[PATCH 18/19] 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.poirier at linaro.org>
Cc: Mike Leach <mike.leach at linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x.c | 42 ++++++++++++++++++-
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 7d5f942c2108..212713ffa37e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.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>
@@ -1712,6 +1713,20 @@ 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 */
@@ -1749,6 +1764,20 @@ static struct amba_driver etm4x_amba_driver = {
 	.id_table	= etm4_ids,
 };
 
+static const struct of_device_id etm4_4_match[] = {
+	{ .compatible	= "arm,coresight-etm-v4.4" },
+	{}
+};
+
+static struct platform_driver etm4_platform_driver = {
+	.probe		= etm4_probe_platform_dev,
+	.driver			= {
+		.name			= "coresight-etm4x",
+		.of_match_table		= etm4_4_match,
+		.suppress_bind_attrs	= true,
+	},
+};
+
 static int __init etm4x_init(void)
 {
 	int ret;
@@ -1761,10 +1790,19 @@ 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;
 }
 device_initcall(etm4x_init);
-- 
2.24.1