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Message-ID: <c3a109b0-1672-484d-99ed-656a43143538@linaro.org>
Date: Tue, 19 Mar 2024 17:16:43 +0100
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Subject: Re: [PATCH v3 2/5] Bluetooth: add quirk for broken address properties
To: Doug Anderson <dianders@chromium.org>,
 Johan Hovold <johan+linaro@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>,
 Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
 Bjorn Andersson <andersson@kernel.org>, Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, cros-qcom-dts-watchers@chromium.org,
 Johan Hedberg <johan.hedberg@gmail.com>,
 Balakrishna Godavarthi <quic_bgodavar@quicinc.com>,
 Matthias Kaehlcke <mka@chromium.org>, Rocky Liao <quic_rjliao@quicinc.com>,
 Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
 linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
 devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
 linux-kernel@vger.kernel.org, stable@vger.kernel.org
References: <20240319152926.1288-1-johan+linaro@kernel.org>
 <20240319152926.1288-3-johan+linaro@kernel.org>
 <CAD=FV=VUFodCAXEJgfpSqZZdtQaw5-8n_-sX_2p6LuQ2ixLRpQ@mail.gmail.com>
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From: Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <CAD=FV=VUFodCAXEJgfpSqZZdtQaw5-8n_-sX_2p6LuQ2ixLRpQ@mail.gmail.com>
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On 3/19/24 17:10, Doug Anderson wrote:
> Hi,
> 
> On Tue, Mar 19, 2024 at 8:29 AM Johan Hovold <johan+linaro@kernel.org> wrote:
>>
>> Some Bluetooth controllers lack persistent storage for the device
>> address and instead one can be provided by the boot firmware using the
>> 'local-bd-address' devicetree property.
>>
>> The Bluetooth devicetree bindings clearly states that the address should
>> be specified in little-endian order, but due to a long-standing bug in
>> the Qualcomm driver which reversed the address some boot firmware has
>> been providing the address in big-endian order instead.
>>
>> Add a new quirk that can be set on platforms with broken firmware and
>> use it to reverse the address when parsing the property so that the
>> underlying driver bug can be fixed.
>>
>> Fixes: 5c0a1001c8be ("Bluetooth: hci_qca: Add helper to set device address")
>> Cc: stable@vger.kernel.org      # 5.1
>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>> ---
>>   include/net/bluetooth/hci.h | 9 +++++++++
>>   net/bluetooth/hci_sync.c    | 5 ++++-
>>   2 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
>> index bdee5d649cc6..191077d8d578 100644
>> --- a/include/net/bluetooth/hci.h
>> +++ b/include/net/bluetooth/hci.h
>> @@ -176,6 +176,15 @@ enum {
>>           */
>>          HCI_QUIRK_USE_BDADDR_PROPERTY,
>>
>> +       /* When this quirk is set, the Bluetooth Device Address provided by
>> +        * the 'local-bd-address' fwnode property is incorrectly specified in
>> +        * big-endian order.
>> +        *
>> +        * This quirk can be set before hci_register_dev is called or
>> +        * during the hdev->setup vendor callback.
>> +        */
>> +       HCI_QUIRK_BDADDR_PROPERTY_BROKEN,
> 
> Like with the binding, I feel like
> "HCI_QUIRK_BDADDR_PROPERTY_BACKWARDS" or
> "HCI_QUIRK_BDADDR_PROPERTY_SWAPPED" would be more documenting but I
> don't feel strongly.

Yeah, I thought the same.. and the binding, perhaps could be generic,
as I have a strong suspicion Qualcomm is not the only vendor who
made such oopsies..

Konrad