[PATCH] ARM: OMAP2+: hwmod: Fix usage of invalid iclk / oclk when clock node is not present

[Paul Walmsley]

Hi Nishanth,

On Mon, 2 Dec 2013, Nishanth Menon wrote:

> commit dc75925d(OMAP: hwmod: Fix the missing braces) introduced
> missing braces, however, we just set return result if clk_get fail
> and we populate the error pointer in clk pointer and pass it along to
> clk_prepare. This is wrong. The intent seems to be retry remaining
> clocks if they are available and warn the ones we cant find clks for.
> 
> With the current logic, we see the following crash:
> omap_hwmod: l3_main: cannot clk_get interface_clk emac_ick
> Unable to handle kernel NULL pointer dereference at virtual address 00000032
> pgd = c0004000
> [00000032] *pgd=00000000
> Internal error: Oops: 5 [#1] SMP ARM
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc1-00044-gcc9fd5a-dirty #19
> task: ce0c3440 ti: ce0c4000 task.ti: ce0c4000
> PC is at __clk_prepare+0x10/0x74
> LR is at clk_prepare+0x14/0x24
>   <snip>
> [<c044d59c>] (__clk_prepare+0x10/0x74) from [<c044d9b0>] (clk_prepare+0x14/0x24)
> [<c044d9b0>] (clk_prepare+0x14/0x24) from [<c077d8c4>] (_init+0x24c/0x3bc)
> [<c077d8c4>] (_init+0x24c/0x3bc) from [<c0027328>] (omap_hwmod_for_each+0x34/0x5c)
> [<c0027328>] (omap_hwmod_for_each+0x34/0x5c) from [<c077dfa0>] (__omap_hwmod_setup_all+0x24/0x40)
> [<c077dfa0>] (__omap_hwmod_setup_all+0x24/0x40) from [<c0008928>] (do_one_initcall+0x38/0x168)
> [<c0008928>] (do_one_initcall+0x38/0x168) from [<c0771be8>] (kernel_init_freeable+0xfc/0x1cc)
> [<c0771be8>] (kernel_init_freeable+0xfc/0x1cc) from [<c0521064>] (kernel_init+0x8/0x110)
> [<c0521064>] (kernel_init+0x8/0x110) from [<c000e568>] (ret_from_fork+0x14/0x2c)
> Code: e92d4038 e2504000 01a05004 0a000005 (e5943034)
> 
> So, just warn and continue instead of proceeding and crashing, with
> missing clock nodes/bad data, we will eventually fail, however we
> should now have enough information to identify the culprit.
> 
> Signed-off-by: Nishanth Menon <nm at ti.com>

Thanks, queued for v3.13-rc.


- Paul