James Clark a77616f5a3 coresight: Fix loss of connection info when a module is unloaded ... [ Upstream commit c45b2835e7 ] child_fwnode should be a read only property based on the DT or ACPI. If it's cleared on the parent device when a child is unloaded, then when the child is loaded again the connection won't be remade. child_dev should be cleared instead which signifies that the connection should be remade when the child_fwnode registers a new coresight_device. Similarly the reference count shouldn't be decremented as long as the parent device exists. The correct place to drop the reference is in coresight_release_platform_data() which is already done. Reproducible on Juno with the following steps: # load all coresight modules. $ cd /sys/bus/coresight/devices/ $ echo 1 > tmc_etr0/enable_sink $ echo 1 > etm0/enable_source # Works fine ^ $ echo 0 > etm0/enable_source $ rmmod coresight-funnel $ modprobe coresight-funnel $ echo 1 > etm0/enable_source -bash: echo: write error: Invalid argument Fixes: 37ea1ffddf ("coresight: Use fwnode handle instead of device names") Fixes: 2af89ebacf ("coresight: Clear the connection field properly") Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20230425143542.2305069-2-james.clark@arm.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-07-23 13:47:23 +02:00
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coresight	coresight: Fix loss of connection info when a module is unloaded	2023-07-23 13:47:23 +02:00
intel_th	intel_th: pci: Add Raptor Lake-S CPU support	2022-08-17 14:24:21 +02:00
stm	stm class: Use correct UUID APIs	2021-04-16 07:26:50 +02:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00