coresight/Kconfig
> > > @@ -65,7 +65,7 @@ config CORESIGHT_SINK_ETBV10
> > > special enhancement or added features.
> > >
> > > config CORESIGHT_SOURCE_ETM3X
> > > - bool "CoreSight Embedded Trace Macrocell 3.x driver"
> > > + tristate "CoreSight Embedded Trace Macrocell 3.x driver"
> > > depends on !ARM64
> > > select CORESIGHT_LINKS_AND_SINKS
> > > help
> > > @@ -74,6 +74,9 @@ config CORESIGHT_SOURCE_ETM3X
> > > This is primarily useful for instruction level tracing.
> Depending
> > > the ETM version data tracing may also be available.
> > >
> > > + To compile this driver as a module, choose M here: the
> > > + module will be called coresight-etm3x.
> > > +
> > > config CORESIGHT_SOURCE_ETM4X
> > > bool "CoreSight Embedded Trace Macrocell 4.x driver"
> > > depends on ARM64
> > > diff --git a/drivers/hwtracing/coresight/Makefile
> b/drivers/hwtracing/coresight/Makefile
> > > index 19497d1d92bf..86b4648844b4 100644
> > > --- a/drivers/hwtracing/coresight/Makefile
> > > +++ b/drivers/hwtracing/coresight/Makefile
> > > @@ -11,8 +11,9 @@ obj-$(CONFIG_CORESIGHT_SINK_TPIU) +=
> coresight-tpiu.o
> > > obj-$(CONFIG_CORESIGHT_SINK_ETBV10) += coresight-etb10.o
> > > obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-funnel.o \
> > > coresight-replicator.o
> > > -obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o
> coresight-etm-cp14.o \
> > > - coresight-etm3x-sysfs.o
> > > +obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o
> > > +coresight-etm3x-y := coresight-etm3x-core.o coresight-etm-cp14.o \
> > > + coresight-etm3x-sysfs.o
> > > obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o \
> > > coresight-etm4x-sysfs.o
> > > obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
> > > diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c
> b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> > > similarity index 90%
> > > rename from drivers/hwtracing/coresight/coresight-etm3x.c
> > > rename to drivers/hwtracing/coresight/coresight-etm3x-core.c
> > > index bf22dcfd3327..56eba0b5c71f 100644
> > > --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> > > +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> > > @@ -782,6 +782,42 @@ static void etm_init_trace_id(struct etm_drvdata
> *drvdata)
> > > drvdata->traceid = coresight_get_trace_id(drvdata->cpu);
> > > }
> > >
> > > +static int __init etm_hp_setup(void)
> > > +{
> > > + int ret;
> > > +
> > > + ret =
> cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
> > > + "arm/coresight:starting",
> > > + etm_starting_cpu,
> etm_dying_cpu);
> >
> > Indentation problem.
> >
> > > +
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
> > > + "arm/coresight:online",
> > > + etm_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(CPUHP_AP_ARM_CORESIGHT_STARTING);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static void etm_hp_clear(void)
> > > +{
> > > + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
> > > + if (hp_online) {
> > > + cpuhp_remove_state_nocalls(hp_online);
> > > + hp_online = 0;
> > > + }
> > > +}
> > > +
> > > static int etm_probe(struct amba_device *adev, const struct amba_id
> *id)
> > > {
> > > int ret;
> > > @@ -824,38 +860,23 @@ static int etm_probe(struct amba_device *adev,
> const struct amba_id *id)
> > > return -ENOMEM;
> > >
> > > cpus_read_lock();
> >
> > Locking is no longer needed.
