RE: [V10 1/8] ACPI: Add support for AMD ACPI based Wifi band RFI mitigation feature
[AMD Official Use Only - General]
> -Original Message-
> From: Simon Horman
> Sent: Sunday, August 27, 2023 11:43 PM
> To: Quan, Evan
> Cc: l...@kernel.org; johan...@sipsolutions.net; da...@davemloft.net;
> eduma...@google.com; k...@kernel.org; pab...@redhat.com; Deucher,
> Alexander ; raf...@kernel.org; Lazar, Lijo
> ; Limonciello, Mario ;
> linux-ker...@vger.kernel.org; linux-a...@vger.kernel.org; amd-
> g...@lists.freedesktop.org; dri-de...@lists.freedesktop.org; linux-
> wirel...@vger.kernel.org; net...@vger.kernel.org
> Subject: Re: [V10 1/8] ACPI: Add support for AMD ACPI based Wifi band RFI
> mitigation feature
>
> On Fri, Aug 25, 2023 at 04:38:39PM +0800, Evan Quan wrote:
> > Due to electrical and mechanical constraints in certain platform
> > designs there may be likely interference of relatively high-powered
> > harmonics of the (G-)DDR memory clocks with local radio module
> > frequency bands used by Wifi 6/6e/7.
> >
> > To mitigate this, AMD has introduced a mechanism that devices can use
> > to notify active use of particular frequencies so that other devices
> > can make relative internal adjustments as necessary to avoid this resonance.
> >
> > Signed-off-by: Evan Quan
>
> ...
>
> > diff --git a/drivers/acpi/amd_wbrf.c b/drivers/acpi/amd_wbrf.c
>
> ...
>
> > +/**
> > + * acpi_amd_wbrf_add_exclusion - broadcast the frequency band the
> device
> > + * is using
> > + *
> > + * @dev: device pointer
> > + * @in: input structure containing the frequency band the device is
> > +using
> > + *
> > + * Broadcast to other consumers the frequency band the device starts
> > + * to use. Underneath the surface the information is cached into an
> > + * internal buffer first. Then a notification is sent to all those
> > + * registered consumers. So then they can retrieve that buffer to
> > + * know the latest active frequency bands. The benifit with such
> > +design
>
> nit: ./checkpatch.pl --codespell suggests benifit -> benefit.
Thanks, will fix that.
Evan
>
> > + * is for those consumers which have not been registered yet, they
> > +can
> > + * still have a chance to retrieve such information later.
> > + */
> > +int acpi_amd_wbrf_add_exclusion(struct device *dev,
> > + struct wbrf_ranges_in_out *in)
> > +{
> > + struct acpi_device *adev = ACPI_COMPANION(dev);
> > + int ret;
> > +
> > + if (!adev)
> > + return -ENODEV;
> > +
> > + ret = wbrf_record(adev, WBRF_RECORD_ADD, in);
> > + if (ret)
> > + return ret;
> > +
> > + blocking_notifier_call_chain(_chain_head,
> > +WBRF_CHANGED,
> > +NULL);
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(acpi_amd_wbrf_add_exclusion);
>
> ...
Re: [V10 1/8] ACPI: Add support for AMD ACPI based Wifi band RFI mitigation feature
On Fri, Aug 25, 2023 at 04:38:39PM +0800, Evan Quan wrote:
> Due to electrical and mechanical constraints in certain platform designs
> there may be likely interference of relatively high-powered harmonics of
> the (G-)DDR memory clocks with local radio module frequency bands used
> by Wifi 6/6e/7.
>
> To mitigate this, AMD has introduced a mechanism that devices can use to
> notify active use of particular frequencies so that other devices can make
> relative internal adjustments as necessary to avoid this resonance.
>
> Signed-off-by: Evan Quan
...
> diff --git a/drivers/acpi/amd_wbrf.c b/drivers/acpi/amd_wbrf.c
...
> +/**
> + * acpi_amd_wbrf_add_exclusion - broadcast the frequency band the device
> + * is using
> + *
> + * @dev: device pointer
> + * @in: input structure containing the frequency band the device is using
> + *
> + * Broadcast to other consumers the frequency band the device starts
> + * to use. Underneath the surface the information is cached into an
> + * internal buffer first. Then a notification is sent to all those
> + * registered consumers. So then they can retrieve that buffer to
> + * know the latest active frequency bands. The benifit with such design
nit: ./checkpatch.pl --codespell suggests benifit -> benefit.
> + * is for those consumers which have not been registered yet, they can
> + * still have a chance to retrieve such information later.
> + */
> +int acpi_amd_wbrf_add_exclusion(struct device *dev,
> + struct wbrf_ranges_in_out *in)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(dev);
> + int ret;
> +
> + if (!adev)
> + return -ENODEV;
> +
> + ret = wbrf_record(adev, WBRF_RECORD_ADD, in);
> + if (ret)
> + return ret;
> +
> + blocking_notifier_call_chain(_chain_head,
> + WBRF_CHANGED,
> + NULL);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(acpi_amd_wbrf_add_exclusion);
...
[V10 1/8] ACPI: Add support for AMD ACPI based Wifi band RFI mitigation feature
Due to electrical and mechanical constraints in certain platform designs
there may be likely interference of relatively high-powered harmonics of
the (G-)DDR memory clocks with local radio module frequency bands used
by Wifi 6/6e/7.
