linux/drivers/i2c
Maxime Bizon 3269bb63eb i2c-mv64xxx: Fix random oops at boot
I have a Marvell board which has the same i2c hw block than mv64xxx, so
I'm trying to use i2c-mv64xxx driver.

But I get the following random oops at boot:

Unable to handle kernel NULL pointer dereference at virtual address 00000002
Backtrace: 
[<c0397e4c>] (mv64xxx_i2c_intr+0x0/0x2b8) from [<c02879c4>] (__do_irq+0x4c/0x8c)
[<c0287978>] (__do_irq+0x0/0x8c) from [<c0287c0c>] (do_level_IRQ+0x68/0xc0)
 r8 = C0501E08  r7 = 00000005  r6 = C0501E08  r5 = 00000005
 r4 = C048BB78 
[<c0287ba4>] (do_level_IRQ+0x0/0xc0) from [<c02885f8>] (asm_do_IRQ+0x50/0x134)
 r6 = C0449C78  r5 = F1020000  r4 = FFFFFFFF 
[<c02885a8>] (asm_do_IRQ+0x0/0x134) from [<c02869c4>] (__irq_svc+0x24/0x100)
 r8 = C1CAC400  r7 = 00000005  r6 = 00000002  r5 = F1020000
 r4 = FFFFFFFF 
[<c0287efc>] (setup_irq+0x0/0x124) from [<c02880d0>] (request_irq+0xb0/0xd0)
 r7 = C041B2AC  r6 = C0397E4C  r5 = 00000000  r4 = 00000005
[<c0288020>] (request_irq+0x0/0xd0) from [<c03985f4>] (mv64xxx_i2c_probe+0x148/0x244)
[<c03984ac>] (mv64xxx_i2c_probe+0x0/0x244) from [<c038bedc>] (platform_drv_probe+0x20/0x24)


The oops is caused by a spurious interrupt that occurs when request_irq
is called. mv64xxx_i2c_fsm() tries to read drv_data->msg, which is NULL.

I noticed that hardware init is done after requesting irq. Thus any
pending irq from previous hardware usage may cause this.

The following patch fixes it:


Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-01-05 17:54:05 +01:00
..
algos i2c: Discard the i2c algo del_bus wrappers 2006-12-10 21:21:33 +01:00
busses i2c-mv64xxx: Fix random oops at boot 2007-01-05 17:54:05 +01:00
chips [PATCH] fix more workqueue build breakage (tps65010) 2006-12-13 09:05:46 -08:00
i2c-core.c i2c: Migration aids for i2c_adapter.dev removal 2007-01-04 13:07:04 +01:00
i2c-dev.c i2c: Refactor a kfree in i2c-dev 2006-12-10 21:21:33 +01:00
Kconfig i2c: Fix copy-n-paste in subsystem Kconfig 2006-09-26 15:38:51 -07:00
Makefile [PATCH] hwmon: hwmon vs i2c, second round (07/11) 2005-09-05 09:14:22 -07:00