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Message-ID: <c52865b2-8608-4a47-967a-6cf3e11b197a@arm.com>
Date: Wed, 6 Mar 2024 11:44:32 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
linux-arm-kernel@...ts.infradead.org
Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>,
Sudeep Holla <sudeep.holla@....com>, Mike Leach <mike.leach@...aro.org>,
James Clark <james.clark@....com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, coresight@...ts.linaro.org,
linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH V5 07/11] coresight: catu: Move ACPI support from AMBA
driver to platform driver
On 3/5/24 23:02, Suzuki K Poulose wrote:
> 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@...nel.org>
>> Cc: Sudeep Holla <sudeep.holla@....com>
>> Cc: Suzuki K Poulose <suzuki.poulose@....com>
>> Cc: Mike Leach <mike.leach@...aro.org>
>> Cc: James Clark <james.clark@....com>
>> Cc: linux-acpi@...r.kernel.org
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-kernel@...r.kernel.org
>> Cc: coresight@...ts.linaro.org
>> Acked-by: Sudeep Holla <sudeep.holla@....com> # For ACPI related changes
>> Reviewed-by: James Clark <james.clark@....com>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
>> ---
>> 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@....com>
>> */
>> +#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 ?
Agreed, though it seems unnecessary, there is a small difference in there. In the platform
driver case i.e catu_platform_probe(), clk_put() is called on platform clock drvdata->pclk
(just enabled earlier) for cases when devm_ioremap_resource() fails.
To remove this redundancy, let's move devm_ioremap_resource() into it's AMBA caller i.e
catu_probe() thus dropping struct resource argument from __catu_probe(). Similar situation
is present in coresight-cpu-debug driver as well, will fix that.
But there are some other drivers in the series where coresight_get_enable_apb_pclk() called
on 'drvdata->pclk' and devm_ioremap_resource() is attempted inside the factored __xxx_probe()
function which is common for both AMBA and platform drivers.
Such drivers are ...
- tpiu
- tmc
- stm
- replicator
IMHO it would be better to follow same scheme for all drivers in the series. Please do let
me know which method will be preferred.
>
>> +
>> + 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) ?
Agreed, although drvdata is derived in __xxx_remove() functions, a pre-check here is not
required - similar to the AMBA remove path. Sure, will drop them across drivers.
>
> 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;
>
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