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 <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: James Clark <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
.../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)
--
2.25.1
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 <[email protected]>
> Cc: Mike Leach <[email protected]>
> Cc: James Clark <[email protected]>
> Cc: Alexander Shishkin <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Anshuman Khandual <[email protected]>
> ---
> .../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 <[email protected]>
On Thu, 4 Apr 2024 12:59:34 +0530, 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.
>
> [...]
Applied, thanks!
[1/1] coresight: tmc: Enable SG capability on ACPI based SoC-400 TMC ETR devices
https://git.kernel.org/coresight/c/8877ef45ef9ec281849870d88039f8dc84cde774
Best regards,
--
Suzuki K Poulose <[email protected]>