coresight: tpiu: Move ACPI support from AMBA driver to platform driver

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. But first this renames and then refactors tpiu_probe()
and tpiu_remove(), making sure it can be used both for platform and AMBA
drivers. This also moves pm_runtime_put() from tpiu_probe() to the callers.
While here, this also sorts the included headers in alphabetic order.

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
Tested-by: Sudeep Holla <sudeep.holla@arm.com> # Boot and driver probe only
Acked-by: Sudeep Holla <sudeep.holla@arm.com> # For ACPI related changes
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240314055843.2625883-9-anshuman.khandual@arm.com

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},
 };

drivers/hwtracing/coresight/coresight-tpiu.c

@@ -5,17 +5,19 @@
  * Description: CoreSight Trace Port Interface Unit driver
  */
 
-#include <linux/atomic.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/device.h>
-#include <linux/io.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-#include <linux/pm_runtime.h>
-#include <linux/coresight.h>
+#include <linux/acpi.h>
 #include <linux/amba/bus.h>
+#include <linux/atomic.h>
 #include <linux/clk.h>
+#include <linux/coresight.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
 
 #include "coresight-priv.h"
 
@@ -52,11 +54,13 @@ DEFINE_CORESIGHT_DEVLIST(tpiu_devs, "tpiu");
 /*
  * @base:	memory mapped base address for this component.
  * @atclk:	optional clock for the core parts of the TPIU.
+ * @pclk:	APB clock if present, otherwise NULL
  * @csdev:	component vitals needed by the framework.
  */
 struct tpiu_drvdata {
 	void __iomem		*base;
 	struct clk		*atclk;
+	struct clk		*pclk;
 	struct coresight_device	*csdev;
 	spinlock_t		spinlock;
 };
@@ -122,14 +126,12 @@ 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);
@@ -142,12 +144,16 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 
 	spin_lock_init(&drvdata->spinlock);
 
-	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 */
@@ -173,21 +179,34 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 	desc.dev = dev;
 	drvdata->csdev = coresight_register(&desc);
 
-	if (!IS_ERR(drvdata->csdev)) {
-		pm_runtime_put(&adev->dev);
+	if (!IS_ERR(drvdata->csdev))
 		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);
+	int ret;
+
+	ret = __tpiu_probe(&adev->dev, &adev->res);
+	if (!ret)
+		pm_runtime_put(&adev->dev);
+	return ret;
+}
+
+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)
 {
@@ -196,6 +215,8 @@ 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;
 }
 
@@ -206,6 +227,8 @@ 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
@@ -245,7 +268,67 @@ static struct amba_driver tpiu_driver = {
 	.id_table	= tpiu_ids,
 };
 
-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);
+	pm_runtime_put(&pdev->dev);
+	if (ret)
+		pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int tpiu_platform_remove(struct platform_device *pdev)
+{
+	struct tpiu_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
+
+	if (WARN_ON(!drvdata))
+		return -ENODEV;
+
+	__tpiu_remove(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	if (!IS_ERR_OR_NULL(drvdata->pclk))
+		clk_put(drvdata->pclk);
+	return 0;
+}
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id tpiu_acpi_ids[] = {
+	{"ARMHC979", 0, 0, 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,
+	},
+};
+
+static int __init tpiu_init(void)
+{
+	return coresight_init_driver("tpiu", &tpiu_driver, &tpiu_platform_driver);
+}
+
+static void __exit tpiu_exit(void)
+{
+	coresight_remove_driver(&tpiu_driver, &tpiu_platform_driver);
+}
+module_init(tpiu_init);
+module_exit(tpiu_exit);
 
 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");