@@ -19,21 +19,6 @@ err:
return ret;
}
-static int of_remove_populated_child(struct device *dev, void *d)
-{
- struct platform_device *pdev = to_platform_device(dev);
-
- of_device_unregister(pdev);
- return 0;
-}
-
-static int am335x_child_remove(struct platform_device *pdev)
-{
- device_for_each_child(&pdev->dev, NULL, of_remove_populated_child);
- pm_runtime_disable(&pdev->dev);
- return 0;
-}
-
static const struct of_device_id am335x_child_of_match[] = {
{ .compatible = "ti,am33xx-usb" },
{ },
@@ -42,13 +27,17 @@ MODULE_DEVICE_TABLE(of, am335x_child_of_match);
static struct platform_driver am335x_child_driver = {
.probe = am335x_child_probe,
- .remove = am335x_child_remove,
.driver = {
.name = "am335x-usb-childs",
.of_match_table = am335x_child_of_match,
},
};
-module_platform_driver(am335x_child_driver);
+static int __init am335x_child_init(void)
+{
+ return platform_driver_register(&am335x_child_driver);
+}
+module_init(am335x_child_init);
+
MODULE_DESCRIPTION("AM33xx child devices");
MODULE_LICENSE("GPL v2");
At probe time, the musb_am335x driver register its childs by calling of_platform_populate(), which registers all childs in the devicetree hierarchy recursively. On the other side, the driver's remove() function uses of_device_unregister() to remove each child of musb_am335x's. However, when musb_dsps is loaded, its devices are attached to the musb_am335x device as musb_am335x childs. Hence, musb_am335x remove() will attempt to unregister the devices registered by musb_dsps, which produces a kernel panic. In other words, the childs in the "struct device" hierarchy are not the same as the childs in the "devicetree" hierarchy. Ideally, we should enforce the removal of the devices registered by musb_am335x *only*, instead of all its child devices. However, because of the recursive nature of of_platform_populate, this doesn't seem possible. Therefore, as the only solution at hand, this commit disables musb_am335x driver removal capability, preventing it from being ever removed. This was originally suggested by Sebastian Siewior: https://www.mail-archive.com/linux-omap@vger.kernel.org/msg104946.html And for reference, here's the panic upon module removal: musb-hdrc musb-hdrc.0.auto: remove, state 4 usb usb1: USB disconnect, device number 1 musb-hdrc musb-hdrc.0.auto: USB bus 1 deregistered Unable to handle kernel NULL pointer dereference at virtual address 0000008c pgd = de11c000 [0000008c] *pgd=9e174831, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] ARM Modules linked in: musb_am335x(-) musb_dsps musb_hdrc usbcore usb_common CPU: 0 PID: 623 Comm: modprobe Not tainted 3.15.0-rc4-00001-g24efd13 #69 task: de1b7500 ti: de122000 task.ti: de122000 PC is at am335x_shutdown+0x10/0x28 LR is at am335x_shutdown+0xc/0x28 pc : [<c0327798>] lr : [<c0327794>] psr: a0000013 sp : de123df8 ip : 00000004 fp : 00028f00 r10: 00000000 r9 : de122000 r8 : c000e6c4 r7 : de0e3c10 r6 : de0e3800 r5 : de624010 r4 : de1ec750 r3 : de0e3810 r2 : 00000000 r1 : 00000001 r0 : 00000000 Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: 9e11c019 DAC: 00000015 Process modprobe (pid: 623, stack limit = 0xde122240) Stack: (0xde123df8 to 0xde124000) 3de0: de0e3810 bf054488 3e00: bf05444c de624010 60000013 bf043650 000012fc de624010 de0e3810 bf043a20 3e20: de0e3810 bf04b240 c0635b88 c02ca37c c02ca364 c02c8db0 de1b7500 de0e3844 3e40: de0e3810 c02c8e28 c0635b88 de02824c de0e3810 c02c884c de0e3800 de0e3810 3e60: de0e3818 c02c5b20 bf05417c de0e3800 de0e3800 c0635b88 de0f2410 c02ca838 3e80: