From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kevin Hilman <khilman@deeprootsystems.com>
Subject: Re: [PATCH] Serial: Avoid enabling clocks when clock node is null.
Date: Tue, 20 Apr 2010 16:30:29 -0700
Message-ID: <87mxwxbt2i.fsf@deeprootsystems.com>
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In-Reply-To: <40436.192.168.10.89.1271750521.squirrel@dbdmail.itg.ti.com> (Govindraj R.'s message of "Tue\, 20 Apr 2010 13\:32\:01 +0530 \(IST\)")
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To: "Govindraj.R" <govindraj.raja@ti.com>
Cc: linux-omap@vger.kernel.org, Tony Lindgren <tony@atomide.com>, Venkatraman S <svenkatr@ti.com>

"Govindraj.R" <govindraj.raja@ti.com> writes:

> This patch ensures that if a particular uart clock node
> was not acquired then do not proceed with enabling clock
> and device registration for that uart.
>
> Without this patch if uart_ick/fck value was null
> then it throw oops as below and boot will halt.
>
> <1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
> <1>pgd = c0004000
> <1>[0000001c] *pgd=00000000
> <0>Internal error: Oops: 5 [#1]
> <0>last sysfs file:
> <d>Modules linked in:
> CPU: 0    Not tainted  (2.6.34-rc3-00006-g7da06f1-dirty #15)
> PC is at omap_serial_init_port+0x64/0x3a0
> LR is at 0x8
> pc : [<c000f51c>]    lr : [<00000008>]    psr: 60000013
> sp : dfc2bf80  ip : 00000000  fp : 00000000
> r10: 000007c8  r9 : c05c65f8  r8 : 00000000
> r7 : c05c6dc0  r6 : c000b44c  r5 : 00000000  r4 : 00000004
> r3 : 00000007  r2 : c05c6538  r1 : fb020000  r0 : c05c6dc0
> Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
> Control: 10c5387f  Table: 80004019  DAC: 00000017
> <0>Process swapper (pid: 1, stack limit = 0xdfc2a2f0)
> <0>Stack: (0xdfc2bf80 to 0xdfc2c000)
> <0>bf80: 00000003 fb020000 00000004 00000000 c000b44c 00000000 00000000 00000000
> <0>bfa0: 00000000 c000f880 c002e288 c00135e0 c002e288 c00137f4 c002e288 c000b464
> <0>bfc0: c002e288 c003e34c 00000031 00000000 00000000 00000192 00000000 c002e288
> <0>bfe0: 00000000 00000000 00000000 c0008578 00000000 c003f970 ffffffff ffffffff
> [<c000f51c>] (omap_serial_init_port+0x64/0x3a0) from [<c000f880>] (omap_serial_init+0x28/0x3c)
> [<c000f880>] (omap_serial_init+0x28/0x3c) from [<c00135e0>] (zoom_peripherals_init+0x44/0x6c)
> [<c00135e0>] (zoom_peripherals_init+0x44/0x6c) from [<c00137f4>] (omap_sdp_init+0x14/0x54)
> [<c00137f4>] (omap_sdp_init+0x14/0x54) from [<c000b464>] (customize_machine+0x18/0x24)
> [<c000b464>] (customize_machine+0x18/0x24) from [<c003e34c>] (do_one_initcall+0x5c/0x1b8)
> [<c003e34c>] (do_one_initcall+0x5c/0x1b8) from [<c0008578>] (kernel_init+0x90/0x144)
> [<c0008578>] (kernel_init+0x90/0x144) from [<c003f970>] (kernel_thread_exit+0x0/0x8)
> <0>Code: eb00ef8f e597c06c e3a0e008 e3a03007 (e5dc201c)
> <4>---[ end trace 1b75b31a2719ed1c ]---
> <0>Kernel panic - not syncing: Attempted to kill init!
>
> Cc: Tony Lindgren <tony@atomide.com>
> Cc: Kevin Hilman <khilman@deeprootsystems.com>
> Reported-by: Venkatraman S <svenkatr@ti.com>
> Signed-off-by: Govindraj.R <govindraj.raja@ti.com>

Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

Should be queued for -fixes.

Kevin