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, 967 insertions, 0 deletions

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
new file mode 100644
index 000000000..dfd2b357f
--- /dev/null
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -0,0 +1,967 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx AXIS FIFO: interface to the Xilinx AXI-Stream FIFO IP core
+ *
+ * Copyright (C) 2018 Jacob Feder
+ *
+ * Authors:  Jacob Feder <jacobsfeder@gmail.com>
+ *
+ * See Xilinx PG080 document for IP details
+ */
+
+/* ----------------------------
+ *           includes
+ * ----------------------------
+ */
+
+#include <linux/kernel.h>
+#include <linux/wait.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/moduleparam.h>
+#include <linux/interrupt.h>
+#include <linux/param.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/jiffies.h>
+#include <linux/miscdevice.h>
+
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+
+/* ----------------------------
+ *       driver parameters
+ * ----------------------------
+ */
+
+#define DRIVER_NAME "axis_fifo"
+
+#define READ_BUF_SIZE 128U /* read buffer length in words */
+#define WRITE_BUF_SIZE 128U /* write buffer length in words */
+
+/* ----------------------------
+ *     IP register offsets
+ * ----------------------------
+ */
+
+#define XLLF_ISR_OFFSET  0x00000000  /* Interrupt Status */
+#define XLLF_IER_OFFSET  0x00000004  /* Interrupt Enable */
+
+#define XLLF_TDFR_OFFSET 0x00000008  /* Transmit Reset */
+#define XLLF_TDFV_OFFSET 0x0000000c  /* Transmit Vacancy */
+#define XLLF_TDFD_OFFSET 0x00000010  /* Transmit Data */
+#define XLLF_TLR_OFFSET  0x00000014  /* Transmit Length */
+
+#define XLLF_RDFR_OFFSET 0x00000018  /* Receive Reset */
+#define XLLF_RDFO_OFFSET 0x0000001c  /* Receive Occupancy */
+#define XLLF_RDFD_OFFSET 0x00000020  /* Receive Data */
+#define XLLF_RLR_OFFSET  0x00000024  /* Receive Length */
+#define XLLF_SRR_OFFSET  0x00000028  /* Local Link Reset */
+#define XLLF_TDR_OFFSET  0x0000002C  /* Transmit Destination */
+#define XLLF_RDR_OFFSET  0x00000030  /* Receive Destination */
+
+/* ----------------------------
+ *     reset register masks
+ * ----------------------------
+ */
+
+#define XLLF_RDFR_RESET_MASK        0x000000a5 /* receive reset value */
+#define XLLF_TDFR_RESET_MASK        0x000000a5 /* Transmit reset value */
+#define XLLF_SRR_RESET_MASK         0x000000a5 /* Local Link reset value */
+
+/* ----------------------------
+ *       interrupt masks
+ * ----------------------------
+ */
+
+#define XLLF_INT_RPURE_MASK       0x80000000 /* Receive under-read */
+#define XLLF_INT_RPORE_MASK       0x40000000 /* Receive over-read */
+#define XLLF_INT_RPUE_MASK        0x20000000 /* Receive underrun (empty) */
+#define XLLF_INT_TPOE_MASK        0x10000000 /* Transmit overrun */
+#define XLLF_INT_TC_MASK          0x08000000 /* Transmit complete */
+#define XLLF_INT_RC_MASK          0x04000000 /* Receive complete */
+#define XLLF_INT_TSE_MASK         0x02000000 /* Transmit length mismatch */
+#define XLLF_INT_TRC_MASK         0x01000000 /* Transmit reset complete */
+#define XLLF_INT_RRC_MASK         0x00800000 /* Receive reset complete */
+#define XLLF_INT_TFPF_MASK        0x00400000 /* Tx FIFO Programmable Full */
+#define XLLF_INT_TFPE_MASK        0x00200000 /* Tx FIFO Programmable Empty */
+#define XLLF_INT_RFPF_MASK        0x00100000 /* Rx FIFO Programmable Full */
+#define XLLF_INT_RFPE_MASK        0x00080000 /* Rx FIFO Programmable Empty */
+#define XLLF_INT_ALL_MASK         0xfff80000 /* All the ints */
