lkml.org 
[lkml]   [2021]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v7 25/28] coresight: etm4x: Add support for sysreg only devices
Date
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 <mike.leach@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
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 63a5e11b5f3f..3d3165dd09d4 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);
etm4_pm_clear();
}

--
2.24.1
\
 
 \ /
  Last update: 2021-01-11 00:11    [W:0.192 / U:7.432 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site