usb: musb: omap2430: fix kernel panic on reboot

Cancel idle timer in musb_platform_exit.

The idle timer could trigger after clock had been disabled leading to
kernel panic when MUSB_DEVCTL is accessed in musb_do_idle on 2.6.37.

The fault below is no longer triggered on 2.6.38-rc4 (clock is disabled
later, and only if compiled as a module, and the offending memory access
has moved) but the timer should be cancelled nonetheless.

Rebooting... musb_hdrc musb_hdrc: remove, state 4
usb usb1: USB disconnect, address 1
musb_hdrc musb_hdrc: USB bus 1 deregistered
Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa0ab060
Internal error: : 1028 [#1] PREEMPT
last sysfs file: /sys/kernel/uevent_seqnum
Modules linked in:
CPU: 0    Not tainted  (2.6.37+ #6)
PC is at musb_do_idle+0x24/0x138
LR is at musb_do_idle+0x18/0x138
pc : [<c02377d8>]    lr : [<c02377cc>]    psr: 80000193
sp : cf2bdd80  ip : cf2bdd80  fp : c048a20c
r10: c048a60c  r9 : c048a40c  r8 : cf85e110
r7 : cf2bc000  r6 : 40000113  r5 : c0489800  r4 : cf85e110
r3 : 00000004  r2 : 00000006  r1 : fa0ab000  r0 : cf8a7000
Flags: Nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 10c5387d  Table: 8faac019  DAC: 00000015
Process reboot (pid: 769, stack limit = 0xcf2bc2f0)
Stack: (0xcf2bdd80 to 0xcf2be000)
dd80: 00000103 c0489800 c02377b4 c005fa34 00000555 c0071a8c c04a3858 cf2bdda8
dda0: 00000555 c048a00c cf2bdda8 cf2bdda8 1838beb0 00000103 00000004 cf2bc000
ddc0: 00000001 00000001 c04896c8 0000000a 00000000 c005ac14 00000001 c003f32c
dde0: 00000000 00000025 00000000 cf2bc000 00000002 00000001 cf2bc000 00000000
de00: 00000001 c005ad08 cf2bc000 c002e07c c03ec039 ffffffff fa200000 c0033608
de20: 00000001 00000000 cf852c14 cf81f200 c045b714 c045b708 cf2bc000 c04a37e8
de40: c0033c04 cf2bc000 00000000 00000001 cf2bde68 cf2bde68 c01c3abc c004f7d8
de60: 60000013 ffffffff c0033c04 00000000 01234567 fee1dead 00000000 c006627c
de80: 00000001 c00662c8 28121969 c00663ec cfa38c40 cf9f6a00 cf2bded0 cf9f6a0c
dea0: 00000000 cf92f000 00008914 c02cd284 c04a55c8 c028b398 c00715c0 becf24a8
dec0: 30687465 00000000 00000000 00000000 00000002 1301a8c0 00000000 00000000
dee0: 00000002 1301a8c0 00000000 00000000 c0450494 cf527920 00011f10 cf2bdf08
df00: 00011f10 cf2bdf10 00011f10 cf2bdf18 c00f0b44 c004f7e8 cf2bdf18 cf2bdf18
df20: 00011f10 cf2bdf30 00011f10 cf2bdf38 cf401300 cf486100 00000008 c00d2b28
df40: 00011f10 cf401300 00200200 c00d3388 00011f10 cfb63a88 cfb63a80 c00c2f08
df60: 00000000 00000000 cfb63a80 00000000 cf0a3480 00000006 c0033c04 cfb63a80
df80: 00000000 c00c0104 00000003 cf0a3480 cfb63a80 00000000 00000001 00000004
dfa0: 00000058 c0033a80 00000000 00000001 fee1dead 28121969 01234567 00000000
dfc0: 00000000 00000001 00000004 00000058 00000001 00000001 00000000 00000001
dfe0: 4024d200 becf2cb0 00009210 4024d218 60000010 fee1dead 00000000 00000000
[<c02377d8>] (musb_do_idle+0x24/0x138) from [<c005fa34>] (run_timer_softirq+0x1a8/0x26)
[<c005fa34>] (run_timer_softirq+0x1a8/0x26c) from [<c005ac14>] (__do_softirq+0x88/0x13)
[<c005ac14>] (__do_softirq+0x88/0x138) from [<c005ad08>] (irq_exit+0x44/0x98)
[<c005ad08>] (irq_exit+0x44/0x98) from [<c002e07c>] (asm_do_IRQ+0x7c/0xa0)
[<c002e07c>] (asm_do_IRQ+0x7c/0xa0) from [<c0033608>] (__irq_svc+0x48/0xa8)
Exception stack(0xcf2bde20 to 0xcf2bde68)
de20: 00000001 00000000 cf852c14 cf81f200 c045b714 c045b708 cf2bc000 c04a37e8
de40: c0033c04 cf2bc000 00000000 00000001 cf2bde68 cf2bde68 c01c3abc c004f7d8
de60: 60000013 ffffffff
[<c0033608>] (__irq_svc+0x48/0xa8) from [<c004f7d8>] (sub_preempt_count+0x0/0xb8)
Code: ebf86030 e5940098 e594108c e5902010 (e5d13060)
---[ end trace 3689c0d808f9bf7c ]---
Kernel panic - not syncing: Fatal exception in interrupt

Cc: stable@kernel.org
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/omap2430.c

@@ -362,6 +362,7 @@ static int omap2430_musb_init(struct musb *musb)
 
 static int omap2430_musb_exit(struct musb *musb)
 {
+	del_timer_sync(&musb_idle_timer);
 
 	omap2430_low_level_exit(musb);
 	otg_put_transceiver(musb->xceiv);