linux-kernel - Re: [PATCH] Bluetooth: qca: generalise device address check

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Message-ID: <CAD=FV=V-pG9+5fLonNvydmjS=ziUFUHAyF8T7YTkEHiO405aSA@mail.gmail.com>
Date: Fri, 26 Apr 2024 10:23:15 -0700
From: Doug Anderson <dianders@...omium.org>
To: Johan Hovold <johan+linaro@...nel.org>
Cc: Marcel Holtmann <marcel@...tmann.org>, Luiz Augusto von Dentz <luiz.dentz@...il.com>, 
	linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org, 
	stable@...r.kernel.org, Janaki Ramaiah Thota <quic_janathot@...cinc.com>
Subject: Re: [PATCH] Bluetooth: qca: generalise device address check

Hi,

On Fri, Apr 26, 2024 at 9:00 AM Johan Hovold <johan+linaro@...nel.org> wrote:
>
> The default device address apparently comes from the NVM configuration
> file and can differ quite a bit.
>
> Store the default address when parsing the configuration file and use it
> to determine whether the controller has been provisioned with an
> address.
>
> This makes sure that devices without a unique address start as
> unconfigured unless a valid address has been provided in the devicetree.
>
> Fixes: 00567f70051a ("Bluetooth: qca: fix invalid device address check")
> Cc: stable@...r.kernel.org      # 6.5
> Cc: Doug Anderson <dianders@...omium.org>
> Cc: Janaki Ramaiah Thota <quic_janathot@...cinc.com>
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
> ---
>  drivers/bluetooth/btqca.c | 21 ++++++++++++---------
>  drivers/bluetooth/btqca.h |  2 ++
>  2 files changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
> index cfa71708397b..d7a6738e4691 100644
> --- a/drivers/bluetooth/btqca.c
> +++ b/drivers/bluetooth/btqca.c
> @@ -15,9 +15,6 @@
>
>  #define VERSION "0.1"
>
> -#define QCA_BDADDR_DEFAULT (&(bdaddr_t) {{ 0xad, 0x5a, 0x00, 0x00, 0x00, 0x00 }})
> -#define QCA_BDADDR_WCN3991 (&(bdaddr_t) {{ 0xad, 0x5a, 0x00, 0x00, 0x98, 0x39 }})
> -
>  int qca_read_soc_version(struct hci_dev *hdev, struct qca_btsoc_version *ver,
>                          enum qca_btsoc_type soc_type)
>  {
> @@ -351,6 +348,11 @@ static void qca_tlv_check_data(struct hci_dev *hdev,
>
>                         /* Update NVM tags as needed */
>                         switch (tag_id) {
> +                       case EDL_TAG_ID_BD_ADDR:
> +                               if (tag_len != sizeof(bdaddr_t))
> +                                       break;
> +                               memcpy(&config->bdaddr, tlv_nvm->data, sizeof(bdaddr_t));
> +                               break;
>                         case EDL_TAG_ID_HCI:

nit: blank line after "break" ?

Also note that on my firmware I never see this tag and thus your patch
breaks trogdor. Specifically I put a printout here and it never gets
hit.

I printed all the tags/lengths:

[   17.961087] DOUG: id 0xde02, len 0x0010
[   17.965081] DOUG: id 0x0000, len 0x0000
[   17.969050] DOUG: id 0x0000, len 0x0011
[   17.973025] DOUG: id 0x0000, len 0x0a00
[   17.976991] DOUG: id 0x0303, len 0x0303
[   17.981066] DOUG: id 0x0033, len 0x1001

Probably EDL_TAG_ID_BD_ADDR should have been 0xde02, not just 2.
..but then the size is wrong? When I print out the bytes in ID 0xde02
I see the address you're looking for 4 bytes in...

[   17.663602] DOUG: 0x00
[   17.666132] DOUG: 0x00
[   17.668638] DOUG: 0x00
[   17.671237] DOUG: 0x00
[   17.673689] DOUG: 0xad
[   17.676120] DOUG: 0x5a
[   17.678551] DOUG: 0x00
[   17.680980] DOUG: 0x00
[   17.683409] DOUG: 0x98
[   17.685846] DOUG: 0x39
[   17.688278] DOUG: 0x08
[   17.690704] DOUG: 0x00
[   17.693137] DOUG: 0x08
[   17.693139] DOUG: 0x00
[   17.693139] DOUG: 0x00
[   17.693140] DOUG: 0x00


> @@ -624,6 +626,9 @@ static int qca_check_bdaddr(struct hci_dev *hdev)
>         if (bacmp(&hdev->public_addr, BDADDR_ANY))
>                 return 0;
>
> +       if (!bacmp(&config->bdaddr, BDADDR_ANY))
> +               return 0;

The above test feels non-obvious enough to deserve a comment. Could
you add one? That would also help alleviate my confusion since I
_think_ your if test is unneeded and maybe wrong? Let's say that the
firmware didn't have a default address stored in it. It still seems
like we could try to read the address and then if the firmware gave
back BDADDR_ANY (0) we should set the `HCI_QUIRK_USE_BDADDR_PROPERTY`
property, right?