Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

6 files changed, 972 insertions, 0 deletions

diff --git a/drivers/hid/surface-hid/Kconfig b/drivers/hid/surface-hid/Kconfig
new file mode 100644
index 000000000..7ce9b5d64
--- /dev/null
+++ b/drivers/hid/surface-hid/Kconfig
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0+
+menu "Surface System Aggregator Module HID support"
+	depends on SURFACE_AGGREGATOR
+	depends on INPUT
+
+config SURFACE_HID
+	tristate "HID transport driver for Surface System Aggregator Module"
+	depends on SURFACE_AGGREGATOR_REGISTRY
+	select SURFACE_HID_CORE
+	help
+	  Driver to support integrated HID devices on newer Microsoft Surface
+	  models.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  7th-generation Microsoft Surface devices, i.e. Surface Book 3 and
+	  Surface Laptop 3. On those models, it is mainly used to connect the
+	  integrated touchpad and keyboard.
+
+	  Say M or Y here, if you want support for integrated HID devices, i.e.
+	  integrated touchpad and keyboard, on 7th generation Microsoft Surface
+	  models.
+
+config SURFACE_KBD
+	tristate "HID keyboard transport driver for Surface System Aggregator Module"
+	select SURFACE_HID_CORE
+	help
+	  Driver to support HID keyboards on Surface Laptop 1 and 2 devices.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  Microsoft Surface Laptops 1 and 2. It is used to connect the
+	  integrated keyboard on those devices.
+
+	  Say M or Y here, if you want support for the integrated keyboard on
+	  Microsoft Surface Laptops 1 and 2.
+
+endmenu
+
+config SURFACE_HID_CORE
+	tristate
+	select HID
diff --git a/drivers/hid/surface-hid/Makefile b/drivers/hid/surface-hid/Makefile
new file mode 100644
index 000000000..4ae11cf09
--- /dev/null
+++ b/drivers/hid/surface-hid/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Makefile - Surface System Aggregator Module (SSAM) HID transport driver.
+#
+obj-$(CONFIG_SURFACE_HID_CORE)	+= surface_hid_core.o
+obj-$(CONFIG_SURFACE_HID)	+= surface_hid.o
+obj-$(CONFIG_SURFACE_KBD)	+= surface_kbd.o
diff --git a/drivers/hid/surface-hid/surface_hid.c b/drivers/hid/surface-hid/surface_hid.c
new file mode 100644
index 000000000..61e5814b0
--- /dev/null
+++ b/drivers/hid/surface-hid/surface_hid.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Surface System Aggregator Module (SSAM) HID transport driver for the
+ * generic HID interface (HID/TC=0x15 subsystem). Provides support for
+ * integrated HID devices on Surface Laptop 3, Book 3, and later.
+ *
+ * Copyright (C) 2019-2021 Blaž Hrastnik <blaz@mxxn.io>,
+ *                         Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/hid.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
+
+#include "surface_hid_core.h"
+
+
+/* -- SAM interface. -------------------------------------------------------- */
+
+struct surface_hid_buffer_slice {
+	__u8 entry;
+	__le32 offset;
+	__le32 length;
+	__u8 end;
+	__u8 data[];
+} __packed;
+
+static_assert(sizeof(struct surface_hid_buffer_slice) == 10);
+
+enum surface_hid_cid {
+	SURFACE_HID_CID_OUTPUT_REPORT      = 0x01,
+	SURFACE_HID_CID_GET_FEATURE_REPORT = 0x02,
+	SURFACE_HID_CID_SET_FEATURE_REPORT = 0x03,
+	SURFACE_HID_CID_GET_DESCRIPTOR     = 0x04,
+};
+
+static int ssam_hid_get_descriptor(struct surface_hid_device *shid, u8 entry, u8 *buf, size_t len)
+{
+	u8 buffer[sizeof(struct surface_hid_buffer_slice) + 0x76];
+	struct surface_hid_buffer_slice *slice;
+	struct ssam_request rqst;
+	struct ssam_response rsp;
+	u32 buffer_len, offset, length;
+	int status;
+
+	/*
+	 * Note: The 0x76 above has been chosen because that's what's used by
+	 * the Windows driver. Together with the header, this leads to a 128
+	 * byte payload in total.
