Re: [PATCH V5 07/11] coresight: catu: Move ACPI support from AMBA driver to platform driver

From: Suzuki K Poulose
Date: Tue Mar 05 2024 - 12:33:22 EST

On 22/02/2024 08:21, Anshuman Khandual wrote:
Add support for the catu devices in a new 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 catu_probe()
and catu_remove(), making sure it can be used both for platform and AMBA
drivers. This also moves pm_runtime_put() from catu_probe() to the callers.

Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: James Clark <james.clark@xxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: coresight@xxxxxxxxxxxxxxxx
Acked-by: Sudeep Holla <sudeep.holla@xxxxxxx> # For ACPI related changes
Reviewed-by: James Clark <james.clark@xxxxxxx>
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
Changes in V5:

- Updated commit message regarding catu_probe/remove() refactoring and renaming

drivers/acpi/arm64/amba.c | 1 -
drivers/hwtracing/coresight/coresight-catu.c | 142 ++++++++++++++++---
drivers/hwtracing/coresight/coresight-catu.h | 1 +
3 files changed, 124 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
index afb6afb66967..587061b0fd2f 100644
--- a/drivers/acpi/arm64/amba.c
+++ b/drivers/acpi/arm64/amba.c
@@ -27,7 +27,6 @@ static const struct acpi_device_id amba_id_list[] = {
{"ARMHC503", 0}, /* ARM CoreSight Debug */
{"ARMHC979", 0}, /* ARM CoreSight TPIU */
{"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
- {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
{"", 0},
};
diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
index 3949ded0d4fa..a3ea46b53898 100644
--- a/drivers/hwtracing/coresight/coresight-catu.c
+++ b/drivers/hwtracing/coresight/coresight-catu.c
@@ -7,6 +7,8 @@
* Author: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
*/
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
#include <linux/amba/bus.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
@@ -502,28 +504,20 @@ static const struct coresight_ops catu_ops = {
.helper_ops = &catu_helper_ops,
};
-static int catu_probe(struct amba_device *adev, const struct amba_id *id)
+static int __catu_probe(struct device *dev, struct resource *res)
{
int ret = 0;
u32 dma_mask;
- struct catu_drvdata *drvdata;
+ struct catu_drvdata *drvdata = dev_get_drvdata(dev);
struct coresight_desc catu_desc;
struct coresight_platform_data *pdata = NULL;
- struct device *dev = &adev->dev;
void __iomem *base;
catu_desc.name = coresight_alloc_device_name(&catu_devs, dev);
if (!catu_desc.name)
return -ENOMEM;
- drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
- if (!drvdata) {
- ret = -ENOMEM;
- goto out;
- }
-
- dev_set_drvdata(dev, drvdata);
- base = devm_ioremap_resource(dev, &adev->res);
+ base = devm_ioremap_resource(dev, res);
if (IS_ERR(base)) {
ret = PTR_ERR(base);
goto out;
@@ -567,19 +561,39 @@ static int catu_probe(struct amba_device *adev, const struct amba_id *id)
drvdata->csdev = coresight_register(&catu_desc);
if (IS_ERR(drvdata->csdev))
ret = PTR_ERR(drvdata->csdev);
- else
- pm_runtime_put(&adev->dev);
out:
return ret;
}
-static void catu_remove(struct amba_device *adev)
+static int catu_probe(struct amba_device *adev, const struct amba_id *id)
{
- struct catu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+ struct catu_drvdata *drvdata;
+ int ret;
+
+ drvdata = devm_kzalloc(&adev->dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ amba_set_drvdata(adev, drvdata);
+ ret = __catu_probe(&adev->dev, &adev->res);
+ if (!ret)
+ pm_runtime_put(&adev->dev);
+
+ return ret;
+}
+
+static void __catu_remove(struct device *dev)
+{
+ struct catu_drvdata *drvdata = dev_get_drvdata(dev);
coresight_unregister(drvdata->csdev);
}
+static void catu_remove(struct amba_device *adev)
+{
+ __catu_remove(&adev->dev);
+}
+
static struct amba_id catu_ids[] = {
CS_AMBA_ID(0x000bb9ee),
{},
@@ -598,13 +612,103 @@ static struct amba_driver catu_driver = {
.id_table = catu_ids,
};
+static int catu_platform_probe(struct platform_device *pdev)
+{
+ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ struct catu_drvdata *drvdata;
+ int ret = 0;
+
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ drvdata->pclk = coresight_get_enable_apb_pclk(&pdev->dev);
+ if (IS_ERR(drvdata->pclk))
+ return -ENODEV;


