On 4/23/25 20:47, Leo Yan wrote:
The programming clock is enabled by AMBA bus driver before a dynamic probe. As a result, a CoreSight driver may redundantly enable the same clock.
Are you sure AMBA bus driver always enables such clocks in all scenarios ? Even if that is true - why cannot coresight_get_enable_apb_pclk() ensured to be called only for the platform drivers cases via code re-organization, rather than changing the coresight_get_enable_apb_pclk() helper itself.
To avoid this, add a check for device type and skip enabling the programming clock for AMBA devices. The returned NULL pointer will be tolerated by the drivers.
Fixes: 73d779a03a76 ("coresight: etm4x: Change etm4_platform_driver driver for MMIO devices") Signed-off-by: Leo Yan leo.yan@arm.com
include/linux/coresight.h | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index b888f6ed59b2..26eb4a61b992 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -476,15 +476,18 @@ static inline bool is_coresight_device(void __iomem *base)
- Returns:
- clk - Clock is found and enabled
*/
- NULL - Clock is not needed as it is managed by the AMBA bus driver
- ERROR - Clock is found but failed to enable
static inline struct clk *coresight_get_enable_apb_pclk(struct device *dev) {
- struct clk *pclk;
- struct clk *pclk = NULL;
- pclk = devm_clk_get_enabled(dev, "apb_pclk");
- if (IS_ERR(pclk))
pclk = devm_clk_get_enabled(dev, "apb");
- if (!dev_is_amba(dev)) {
pclk = devm_clk_get_enabled(dev, "apb_pclk");if (IS_ERR(pclk))pclk = devm_clk_get_enabled(dev, "apb");- }
return pclk; }