+	 */
+
+	buffer_len = ARRAY_SIZE(buffer) - sizeof(struct surface_hid_buffer_slice);
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.command_id = SURFACE_HID_CID_GET_DESCRIPTOR;
+	rqst.instance_id = shid->uid.instance;
+	rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
+	rqst.length = sizeof(struct surface_hid_buffer_slice);
+	rqst.payload = buffer;
+
+	rsp.capacity = ARRAY_SIZE(buffer);
+	rsp.pointer = buffer;
+
+	slice = (struct surface_hid_buffer_slice *)buffer;
+	slice->entry = entry;
+	slice->end = 0;
+
+	offset = 0;
+	length = buffer_len;
+
+	while (!slice->end && offset < len) {
+		put_unaligned_le32(offset, &slice->offset);
+		put_unaligned_le32(length, &slice->length);
+
+		rsp.length = 0;
+
+		status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp,
+				    sizeof(*slice));
+		if (status)
+			return status;
+
+		offset = get_unaligned_le32(&slice->offset);
+		length = get_unaligned_le32(&slice->length);
+
+		/* Don't mess stuff up in case we receive garbage. */
+		if (length > buffer_len || offset > len)
+			return -EPROTO;
+
+		if (offset + length > len)
+			length = len - offset;
+
+		memcpy(buf + offset, &slice->data[0], length);
+
+		offset += length;
+		length = buffer_len;
+	}
+
+	if (offset != len) {
+		dev_err(shid->dev, "unexpected descriptor length: got %u, expected %zu\n",
+			offset, len);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static int ssam_hid_set_raw_report(struct surface_hid_device *shid, u8 rprt_id, bool feature,
+				   u8 *buf, size_t len)
+{
+	struct ssam_request rqst;
+	u8 cid;
+
+	if (feature)
+		cid = SURFACE_HID_CID_SET_FEATURE_REPORT;
+	else
+		cid = SURFACE_HID_CID_OUTPUT_REPORT;
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.instance_id = shid->uid.instance;
+	rqst.command_id = cid;
+	rqst.flags = 0;
+	rqst.length = len;
+	rqst.payload = buf;
+
+	buf[0] = rprt_id;
+
+	return ssam_retry(ssam_request_do_sync, shid->ctrl, &rqst, NULL);
+}
+
+static int ssam_hid_get_raw_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	struct ssam_request rqst;
+	struct ssam_response rsp;
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.instance_id = shid->uid.instance;
+	rqst.command_id = SURFACE_HID_CID_GET_FEATURE_REPORT;
+	rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
+	rqst.length = sizeof(rprt_id);
+	rqst.payload = &rprt_id;
+
+	rsp.capacity = len;
+	rsp.length = 0;
+	rsp.pointer = buf;
+
+	return ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(rprt_id));
+}
+
+static u32 ssam_hid_event_fn(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct surface_hid_device *shid = container_of(nf, struct surface_hid_device, notif);
+
+	if (event->command_id != 0x00)
+		return 0;
+
+	hid_input_report(shid->hid, HID_INPUT_REPORT, (u8 *)&event->data[0], event->length, 0);
+	return SSAM_NOTIF_HANDLED;
+}
+
+
+/* -- Transport driver. ----------------------------------------------------- */
+
+static int shid_output_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	int status;
+
+	status = ssam_hid_set_raw_report(shid, rprt_id, false, buf, len);
+	return status >= 0 ? len : status;