---8>---

+
+ if (res) {
+ drvdata->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(drvdata->base)) {
+ clk_put(drvdata->pclk);
+ return PTR_ERR(drvdata->base);
+ }
+ }

---<8---

The above section seems unncessary as we already try to map the base in __catu_probe ?

+
+ pm_runtime_get_noresume(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
+ dev_set_drvdata(&pdev->dev, drvdata);
+ ret = __catu_probe(&pdev->dev, res);
+ pm_runtime_put(&pdev->dev);
+ if (ret)
+ pm_runtime_disable(&pdev->dev);
+
+ return ret;
+}
+
+static int catu_platform_remove(struct platform_device *pdev)
+{
+ struct catu_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
+
+ if (drvdata)
+ __catu_remove(&pdev->dev);

I don't understand the need for if () check here (and on all the other drivers). Even if we have a drvdata != NULL, what guarantees that
the drvdata->csdev is valid (which is used in xx_remove) ?

Suzuki

+
+ pm_runtime_disable(&pdev->dev);
+ if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
+ clk_put(drvdata->pclk);
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int catu_runtime_suspend(struct device *dev)
+{
+ struct catu_drvdata *drvdata = dev_get_drvdata(dev);
+
+ if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
+ clk_disable_unprepare(drvdata->pclk);
+ return 0;
+}
+
+static int catu_runtime_resume(struct device *dev)
+{
+ struct catu_drvdata *drvdata = dev_get_drvdata(dev);
+
+ if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
+ clk_prepare_enable(drvdata->pclk);
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops catu_dev_pm_ops = {
+ SET_RUNTIME_PM_OPS(catu_runtime_suspend, catu_runtime_resume, NULL)
+};
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id catu_acpi_ids[] = {
+ {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
+ {},
+};
+
+MODULE_DEVICE_TABLE(acpi, catu_acpi_ids);
+#endif
+
+static struct platform_driver catu_platform_driver = {
+ .probe = catu_platform_probe,
+ .remove = catu_platform_remove,
+ .driver = {
+ .name = "coresight-catu-platform",
+ .acpi_match_table = ACPI_PTR(catu_acpi_ids),
+ .suppress_bind_attrs = true,
+ .pm = &catu_dev_pm_ops,
+ },
+};
+
static int __init catu_init(void)
{
int ret;
- ret = amba_driver_register(&catu_driver);
- if (ret)
- pr_info("Error registering catu driver\n");
+ ret = coresight_init_driver("catu", &catu_driver, &catu_platform_driver);
tmc_etr_set_catu_ops(&etr_catu_buf_ops);
return ret;
}
@@ -612,7 +716,7 @@ static int __init catu_init(void)
static void __exit catu_exit(void)
{
tmc_etr_remove_catu_ops();
- amba_driver_unregister(&catu_driver);
+ coresight_remove_driver(&catu_driver, &catu_platform_driver);
}
module_init(catu_init);
diff --git a/drivers/hwtracing/coresight/coresight-catu.h b/drivers/hwtracing/coresight/coresight-catu.h
index 442e034bbfba..141feac1c14b 100644
--- a/drivers/hwtracing/coresight/coresight-catu.h
+++ b/drivers/hwtracing/coresight/coresight-catu.h
@@ -61,6 +61,7 @@
#define CATU_IRQEN_OFF 0x0
struct catu_drvdata {
+ struct clk *pclk;
void __iomem *base;
struct coresight_device *csdev;
int irq;