bf05417c de0e3800 bf055438 c02ca8cc de0e3c10 bf054194 de0e3c10 c02ca37c 3ea0: c02ca364 c02c8db0 de1b7500 de0e3c44 de0e3c10 c02c8e28 c0635b88 de02824c 3ec0: de0e3c10 c02c884c de0e3c10 de0e3c10 de0e3c18 c02c5b20 de0e3c10 de0e3c10 3ee0: 00000000 bf059000 a0000013 c02c5bc0 00000000 bf05900c de0e3c10 c02c5c48 3f00: de0dd0c0 de1ec970 de0f2410 bf05929c de0f2444 bf05902c de0f2410 c02ca37c 3f20: c02ca364 c02c8db0 bf05929c de0f2410 bf05929c c02c94c8 bf05929c 00000000 3f40: 00000800 c02c8ab4 bf0592e0 c007fc40 c00dd820 6273756d 336d615f 00783533 3f60: c064a0ac de1b7500 de122000 de1b7500 c000e590 00000001 c000e6c4 c0060160 3f80: 00028e70 00028e70 00028ea4 00000081 60000010 00028e70 00028e70 00028ea4 3fa0: 00000081 c000e500 00028e70 00028e70 00028ea4 00000800 becb59f8 00027608 3fc0: 00028e70 00028e70 00028ea4 00000081 00000001 00000001 00000000 00028f00 3fe0: b6e6b6f0 becb59d4 000160e8 b6e6b6fc 60000010 00028ea4 00000000 00000000 [<c0327798>] (am335x_shutdown) from [<bf054488>] (dsps_musb_exit+0x3c/0x4c [musb_dsps]) [<bf054488>] (dsps_musb_exit [musb_dsps]) from [<bf043650>] (musb_shutdown+0x80/0x90 [musb_hdrc]) [<bf043650>] (musb_shutdown [musb_hdrc]) from [<bf043a20>] (musb_remove+0x24/0x68 [musb_hdrc]) [<bf043a20>] (musb_remove [musb_hdrc]) from [<c02ca37c>] (platform_drv_remove+0x18/0x1c) [<c02ca37c>] (platform_drv_remove) from [<c02c8db0>] (__device_release_driver+0x70/0xc8) [<c02c8db0>] (__device_release_driver) from [<c02c8e28>] (device_release_driver+0x20/0x2c) [<c02c8e28>] (device_release_driver) from [<c02c884c>] (bus_remove_device+0xdc/0x10c) [<c02c884c>] (bus_remove_device) from [<c02c5b20>] (device_del+0x104/0x198) [<c02c5b20>] (device_del) from [<c02ca838>] (platform_device_del+0x14/0x9c) [<c02ca838>] (platform_device_del) from [<c02ca8cc>] (platform_device_unregister+0xc/0x20) [<c02ca8cc>] (platform_device_unregister) from [<bf054194>] (dsps_remove+0x18/0x38 [musb_dsps]) [<bf054194>] (dsps_remove [musb_dsps]) from [<c02ca37c>] (platform_drv_remove+0x18/0x1c) [<c02ca37c>] (platform_drv_remove) from [<c02c8db0>] (__device_release_driver+0x70/0xc8) [<c02c8db0>] (__device_release_driver) from [<c02c8e28>] (device_release_driver+0x20/0x2c) [<c02c8e28>] (device_release_driver) from [<c02c884c>] (bus_remove_device+0xdc/0x10c) [<c02c884c>] (bus_remove_device) from [<c02c5b20>] (device_del+0x104/0x198) [<c02c5b20>] (device_del) from [<c02c5bc0>] (device_unregister+0xc/0x20) [<c02c5bc0>] (device_unregister) from [<bf05900c>] (of_remove_populated_child+0xc/0x14 [musb_am335x]) [<bf05900c>] (of_remove_populated_child [musb_am335x]) from [<c02c5c48>] (device_for_each_child+0x44/0x70) [<c02c5c48>] (device_for_each_child) from [<bf05902c>] (am335x_child_remove+0x18/0x30 [musb_am335x]) [<bf05902c>] (am335x_child_remove [musb_am335x]) from [<c02ca37c>] (platform_drv_remove+0x18/0x1c) [<c02ca37c>] (platform_drv_remove) from [<c02c8db0>] (__device_release_driver+0x70/0xc8) [<c02c8db0>] (__device_release_driver) from [<c02c94c8>] (driver_detach+0xb4/0xb8) [<c02c94c8>] (driver_detach) from [<c02c8ab4>] (bus_remove_driver+0x4c/0xa0) [<c02c8ab4>] (bus_remove_driver) from [<c007fc40>] (SyS_delete_module+0x128/0x1cc) [<c007fc40>] (SyS_delete_module) from [<c000e500>] (ret_fast_syscall+0x0/0x48) Fixes: 97238b35d5bb ("usb: musb: dsps: use proper child nodes") Cc: <stable@vger.kernel.org> # v3.12+ Acked-by: George Cherian <george.cherian@ti.com> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> --- drivers/usb/musb/musb_am335x.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-)