+}
+
+static int shid_get_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	int status;
+
+	status = ssam_hid_get_raw_report(shid, rprt_id, buf, len);
+	return status >= 0 ? len : status;
+}
+
+static int shid_set_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	int status;
+
+	status = ssam_hid_set_raw_report(shid, rprt_id, true, buf, len);
+	return status >= 0 ? len : status;
+}
+
+
+/* -- Driver setup. --------------------------------------------------------- */
+
+static int surface_hid_probe(struct ssam_device *sdev)
+{
+	struct surface_hid_device *shid;
+
+	shid = devm_kzalloc(&sdev->dev, sizeof(*shid), GFP_KERNEL);
+	if (!shid)
+		return -ENOMEM;
+
+	shid->dev = &sdev->dev;
+	shid->ctrl = sdev->ctrl;
+	shid->uid = sdev->uid;
+
+	shid->notif.base.priority = 1;
+	shid->notif.base.fn = ssam_hid_event_fn;
+	shid->notif.event.reg = SSAM_EVENT_REGISTRY_REG(sdev->uid.target);
+	shid->notif.event.id.target_category = sdev->uid.category;
+	shid->notif.event.id.instance = sdev->uid.instance;
+	shid->notif.event.mask = SSAM_EVENT_MASK_STRICT;
+	shid->notif.event.flags = 0;
+
+	shid->ops.get_descriptor = ssam_hid_get_descriptor;
+	shid->ops.output_report = shid_output_report;
+	shid->ops.get_feature_report = shid_get_feature_report;
+	shid->ops.set_feature_report = shid_set_feature_report;
+
+	ssam_device_set_drvdata(sdev, shid);
+	return surface_hid_device_add(shid);
+}
+
+static void surface_hid_remove(struct ssam_device *sdev)
+{
+	surface_hid_device_destroy(ssam_device_get_drvdata(sdev));
+}
+
+static const struct ssam_device_id surface_hid_match[] = {
+	{ SSAM_SDEV(HID, ANY, SSAM_SSH_IID_ANY, 0x00) },
+	{ },
+};
+MODULE_DEVICE_TABLE(ssam, surface_hid_match);
+
+static struct ssam_device_driver surface_hid_driver = {
+	.probe = surface_hid_probe,
+	.remove = surface_hid_remove,
+	.match_table = surface_hid_match,
+	.driver = {
+		.name = "surface_hid",
+		.pm = &surface_hid_pm_ops,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_ssam_device_driver(surface_hid_driver);
+
+MODULE_AUTHOR("Blaž Hrastnik <blaz@mxxn.io>");
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("HID transport driver for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/surface-hid/surface_hid_core.c b/drivers/hid/surface-hid/surface_hid_core.c
new file mode 100644
index 000000000..87637f813
--- /dev/null
+++ b/drivers/hid/surface-hid/surface_hid_core.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Common/core components for the Surface System Aggregator Module (SSAM) HID
+ * transport driver. Provides support for integrated HID devices on Microsoft
+ * Surface models.
+ *
+ * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/hid.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/usb/ch9.h>
+
+#include <linux/surface_aggregator/controller.h>
+
+#include "surface_hid_core.h"
+
+
+/* -- Utility functions. ---------------------------------------------------- */
+
+static bool surface_hid_is_hot_removed(struct surface_hid_device *shid)
+{
+	/*
+	 * Non-ssam client devices, i.e. platform client devices, cannot be
+	 * hot-removed.