To mitigate this, AMD has introduced a mechanism that devices can use to
notify active use of particular frequencies so that other devices can make
relative internal adjustments as necessary to avoid this resonance.
Signed-off-by: Evan Quan
---
drivers/acpi/Kconfig | 17 ++
drivers/acpi/Makefile | 2 +
drivers/acpi/amd_wbrf.c | 414 ++
include/linux/acpi_amd_wbrf.h | 140
4 files changed, 573 insertions(+)
create mode 100644 drivers/acpi/amd_wbrf.c
create mode 100644 include/linux/acpi_amd_wbrf.h
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 00dd309b6682..a092ea72d152 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -594,6 +594,23 @@ config ACPI_PRMT
substantially increase computational overhead related to the
initialization of some server systems.
+config WBRF_AMD_ACPI
+ bool "ACPI based WBRF mechanism introduced by AMD"
+ depends on ACPI
+ default n
+ help
+ Wifi band RFI mitigation mechanism allows multiple drivers from
+ different domains to notify the frequencies in use so that hardware
+ can be reconfigured to avoid harmonic conflicts.
+
+ AMD has introduced an ACPI based mechanism to support WBRF for some
+ platforms with AMD dGPU and WLAN. This needs support from BIOS
equipped
+ with necessary AML implementations and dGPU firmwares.
+
+ Before enabling this ACPI based mechanism, it is suggested to confirm
+ with the hardware designer/provider first whether your platform
+ equipped with necessary BIOS and firmwares.
+
endif # ACPI
config X86_PM_TIMER
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 3fc5a0d54f6e..9185d16e4495 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -133,3 +133,5 @@ obj-$(CONFIG_ARM64) += arm64/
obj-$(CONFIG_ACPI_VIOT)+= viot.o
obj-$(CONFIG_RISCV)+= riscv/
+
+obj-$(CONFIG_WBRF_AMD_ACPI)+= amd_wbrf.o
diff --git a/drivers/acpi/amd_wbrf.c b/drivers/acpi/amd_wbrf.c
new file mode 100644
index ..98663b2bfd54
--- /dev/null
+++ b/drivers/acpi/amd_wbrf.c
@@ -0,0 +1,414 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Wifi Band Exclusion Interface (AMD ACPI Implementation)
+ * Copyright (C) 2023 Advanced Micro Devices
+ *
+ */
+
+#include
+#include
+
+#define ACPI_AMD_WBRF_METHOD "\\WBRF"
+
+/*
+ * Functions bit vector for WBRF method
+ *
+ * Bit 0: Supported for any functions other than function 0.
+ * Bit 1: Function 1 (Add / Remove frequency) is supported.
+ * Bit 2: Function 2 (Get frequency list) is supported.
+ */
+#define WBRF_ENABLED 0x0
+#define WBRF_RECORD0x1
+#define WBRF_RETRIEVE 0x2
+
+/* record actions */
+#define WBRF_RECORD_ADD0x0
+#define WBRF_RECORD_REMOVE 0x1
+
+#define WBRF_REVISION 0x1
+
+/*
+ * The data structure used for WBRF_RETRIEVE is not naturally aligned.
+ * And unfortunately the design has been settled down.
+ */
+struct amd_wbrf_ranges_out {
+ u32 num_of_ranges;
+ struct exclusion_range band_list[MAX_NUM_OF_WBRF_RANGES];
+} __packed;
+
+static const guid_t wifi_acpi_dsm_guid =
+ GUID_INIT(0x7b7656cf, 0xdc3d, 0x4c1c,
+ 0x83, 0xe9, 0x66, 0xe7, 0x21, 0xde, 0x30, 0x70);
+
+static BLOCKING_NOTIFIER_HEAD(wbrf_chain_head);
+
+static int wbrf_dsm(struct acpi_device *adev,
+ u8 fn,
+ union acpi_object *argv4)
+{
+ union acpi_object *obj;
+ int rc;
+
+ obj = acpi_evaluate_dsm(adev->handle, _acpi_dsm_guid,
+ WBRF_REVISION, fn, argv4);
+ if (!obj)
+ return -ENXIO;
+
+ switch (obj->type) {
+ case ACPI_TYPE_INTEGER:
+ rc = obj->integer.value ? -EINVAL : 0;
+ break;
+ default:
+ rc = -EOPNOTSUPP;
+ }
+
+ ACPI_FREE(obj);
+
+ return rc;
+}
+
+static int wbrf_record(struct acpi_device *adev, uint8_t action,
+ struct wbrf_ranges_in_out *in)
+{
+ union acpi_object argv4;
+ union acpi_object *tmp;
+ u32 num_of_ranges = 0;
+ u32 num_of_elements;
+ u32 arg_idx = 0;
+ u32 loop_idx;
+ int ret;
+
+ if (!in)
+ return -EINVAL;
+
+ for (loop_idx = 0; loop_idx < ARRAY_SIZE(in->band_list);
+loop_idx++)
+ if (in->band_list[loop_idx].start &&
+ in->band_list[loop_idx].end)
+ num_of_ranges++;
+
+ /*
+* The valid entry counter does not
