Re: [PATCH V3 4/4] coresight: trbe: Enable ACPI based TRBE devices

From: Suzuki K Poulose
Date: Mon Aug 07 2023 - 07:41:47 EST


On 07/08/2023 05:43, Anshuman Khandual wrote:


On 8/3/23 11:26, Anshuman Khandual wrote:
This detects and enables ACPI based TRBE devices via the dummy platform
device created earlier for this purpose.

Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: coresight@xxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-trbe.c | 9 +++++++++
drivers/hwtracing/coresight/coresight-trbe.h | 1 +
2 files changed, 10 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index e1d9d06e7725..f884883e9018 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1537,7 +1537,16 @@ static const struct of_device_id arm_trbe_of_match[] = {
};
MODULE_DEVICE_TABLE(of, arm_trbe_of_match);
+#ifdef CONFIG_ACPI
+static const struct platform_device_id arm_trbe_acpi_match[] = {
+ { ARMV8_TRBE_PDEV_NAME, 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
+#endif
+
static struct platform_driver arm_trbe_driver = {
+ .id_table = arm_trbe_acpi_match,

The build problem [1] reported on the first version of the series still exists
here i.e arm_trbe_acpi_match is hidden without CONFIG_ACPI. I had assumed that
CONFIG_CORESIGHT always enables CONFIG_ACPI, which is not the case. Following
random config (with CONFIG_ACPI=n and CONFIG_CORESIGHT_TRBE=y) easily triggers
the build problem.

https://download.01.org/0day-ci/archive/20230805/202308052123.uqR35d19-lkp@xxxxxxxxx/config

make CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 -s -j 128
drivers/hwtracing/coresight/coresight-trbe.c:1563:23: error: implicit declaration of function ‘ACPI_PTR’ [-Werror=implicit-function-declaration]
1563 | .acpi_match_table = ACPI_PTR(arm_trbe_acpi_match),
| ^~~~~~~~
drivers/hwtracing/coresight/coresight-trbe.c:1563:32: error: ‘arm_trbe_acpi_match’ undeclared here (not in a function); did you mean ‘arm_trbe_of_match’?
1563 | .acpi_match_table = ACPI_PTR(arm_trbe_acpi_match),
| ^~~~~~~~~~~~~~~~~~~
| arm_trbe_of_match

Following config wrap around fixes the problem.

--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1557,7 +1557,9 @@ MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
#endif
static struct platform_driver arm_trbe_driver = {
+#ifdef CONFIG_ACPI
.id_table = arm_trbe_acpi_match,
+#endif
.driver = {
.name = DRVNAME,
.of_match_table = of_match_ptr(arm_trbe_of_match),

Please not that unlike other coresight drivers, TRBE is not using 'acpi_device_id'
based "acpi_match_table = ACPI_PTR" construct. But regardless, ACPI_PTR() seems to
be an alternate (probably better) solution as well.

--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1557,7 +1557,7 @@ MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
#endif
static struct platform_driver arm_trbe_driver = {
- .id_table = arm_trbe_acpi_match,
+ .id_table = ACPI_PTR(arm_trbe_acpi_match),

This is preferred.

.driver = {
.name = DRVNAME,
.of_match_table = of_match_ptr(arm_trbe_of_match),
diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h
index 94e67009848a..fce1735d5c58 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.h
+++ b/drivers/hwtracing/coresight/coresight-trbe.h
@@ -7,6 +7,7 @@
*
* Author: Anshuman Khandual <anshuman.khandual@xxxxxxx>
*/
+#include <linux/acpi.h>

Shouldn't this be added in trbe.c ? Does trbe.h depend on any ACPI headers ?

Suzuki