[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 4 Apr 2024 11:53:25 +0100
From: James Clark <james.clark@....com>
To: Anshuman Khandual <anshuman.khandual@....com>,
linux-arm-kernel@...ts.infradead.org, suzuki.poulose@....com
Cc: sudeep.holla@....com, Mike Leach <mike.leach@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] coresight: tmc: Enable SG capability on ACPI based
SoC-400 TMC ETR devices
On 04/04/2024 08:29, Anshuman Khandual wrote:
> This detects and enables the scatter gather capability (SG) on ACPI based
> Soc-400 TMC ETR devices via a new property called 'arm-armhc97c-sg-enable'.
> The updated ACPI spec can be found below, which contains this new property.
>
> https://developer.arm.com/documentation/den0067/latest/
>
> This preserves current handling for the property 'arm,scatter-gather' both
> on ACPI and DT based platforms i.e the presence of the property is checked
> instead of the value.
>
> Cc: Suzuki K Poulose <suzuki.poulose@....com>
> Cc: Mike Leach <mike.leach@...aro.org>
> Cc: James Clark <james.clark@....com>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: coresight@...ts.linaro.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
> .../hwtracing/coresight/coresight-tmc-core.c | 28 ++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index 72005b0c633e..2b277499b59a 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -4,6 +4,7 @@
> * Description: CoreSight Trace Memory Controller driver
> */
>
> +#include <linux/acpi.h>
> #include <linux/kernel.h>
> #include <linux/init.h>
> #include <linux/types.h>
> @@ -360,7 +361,32 @@ static const struct attribute_group *coresight_etr_groups[] = {
>
> static inline bool tmc_etr_can_use_sg(struct device *dev)
> {
> - return fwnode_property_present(dev->fwnode, "arm,scatter-gather");
> + int ret;
> + u8 val_u8;
> +
> + /*
> + * Presence of the property 'arm,scatter-gather' is checked
> + * on the platform for the feature support, rather than its
> + * value.
> + */
> + if (is_of_node(dev->fwnode)) {
> + return fwnode_property_present(dev->fwnode, "arm,scatter-gather");
> + } else if (is_acpi_device_node(dev->fwnode)) {
> + /*
> + * TMC_DEVID_NOSCAT test in tmc_etr_setup_caps(), has already ensured
> + * this property is only checked for Coresight SoC 400 TMC configured
> + * as ETR.
> + */
> + ret = fwnode_property_read_u8(dev->fwnode, "arm-armhc97c-sg-enable", &val_u8);
> + if (!ret)
> + return !!val_u8;
> +
> + if (fwnode_property_present(dev->fwnode, "arm,scatter-gather")) {
> + pr_warn_once("Deprecated ACPI property - arm,scatter-gather\n");
> + return true;
> + }
> + }
> + return false;
> }
>
> static inline bool tmc_etr_has_non_secure_access(struct tmc_drvdata *drvdata)
Reviewed-by: James Clark <james.clark@....com>
Powered by blists - more mailing lists