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().
  ...

1 files changed, 847 insertions, 0 deletions

diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
new file mode 100644
index 000000000..21143dba8
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -0,0 +1,847 @@
+// SPDX-License-Identifier: GPL-2.0
+// SPI interface for ChromeOS Embedded Controller
+//
+// Copyright (C) 2012 Google, Inc
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <uapi/linux/sched/types.h>
+
+#include "cros_ec.h"
+
+/* The header byte, which follows the preamble */
+#define EC_MSG_HEADER			0xec
+
+/*
+ * Number of EC preamble bytes we read at a time. Since it takes
+ * about 400-500us for the EC to respond there is not a lot of
+ * point in tuning this. If the EC could respond faster then
+ * we could increase this so that might expect the preamble and
+ * message to occur in a single transaction. However, the maximum
+ * SPI transfer size is 256 bytes, so at 5MHz we need a response
+ * time of perhaps <320us (200 bytes / 1600 bits).
+ */
+#define EC_MSG_PREAMBLE_COUNT		32
+
+/*
+ * Allow for a long time for the EC to respond.  We support i2c
+ * tunneling and support fairly long messages for the tunnel (249
+ * bytes long at the moment).  If we're talking to a 100 kHz device
+ * on the other end and need to transfer ~256 bytes, then we need:
+ *  10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
+ *
+ * We'll wait 8 times that to handle clock stretching and other
+ * paranoia.  Note that some battery gas gauge ICs claim to have a
+ * clock stretch of 144ms in rare situations.  That's incentive for
+ * not directly passing i2c through, but it's too late for that for
+ * existing hardware.
+ *
+ * It's pretty unlikely that we'll really see a 249 byte tunnel in
+ * anything other than testing.  If this was more common we might
+ * consider having slow commands like this require a GET_STATUS
+ * wait loop.  The 'flash write' command would be another candidate
+ * for this, clocking in at 2-3ms.
+ */
+#define EC_MSG_DEADLINE_MS		200
+
+/*
+  * Time between raising the SPI chip select (for the end of a
+  * transaction) and dropping it again (for the next transaction).
+  * If we go too fast, the EC will miss the transaction. We know that we
+  * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be
+  * safe.
+  */
+#define EC_SPI_RECOVERY_TIME_NS	(200 * 1000)
+
+/**
+ * struct cros_ec_spi - information about a SPI-connected EC
+ *
+ * @spi: SPI device we are connected to
+ * @last_transfer_ns: time that we last finished a transfer.
+ * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
+ *      is sent when we want to turn on CS at the start of a transaction.
+ * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
+ *      is sent when we want to turn off CS at the end of a transaction.
+ * @high_pri_worker: Used to schedule high priority work.
+ */
+struct cros_ec_spi {
+	struct spi_device *spi;
+	s64 last_transfer_ns;
+	unsigned int start_of_msg_delay;
+	unsigned int end_of_msg_delay;
+	struct kthread_worker *high_pri_worker;
+};
+
+typedef int (*cros_ec_xfer_fn_t) (struct cros_ec_device *ec_dev,
+				  struct cros_ec_command *ec_msg);
+
+/**
+ * struct cros_ec_xfer_work_params - params for our high priority workers
+ *
+ * @work: The work_struct needed to queue work
+ * @fn: The function to use to transfer
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ * @ret: The return value of the function
+ */
+
+struct cros_ec_xfer_work_params {
+	struct kthread_work work;
+	cros_ec_xfer_fn_t fn;
+	struct cros_ec_device *ec_dev;
+	struct cros_ec_command *ec_msg;
+	int ret;
+};
+
+static void debug_packet(struct device *dev, const char *name, u8 *ptr,
+			 int len)
+{
+#ifdef DEBUG
+	int i;
+
+	dev_dbg(dev, "%s: ", name);
+	for (i = 0; i < len; i++)
+		pr_cont(" %02x", ptr[i]);
+
+	pr_cont("\n");
+#endif
+}
+
+static int terminate_request(struct cros_ec_device *ec_dev)
+{
+	struct cros_ec_spi *ec_spi = ec_dev->priv;
+	struct spi_message msg;
+	struct spi_transfer trans;
+	int ret;
+
+	/*
+	 * Turn off CS, possibly adding a delay to ensure the rising edge
+	 * doesn't come too soon after the end of the data.
