Re: [PATCH v2 16/35] brcmfmac: acpi: Add support for fetching Apple ACPI properties

[Arend van Spriel]

On 1/4/2022 8:26 AM, Hector Martin wrote:
> On DT platforms, the module-instance and antenna-sku-info properties
> are passed in the DT. On ACPI platforms, module-instance is passed via
> the analogous Apple device property mechanism, while the antenna SKU
> info is instead obtained via an ACPI method that grabs it from
> non-volatile storage.
>
> Add support for this, to allow proper firmware selection on Apple
> platforms.
>
> Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
> ---
>   .../broadcom/brcm80211/brcmfmac/Makefile      |  2 +
>   .../broadcom/brcm80211/brcmfmac/acpi.c        | 47 +++++++++++++++++++
>   .../broadcom/brcm80211/brcmfmac/common.c      |  1 +
>   .../broadcom/brcm80211/brcmfmac/common.h      |  9 ++++
>   4 files changed, 59 insertions(+)
>   create mode 100644 drivers/net/wireless/broadcom/brcm80211/brcmfmac/acpi.c

[...]

> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/acpi.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/acpi.c
> new file mode 100644
> index 000000000000..2b1a4448b291
> --- /dev/null
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/acpi.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: ISC
> +/*
> + * Copyright The Asahi Linux Contributors
> + */
> +
> +#include <linux/acpi.h>
> +#include "debug.h"
> +#include "core.h"
> +#include "common.h"
> +
> +void brcmf_acpi_probe(struct device *dev, enum brcmf_bus_type bus_type,
> +		      struct brcmf_mp_device *settings)
> +{
> +	acpi_status status;
> +	const union acpi_object *o;
> +	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_device *adev = ACPI_COMPANION(dev);
> +
> +	if (!adev)
> +		return;
> +
> +	if (!ACPI_FAILURE(acpi_dev_get_property(adev, "module-instance",
> +						ACPI_TYPE_STRING, &o))) {
> +		brcmf_dbg(INFO, "ACPI module-instance=%s\n", o->string.pointer);
> +		settings->board_type = devm_kasprintf(dev, GFP_KERNEL,
> +						      "apple,%s",
> +						      o->string.pointer);
> +	} else {
> +		brcmf_dbg(INFO, "No ACPI module-instance\n");

Do you need to obtain the antenna-sku when there is no module-instance?

> +	}
> +
> +	status = acpi_evaluate_object(adev->handle, "RWCV", NULL, &buf);

Can you clarify what the above does? What does the "RWCV" mean?

> +	o = buf.pointer;
> +	if (!ACPI_FAILURE(status) && o && o->type == ACPI_TYPE_BUFFER &&
> +	    o->buffer.length >= 2) {
> +		char *antenna_sku = devm_kzalloc(dev, 3, GFP_KERNEL);
> +
> +		memcpy(antenna_sku, o->buffer.pointer, 2);
> +		brcmf_dbg(INFO, "ACPI RWCV data=%*phN antenna-sku=%s\n",
> +			  (int)o->buffer.length, o->buffer.pointer,
> +			  antenna_sku);
> +
> +		settings->antenna_sku = antenna_sku;
> +	} else {
> +		brcmf_dbg(INFO, "No ACPI antenna-sku\n");
> +	}
> +}

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