> >
> > > - etmdrvdata[drvdata->cpu] = drvdata;
> > >
> > > if (smp_call_function_single(drvdata->cpu,
> > > etm_init_arch_data, drvdata, 1))
> > > dev_err(dev, "ETM arch init failed\n");
> > >
> > > - if (!etm_count++) {
> > > -
> cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
> > > -
> "arm/coresight:starting",
> > > - etm_starting_cpu,
> etm_dying_cpu);
> > > - ret =
> cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
> > > -
> "arm/coresight:online",
> > > - etm_online_cpu,
> NULL);
> > > - if (ret < 0)
> > > - goto err_arch_supported;
> > > - hp_online = ret;
> > > - }
> > > cpus_read_unlock();
> > >
> > > - if (etm_arch_supported(drvdata->arch) == false) {
> > > - ret = -EINVAL;
> > > - goto err_arch_supported;
> > > - }
> > > + if (etm_arch_supported(drvdata->arch) == false)
> > > + return -EINVAL;
> > >
> > > etm_init_trace_id(drvdata);
> > > etm_set_default(&drvdata->config);
> > >
> > > pdata = coresight_get_platform_data(dev);
> > > - if (IS_ERR(pdata)) {
> > > - ret = PTR_ERR(pdata);
> > > - goto err_arch_supported;
> > > - }
> > > + if (IS_ERR(pdata))
> > > + return PTR_ERR(pdata);
> > > +
> > > adev->dev.platform_data = pdata;
> > >
> > > desc.type = CORESIGHT_DEV_TYPE_SOURCE;
> > > @@ -865,17 +886,17 @@ static int etm_probe(struct amba_device *adev,
> const struct amba_id *id)
> > > desc.dev = dev;
> > > desc.groups = coresight_etm_groups;
> > > drvdata->csdev = coresight_register(&desc);
> > > - if (IS_ERR(drvdata->csdev)) {
> > > - ret = PTR_ERR(drvdata->csdev);
> > > - goto err_arch_supported;
> > > - }
> > > + if (IS_ERR(drvdata->csdev))
> > > + return PTR_ERR(drvdata->csdev);
> > >
> > > ret = etm_perf_symlink(drvdata->csdev, true);
> > > if (ret) {
> > > coresight_unregister(drvdata->csdev);
> > > - goto err_arch_supported;
> > > + return ret;
> > > }
> > >
> > > + etmdrvdata[drvdata->cpu] = drvdata;
> > > +
> > > pm_runtime_put(&adev->dev);
> > > dev_info(&drvdata->csdev->dev,
> > > "%s initialized\n", (char *)coresight_get_uci_data(id));
> > > @@ -885,14 +906,40 @@ static int etm_probe(struct amba_device *adev,
> const struct amba_id *id)
> > > }
> > >
> > > return 0;
> > > +}
> > >
> > > -err_arch_supported:
> > > - if (--etm_count == 0) {
> > > -
> cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
> > > - if (hp_online)
> > > - cpuhp_remove_state_nocalls(hp_online);
> > > - }
> > > - return ret;
> > > +static void __exit clear_etmdrvdata(void *info)
> > > +{
> > > + int cpu = *(int *)info;
> > > +
> > > + etmdrvdata[cpu] = NULL;
> > > +}
> > > +
> > > +static int __exit etm_remove(struct amba_device *adev)
> > > +{
> > > + struct etm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
> > > +
> > > + etm_perf_symlink(drvdata->csdev, false);
> > > +
> > > + /*
> > > + * Taking hotplug lock here to avoid racing between etm_remove and
> > > + * CPU hotplug call backs.
> > > + */
> > > + cpus_read_lock();
> > > + /*
> > > + * The readers for etmdrvdata[] are CPU hotplug call backs
> > > + * and PM notification call backs. Change etmdrvdata[i] on
> > > + * CPU i ensures these call backs has consistent view
> > > + * inside one call back function.
> > > + */
> > > + if (smp_call_function_single(drvdata->cpu, clear_etmdrvdata,
> &drvdata->cpu, 1))
> > > + etmdrvdata[drvdata->cpu] = NULL;
> > > +
> > > + cpus_read_unlock();
> > > +
> > > + coresight_unregister(drvdata->csdev);
> > > +
> > > + return 0;
> > > }
> > >
> > > #ifdef CONFIG_PM
> > > @@ -937,6 +984,8 @@ static const struct amba_id etm_ids[] = {
> > > { 0, 0},
> > > };
> > >
> > > +MODULE_DEVICE_TABLE(amba, etm_ids);
> > > +
> > > static struct amba_driver etm_driver = {
> > > .drv = {
> > > .name = "coresight-etm3x",
> > > @@ -945,6 +994,39 @@ static struct amba_driver etm_driver = {
> > > .suppress_bind_attrs = true,
> > > },
> > > .probe = etm_probe,
> > > + .remove = etm_remove,
> > > .id_table = etm_ids,
> > > };
> > > -builtin_amba_driver(etm_driver);
> > > +
> > > +static int __init etm_init(void)
> > > +{
> > > + int ret;
> > > +
> > > + ret = etm_hp_setup();
> > > +
> > > + /* etm_pm_setup() does its own cleanup - exit on error */
> >
> > Copy/paste error --> s/etm_pm_setup/etm_hp_setup
> >
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = amba_driver_register(&etm_driver);
> > > + if (ret) {
> > > + pr_err("Error registering etm3x driver\n");
> > > + etm_hp_clear();
> > > + }
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static void __exit etm_exit(void)
> > > +{
> > > + amba_driver_unregister(&etm_driver);
> > > + etm_hp_clear();
> > > +}
> > > +
> > > +module_init(etm_init);
> > > +module_exit(etm_exit);
> > > +
> > > +MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
> > > +MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
> > > +MODULE_DESCRIPTION("Arm CoreSight Program Flow Trace driver");
> > > +MODULE_LICENSE("GPL v2");
> > > --
> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum,
> > > a Linux Foundation Collaborative Project
> > >