+	 */
+	spi_message_init(&msg);
+	memset(&trans, 0, sizeof(trans));
+	trans.delay.value = ec_spi->end_of_msg_delay;
+	trans.delay.unit = SPI_DELAY_UNIT_USECS;
+	spi_message_add_tail(&trans, &msg);
+
+	ret = spi_sync_locked(ec_spi->spi, &msg);
+
+	/* Reset end-of-response timer */
+	ec_spi->last_transfer_ns = ktime_get_ns();
+	if (ret < 0) {
+		dev_err(ec_dev->dev,
+			"cs-deassert spi transfer failed: %d\n",
+			ret);
+	}
+
+	return ret;
+}
+
+/**
+ * receive_n_bytes - receive n bytes from the EC.
+ *
+ * Assumes buf is a pointer into the ec_dev->din buffer
+ *
+ * @ec_dev: ChromeOS EC device.
+ * @buf: Pointer to the buffer receiving the data.
+ * @n: Number of bytes received.
+ */
+static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
+{
+	struct cros_ec_spi *ec_spi = ec_dev->priv;
+	struct spi_transfer trans;
+	struct spi_message msg;
+	int ret;
+
+	if (buf - ec_dev->din + n > ec_dev->din_size)
+		return -EINVAL;
+
+	memset(&trans, 0, sizeof(trans));
+	trans.cs_change = 1;
+	trans.rx_buf = buf;
+	trans.len = n;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&trans, &msg);
+	ret = spi_sync_locked(ec_spi->spi, &msg);
+	if (ret < 0)
+		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+
+	return ret;
+}
+
+/**
+ * cros_ec_spi_receive_packet - Receive a packet from the EC.
+ *
+ * This function has two phases: reading the preamble bytes (since if we read
+ * data from the EC before it is ready to send, we just get preamble) and
+ * reading the actual message.
+ *
+ * The received data is placed into ec_dev->din.
+ *
+ * @ec_dev: ChromeOS EC device
+ * @need_len: Number of message bytes we need to read
+ */
+static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
+				      int need_len)
+{
+	struct ec_host_response *response;
+	u8 *ptr, *end;
+	int ret;
+	unsigned long deadline;
+	int todo;
+
+	if (ec_dev->din_size < EC_MSG_PREAMBLE_COUNT)
+		return -EINVAL;
+
+	/* Receive data until we see the header byte */
+	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
+	while (true) {
+		unsigned long start_jiffies = jiffies;
+
+		ret = receive_n_bytes(ec_dev,
+				      ec_dev->din,
+				      EC_MSG_PREAMBLE_COUNT);
+		if (ret < 0)
+			return ret;
+
+		ptr = ec_dev->din;
+		for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
+			if (*ptr == EC_SPI_FRAME_START) {
+				dev_dbg(ec_dev->dev, "msg found at %zd\n",
+					ptr - ec_dev->din);
+				break;
+			}
+		}
+		if (ptr != end)
+			break;
+
+		/*
+		 * Use the time at the start of the loop as a timeout.  This
+		 * gives us one last shot at getting the transfer and is useful
+		 * in case we got context switched out for a while.
+		 */
+		if (time_after(start_jiffies, deadline)) {
+			dev_warn(ec_dev->dev, "EC failed to respond in time\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	/*
+	 * ptr now points to the header byte. Copy any valid data to the
+	 * start of our buffer
+	 */
+	todo = end - ++ptr;
+	todo = min(todo, need_len);
+	memmove(ec_dev->din, ptr, todo);
+	ptr = ec_dev->din + todo;
+	dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
+		need_len, todo);
+	need_len -= todo;
+
+	/* If the entire response struct wasn't read, get the rest of it. */
+	if (todo < sizeof(*response)) {
+		ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
+		if (ret < 0)
+			return -EBADMSG;
+		ptr += (sizeof(*response) - todo);
+		todo = sizeof(*response);
+	}
+
+	response = (struct ec_host_response *)ec_dev->din;
+
+	/* Abort if data_len is too large. */
+	if (response->data_len > ec_dev->din_size)
+		return -EMSGSIZE;
+
+	/* Receive data until we have it all */
+	while (need_len > 0) {
+		/*
+		 * We can't support transfers larger than the SPI FIFO size
+		 * unless we have DMA. We don't have DMA on the ISP SPI ports
+		 * for Exynos. We need a way of asking SPI driver for
+		 * maximum-supported transfer size.
