On Sat, 15 Feb 2020 at 04:34, Anatolij Gustschin agust@denx.de wrote:
Currently when booting the kernel on i.MX8 U-Boot hangs in an endless loop when switching off dma, connectivity or lsio power domains during device removal. It hapens first when removing gpio0 (gpio@5d080000) device, here its power domain device 'lsio_gpio0' is obtained for switching off power. Since the obtained 'lsio_gpio0' device is removed afterwards, its power domain is also switched off and here the parent power domain device 'lsio_power_domain' is optained for switching off the power. Thereafter, when the obtained 'lsio_power_domain' is removed, device_remove() removes its first child 'lsio_gpio0'. During this child removal the 'lsio_power_domain' device is obtained again for switching and when removing it later, the same child removal is repeated, so we are stuck in an endless loop. Below is a snippet from dm tree on i.MX8QXP for better illustration of the DM devices relationship:
Class Index Probed Driver Name
root 0 [ + ] root_driver root_driver ... simple_bus 0 [ + ] generic_simple_bus |-- imx8qx-pm power_doma 0 [ + ] imx8_power_domain | |-- lsio_power_domain power_doma 1 [ + ] imx8_power_domain | | |-- lsio_gpio0 power_doma 2 [ + ] imx8_power_domain | | |-- lsio_gpio1
Do not remove a power domain device if it is a parent of the currently controlled device.
Fixes: 52edfed65de9 ("dm: core: device: switch off power domain after device removal") Signed-off-by: Anatolij Gustschin agust@denx.de Reported-by: Oliver Graute oliver.graute@gmail.com Reported-by: Fabio Estevam festevam@gmail.com
drivers/power/domain/power-domain-uclass.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
Can we have a sandbox test for this case?
Reviewed-by: Simon Glass sjg@chromium.org
Regards, Simon