+	 */
+	if (!is_ssam_device(shid->dev))
+		return false;
+
+	return ssam_device_is_hot_removed(to_ssam_device(shid->dev));
+}
+
+
+/* -- Device descriptor access. --------------------------------------------- */
+
+static int surface_hid_load_hid_descriptor(struct surface_hid_device *shid)
+{
+	int status;
+
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
+	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_HID,
+			(u8 *)&shid->hid_desc, sizeof(shid->hid_desc));
+	if (status)
+		return status;
+
+	if (shid->hid_desc.desc_len != sizeof(shid->hid_desc)) {
+		dev_err(shid->dev, "unexpected HID descriptor length: got %u, expected %zu\n",
+			shid->hid_desc.desc_len, sizeof(shid->hid_desc));
+		return -EPROTO;
+	}
+
+	if (shid->hid_desc.desc_type != HID_DT_HID) {
+		dev_err(shid->dev, "unexpected HID descriptor type: got %#04x, expected %#04x\n",
+			shid->hid_desc.desc_type, HID_DT_HID);
+		return -EPROTO;
+	}
+
+	if (shid->hid_desc.num_descriptors != 1) {
+		dev_err(shid->dev, "unexpected number of descriptors: got %u, expected 1\n",
+			shid->hid_desc.num_descriptors);
+		return -EPROTO;
+	}
+
+	if (shid->hid_desc.report_desc_type != HID_DT_REPORT) {
+		dev_err(shid->dev, "unexpected report descriptor type: got %#04x, expected %#04x\n",
+			shid->hid_desc.report_desc_type, HID_DT_REPORT);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static int surface_hid_load_device_attributes(struct surface_hid_device *shid)
+{
+	int status;
+
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
+	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_ATTRS,
+			(u8 *)&shid->attrs, sizeof(shid->attrs));
+	if (status)
+		return status;
+
+	if (get_unaligned_le32(&shid->attrs.length) != sizeof(shid->attrs)) {
+		dev_err(shid->dev, "unexpected attribute length: got %u, expected %zu\n",
+			get_unaligned_le32(&shid->attrs.length), sizeof(shid->attrs));
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+
+/* -- Transport driver (common). -------------------------------------------- */
+
+static int surface_hid_start(struct hid_device *hid)
+{
+	struct surface_hid_device *shid = hid->driver_data;
+
+	return ssam_notifier_register(shid->ctrl, &shid->notif);
+}
+
+static void surface_hid_stop(struct hid_device *hid)
+{
+	struct surface_hid_device *shid = hid->driver_data;
+	bool hot_removed;
+
+	/*
+	 * Communication may fail for devices that have been hot-removed. This
+	 * also includes unregistration of HID events, so we need to check this
+	 * here. Only if the device has not been marked as hot-removed, we can
+	 * safely disable events.
+	 */
+	hot_removed = surface_hid_is_hot_removed(shid);
+
+	/* Note: This call will log errors for us, so ignore them here. */
+	__ssam_notifier_unregister(shid->ctrl, &shid->notif, !hot_removed);
+}
+
+static int surface_hid_open(struct hid_device *hid)
+{
+	return 0;
+}
+
+static void surface_hid_close(struct hid_device *hid)
+{
+}
+
+static int surface_hid_parse(struct hid_device *hid)
+{
+	struct surface_hid_device *shid = hid->driver_data;
+	size_t len = get_unaligned_le16(&shid->hid_desc.report_desc_len);
+	u8 *buf;
+	int status;
+
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
+	buf = kzalloc(len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_REPORT, buf, len);
+	if (!status)
+		status = hid_parse_report(hid, buf, len);
+
+	kfree(buf);
+	return status;
+}
+
+static int surface_hid_raw_request(struct hid_device *hid, unsigned char reportnum, u8 *buf,
+				   size_t len, unsigned char rtype, int reqtype)
+{
+	struct surface_hid_device *shid = hid->driver_data;
+
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
+	if (rtype == HID_OUTPUT_REPORT && reqtype == HID_REQ_SET_REPORT)
+		return shid->ops.output_report(shid, reportnum, buf, len);
+
+	else if (rtype == HID_FEATURE_REPORT && reqtype == HID_REQ_GET_REPORT)
