[PATCH v4 5/5] OMAP: mailbox: add notification support for multiple readers

[Varadarajan, Charulatha]

On Wed, Nov 24, 2010 at 18:39, Kanigeri, Hari <h-kanigeri2 at ti.com> wrote:
> On Tue, Nov 23, 2010 at 11:29 PM, Varadarajan, Charulatha <charu at ti.com> wrote:
>> On Wed, Nov 24, 2010 at 02:56, Hari Kanigeri <h-kanigeri2 at ti.com> wrote:
>>> In the current mailbox driver, the mailbox internal pointer for
>>> callback can be directly manipulated by the Users, so a second
>>> User can easily corrupt the first user's callback pointer.
>>> The initial effort to correct this issue can be referred here:
>>> https://patchwork.kernel.org/patch/107520/
>>>
>>> Along with fixing the above stated issue, this patch  adds the
>>> flexibility option to register notifications from
>>> multiple readers to the events received on a mailbox instance.
>>> The discussion regarding this can be referred here.
>>> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg30671.html
>>>
>>> Signed-off-by: Hari Kanigeri <h-kanigeri2 at ti.com>
>>> Signed-off-by: Fernando Guzman Lugo <x0095840 at ti.com>
>>> ---
>>>  arch/arm/plat-omap/include/plat/mailbox.h |    7 +-
>>>  arch/arm/plat-omap/mailbox.c              |  104 ++++++++++++++++-------------
>>>  2 files changed, 62 insertions(+), 49 deletions(-)
>>>
>>
>> <<snip>>
>>
>>> @@ -363,10 +372,13 @@ int omap_mbox_register(struct device *parent, struct omap_mbox **list)
>>>                        ret = PTR_ERR(mbox->dev);
>>>                        goto err_out;
>>>                }
>>> +
>>
>> Do this change in the patch where the below code was added.
>
> I am sorry I didn't get you. you mean BLOCKING_INIT_NOTIFIER_HEAD line
> ? yes, it is needed for this patch.

No. I was saying that adding a new line could be done in the patch where this
piece of code (below 4 lines) was introduced. Sorry if that was not clear :-(

>>
>>>                if (cpu_is_omap44xx())
>>>                        mbox->rev = OMAP_MBOX_IP_VERSION_2;
>>>                else
>>>                        mbox->rev = OMAP_MBOX_IP_LEGACY;
>>> +
>>> +               BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
>>>        }
>>>        return 0;
>>>
>>> --
>>> 1.7.0
>>>
>>
>
>
>
> --
> Thank you,
> Best regards,
> Hari Kanigeri
>