Subject: Re: [PATCH wireless-drivers-next] brcmfmac: add basic validation of
 shared RAM address
To:     =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <zajec5@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>
Cc:     "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" 
        <brcm80211-dev-list.pdl@broadcom.com>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" 
        <brcm80211-dev-list.pdl@broadcom.com>,
        brcm80211-dev-list@cypress.com,
        =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>
References: <20190220103047.8960-1-zajec5@gmail.com>
 <CACna6rwwDN6svzWMGbxYXDp5CN8C=A=fV224QcfoLcACQQgLDA@mail.gmail.com>
From:   Arend Van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <92e8bf1e-3be9-96f2-93e9-ac504a609929@broadcom.com>
Date:   Thu, 21 Feb 2019 09:59:19 +0100
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On 2/21/2019 9:01 AM, Rafał Miłecki wrote:
> On Wed, 20 Feb 2019 at 11:31, Rafał Miłecki <zajec5@gmail.com> wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>>
>> While experimenting with firmware loading I ended up in a state of
>> firmware reporting shared RAM address 0x04000001. It was causing:
>> [   94.448015] Unable to handle kernel paging request at virtual address cd680001
>> due to reading out of the mapped memory.
>>
>> This patch adds some basic validation to avoid kernel crashes due to the
>> unexpected firmware behavior.
> 
> For a reference for the further hackers. That has been caused by a
> BCMA_CORE_SYS_MEM core on my BCM4366/4 not being up.

Thanks, Rafał

Does that happen all the time or in some specific scenario. Anyway, it 
seems like we need to add a check in brcmf_chip_sysmem_ramsize() and 
bringup the core if needed. Although, I am curious in what the state the 
other cores are at that time. Might need a chip-wide reset.

Regards,
Arend