+#define XLLF_INT_ERROR_MASK       0xf2000000 /* Error status ints */
+#define XLLF_INT_RXERROR_MASK     0xe0000000 /* Receive Error status ints */
+#define XLLF_INT_TXERROR_MASK     0x12000000 /* Transmit Error status ints */
+
+/* ----------------------------
+ *           globals
+ * ----------------------------
+ */
+static int read_timeout = 1000; /* ms to wait before read() times out */
+static int write_timeout = 1000; /* ms to wait before write() times out */
+
+/* ----------------------------
+ * module command-line arguments
+ * ----------------------------
+ */
+
+module_param(read_timeout, int, 0444);
+MODULE_PARM_DESC(read_timeout, "ms to wait before blocking read() timing out; set to -1 for no timeout");
+module_param(write_timeout, int, 0444);
+MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing out; set to -1 for no timeout");
+
+/* ----------------------------
+ *            types
+ * ----------------------------
+ */
+
+struct axis_fifo {
+	int irq; /* interrupt */
+	void __iomem *base_addr; /* kernel space memory */
+
+	unsigned int rx_fifo_depth; /* max words in the receive fifo */
+	unsigned int tx_fifo_depth; /* max words in the transmit fifo */
+	int has_rx_fifo; /* whether the IP has the rx fifo enabled */
+	int has_tx_fifo; /* whether the IP has the tx fifo enabled */
+
+	wait_queue_head_t read_queue; /* wait queue for asynchronos read */
+	struct mutex read_lock; /* lock for reading */
+	wait_queue_head_t write_queue; /* wait queue for asynchronos write */
+	struct mutex write_lock; /* lock for writing */
+	unsigned int write_flags; /* write file flags */
+	unsigned int read_flags; /* read file flags */
+
+	struct device *dt_device; /* device created from the device tree */
+	struct miscdevice miscdev;
+};
+
+/* ----------------------------
+ *         sysfs entries
+ * ----------------------------
+ */
+
+static ssize_t sysfs_write(struct device *dev, const char *buf,
+			   size_t count, unsigned int addr_offset)
+{
+	struct axis_fifo *fifo = dev_get_drvdata(dev);
+	unsigned long tmp;
+	int rc;
+
+	rc = kstrtoul(buf, 0, &tmp);
+	if (rc < 0)
+		return rc;
+
+	iowrite32(tmp, fifo->base_addr + addr_offset);
+
+	return count;
+}
+
+static ssize_t sysfs_read(struct device *dev, char *buf,
+			  unsigned int addr_offset)
+{
+	struct axis_fifo *fifo = dev_get_drvdata(dev);
+	unsigned int read_val;
+	unsigned int len;
+	char tmp[32];
+
+	read_val = ioread32(fifo->base_addr + addr_offset);
+	len =  snprintf(tmp, sizeof(tmp), "0x%x\n", read_val);
+	memcpy(buf, tmp, len);
+
+	return len;
+}
+
+static ssize_t isr_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_ISR_OFFSET);
+}
+
+static ssize_t isr_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_ISR_OFFSET);
+}
+
+static DEVICE_ATTR_RW(isr);
+
+static ssize_t ier_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_IER_OFFSET);
+}
+
+static ssize_t ier_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_IER_OFFSET);
+}
+
+static DEVICE_ATTR_RW(ier);
+
+static ssize_t tdfr_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_TDFR_OFFSET);
+}
+
+static DEVICE_ATTR_WO(tdfr);
+
+static ssize_t tdfv_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_TDFV_OFFSET);
+}
+
+static DEVICE_ATTR_RO(tdfv);
+
+static ssize_t tdfd_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_TDFD_OFFSET);
+}
+
+static DEVICE_ATTR_WO(tdfd);
+
+static ssize_t tlr_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_TLR_OFFSET);
+}
+
+static DEVICE_ATTR_WO(tlr);
+
+static ssize_t rdfr_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_RDFR_OFFSET);
+}
+
+static DEVICE_ATTR_WO(rdfr);