+		return shid->ops.get_feature_report(shid, reportnum, buf, len);
+
+	else if (rtype == HID_FEATURE_REPORT && reqtype == HID_REQ_SET_REPORT)
+		return shid->ops.set_feature_report(shid, reportnum, buf, len);
+
+	return -EIO;
+}
+
+static struct hid_ll_driver surface_hid_ll_driver = {
+	.start       = surface_hid_start,
+	.stop        = surface_hid_stop,
+	.open        = surface_hid_open,
+	.close       = surface_hid_close,
+	.parse       = surface_hid_parse,
+	.raw_request = surface_hid_raw_request,
+};
+
+
+/* -- Common device setup. -------------------------------------------------- */
+
+int surface_hid_device_add(struct surface_hid_device *shid)
+{
+	int status;
+
+	status = surface_hid_load_hid_descriptor(shid);
+	if (status)
+		return status;
+
+	status = surface_hid_load_device_attributes(shid);
+	if (status)
+		return status;
+
+	shid->hid = hid_allocate_device();
+	if (IS_ERR(shid->hid))
+		return PTR_ERR(shid->hid);
+
+	shid->hid->dev.parent = shid->dev;
+	shid->hid->bus = BUS_HOST;
+	shid->hid->vendor = get_unaligned_le16(&shid->attrs.vendor);
+	shid->hid->product = get_unaligned_le16(&shid->attrs.product);
+	shid->hid->version = get_unaligned_le16(&shid->hid_desc.hid_version);
+	shid->hid->country = shid->hid_desc.country_code;
+
+	snprintf(shid->hid->name, sizeof(shid->hid->name), "Microsoft Surface %04X:%04X",
+		 shid->hid->vendor, shid->hid->product);
+
+	strscpy(shid->hid->phys, dev_name(shid->dev), sizeof(shid->hid->phys));
+
+	shid->hid->driver_data = shid;
+	shid->hid->ll_driver = &surface_hid_ll_driver;
+
+	status = hid_add_device(shid->hid);
+	if (status)
+		hid_destroy_device(shid->hid);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(surface_hid_device_add);
+
+void surface_hid_device_destroy(struct surface_hid_device *shid)
+{
+	hid_destroy_device(shid->hid);
+}
+EXPORT_SYMBOL_GPL(surface_hid_device_destroy);
+
+
+/* -- PM ops. --------------------------------------------------------------- */
+
+#ifdef CONFIG_PM_SLEEP
+
+static int surface_hid_suspend(struct device *dev)
+{
+	struct surface_hid_device *d = dev_get_drvdata(dev);
+
+	return hid_driver_suspend(d->hid, PMSG_SUSPEND);
+}
+
+static int surface_hid_resume(struct device *dev)
+{
+	struct surface_hid_device *d = dev_get_drvdata(dev);
+
+	return hid_driver_resume(d->hid);
+}
+
+static int surface_hid_freeze(struct device *dev)
+{
+	struct surface_hid_device *d = dev_get_drvdata(dev);
+
+	return hid_driver_suspend(d->hid, PMSG_FREEZE);
+}
+
+static int surface_hid_poweroff(struct device *dev)
+{
+	struct surface_hid_device *d = dev_get_drvdata(dev);
+
+	return hid_driver_suspend(d->hid, PMSG_HIBERNATE);
+}
+
+static int surface_hid_restore(struct device *dev)
+{
+	struct surface_hid_device *d = dev_get_drvdata(dev);
+
+	return hid_driver_reset_resume(d->hid);
+}
+
+const struct dev_pm_ops surface_hid_pm_ops = {
+	.freeze   = surface_hid_freeze,
+	.thaw     = surface_hid_resume,
+	.suspend  = surface_hid_suspend,
+	.resume   = surface_hid_resume,
+	.poweroff = surface_hid_poweroff,
+	.restore  = surface_hid_restore,
+};
+EXPORT_SYMBOL_GPL(surface_hid_pm_ops);
+
+#else /* CONFIG_PM_SLEEP */
+
+const struct dev_pm_ops surface_hid_pm_ops = { };
+EXPORT_SYMBOL_GPL(surface_hid_pm_ops);
+
+#endif /* CONFIG_PM_SLEEP */
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("HID transport driver core for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/surface-hid/surface_hid_core.h b/drivers/hid/surface-hid/surface_hid_core.h
new file mode 100644
index 000000000..4b1a7b57e
--- /dev/null
+++ b/drivers/hid/surface-hid/surface_hid_core.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Common/core components for the Surface System Aggregator Module (SSAM) HID
+ * transport driver. Provides support for integrated HID devices on Microsoft
+ * Surface models.
