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coresight: tmc: Enable SG capability on ACPI based SoC-400 TMC ETR devices

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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@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240404072934.940760-1-anshuman.khandual@arm.com
This commit is contained in:
Anshuman Khandual 2024-04-04 12:59:34 +05:30 committed by Suzuki K Poulose
parent 2d7e8a64a1
commit 8877ef45ef
1 changed files with 27 additions and 1 deletions
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28
drivers/hwtracing/coresight/coresight-tmc-core.c
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@ -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>
@ -362,7 +363,32 @@ 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)