On Thu, Jan 07, 2021 at 12:38:56PM +0000, Suzuki K Poulose wrote: > Add support for devices with system instruction access only. > They don't have a memory mapped interface and thus are not > AMBA devices. System register access is not permitted to > TRCPDCR and thus skip access to them. > > Cc: Mike Leach <[email protected]> > Cc: Mathieu Poirier <[email protected]> > Signed-off-by: Suzuki K Poulose <[email protected]> > --- > Changes since v5: > - Rebased to accommodate check_arch_features(). > Added comments to explain why we don't pass PID for system > register based devices. > Changes since v4 > - Add "remove" callback for platform_driver. > - Dropped Reviewed-by tag from Mathieu due to the above > > Changes since v3 > - Improve comment over "TRCPDCR" usage with sysreg > - Rename etm_xx => etm4_xx > - Update the compatible to "arm,coresight-etm4x-sysreg" > --- > .../coresight/coresight-etm4x-core.c | 68 +++++++++++++++++-- > 1 file changed, 63 insertions(+), 5 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c > b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index f4fbb65b4cc1..34a6cdff75e7 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -27,6 +27,7 @@ > #include <linux/seq_file.h> > #include <linux/uaccess.h> > #include <linux/perf_event.h> > +#include <linux/platform_device.h> > #include <linux/pm_runtime.h> > #include <linux/property.h> > > @@ -1736,9 +1737,6 @@ static int etm4_probe(struct device *dev, void __iomem > *base, u32 etm_pid) > return -ENOMEM; > } > > - if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > - drvdata->skip_power_up = true; > - > drvdata->base = base; > > spin_lock_init(&drvdata->spinlock); > @@ -1762,6 +1760,11 @@ static int etm4_probe(struct device *dev, void __iomem > *base, u32 etm_pid) > if (!drvdata->arch) > return -EINVAL; > > + /* TRCPDCR is not accessible with system instructions. */ > + if (!desc.access.io_mem || > + fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > + drvdata->skip_power_up = true; > + > etm4_init_trace_id(drvdata); > etm4_set_default(&drvdata->config); > > @@ -1820,6 +1823,25 @@ static int etm4_probe_amba(struct amba_device *adev, > const struct amba_id *id) > return ret; > } > > +static int etm4_probe_platform_dev(struct platform_device *pdev) > +{ > + int ret; > + > + pm_runtime_get_noresume(&pdev->dev); > + pm_runtime_set_active(&pdev->dev); > + pm_runtime_enable(&pdev->dev); > + > + /* > + * System register based devices could match the > + * HW by reading appropriate registers on the HW > + * and thus we could skip the PID. > + */ > + ret = etm4_probe(&pdev->dev, NULL, 0); > + > + pm_runtime_put(&pdev->dev); > + return ret; > +} > + > static struct amba_cs_uci_id uci_id_etm4[] = { > { > /* ETMv4 UCI data */ > @@ -1869,6 +1891,17 @@ static int __exit etm4_remove_amba(struct amba_device > *adev) > return 0; > } > > +static int __exit etm4_remove_platform_dev(struct platform_device *pdev) > +{ > + int ret = 0; > + struct etmv4_drvdata *drvdata = dev_get_drvdata(&pdev->dev); > + > + if (drvdata) > + ret = etm4_remove_dev(drvdata); > + pm_runtime_disable(&pdev->dev); > + return ret; > +} > + > static const struct amba_id etm4_ids[] = { > CS_AMBA_ID(0x000bb95d), /* Cortex-A53 */ > CS_AMBA_ID(0x000bb95e), /* Cortex-A57 */ > @@ -1901,6 +1934,21 @@ static struct amba_driver etm4x_amba_driver = { > .id_table = etm4_ids, > }; > > +static const struct of_device_id etm4_sysreg_match[] = { > + { .compatible = "arm,coresight-etm4x-sysreg" }, > + {} > +}; > + > +static struct platform_driver etm4_platform_driver = { > + .probe = etm4_probe_platform_dev, > + .remove = etm4_remove_platform_dev, > + .driver = { > + .name = "coresight-etm4x", > + .of_match_table = etm4_sysreg_match, > + .suppress_bind_attrs = true, > + }, > +}; > + > static int __init etm4x_init(void) > { > int ret; > @@ -1913,16 +1961,26 @@ static int __init etm4x_init(void) > > ret = amba_driver_register(&etm4x_amba_driver); > if (ret) { > - pr_err("Error registering etm4x driver\n"); > - etm4_pm_clear(); > + pr_err("Error registering etm4x AMBA driver\n"); > + goto clear_pm; > } > > + ret = platform_driver_register(&etm4_platform_driver); > + if (!ret) > + return 0; > + > + pr_err("Error registering etm4x platform driver\n"); > + amba_driver_unregister(&etm4x_amba_driver); > + > +clear_pm: > + etm4_pm_clear(); > return ret; > } > > static void __exit etm4x_exit(void) > { > amba_driver_unregister(&etm4x_amba_driver); > + platform_driver_unregister(&etm4_platform_driver);
Good catch. Reviewed-by: Mathieu Poirier <[email protected]> > etm4_pm_clear(); > } > > -- > 2.24.1 >