+ *
+ * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#ifndef SURFACE_HID_CORE_H
+#define SURFACE_HID_CORE_H
+
+#include <linux/hid.h>
+#include <linux/pm.h>
+#include <linux/types.h>
+
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
+
+enum surface_hid_descriptor_entry {
+	SURFACE_HID_DESC_HID    = 0,
+	SURFACE_HID_DESC_REPORT = 1,
+	SURFACE_HID_DESC_ATTRS  = 2,
+};
+
+struct surface_hid_descriptor {
+	__u8 desc_len;			/* = 9 */
+	__u8 desc_type;			/* = HID_DT_HID */
+	__le16 hid_version;
+	__u8 country_code;
+	__u8 num_descriptors;		/* = 1 */
+
+	__u8 report_desc_type;		/* = HID_DT_REPORT */
+	__le16 report_desc_len;
+} __packed;
+
+static_assert(sizeof(struct surface_hid_descriptor) == 9);
+
+struct surface_hid_attributes {
+	__le32 length;
+	__le16 vendor;
+	__le16 product;
+	__le16 version;
+	__u8 _unknown[22];
+} __packed;
+
+static_assert(sizeof(struct surface_hid_attributes) == 32);
+
+struct surface_hid_device;
+
+struct surface_hid_device_ops {
+	int (*get_descriptor)(struct surface_hid_device *shid, u8 entry, u8 *buf, size_t len);
+	int (*output_report)(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len);
+	int (*get_feature_report)(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len);
+	int (*set_feature_report)(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len);
+};
+
+struct surface_hid_device {
+	struct device *dev;
+	struct ssam_controller *ctrl;
+	struct ssam_device_uid uid;
+
+	struct surface_hid_descriptor hid_desc;
+	struct surface_hid_attributes attrs;
+
+	struct ssam_event_notifier notif;
+	struct hid_device *hid;
+
+	struct surface_hid_device_ops ops;
+};
+
+int surface_hid_device_add(struct surface_hid_device *shid);
+void surface_hid_device_destroy(struct surface_hid_device *shid);
+
+extern const struct dev_pm_ops surface_hid_pm_ops;
+
+#endif /* SURFACE_HID_CORE_H */
diff --git a/drivers/hid/surface-hid/surface_kbd.c b/drivers/hid/surface-hid/surface_kbd.c
new file mode 100644
index 000000000..4fbce201d
--- /dev/null
+++ b/drivers/hid/surface-hid/surface_kbd.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Surface System Aggregator Module (SSAM) HID transport driver for the legacy
+ * keyboard interface (KBD/TC=0x08 subsystem). Provides support for the
+ * integrated HID keyboard on Surface Laptops 1 and 2.