+		 */
+		todo = min(need_len, 256);
+		dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
+			todo, need_len, ptr - ec_dev->din);
+
+		ret = receive_n_bytes(ec_dev, ptr, todo);
+		if (ret < 0)
+			return ret;
+
+		ptr += todo;
+		need_len -= todo;
+	}
+
+	dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
+
+	return 0;
+}
+
+/**
+ * cros_ec_spi_receive_response - Receive a response from the EC.
+ *
+ * This function has two phases: reading the preamble bytes (since if we read
+ * data from the EC before it is ready to send, we just get preamble) and
+ * reading the actual message.
+ *
+ * The received data is placed into ec_dev->din.
+ *
+ * @ec_dev: ChromeOS EC device
+ * @need_len: Number of message bytes we need to read
+ */
+static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
+					int need_len)
+{
+	u8 *ptr, *end;
+	int ret;
+	unsigned long deadline;
+	int todo;
+
+	if (ec_dev->din_size < EC_MSG_PREAMBLE_COUNT)
+		return -EINVAL;
+
+	/* Receive data until we see the header byte */
+	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
+	while (true) {
+		unsigned long start_jiffies = jiffies;
+
+		ret = receive_n_bytes(ec_dev,
+				      ec_dev->din,
+				      EC_MSG_PREAMBLE_COUNT);
+		if (ret < 0)
+			return ret;
+
+		ptr = ec_dev->din;
+		for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
+			if (*ptr == EC_SPI_FRAME_START) {
+				dev_dbg(ec_dev->dev, "msg found at %zd\n",
+					ptr - ec_dev->din);
+				break;
+			}
+		}
+		if (ptr != end)
+			break;
+
+		/*
+		 * Use the time at the start of the loop as a timeout.  This
+		 * gives us one last shot at getting the transfer and is useful
+		 * in case we got context switched out for a while.
+		 */
+		if (time_after(start_jiffies, deadline)) {
+			dev_warn(ec_dev->dev, "EC failed to respond in time\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	/*
+	 * ptr now points to the header byte. Copy any valid data to the
+	 * start of our buffer
+	 */
+	todo = end - ++ptr;
+	todo = min(todo, need_len);
+	memmove(ec_dev->din, ptr, todo);
+	ptr = ec_dev->din + todo;
+	dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
+		 need_len, todo);
+	need_len -= todo;
+
+	/* Receive data until we have it all */
+	while (need_len > 0) {
+		/*
+		 * We can't support transfers larger than the SPI FIFO size
+		 * unless we have DMA. We don't have DMA on the ISP SPI ports
+		 * for Exynos. We need a way of asking SPI driver for
+		 * maximum-supported transfer size.
+		 */
+		todo = min(need_len, 256);
+		dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
+			todo, need_len, ptr - ec_dev->din);
+
+		ret = receive_n_bytes(ec_dev, ptr, todo);
+		if (ret < 0)
+			return ret;
+
+		debug_packet(ec_dev->dev, "interim", ptr, todo);
+		ptr += todo;
+		need_len -= todo;
+	}
+
+	dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
+
+	return 0;
+}
+
+/**
+ * do_cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
+ *
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ */
+static int do_cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
+				   struct cros_ec_command *ec_msg)
+{
+	struct ec_host_response *response;
+	struct cros_ec_spi *ec_spi = ec_dev->priv;
+	struct spi_transfer trans, trans_delay;
+	struct spi_message msg;
+	int i, len;
+	u8 *ptr;
+	u8 *rx_buf;
+	u8 sum;
+	u8 rx_byte;
+	int ret = 0, final_ret;
+	unsigned long delay;
+
+	len = cros_ec_prepare_tx(ec_dev, ec_msg);
+	if (len < 0)
+		return len;
+	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
+
+	/* If it's too soon to do another transaction, wait */
+	delay = ktime_get_ns() - ec_spi->last_transfer_ns;
+	if (delay < EC_SPI_RECOVERY_TIME_NS)
+		ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
+
+	rx_buf = kzalloc(len, GFP_KERNEL);
+	if (!rx_buf)
+		return -ENOMEM;
+
+	spi_bus_lock(ec_spi->spi->master);
+
+	/*
+	 * Leave a gap between CS assertion and clocking of data to allow the
+	 * EC time to wakeup.
