Re: [PATCH v2 08/35] brcmfmac: of: Fetch Apple properties

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

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On 1/4/2022 8:26 AM, Hector Martin wrote:
> On Apple ARM64 platforms, firmware selection requires two properties
> that come from system firmware: the module-instance (aka "island", a
> codename representing a given hardware platform) and the antenna-sku.
> We map Apple's module codenames to board_types in the form
> "apple,<module-instance>".
> 
> The mapped board_type is added to the DTS file in that form, while the
> antenna-sku is forwarded by our bootloader from the Apple Device Tree
> into the FDT. Grab them from the DT so firmware selection can use
> them.
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>
> ---
>   .../wireless/broadcom/brcm80211/brcmfmac/common.h    |  1 +
>   .../net/wireless/broadcom/brcm80211/brcmfmac/of.c    | 12 +++++++++++-
>   2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> index 8b5f49997c8b..d4aa25d646fe 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> @@ -50,6 +50,7 @@ struct brcmf_mp_device {
>   	bool		ignore_probe_fail;
>   	struct brcmfmac_pd_cc *country_codes;
>   	const char	*board_type;
> +	const char	*antenna_sku;
>   	union {
>   		struct brcmfmac_sdio_pd sdio;
>   	} bus;
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> index 513c7e6421b2..085d34176b78 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> @@ -63,14 +63,24 @@ void brcmf_of_probe(struct device *dev, enum brcmf_bus_type bus_type,
>   {
>   	struct brcmfmac_sdio_pd *sdio = &settings->bus.sdio;
>   	struct device_node *root, *np = dev->of_node;
> +	const char *prop;
>   	int irq;
>   	int err;
>   	u32 irqf;
>   	u32 val;
>   
> +	/* Apple ARM64 platforms have their own idea of board type, passed in
> +	 * via the device tree. They also have an antenna SKU parameter
> +	 */
> +	if (!of_property_read_string(np, "brcm,board-type", &prop))
> +		settings->board_type = devm_kstrdup(dev, prop, GFP_KERNEL);
> +
> +	if (!of_property_read_string(np, "apple,antenna-sku", &prop))
> +		settings->antenna_sku = devm_kstrdup(dev, prop, GFP_KERNEL);
> +
>   	/* Set board-type to the first string of the machine compatible prop */
>   	root = of_find_node_by_path("/");

I assume this only returns NULL when there is no device tree. Is that a 
safe assumption (Rob)? If so you could bail out here if root is NULL...

> -	if (root) {
> +	if (root && !settings->board_type) {

...and only check the board_type here. Or only check board_type and 
lookup the root node inside this if-statement if it is not needed 
elsewhere in this probe function.

>   		int i, len;
>   		char *board_type;
>   		const char *tmp;

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