+ *
+ * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/hid.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <linux/surface_aggregator/controller.h>
+
+#include "surface_hid_core.h"
+
+
+/* -- SAM interface (KBD). -------------------------------------------------- */
+
+#define KBD_FEATURE_REPORT_SIZE			7  /* 6 + report ID */
+
+enum surface_kbd_cid {
+	SURFACE_KBD_CID_GET_DESCRIPTOR		= 0x00,
+	SURFACE_KBD_CID_SET_CAPSLOCK_LED	= 0x01,
+	SURFACE_KBD_CID_EVT_INPUT_GENERIC	= 0x03,
+	SURFACE_KBD_CID_EVT_INPUT_HOTKEYS	= 0x04,
+	SURFACE_KBD_CID_GET_FEATURE_REPORT	= 0x0b,
+};
+
+static int ssam_kbd_get_descriptor(struct surface_hid_device *shid, u8 entry, u8 *buf, size_t len)
+{
+	struct ssam_request rqst;
+	struct ssam_response rsp;
+	int status;
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.command_id = SURFACE_KBD_CID_GET_DESCRIPTOR;
+	rqst.instance_id = shid->uid.instance;
+	rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
+	rqst.length = sizeof(entry);
+	rqst.payload = &entry;
+
+	rsp.capacity = len;
+	rsp.length = 0;
+	rsp.pointer = buf;
+
+	status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(entry));
+	if (status)
+		return status;
+
+	if (rsp.length != len) {
+		dev_err(shid->dev, "invalid descriptor length: got %zu, expected, %zu\n",
+			rsp.length, len);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static int ssam_kbd_set_caps_led(struct surface_hid_device *shid, bool value)
+{
+	struct ssam_request rqst;
+	u8 value_u8 = value;
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.command_id = SURFACE_KBD_CID_SET_CAPSLOCK_LED;
+	rqst.instance_id = shid->uid.instance;
+	rqst.flags = 0;
+	rqst.length = sizeof(value_u8);
+	rqst.payload = &value_u8;
+
+	return ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, NULL, sizeof(value_u8));
+}
+
+static int ssam_kbd_get_feature_report(struct surface_hid_device *shid, u8 *buf, size_t len)
+{
+	struct ssam_request rqst;
+	struct ssam_response rsp;
+	u8 payload = 0;
+	int status;
+
+	rqst.target_category = shid->uid.category;
+	rqst.target_id = shid->uid.target;
+	rqst.command_id = SURFACE_KBD_CID_GET_FEATURE_REPORT;
+	rqst.instance_id = shid->uid.instance;
+	rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
+	rqst.length = sizeof(payload);
+	rqst.payload = &payload;
+
+	rsp.capacity = len;
+	rsp.length = 0;
+	rsp.pointer = buf;
+
+	status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(payload));
+	if (status)
+		return status;
+
+	if (rsp.length != len) {
+		dev_err(shid->dev, "invalid feature report length: got %zu, expected, %zu\n",
+			rsp.length, len);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static bool ssam_kbd_is_input_event(const struct ssam_event *event)
+{
+	if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_GENERIC)
+		return true;
+
+	if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_HOTKEYS)
+		return true;
+
+	return false;
+}
+
+static u32 ssam_kbd_event_fn(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct surface_hid_device *shid = container_of(nf, struct surface_hid_device, notif);
+
+	/*
+	 * Check against device UID manually, as registry and device target
+	 * category doesn't line up.
+	 */
+
+	if (shid->uid.category != event->target_category)
+		return 0;
+
+	if (shid->uid.target != event->target_id)
+		return 0;
+
+	if (shid->uid.instance != event->instance_id)
+		return 0;
+
+	if (!ssam_kbd_is_input_event(event))
+		return 0;
+
+	hid_input_report(shid->hid, HID_INPUT_REPORT, (u8 *)&event->data[0], event->length, 0);
+	return SSAM_NOTIF_HANDLED;
+}
+
+
+/* -- Transport driver (KBD). ----------------------------------------------- */
+
+static int skbd_get_caps_led_value(struct hid_device *hid, u8 rprt_id, u8 *buf, size_t len)
+{
+	struct hid_field *field;
+	unsigned int offset, size;
+	int i;
+
+	/* Get LED field. */
+	field = hidinput_get_led_field(hid);
+	if (!field)
+		return -ENOENT;
+
+	/* Check if we got the correct report. */
+	if (len != hid_report_len(field->report))
+		return -ENOENT;
+
+	if (rprt_id != field->report->id)
+		return -ENOENT;
+
+	/* Get caps lock LED index. */
+	for (i = 0; i < field->report_count; i++)
+		if ((field->usage[i].hid & 0xffff) == 0x02)
+			break;
+
+	if (i == field->report_count)
+		return -ENOENT;
+
+	/* Extract value. */
+	size = field->report_size;
+	offset = field->report_offset + i * size;
+	return !!hid_field_extract(hid, buf + 1, size, offset);
+}
+
+static int skbd_output_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	int caps_led;
+	int status;
+
+	caps_led = skbd_get_caps_led_value(shid->hid, rprt_id, buf, len);
+	if (caps_led < 0)
+		return -EIO;  /* Only caps LED output reports are supported. */
+
+	status = ssam_kbd_set_caps_led(shid, caps_led);
+	if (status < 0)
+		return status;
+
+	return len;
+}
+
+static int skbd_get_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	u8 report[KBD_FEATURE_REPORT_SIZE];
+	int status;
+
+	/*
+	 * The keyboard only has a single hard-coded read-only feature report
+	 * of size KBD_FEATURE_REPORT_SIZE. Try to load it and compare its
+	 * report ID against the requested one.
