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

From: Arend van Spriel
Date: Mon Jan 10 2022 - 06:26:45 EST

On 1/10/2022 12:07 PM, Hector Martin wrote:
On 2022/01/10 18:11, Arend van Spriel wrote:
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?

In principle I don't think any machines would have antenna-sku and no
module-instance, though the firmware selection will still work without
it (it'll just end up using the DMI machine name instead).

Right. That was my assumption as well. I would bail out here and skip obtaining the antenna-sku.


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

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

No idea what it *means* :-)

What it is, though, is the ACPI method name to get the antenna-sku.

Wow. So much for meaning-full naming ;-)

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