Message-ID: <629435a5-fb47-2cb5-78b6-e42c943aa397@linaro.org>
Date:   Wed, 8 Mar 2023 18:37:48 +0100
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From:   Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [RFC PATCH] brcmfmac: add 43751 SDIO ids and initialization
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To:     Franky Lin <franky.lin@broadcom.com>,
        Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc:     Arend van Spriel <aspriel@gmail.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>,
        Alexander Prutskov <alep@cypress.com>,
        Joseph chuang <jiac@cypress.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Angus Ainslie <angus@akkea.ca>, linux-wireless@vger.kernel.org,
        linux-mmc@vger.kernel.org, linux-amlogic@lists.infradead.org
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 <6be2c348-b343-876a-a77f-a8297676de6a@free.fr>
 <a215e398-2c49-19d2-0730-5e8c51df1ed9@free.fr>
 <CA+8PC_du5dMwkmAshG2mM9TdeJft5aeAbEdDp0_q3Rxdvpq4MQ@mail.gmail.com>
 <f14407f1-e16f-0074-6e29-c597754ae617@free.fr>
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On 08/03/2023 18:21, Franky Lin wrote:
> On Wed, Mar 8, 2023 at 4:48 AM Marc Gonzalez <marc.w.gonzalez@free.fr> wrote:
>>
>> On 08/03/2023 00:15, Franky Lin wrote:
>>
>>> On Tue, Mar 7, 2023 at 6:40 AM Marc Gonzalez wrote:
>>>
>>>> Through the SDIO bus, the WiFi chip reports 0xaae7 (i.e. 43751)
>>>> hence the /sys/bus/sdio/devices output above.
>>>>
>>>> sdio_read_func_cis() -> sdio_read_cis() which sets
>>>> func->vendor/func->device to 2d0/aae7
>>>>
>>>>
>>>> But when brcmf_chip_recognition() calls ci->ops->read32()
>>>> i.e. brcmf_sdio_buscore_read32()
>>>> [ vs brcmf_sdiod_readl() in brcmf_sdio_probe_attach() ]
>>>>
>>>> [    1.177283] brcmfmac: F1 signature read @0x18000000=0x1042aae8
>>>> [    1.182912] found AXI chip: BCM43752/2
>>>> [    1.186384] BCM43752/2: chip=aae8 rev=2 type=1
>>>>
>>>> Here it reports 0xaae8 (i.e. 43752)
>>>>
>>>> Why the discrepancy?
>>>> Can it cause issues?
>>>> (Sometimes, the whole SDIO bus doesn't probe at boot.
>>>> I am still investigating these intermittent problems.)
>>>>
>>>> Should I use 43751 or 43752 firmware...?
>>>
>>> This question should be answered by the Cypress/Infineon folks but
>>> unfortunately they have been quiet for a long time. In general we use
>>> the id read from 0x18000000 to decide which firmware to load. But be
>>> aware that the rev also matters. There are some examples in
>>> brcmf_sdio_fwnames table that the different firmware name can be
>>> derived from the same chip common id but different rev.
>>>
>>> However sdio device enumeration happens before firmware download so
>>> the intermittent problem you are facing probably is not related to
>>> firmware version.
>>
>> Disclosure: My knowledge of SDIO device enumeration is 0.
>>
>> When the host sends the equivalent of an "identify yourself" message
>> on the SDIO bus, doesn't the reply come from the WiFi device?
>> Why would the device reply 0xaae7 instead of 0xaae8?
>>
>> In other words, who is replying 0xaae7?
> 
> The enumeration response is done by the HW sdio core on the chip.  No
> software involved.

Mark,

This would be the:
	BRCMF_SDIO_DEVICE(SDIO_DEVICE_ID_BROADCOM_CYPRESS_43751, CYW),
which is returned by the SDIO bus and associated the SDIO device with the brcmf driver.

All the other IDs are returned by reading registers/send commands to the SDIO device.

Neil
> 
> Regards,
> - Franky