+
+static ssize_t rdfo_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_RDFO_OFFSET);
+}
+
+static DEVICE_ATTR_RO(rdfo);
+
+static ssize_t rdfd_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_RDFD_OFFSET);
+}
+
+static DEVICE_ATTR_RO(rdfd);
+
+static ssize_t rlr_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_RLR_OFFSET);
+}
+
+static DEVICE_ATTR_RO(rlr);
+
+static ssize_t srr_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_SRR_OFFSET);
+}
+
+static DEVICE_ATTR_WO(srr);
+
+static ssize_t tdr_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	return sysfs_write(dev, buf, count, XLLF_TDR_OFFSET);
+}
+
+static DEVICE_ATTR_WO(tdr);
+
+static ssize_t rdr_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sysfs_read(dev, buf, XLLF_RDR_OFFSET);
+}
+
+static DEVICE_ATTR_RO(rdr);
+
+static struct attribute *axis_fifo_attrs[] = {
+	&dev_attr_isr.attr,
+	&dev_attr_ier.attr,
+	&dev_attr_tdfr.attr,
+	&dev_attr_tdfv.attr,
+	&dev_attr_tdfd.attr,
+	&dev_attr_tlr.attr,
+	&dev_attr_rdfr.attr,
+	&dev_attr_rdfo.attr,
+	&dev_attr_rdfd.attr,
+	&dev_attr_rlr.attr,
+	&dev_attr_srr.attr,
+	&dev_attr_tdr.attr,
+	&dev_attr_rdr.attr,
+	NULL,
+};
+
+static const struct attribute_group axis_fifo_attrs_group = {
+	.name = "ip_registers",
+	.attrs = axis_fifo_attrs,
+};
+
+static const struct attribute_group *axis_fifo_attrs_groups[] = {
+	&axis_fifo_attrs_group,
+	NULL,
+};
+
+/* ----------------------------
+ *        implementation
+ * ----------------------------
+ */
+
+static void reset_ip_core(struct axis_fifo *fifo)
+{
+	iowrite32(XLLF_SRR_RESET_MASK, fifo->base_addr + XLLF_SRR_OFFSET);
+	iowrite32(XLLF_TDFR_RESET_MASK, fifo->base_addr + XLLF_TDFR_OFFSET);
+	iowrite32(XLLF_RDFR_RESET_MASK, fifo->base_addr + XLLF_RDFR_OFFSET);
+	iowrite32(XLLF_INT_TC_MASK | XLLF_INT_RC_MASK | XLLF_INT_RPURE_MASK |
+		  XLLF_INT_RPORE_MASK | XLLF_INT_RPUE_MASK |
+		  XLLF_INT_TPOE_MASK | XLLF_INT_TSE_MASK,
+		  fifo->base_addr + XLLF_IER_OFFSET);
+	iowrite32(XLLF_INT_ALL_MASK, fifo->base_addr + XLLF_ISR_OFFSET);
+}
+
+/**
+ * axis_fifo_read() - Read a packet from AXIS-FIFO character device.
+ * @f: Open file.
+ * @buf: User space buffer to read to.
+ * @len: User space buffer length.
+ * @off: Buffer offset.
+ *
+ * As defined by the device's documentation, we need to check the device's
+ * occupancy before reading the length register and then the data. All these
+ * operations must be executed atomically, in order and one after the other
+ * without missing any.
+ *
+ * Returns the number of bytes read from the device or negative error code
+ *	on failure.
+ */
+static ssize_t axis_fifo_read(struct file *f, char __user *buf,
+			      size_t len, loff_t *off)
+{
+	struct axis_fifo *fifo = (struct axis_fifo *)f->private_data;
+	size_t bytes_available;
+	unsigned int words_available;
+	unsigned int copied;
+	unsigned int copy;
+	unsigned int i;
+	int ret;
+	u32 tmp_buf[READ_BUF_SIZE];
+
+	if (fifo->read_flags & O_NONBLOCK) {
+		/*
+		 * Device opened in non-blocking mode. Try to lock it and then
+		 * check if any packet is available.
+		 */
+		if (!mutex_trylock(&fifo->read_lock))
+			return -EAGAIN;
+
+		if (!ioread32(fifo->base_addr + XLLF_RDFO_OFFSET)) {
+			ret = -EAGAIN;
+			goto end_unlock;
+		}
+	} else {
+		/* opened in blocking mode
+		 * wait for a packet available interrupt (or timeout)
+		 * if nothing is currently available
+		 */
+		mutex_lock(&fifo->read_lock);
+		ret = wait_event_interruptible_timeout(fifo->read_queue,
+			ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
+				 (read_timeout >= 0) ?