+	 */
+	spi_message_init(&msg);
+	if (ec_spi->start_of_msg_delay) {
+		memset(&trans_delay, 0, sizeof(trans_delay));
+		trans_delay.delay.value = ec_spi->start_of_msg_delay;
+		trans_delay.delay.unit = SPI_DELAY_UNIT_USECS;
+		spi_message_add_tail(&trans_delay, &msg);
+	}
+
+	/* Transmit phase - send our message */
+	memset(&trans, 0, sizeof(trans));
+	trans.tx_buf = ec_dev->dout;
+	trans.rx_buf = rx_buf;
+	trans.len = len;
+	trans.cs_change = 1;
+	spi_message_add_tail(&trans, &msg);
+	ret = spi_sync_locked(ec_spi->spi, &msg);
+
+	/* Get the response */
+	if (!ret) {
+		/* Verify that EC can process command */
+		for (i = 0; i < len; i++) {
+			rx_byte = rx_buf[i];
+			/*
+			 * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
+			 * markers are all signs that the EC didn't fully
+			 * receive our command. e.g., if the EC is flashing
+			 * itself, it can't respond to any commands and instead
+			 * clocks out EC_SPI_PAST_END from its SPI hardware
+			 * buffer. Similar occurrences can happen if the AP is
+			 * too slow to clock out data after asserting CS -- the
+			 * EC will abort and fill its buffer with
+			 * EC_SPI_RX_BAD_DATA.
+			 *
+			 * In all cases, these errors should be safe to retry.
+			 * Report -EAGAIN and let the caller decide what to do
+			 * about that.
+			 */
+			if (rx_byte == EC_SPI_PAST_END  ||
+			    rx_byte == EC_SPI_RX_BAD_DATA ||
+			    rx_byte == EC_SPI_NOT_READY) {
+				ret = -EAGAIN;
+				break;
+			}
+		}
+	}
+
+	if (!ret)
+		ret = cros_ec_spi_receive_packet(ec_dev,
+				ec_msg->insize + sizeof(*response));
+	else if (ret != -EAGAIN)
+		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+
+	final_ret = terminate_request(ec_dev);
+
+	spi_bus_unlock(ec_spi->spi->master);
+
+	if (!ret)
+		ret = final_ret;
+	if (ret < 0)
+		goto exit;
+
+	ptr = ec_dev->din;
+
+	/* check response error code */
+	response = (struct ec_host_response *)ptr;
+	ec_msg->result = response->result;
+
+	ret = cros_ec_check_result(ec_dev, ec_msg);
+	if (ret)
+		goto exit;
+
+	len = response->data_len;
+	sum = 0;
+	if (len > ec_msg->insize) {
+		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
+			len, ec_msg->insize);
+		ret = -EMSGSIZE;
+		goto exit;
+	}
+
+	for (i = 0; i < sizeof(*response); i++)
+		sum += ptr[i];
+
+	/* copy response packet payload and compute checksum */
+	memcpy(ec_msg->data, ptr + sizeof(*response), len);
+	for (i = 0; i < len; i++)
+		sum += ec_msg->data[i];
+
+	if (sum) {
+		dev_err(ec_dev->dev,
+			"bad packet checksum, calculated %x\n",
+			sum);
+		ret = -EBADMSG;
+		goto exit;
+	}
+
+	ret = len;
+exit:
+	kfree(rx_buf);
+	if (ec_msg->command == EC_CMD_REBOOT_EC)
+		msleep(EC_REBOOT_DELAY_MS);
+
+	return ret;
+}
+
+/**
+ * do_cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
+ *
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ */
+static int do_cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
+				   struct cros_ec_command *ec_msg)
+{
+	struct cros_ec_spi *ec_spi = ec_dev->priv;
+	struct spi_transfer trans;
+	struct spi_message msg;
+	int i, len;
+	u8 *ptr;
+	u8 *rx_buf;
+	u8 rx_byte;
+	int sum;
+	int ret = 0, final_ret;
+	unsigned long delay;
+
+	len = cros_ec_prepare_tx(ec_dev, ec_msg);
+	if (len < 0)
+		return len;
+	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
