On 15/02/20, Anatolij Gustschin 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(+)
diff --git a/drivers/power/domain/power-domain-uclass.c b/drivers/power/domain/power-domain-uclass.c index d9c623b56e..d8fe4d4877 100644 --- a/drivers/power/domain/power-domain-uclass.c +++ b/drivers/power/domain/power-domain-uclass.c @@ -127,6 +127,18 @@ static int dev_power_domain_ctrl(struct udevice *dev, bool on) ret = power_domain_off(&pd); }
- /*
* For platforms with parent and child power-domain devices* we may not run device_remove() on the power-domain parent* because it will result in removing its children and switching* off their power-domain parent. So we will get here again and* again and will be stuck in an endless loop.*/- if (!on && dev_get_parent(dev) == pd.dev &&
device_get_uclass_id(dev) == UCLASS_POWER_DOMAIN) {return ret;- }
- /*
- power_domain_get() bound the device, thus
- we must remove it again to prevent unbinding
-- 2.17.1
thx, just tested this and now I can drop my revert mentioned here:
https://lists.denx.de/pipermail/u-boot/2020-February/398910.html
Best regards,
Oliver