[AMD Official Use Only - General]

-----Original Message-----
From: Simon Horman <horms@kernel.org>
Sent: Friday, August 11, 2023 5:38 PM
To: Quan, Evan <redacted>
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Subject: Re: [PATCH V8 2/9] drivers core: add ACPI based WBRF mechanism
introduced by AMD

On Thu, Aug 10, 2023 at 03:37:56PM +0800, Evan Quan wrote:

quoted

AMD has introduced an ACPI based mechanism to support WBRF for some
platforms with AMD dGPU + WLAN. This needs support from BIOS equipped
with necessary AML implementations and dGPU firmwares.

For those systems without the ACPI mechanism and developing solutions,
user can use/fall-back the generic WBRF solution for diagnosing potential
interference issues.

And for the platform which does not equip with the necessary AMD ACPI
implementations but with CONFIG_WBRF_AMD_ACPI built as 'y', it will
fall back to generic WBRF solution if the `wbrf` is set as "on".

Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Co-developed-by: Evan Quan <redacted>
Signed-off-by: Evan Quan <redacted>

...

quoted

diff --git a/drivers/acpi/amd_wbrf.c b/drivers/acpi/amd_wbrf.c

...

quoted

+static bool check_acpi_wbrf(acpi_handle handle, u64 rev, u64 funcs)
+{
+	int i;
+	u64 mask = 0;
+	union acpi_object *obj;
+
+	if (funcs == 0)
+		return false;
+
+	obj = acpi_evaluate_wbrf(handle, rev, 0);
+	if (!obj)
+		return false;
+
+	if (obj->type != ACPI_TYPE_BUFFER)
+		return false;
+
+	/*
+	 * Bit vector providing supported functions information.
+	 * Each bit marks support for one specific function of the WBRF

method.

quoted

+	 */
+	for (i = 0; i < obj->buffer.length && i < 8; i++)
+		mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
+
+	ACPI_FREE(obj);
+
+	if ((mask & BIT(WBRF_ENABLED)) &&
+	     (mask & funcs) == funcs)

Hi Evan,

a minor nit from my side: the indentation of the line above seems odd.

Thanks. Will update this.

Evan

	if ((mask & BIT(WBRF_ENABLED)) &&
	    (mask & funcs) == funcs)

quoted

+		return true;
+
+	return false;
+}

...