[Buildroot] [RFC PATCH] package/linux-firmware: Add more Intel WiFi 22000 series

[Yann E. MORIN]

Stefan, All,

On 2022-08-18 15:18 +0200, Stefan Agner spake thusly:
> Add more Intel WiFi 22000 series firmware files. Allow to select the
> firmware version using shell globs.
> 
> Signed-off-by: Stefan Agner <stefan at agner.ch>
> ---
> With the Intel WiFi 22000 series the amount of firmwares is just stagering. So
> much so that it causes size issues in our case.

You know that you can write a post-build script to tweak the target/
directory at the end of the build? That can be a workaround until a
better solution is devised.

> Intel firmwares seem to have an API version, which is the last digit before the
> file ending .ucode. The Linux kernel sources have defines which API each
> individual driver supports (e.g. Linux 5.15 22000 series kernel driver
> supports ucode API 39 up to 66).
> 
> This crude method uses just file glob matching to allow to select firmwares
> which match the kernel in use. However, this approach has a problem: Some
> API versions are missing. E.g. simply using "66" doesn't work since some
> firmware are not available with the latest API supported (e.g.
> iwlwifi-so-a0-gf-a0-64.ucode).
> 
> Also if an older kernel is in use, some firmware files with an older maximum
> API might just be missing, which leads to tar complaining about missing files.
> 
> In this case, we can use 6[46], which happens to select the newest version of
> all firmwares (it seems that firmwares which are available with API version 66
> have only been released with version 63 before).
> 
> However, this of course might be just a coincidence. Ideally Buildroot would
> select the newest version available for a particular API version. Not sure if
> this is easily doable.
> 
> Thoughts?

First: on one hand, I like the simplicity of that patch; if we can't
come up with better, I can see going with it.

But on the other hand, it is also very un-userfriendly. I don't see how
we could _reasonably_ come up with a way to cherry-pick appropriate
firmware files.

First, the linux package depends on linux-frimware, so linux-firmware
can't depend on linux; we could still use a patch-dependency, so that
linux gets at least extracted and patched before linux-firmware gets
installed, but that is going to be tricky to maintain.

We could then grab IWL_22000_UCODE_API_MIN and IWL_22000_UCODE_API_MAX
from drivers/net/wireless/intel/iwlwifi/cfg/22000.c

And then, we'd have to code some non-trivial magic that iterates over
all iwlwifi-Qu{,Z}-*.ucode and check if their API part is in the range,
and for a single "family" of firmwares, keep the highest one (how do we
know that two firmware files are f the same family? Just because they
only differ in API version?) That's a bit brittle...

[--SNIP--]
> diff --git a/package/linux-firmware/linux-firmware.mk b/package/linux-firmware/linux-firmware.mk
> index 64d096df14..2283cd7d5e 100644
> --- a/package/linux-firmware/linux-firmware.mk
> +++ b/package/linux-firmware/linux-firmware.mk
> @@ -436,7 +436,20 @@ LINUX_FIRMWARE_ALL_LICENSE_FILES += LICENSE.QualcommAtheros_ath10k
>  endif
>  
>  ifeq ($(BR2_PACKAGE_LINUX_FIRMWARE_IWLWIFI_22000),y)
> -LINUX_FIRMWARE_FILES += iwlwifi-QuZ-*.ucode iwlwifi-Qu-*.ucode
> +LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB = $(call qstrip,$(BR2_PACKAGE_LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB))
> +LINUX_FIRMWARE_FILES += \
> +	iwlwifi-Qu-b0-hr-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-Qu-c0-hr-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-Qu-b0-jf-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-Qu-c0-jf-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-QuZ-a0-hr-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-QuZ-a0-jf-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-cc-a0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-so-a0-jf-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-so-a0-hr-b0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-so-a0-gf-a0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-ty-a0-gf-a0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode \
> +	iwlwifi-so-a0-gf4-a0-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode

This list is not entirely alphabetically sorted.

Also, why do you extend the prefixes, from iwlwifi-QuZ- and iwlwifi-Qu-,
to include extra c0, b0, a0 and so on? Why can we just have:
    iwlwifi-Qu-*-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode
    iwlwifi-QuZ-*-$(LINUX_FIRMWARE_IWLWIFI_22000_UCODE_API_GLOB).ucode

Oh, and in at least linu 5.17, there are also references to
iwlwifi-QuQnj-, iwlwifi-SoSnj- and a bunch of others. And
specifically, there is also iwlwifi-cc-a0- which in Buildroot is
installed with BR2_PACKAGE_LINUX_FIRMWARE_IWLWIFI_22260 and not
BR2_PACKAGE_LINUX_FIRMWARE_IWLWIFI_22000

So, maybe we could split the families further as an alternate solution?

Regards,
Yann E. MORIN.

>  LINUX_FIRMWARE_ALL_LICENSE_FILES += LICENCE.iwlwifi_firmware
>  endif
>  
> -- 
> 2.37.2
> 
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> buildroot at buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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