+				  msecs_to_jiffies(read_timeout) :
+				  MAX_SCHEDULE_TIMEOUT);
+
+		if (ret <= 0) {
+			if (ret == 0) {
+				ret = -EAGAIN;
+			} else if (ret != -ERESTARTSYS) {
+				dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in read (ret=%i)\n",
+					ret);
+			}
+
+			goto end_unlock;
+		}
+	}
+
+	bytes_available = ioread32(fifo->base_addr + XLLF_RLR_OFFSET);
+	if (!bytes_available) {
+		dev_err(fifo->dt_device, "received a packet of length 0 - fifo core will be reset\n");
+		reset_ip_core(fifo);
+		ret = -EIO;
+		goto end_unlock;
+	}
+
+	if (bytes_available > len) {
+		dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu) - fifo core will be reset\n",
+			bytes_available, len);
+		reset_ip_core(fifo);
+		ret = -EINVAL;
+		goto end_unlock;
+	}
+
+	if (bytes_available % sizeof(u32)) {
+		/* this probably can't happen unless IP
+		 * registers were previously mishandled
+		 */
+		dev_err(fifo->dt_device, "received a packet that isn't word-aligned - fifo core will be reset\n");
+		reset_ip_core(fifo);
+		ret = -EIO;
+		goto end_unlock;
+	}
+
+	words_available = bytes_available / sizeof(u32);
+
+	/* read data into an intermediate buffer, copying the contents
+	 * to userspace when the buffer is full
+	 */
+	copied = 0;
+	while (words_available > 0) {
+		copy = min(words_available, READ_BUF_SIZE);
+
+		for (i = 0; i < copy; i++) {
+			tmp_buf[i] = ioread32(fifo->base_addr +
+					      XLLF_RDFD_OFFSET);
+		}
+
+		if (copy_to_user(buf + copied * sizeof(u32), tmp_buf,
+				 copy * sizeof(u32))) {
+			reset_ip_core(fifo);
+			ret = -EFAULT;
+			goto end_unlock;
+		}
+
+		copied += copy;
+		words_available -= copy;
+	}
+
+	ret = bytes_available;
+
+end_unlock:
+	mutex_unlock(&fifo->read_lock);
+
+	return ret;
+}
+
+/**
+ * axis_fifo_write() - Write buffer to AXIS-FIFO character device.
+ * @f: Open file.
+ * @buf: User space buffer to write to the device.
+ * @len: User space buffer length.
+ * @off: Buffer offset.
+ *
+ * As defined by the device's documentation, we need to write to the device's
+ * data buffer then to the device's packet length register atomically. Also,
+ * we need to lock before checking if the device has available space to avoid
+ * any concurrency issue.
+ *
+ * Returns the number of bytes written to the device or negative error code
+ *	on failure.
+ */
+static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
+			       size_t len, loff_t *off)
+{
+	struct axis_fifo *fifo = (struct axis_fifo *)f->private_data;
+	unsigned int words_to_write;
+	unsigned int copied;
+	unsigned int copy;
+	unsigned int i;
+	int ret;
+	u32 tmp_buf[WRITE_BUF_SIZE];
+
+	if (len % sizeof(u32)) {
+		dev_err(fifo->dt_device,
+			"tried to send a packet that isn't word-aligned\n");
+		return -EINVAL;
+	}
+
+	words_to_write = len / sizeof(u32);
+
+	if (!words_to_write) {
+		dev_err(fifo->dt_device,
+			"tried to send a packet of length 0\n");
+		return -EINVAL;
+	}
+
+	if (words_to_write > fifo->tx_fifo_depth) {
+		dev_err(fifo->dt_device, "tried to write more words [%u] than slots in the fifo buffer [%u]\n",
+			words_to_write, fifo->tx_fifo_depth);
+		return -EINVAL;
+	}
+
+	if (fifo->write_flags & O_NONBLOCK) {
+		/*
+		 * Device opened in non-blocking mode. Try to lock it and then
+		 * check if there is any room to write the given buffer.
+		 */
+		if (!mutex_trylock(&fifo->write_lock))
+			return -EAGAIN;
+
+		if (words_to_write > ioread32(fifo->base_addr +
+					      XLLF_TDFV_OFFSET)) {
+			ret = -EAGAIN;
+			goto end_unlock;
+		}
+	} else {
+		/* opened in blocking mode */
+
+		/* wait for an interrupt (or timeout) if there isn't
+		 * currently enough room in the fifo
+		 */
+		mutex_lock(&fifo->write_lock);
+		ret = wait_event_interruptible_timeout(fifo->write_queue,
+			ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
+				 >= words_to_write,
+				 (write_timeout >= 0) ?
