[RFC PATCH] brcmfmac: add 43751 SDIO ids and initialization

[Franky Lin]

On Wed, Mar 8, 2023 at 4:48 AM Marc Gonzalez <marc.w.gonzalez at 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.

Regards,
- Franky
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