Re: [PATCH v2 09/35] brcmfmac: pcie: Perform firmware selection for Apple platforms

[Arend van Spriel <arend.vanspriel@broadcom.com>]

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On 1/4/2022 8:26 AM, Hector Martin wrote:
> On Apple platforms, firmware selection uses the following elements:
> 
>    Property         Example   Source
>    ==============   =======   ========================
> * Chip name        4378      Device ID
> * Chip revision    B1        OTP
> * Platform         shikoku   DT (ARM64) or ACPI (x86)
> * Module type      RASP      OTP
> * Module vendor    m         OTP
> * Module version   6.11      OTP
> * Antenna SKU      X3        DT (ARM64) or ACPI (x86)
> 
> In macOS, these firmwares are stored using filenames in this format
> under /usr/share/firmware/wifi:
> 
>      C-4378__s-B1/P-shikoku-X3_M-RASP_V-m__m-6.11.txt
> 
> To prepare firmwares for Linux, we rename these to a scheme following
> the existing brcmfmac convention:
> 
>      brcmfmac<chip><lower(rev)>-pcie.apple,<platform>-<mod_type>-\
> 	<mod_vendor>-<mod_version>-<antenna_sku>.txt
> 
> The NVRAM uses all the components, while the firmware and CLM blob only
> use the chip/revision/platform/antenna_sku:
> 
>      brcmfmac<chip><lower(rev)>-pcie.apple,<platform>-<antenna_sku>.bin
> 
> e.g.
> 
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-m-6.11-X3.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-X3.bin
> 
> In addition, since there are over 1000 files in total, many of which are
> symlinks or outright duplicates, we deduplicate and prune the firmware
> tree to reduce firmware filenames to fewer dimensions. For example, the
> shikoku platform (MacBook Air M1 2020) simplifies to just 4 files:
> 
>      brcm/brcmfmac4378b1-pcie.apple,shikoku.clm_blob
>      brcm/brcmfmac4378b1-pcie.apple,shikoku.bin
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-m.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-u.txt
> 
> This reduces the total file count to around 170, of which 75 are
> symlinks and 95 are regular files: 7 firmware blobs, 27 CLM blobs, and
> 61 NVRAM config files. We also slightly process NVRAM files to correct
> some formatting issues.
> 
> To handle this, the driver must try the following path formats when
> looking for firmware files:
> 
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-m-6.11-X3.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-m-6.11.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP-m.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-RASP.txt
>      brcm/brcmfmac4378b1-pcie.apple,shikoku-X3.txt *
>      brcm/brcmfmac4378b1-pcie.apple,shikoku.txt
> 
> * Not relevant for NVRAM, only for firmware/CLM.
> 
> The chip revision nominally comes from OTP on Apple platforms, but it
> can be mapped to the PCI revision number, so we ignore the OTP revision
> and continue to use the existing PCI revision mechanism to identify chip
> revisions, as the driver already does for other chips. Unfortunately,
> the mapping is not consistent between different chip types, so this has
> to be determined experimentally.

Not sure I understand this. The chip revision comes from the chipcommon 
register [1]. Maybe that is what you mean by "PCI revision number". For 
some chips it is possible OTP is used to override that.

Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
>   .../broadcom/brcm80211/brcmfmac/pcie.c        | 58 ++++++++++++++++++-
>   1 file changed, 56 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
> index 74c9a4f74813..250e0bd40cb3 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
> @@ -2094,8 +2094,62 @@ brcmf_pcie_prepare_fw_request(struct brcmf_pciedev_info *devinfo)
>   	fwreq->domain_nr = pci_domain_nr(devinfo->pdev->bus) + 1;
>   	fwreq->bus_nr = devinfo->pdev->bus->number;
>   
> -	brcmf_dbg(PCIE, "Board: %s\n", devinfo->settings->board_type);
> -	fwreq->board_types[0] = devinfo->settings->board_type;
> +	/* Apple platforms with fancy firmware/NVRAM selection */
> +	if (devinfo->settings->board_type &&
> +	    devinfo->settings->antenna_sku &&
> +	    devinfo->otp.valid) {
> +		char *buf;
> +		int len;
> +
> +		brcmf_dbg(PCIE, "Apple board: %s\n",
> +			  devinfo->settings->board_type);

maybe good to use local reference for devinfo->settings->board_type, 
which is used several times below.

> +
> +		/* Example: apple,shikoku-RASP-m-6.11-X3 */
> +		len = (strlen(devinfo->settings->board_type) + 1 +
> +		       strlen(devinfo->otp.module) + 1 +
> +		       strlen(devinfo->otp.vendor) + 1 +
> +		       strlen(devinfo->otp.version) + 1 +
> +		       strlen(devinfo->settings->antenna_sku) + 1);
> +
> +		/* apple,shikoku */
> +		fwreq->board_types[5] = devinfo->settings->board_type;

[1] 
https://elixir.bootlin.com/linux/latest/source/include/linux/bcma/bcma_driver_chipcommon.h#L12

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