| Message ID | 20200217084211.17967-1-agust@denx.de |
|---|---|
| State | Accepted |
| Commit | 3e4fcfa4bcd74fee409694d24ee580a2826bbe9a |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | [v2] power-domain: fix hang in endless loop on i.MX8 | expand |
Hi Anatolij, On Mon, Feb 17, 2020 at 5:42 AM 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> I also had to apply the following change in order to boot a i.MX8QXP MEK board: --- a/arch/arm/mach-imx/imx8/fdt.c +++ b/arch/arm/mach-imx/imx8/fdt.c @@ -280,6 +280,8 @@ int ft_system_setup(void *blob, bd_t *bd) { int ret; + return 0; + update_fdt_with_owned_resources(blob); if (is_imx8qm()) { With your patch and this change a 4.14.98 NXP kernel can boot, but not a 4.19.35 NXP nor a mainline kernel. Tested-by: Fabio Estevam <festevam@gmail.com>
On Mon, Feb 17, 2020 at 2:27 PM Fabio Estevam <festevam@gmail.com> wrote: > I also had to apply the following change in order to boot a i.MX8QXP MEK board: > > --- a/arch/arm/mach-imx/imx8/fdt.c > +++ b/arch/arm/mach-imx/imx8/fdt.c > @@ -280,6 +280,8 @@ int ft_system_setup(void *blob, bd_t *bd) > { > int ret; > > + return 0; > + > update_fdt_with_owned_resources(blob); > > if (is_imx8qm()) { > > With your patch and this change a 4.14.98 NXP kernel can boot, but not > a 4.19.35 NXP nor a mainline kernel. > > Tested-by: Fabio Estevam <festevam@gmail.com> Correction: the above change is not needed now. I saw an issue with the command line and I sent a fix. This patch plus the one that fixes the command line are enough to get i.MX8QXP MEK board booting a mainline kernel. Thanks
On Mon, Feb 17, 2020 at 09:42:11AM +0100, 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 Applied to u-boot/master, thanks!
diff --git a/drivers/power/domain/power-domain-uclass.c b/drivers/power/domain/power-domain-uclass.c index d9c623b56e..2b7a1cb8fe 100644 --- a/drivers/power/domain/power-domain-uclass.c +++ b/drivers/power/domain/power-domain-uclass.c @@ -127,6 +127,17 @@ 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
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> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com> --- Changes in v2: - drop braces - add RB tags drivers/power/domain/power-domain-uclass.c | 11 +++++++++++ 1 file changed, 11 insertions(+)