[PATCH v3 25/26] coresight: etm4x: Add support for sysreg only devices

[Suzuki K Poulose]

Add support for devices with system instruction access only.
They don't have a memory mapped interface and thus are not
AMBA devices.

Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Cc: Mike Leach <mike.le...@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
---
 .../coresight/coresight-etm4x-core.c          | 50 +++++++++++++++++--
 1 file changed, 45 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c 
b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 25fab5513604..50a574228866 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -26,6 +26,7 @@
 #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>
 #include <asm/sections.h>
@@ -1623,9 +1624,6 @@ static int etm4_probe(struct device *dev, void __iomem 
*base)
                        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);
@@ -1648,6 +1646,11 @@ static int etm4_probe(struct device *dev, void __iomem 
*base)
        if (!drvdata->arch)
                return -EINVAL;
 
+       /* Skip programming TRCPDCR for 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);
 
@@ -1706,6 +1709,20 @@ 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);
+
+       ret = etm4_probe(&pdev->dev, NULL);
+
+       pm_runtime_put(&pdev->dev);
+       return ret;
+}
+
 static struct amba_cs_uci_id uci_id_etm4[] = {
        {
                /*  ETMv4 UCI data */
@@ -1781,6 +1798,20 @@ static struct amba_driver etm4x_amba_driver = {
        .id_table       = etm4_ids,
 };
 
+static const struct of_device_id etm_sysreg_match[] = {
+       { .compatible   = "arm,coresight-etm-sysreg" },
+       {}
+};
+
+static struct platform_driver etm4_platform_driver = {
+       .probe          = etm4_probe_platform_dev,
+       .driver                 = {
+               .name                   = "coresight-etm4x",
+               .of_match_table         = etm_sysreg_match,
+               .suppress_bind_attrs    = true,
+       },
+};
+
 static int __init etm4x_init(void)
 {
        int ret;
@@ -1793,10 +1824,19 @@ 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;
 }
 
-- 
2.24.1