+
+	/* If it's too soon to do another transaction, wait */
+	delay = ktime_get_ns() - ec_spi->last_transfer_ns;
+	if (delay < EC_SPI_RECOVERY_TIME_NS)
+		ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
+
+	rx_buf = kzalloc(len, GFP_KERNEL);
+	if (!rx_buf)
+		return -ENOMEM;
+
+	spi_bus_lock(ec_spi->spi->master);
+
+	/* Transmit phase - send our message */
+	debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
+	memset(&trans, 0, sizeof(trans));
+	trans.tx_buf = ec_dev->dout;
+	trans.rx_buf = rx_buf;
+	trans.len = len;
+	trans.cs_change = 1;
+	spi_message_init(&msg);
+	spi_message_add_tail(&trans, &msg);
+	ret = spi_sync_locked(ec_spi->spi, &msg);
+
+	/* Get the response */
+	if (!ret) {
+		/* Verify that EC can process command */
+		for (i = 0; i < len; i++) {
+			rx_byte = rx_buf[i];
+			/* See comments in cros_ec_pkt_xfer_spi() */
+			if (rx_byte == EC_SPI_PAST_END  ||
+			    rx_byte == EC_SPI_RX_BAD_DATA ||
+			    rx_byte == EC_SPI_NOT_READY) {
+				ret = -EAGAIN;
+				break;
+			}
+		}
+	}
+
+	if (!ret)
+		ret = cros_ec_spi_receive_response(ec_dev,
+				ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
+	else if (ret != -EAGAIN)
+		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+
+	final_ret = terminate_request(ec_dev);
+
+	spi_bus_unlock(ec_spi->spi->master);
+
+	if (!ret)
+		ret = final_ret;
+	if (ret < 0)
+		goto exit;
+
+	ptr = ec_dev->din;
+
+	/* check response error code */
+	ec_msg->result = ptr[0];
+	ret = cros_ec_check_result(ec_dev, ec_msg);
+	if (ret)
+		goto exit;
+
+	len = ptr[1];
+	sum = ptr[0] + ptr[1];
+	if (len > ec_msg->insize) {
+		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
+			len, ec_msg->insize);
+		ret = -ENOSPC;
+		goto exit;
+	}
+
+	/* copy response packet payload and compute checksum */
+	for (i = 0; i < len; i++) {
+		sum += ptr[i + 2];
+		if (ec_msg->insize)
+			ec_msg->data[i] = ptr[i + 2];
+	}
+	sum &= 0xff;
+
+	debug_packet(ec_dev->dev, "in", ptr, len + 3);
+
+	if (sum != ptr[len + 2]) {
+		dev_err(ec_dev->dev,
+			"bad packet checksum, expected %02x, got %02x\n",
+			sum, ptr[len + 2]);
+		ret = -EBADMSG;
+		goto exit;
+	}
+
+	ret = len;
+exit:
+	kfree(rx_buf);
+	if (ec_msg->command == EC_CMD_REBOOT_EC)
+		msleep(EC_REBOOT_DELAY_MS);
+
+	return ret;
+}
+
+static void cros_ec_xfer_high_pri_work(struct kthread_work *work)
+{
+	struct cros_ec_xfer_work_params *params;
+
+	params = container_of(work, struct cros_ec_xfer_work_params, work);
+	params->ret = params->fn(params->ec_dev, params->ec_msg);
+}
+
+static int cros_ec_xfer_high_pri(struct cros_ec_device *ec_dev,
+				 struct cros_ec_command *ec_msg,
+				 cros_ec_xfer_fn_t fn)
+{
+	struct cros_ec_spi *ec_spi = ec_dev->priv;
+	struct cros_ec_xfer_work_params params = {
+		.work = KTHREAD_WORK_INIT(params.work,
+					  cros_ec_xfer_high_pri_work),
+		.ec_dev = ec_dev,
+		.ec_msg = ec_msg,
+		.fn = fn,
+	};
+
+	/*
+	 * This looks a bit ridiculous.  Why do the work on a
+	 * different thread if we're just going to block waiting for
+	 * the thread to finish?  The key here is that the thread is
+	 * running at high priority but the calling context might not
+	 * be.  We need to be at high priority to avoid getting
+	 * context switched out for too long and the EC giving up on
+	 * the transfer.