+				  msecs_to_jiffies(write_timeout) :
+				  MAX_SCHEDULE_TIMEOUT);
+
+		if (ret <= 0) {
+			if (ret == 0) {
+				ret = -EAGAIN;
+			} else if (ret != -ERESTARTSYS) {
+				dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in write (ret=%i)\n",
+					ret);
+			}
+
+			goto end_unlock;
+		}
+	}
+
+	/* write data from an intermediate buffer into the fifo IP, refilling
+	 * the buffer with userspace data as needed
+	 */
+	copied = 0;
+	while (words_to_write > 0) {
+		copy = min(words_to_write, WRITE_BUF_SIZE);
+
+		if (copy_from_user(tmp_buf, buf + copied * sizeof(u32),
+				   copy * sizeof(u32))) {
+			reset_ip_core(fifo);
+			ret = -EFAULT;
+			goto end_unlock;
+		}
+
+		for (i = 0; i < copy; i++)
+			iowrite32(tmp_buf[i], fifo->base_addr +
+				  XLLF_TDFD_OFFSET);
+
+		copied += copy;
+		words_to_write -= copy;
+	}
+
+	ret = copied * sizeof(u32);
+
+	/* write packet size to fifo */
+	iowrite32(ret, fifo->base_addr + XLLF_TLR_OFFSET);
+
+end_unlock:
+	mutex_unlock(&fifo->write_lock);
+
+	return ret;
+}
+
+static irqreturn_t axis_fifo_irq(int irq, void *dw)
+{
+	struct axis_fifo *fifo = (struct axis_fifo *)dw;
+	unsigned int pending_interrupts;
+
+	do {
+		pending_interrupts = ioread32(fifo->base_addr +
+					      XLLF_IER_OFFSET) &
+					      ioread32(fifo->base_addr
+					      + XLLF_ISR_OFFSET);
+		if (pending_interrupts & XLLF_INT_RC_MASK) {
+			/* packet received */
+
+			/* wake the reader process if it is waiting */
+			wake_up(&fifo->read_queue);
+
+			/* clear interrupt */
+			iowrite32(XLLF_INT_RC_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TC_MASK) {
+			/* packet sent */
+
+			/* wake the writer process if it is waiting */
+			wake_up(&fifo->write_queue);
+
+			iowrite32(XLLF_INT_TC_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TFPF_MASK) {
+			/* transmit fifo programmable full */
+
+			iowrite32(XLLF_INT_TFPF_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TFPE_MASK) {
+			/* transmit fifo programmable empty */
+
+			iowrite32(XLLF_INT_TFPE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RFPF_MASK) {
+			/* receive fifo programmable full */
+
+			iowrite32(XLLF_INT_RFPF_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RFPE_MASK) {
+			/* receive fifo programmable empty */
+
+			iowrite32(XLLF_INT_RFPE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TRC_MASK) {
+			/* transmit reset complete interrupt */
+
+			iowrite32(XLLF_INT_TRC_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RRC_MASK) {
+			/* receive reset complete interrupt */
+
+			iowrite32(XLLF_INT_RRC_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RPURE_MASK) {
+			/* receive fifo under-read error interrupt */
+			dev_err(fifo->dt_device,
+				"receive under-read interrupt\n");
+
+			iowrite32(XLLF_INT_RPURE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RPORE_MASK) {
+			/* receive over-read error interrupt */
+			dev_err(fifo->dt_device,
+				"receive over-read interrupt\n");
+
+			iowrite32(XLLF_INT_RPORE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_RPUE_MASK) {
+			/* receive underrun error interrupt */
+			dev_err(fifo->dt_device,
+				"receive underrun error interrupt\n");
+
+			iowrite32(XLLF_INT_RPUE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TPOE_MASK) {
+			/* transmit overrun error interrupt */
+			dev_err(fifo->dt_device,
+				"transmit overrun error interrupt\n");
+
+			iowrite32(XLLF_INT_TPOE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts & XLLF_INT_TSE_MASK) {
+			/* transmit length mismatch error interrupt */
+			dev_err(fifo->dt_device,
+				"transmit length mismatch error interrupt\n");
+
