[PATCH 4/7] coresight: tpiu: Move ACPI support from AMBA driver to platform driver

[Anshuman Khandual <anshuman.khandual@arm.com>]

Add support for the tpiu device in the platform driver, which can then be
used on ACPI based platforms. This change would now allow runtime power
management for ACPI based systems. The driver would try to enable the APB
clock if available.

Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: linux-acpi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: coresight@lists.linaro.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 drivers/acpi/arm64/amba.c                    |  1 -
 drivers/hwtracing/coresight/coresight-tpiu.c | 76 ++++++++++++++++++--
 2 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
index 56a7e020555b..8e1783166c33 100644
--- a/drivers/acpi/arm64/amba.c
+++ b/drivers/acpi/arm64/amba.c
@@ -25,7 +25,6 @@ static const struct acpi_device_id amba_id_list[] = {
 	{"ARMHC501", 0}, /* ARM CoreSight ETR */
 	{"ARMHC502", 0}, /* ARM CoreSight STM */
 	{"ARMHC503", 0}, /* ARM CoreSight Debug */
-	{"ARMHC979", 0}, /* ARM CoreSight TPIU */
 	{"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
 	{"", 0},
 };
diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index 59eac93fd6bb..ea8827d289ca 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -5,6 +5,8 @@
  * Description: CoreSight Trace Port Interface Unit driver
  */
 
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
 #include <linux/atomic.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -57,6 +59,7 @@ DEFINE_CORESIGHT_DEVLIST(tpiu_devs, "tpiu");
 struct tpiu_drvdata {
 	void __iomem		*base;
 	struct clk		*atclk;
+	struct clk		*pclk;
 	struct coresight_device	*csdev;
 };
 
@@ -114,14 +117,12 @@ static const struct coresight_ops tpiu_cs_ops = {
 	.sink_ops	= &tpiu_sink_ops,
 };
 
-static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
+static int __tpiu_probe(struct device *dev, struct resource *res)
 {
 	int ret;
 	void __iomem *base;
-	struct device *dev = &adev->dev;
 	struct coresight_platform_data *pdata = NULL;
 	struct tpiu_drvdata *drvdata;
-	struct resource *res = &adev->res;
 	struct coresight_desc desc = { 0 };
 
 	desc.name = coresight_alloc_device_name(&tpiu_devs, dev);
@@ -132,12 +133,16 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 	if (!drvdata)
 		return -ENOMEM;
 
-	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
+	drvdata->atclk = devm_clk_get(dev, "atclk"); /* optional */
 	if (!IS_ERR(drvdata->atclk)) {
 		ret = clk_prepare_enable(drvdata->atclk);
 		if (ret)
 			return ret;
 	}
+
+	drvdata->pclk = coresight_get_enable_apb_pclk(dev);
+	if (IS_ERR(drvdata->pclk))
+		return -ENODEV;
 	dev_set_drvdata(dev, drvdata);
 
 	/* Validity for the resource is already checked by the AMBA core */
@@ -164,20 +169,30 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 	drvdata->csdev = coresight_register(&desc);
 
 	if (!IS_ERR(drvdata->csdev)) {
-		pm_runtime_put(&adev->dev);
+		pm_runtime_put(dev);
 		return 0;
 	}
 
 	return PTR_ERR(drvdata->csdev);
 }
 
-static void tpiu_remove(struct amba_device *adev)
+static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 {
-	struct tpiu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+	return __tpiu_probe(&adev->dev, &adev->res);
+}
+
+static void __tpiu_remove(struct device *dev)
+{
+	struct tpiu_drvdata *drvdata = dev_get_drvdata(dev);
 
 	coresight_unregister(drvdata->csdev);
 }
 
+static void tpiu_remove(struct amba_device *adev)
+{
+	__tpiu_remove(&adev->dev);
+}
+
 #ifdef CONFIG_PM
 static int tpiu_runtime_suspend(struct device *dev)
 {
@@ -186,6 +201,8 @@ static int tpiu_runtime_suspend(struct device *dev)
 	if (drvdata && !IS_ERR(drvdata->atclk))
 		clk_disable_unprepare(drvdata->atclk);
 
+	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
+		clk_disable_unprepare(drvdata->pclk);
 	return 0;
 }
 
@@ -196,6 +213,8 @@ static int tpiu_runtime_resume(struct device *dev)
 	if (drvdata && !IS_ERR(drvdata->atclk))
 		clk_prepare_enable(drvdata->atclk);
 
+	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
+		clk_prepare_enable(drvdata->pclk);
 	return 0;
 }
 #endif
@@ -237,6 +256,49 @@ static struct amba_driver tpiu_driver = {
 
 module_amba_driver(tpiu_driver);
 
+static int tpiu_platform_probe(struct platform_device *pdev)
+{
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	int ret;
+
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = __tpiu_probe(&pdev->dev, res);
+	if (ret) {
+		pm_runtime_put_noidle(&pdev->dev);
+		pm_runtime_disable(&pdev->dev);
+	}
+	return ret;
+}
+
+static int tpiu_platform_remove(struct platform_device *pdev)
+{
+	__tpiu_remove(&pdev->dev);
+	return 0;
+}
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id tpiu_acpi_ids[] = {
+	{"ARMHC979", 0}, /* ARM CoreSight TPIU */
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, tpiu_acpi_ids);
+#endif
+
+static struct platform_driver tpiu_platform_driver = {
+	.probe	= tpiu_platform_probe,
+	.remove	= tpiu_platform_remove,
+	.driver = {
+		.name			= "coresight-tpiu-platform",
+		.acpi_match_table	= ACPI_PTR(tpiu_acpi_ids),
+		.suppress_bind_attrs	= true,
+		.pm			= &tpiu_dev_pm_ops,
+	},
+};
+module_platform_driver(tpiu_platform_driver);
+
 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
 MODULE_DESCRIPTION("Arm CoreSight TPIU (Trace Port Interface Unit) driver");
-- 
2.25.1