+	 */
+
+	if (len < ARRAY_SIZE(report))
+		return -ENOSPC;
+
+	status = ssam_kbd_get_feature_report(shid, report, ARRAY_SIZE(report));
+	if (status < 0)
+		return status;
+
+	if (rprt_id != report[0])
+		return -ENOENT;
+
+	memcpy(buf, report, ARRAY_SIZE(report));
+	return len;
+}
+
+static int skbd_set_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
+{
+	/* Not supported. See skbd_get_feature_report() for details. */
+	return -EIO;
+}
+
+
+/* -- Driver setup. --------------------------------------------------------- */
+
+static int surface_kbd_probe(struct platform_device *pdev)
+{
+	struct ssam_controller *ctrl;
+	struct surface_hid_device *shid;
+
+	/* Add device link to EC. */
+	ctrl = ssam_client_bind(&pdev->dev);
+	if (IS_ERR(ctrl))
+		return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);
+
+	shid = devm_kzalloc(&pdev->dev, sizeof(*shid), GFP_KERNEL);
+	if (!shid)
+		return -ENOMEM;
+
+	shid->dev = &pdev->dev;
+	shid->ctrl = ctrl;
+
+	shid->uid.domain = SSAM_DOMAIN_SERIALHUB;
+	shid->uid.category = SSAM_SSH_TC_KBD;
+	shid->uid.target = SSAM_SSH_TID_KIP;
+	shid->uid.instance = 0;
+	shid->uid.function = 0;
+
+	shid->notif.base.priority = 1;
+	shid->notif.base.fn = ssam_kbd_event_fn;
+	shid->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
+	shid->notif.event.id.target_category = shid->uid.category;
+	shid->notif.event.id.instance = shid->uid.instance;
+	shid->notif.event.mask = SSAM_EVENT_MASK_NONE;
+	shid->notif.event.flags = 0;
+
+	shid->ops.get_descriptor = ssam_kbd_get_descriptor;
+	shid->ops.output_report = skbd_output_report;
+	shid->ops.get_feature_report = skbd_get_feature_report;
+	shid->ops.set_feature_report = skbd_set_feature_report;
+
+	platform_set_drvdata(pdev, shid);
+	return surface_hid_device_add(shid);
+}
+
+static int surface_kbd_remove(struct platform_device *pdev)
+{
+	surface_hid_device_destroy(platform_get_drvdata(pdev));
+	return 0;
+}
+
+static const struct acpi_device_id surface_kbd_match[] = {
+	{ "MSHW0096" },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, surface_kbd_match);
+
+static struct platform_driver surface_kbd_driver = {
+	.probe = surface_kbd_probe,
+	.remove = surface_kbd_remove,
+	.driver = {
+		.name = "surface_keyboard",
+		.acpi_match_table = surface_kbd_match,
+		.pm = &surface_hid_pm_ops,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_platform_driver(surface_kbd_driver);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("HID legacy transport driver for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");