+			iowrite32(XLLF_INT_TSE_MASK & XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		} else if (pending_interrupts) {
+			/* unknown interrupt type */
+			dev_err(fifo->dt_device,
+				"unknown interrupt(s) 0x%x\n",
+				pending_interrupts);
+
+			iowrite32(XLLF_INT_ALL_MASK,
+				  fifo->base_addr + XLLF_ISR_OFFSET);
+		}
+	} while (pending_interrupts);
+
+	return IRQ_HANDLED;
+}
+
+static int axis_fifo_open(struct inode *inod, struct file *f)
+{
+	struct axis_fifo *fifo = container_of(f->private_data,
+					      struct axis_fifo, miscdev);
+	f->private_data = fifo;
+
+	if (((f->f_flags & O_ACCMODE) == O_WRONLY) ||
+	    ((f->f_flags & O_ACCMODE) == O_RDWR)) {
+		if (fifo->has_tx_fifo) {
+			fifo->write_flags = f->f_flags;
+		} else {
+			dev_err(fifo->dt_device, "tried to open device for write but the transmit fifo is disabled\n");
+			return -EPERM;
+		}
+	}
+
+	if (((f->f_flags & O_ACCMODE) == O_RDONLY) ||
+	    ((f->f_flags & O_ACCMODE) == O_RDWR)) {
+		if (fifo->has_rx_fifo) {
+			fifo->read_flags = f->f_flags;
+		} else {
+			dev_err(fifo->dt_device, "tried to open device for read but the receive fifo is disabled\n");
+			return -EPERM;
+		}
+	}
+
+	return 0;
+}
+
+static int axis_fifo_close(struct inode *inod, struct file *f)
+{
+	f->private_data = NULL;
+
+	return 0;
+}
+
+static const struct file_operations fops = {
+	.owner = THIS_MODULE,
+	.open = axis_fifo_open,
+	.release = axis_fifo_close,
+	.read = axis_fifo_read,
+	.write = axis_fifo_write
+};
+
+/* read named property from the device tree */
+static int get_dts_property(struct axis_fifo *fifo,
+			    char *name, unsigned int *var)
+{
+	int rc;
+
+	rc = of_property_read_u32(fifo->dt_device->of_node, name, var);
+	if (rc) {
+		dev_err(fifo->dt_device, "couldn't read IP dts property '%s'",
+			name);
+		return rc;
+	}
+	dev_dbg(fifo->dt_device, "dts property '%s' = %u\n",
+		name, *var);
+
+	return 0;
+}
+
+static int axis_fifo_parse_dt(struct axis_fifo *fifo)
+{
+	int ret;
+	unsigned int value;
+
+	ret = get_dts_property(fifo, "xlnx,axi-str-rxd-tdata-width", &value);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,axi-str-rxd-tdata-width property\n");
+		goto end;
+	} else if (value != 32) {
+		dev_err(fifo->dt_device, "xlnx,axi-str-rxd-tdata-width only supports 32 bits\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,axi-str-txd-tdata-width", &value);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,axi-str-txd-tdata-width property\n");
+		goto end;
+	} else if (value != 32) {
+		dev_err(fifo->dt_device, "xlnx,axi-str-txd-tdata-width only supports 32 bits\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,rx-fifo-depth",
+			       &fifo->rx_fifo_depth);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,rx-fifo-depth property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,tx-fifo-depth",
+			       &fifo->tx_fifo_depth);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,tx-fifo-depth property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	/* IP sets TDFV to fifo depth - 4 so we will do the same */
+	fifo->tx_fifo_depth -= 4;
+
+	ret = get_dts_property(fifo, "xlnx,use-rx-data", &fifo->has_rx_fifo);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,use-rx-data property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,use-tx-data", &fifo->has_tx_fifo);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,use-tx-data property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+end:
+	return ret;
+}
+
+static int axis_fifo_probe(struct platform_device *pdev)
+{
+	struct resource *r_mem; /* IO mem resources */
+	struct device *dev = &pdev->dev; /* OS device (from device tree) */
+	struct axis_fifo *fifo = NULL;
+	char *device_name;
+	int rc = 0; /* error return value */