+	 */
+	kthread_queue_work(ec_spi->high_pri_worker, &params.work);
+	kthread_flush_work(&params.work);
+
+	return params.ret;
+}
+
+static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
+				struct cros_ec_command *ec_msg)
+{
+	return cros_ec_xfer_high_pri(ec_dev, ec_msg, do_cros_ec_pkt_xfer_spi);
+}
+
+static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
+				struct cros_ec_command *ec_msg)
+{
+	return cros_ec_xfer_high_pri(ec_dev, ec_msg, do_cros_ec_cmd_xfer_spi);
+}
+
+static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	u32 val;
+	int ret;
+
+	ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
+	if (!ret)
+		ec_spi->start_of_msg_delay = val;
+
+	ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
+	if (!ret)
+		ec_spi->end_of_msg_delay = val;
+}
+
+static void cros_ec_spi_high_pri_release(void *worker)
+{
+	kthread_destroy_worker(worker);
+}
+
+static int cros_ec_spi_devm_high_pri_alloc(struct device *dev,
+					   struct cros_ec_spi *ec_spi)
+{
+	int err;
+
+	ec_spi->high_pri_worker =
+		kthread_create_worker(0, "cros_ec_spi_high_pri");
+
+	if (IS_ERR(ec_spi->high_pri_worker)) {
+		err = PTR_ERR(ec_spi->high_pri_worker);
+		dev_err(dev, "Can't create cros_ec high pri worker: %d\n", err);
+		return err;
+	}
+
+	err = devm_add_action_or_reset(dev, cros_ec_spi_high_pri_release,
+				       ec_spi->high_pri_worker);
+	if (err)
+		return err;
+
+	sched_set_fifo(ec_spi->high_pri_worker->task);
+
+	return 0;
+}
+
+static int cros_ec_spi_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct cros_ec_device *ec_dev;
+	struct cros_ec_spi *ec_spi;
+	int err;
+
+	spi->rt = true;
+	err = spi_setup(spi);
+	if (err < 0)
+		return err;
+
+	ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
+	if (ec_spi == NULL)
+		return -ENOMEM;
+	ec_spi->spi = spi;
+	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
+	if (!ec_dev)
+		return -ENOMEM;
+
+	/* Check for any DT properties */
+	cros_ec_spi_dt_probe(ec_spi, dev);
+
+	spi_set_drvdata(spi, ec_dev);
+	ec_dev->dev = dev;
+	ec_dev->priv = ec_spi;
+	ec_dev->irq = spi->irq;
+	ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
+	ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
+	ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
+	ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
+			   sizeof(struct ec_host_response) +
+			   sizeof(struct ec_response_get_protocol_info);
+	ec_dev->dout_size = sizeof(struct ec_host_request);
+
+	ec_spi->last_transfer_ns = ktime_get_ns();
+
+	err = cros_ec_spi_devm_high_pri_alloc(dev, ec_spi);
+	if (err)
+		return err;
+
+	err = cros_ec_register(ec_dev);
+	if (err) {
+		dev_err(dev, "cannot register EC\n");
+		return err;
+	}
+
+	device_init_wakeup(&spi->dev, true);
+
+	return 0;
+}
+
+static void cros_ec_spi_remove(struct spi_device *spi)
+{
+	struct cros_ec_device *ec_dev = spi_get_drvdata(spi);
+
+	cros_ec_unregister(ec_dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cros_ec_spi_suspend(struct device *dev)
+{
+	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
+
+	return cros_ec_suspend(ec_dev);
+}
+
+static int cros_ec_spi_resume(struct device *dev)
+{
+	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
+
+	return cros_ec_resume(ec_dev);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
+			 cros_ec_spi_resume);
+
+static const struct of_device_id cros_ec_spi_of_match[] = {
+	{ .compatible = "google,cros-ec-spi", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
+
+static const struct spi_device_id cros_ec_spi_id[] = {
+	{ "cros-ec-spi", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
+
+static struct spi_driver cros_ec_driver_spi = {
+	.driver	= {
+		.name	= "cros-ec-spi",
+		.of_match_table = cros_ec_spi_of_match,
+		.pm	= &cros_ec_spi_pm_ops,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.probe		= cros_ec_spi_probe,
+	.remove		= cros_ec_spi_remove,
+	.id_table	= cros_ec_spi_id,
+};
+
+module_spi_driver(cros_ec_driver_spi);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("SPI interface for ChromeOS Embedded Controller");