+
+	/* ----------------------------
+	 *     init wrapper device
+	 * ----------------------------
+	 */
+
+	device_name = devm_kzalloc(dev, 32, GFP_KERNEL);
+	if (!device_name)
+		return -ENOMEM;
+
+	/* allocate device wrapper memory */
+	fifo = devm_kzalloc(dev, sizeof(*fifo), GFP_KERNEL);
+	if (!fifo)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, fifo);
+	fifo->dt_device = dev;
+
+	init_waitqueue_head(&fifo->read_queue);
+	init_waitqueue_head(&fifo->write_queue);
+
+	mutex_init(&fifo->read_lock);
+	mutex_init(&fifo->write_lock);
+
+	/* ----------------------------
+	 *   init device memory space
+	 * ----------------------------
+	 */
+
+	/* get iospace for the device */
+	r_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r_mem) {
+		dev_err(fifo->dt_device, "invalid address\n");
+		rc = -ENODEV;
+		goto err_initial;
+	}
+
+	/* request physical memory */
+	fifo->base_addr = devm_ioremap_resource(fifo->dt_device, r_mem);
+	if (IS_ERR(fifo->base_addr)) {
+		rc = PTR_ERR(fifo->base_addr);
+		goto err_initial;
+	}
+
+	dev_dbg(fifo->dt_device, "remapped memory to 0x%p\n", fifo->base_addr);
+
+	/* create unique device name */
+	snprintf(device_name, 32, "%s_%pa", DRIVER_NAME, &r_mem->start);
+	dev_dbg(fifo->dt_device, "device name [%s]\n", device_name);
+
+	/* ----------------------------
+	 *          init IP
+	 * ----------------------------
+	 */
+
+	rc = axis_fifo_parse_dt(fifo);
+	if (rc)
+		goto err_initial;
+
+	reset_ip_core(fifo);
+
+	/* ----------------------------
+	 *    init device interrupts
+	 * ----------------------------
+	 */
+
+	/* get IRQ resource */
+	rc = platform_get_irq(pdev, 0);
+	if (rc < 0)
+		goto err_initial;
+
+	/* request IRQ */
+	fifo->irq = rc;
+	rc = devm_request_irq(fifo->dt_device, fifo->irq, &axis_fifo_irq, 0,
+			      DRIVER_NAME, fifo);
+	if (rc) {
+		dev_err(fifo->dt_device, "couldn't allocate interrupt %i\n",
+			fifo->irq);
+		goto err_initial;
+	}
+
+	/* ----------------------------
+	 *      init char device
+	 * ----------------------------
+	 */
+
+	/* create character device */
+	fifo->miscdev.fops = &fops;
+	fifo->miscdev.minor = MISC_DYNAMIC_MINOR;
+	fifo->miscdev.name = device_name;
+	fifo->miscdev.groups = axis_fifo_attrs_groups;
+	fifo->miscdev.parent = dev;
+	rc = misc_register(&fifo->miscdev);
+	if (rc < 0)
+		goto err_initial;
+
+	dev_info(fifo->dt_device, "axis-fifo created at %pa mapped to 0x%pa, irq=%i\n",
+		 &r_mem->start, &fifo->base_addr, fifo->irq);
+
+	return 0;
+
+err_initial:
+	dev_set_drvdata(dev, NULL);
+	return rc;
+}
+
+static int axis_fifo_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct axis_fifo *fifo = dev_get_drvdata(dev);
+
+	misc_deregister(&fifo->miscdev);
+	dev_set_drvdata(dev, NULL);
+
+	return 0;
+}
+
+static const struct of_device_id axis_fifo_of_match[] = {
+	{ .compatible = "xlnx,axi-fifo-mm-s-4.1", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, axis_fifo_of_match);
+
+static struct platform_driver axis_fifo_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table	= axis_fifo_of_match,
+	},
+	.probe		= axis_fifo_probe,
+	.remove		= axis_fifo_remove,
+};
+
+static int __init axis_fifo_init(void)
+{
+	pr_info("axis-fifo driver loaded with parameters read_timeout = %i, write_timeout = %i\n",
+		read_timeout, write_timeout);
+	return platform_driver_register(&axis_fifo_driver);
+}
+
+module_init(axis_fifo_init);
+
+static void __exit axis_fifo_exit(void)
+{
+	platform_driver_unregister(&axis_fifo_driver);
+}
+
+module_exit(axis_fifo_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jacob Feder <jacobsfeder@gmail.com>");
+MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO v4.1 IP core driver");