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-rw-r--r--drivers/net/caif/Kconfig33
-rw-r--r--drivers/net/caif/Makefile8
-rw-r--r--drivers/net/caif/caif_serial.c453
-rw-r--r--drivers/net/caif/caif_virtio.c792
4 files changed, 1286 insertions, 0 deletions
diff --git a/drivers/net/caif/Kconfig b/drivers/net/caif/Kconfig
new file mode 100644
index 000000000..709660cb3
--- /dev/null
+++ b/drivers/net/caif/Kconfig
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# CAIF physical drivers
+#
+
+menuconfig CAIF_DRIVERS
+ bool "CAIF transport drivers"
+ depends on CAIF
+ help
+ Enable this to see CAIF physical drivers.
+
+if CAIF_DRIVERS
+
+config CAIF_TTY
+ tristate "CAIF TTY transport driver"
+ depends on CAIF && TTY
+ default n
+ help
+ The CAIF TTY transport driver is a Line Discipline (ldisc)
+ identified as N_CAIF. When this ldisc is opened from user space
+ it will redirect the TTY's traffic into the CAIF stack.
+
+config CAIF_VIRTIO
+ tristate "CAIF virtio transport driver"
+ depends on CAIF && HAS_DMA
+ select VHOST_RING
+ select VIRTIO
+ select GENERIC_ALLOCATOR
+ default n
+ help
+ The CAIF driver for CAIF over Virtio.
+
+endif # CAIF_DRIVERS
diff --git a/drivers/net/caif/Makefile b/drivers/net/caif/Makefile
new file mode 100644
index 000000000..97f664f80
--- /dev/null
+++ b/drivers/net/caif/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-$(CONFIG_CAIF_DEBUG) := -DDEBUG
+
+# Serial interface
+obj-$(CONFIG_CAIF_TTY) += caif_serial.o
+
+# Virtio interface
+obj-$(CONFIG_CAIF_VIRTIO) += caif_virtio.o
diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c
new file mode 100644
index 000000000..688075859
--- /dev/null
+++ b/drivers/net/caif/caif_serial.c
@@ -0,0 +1,453 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author: Sjur Brendeland
+ */
+
+#include <linux/hardirq.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/tty.h>
+#include <linux/file.h>
+#include <linux/if_arp.h>
+#include <net/caif/caif_device.h>
+#include <net/caif/cfcnfg.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sjur Brendeland");
+MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_LDISC(N_CAIF);
+
+#define SEND_QUEUE_LOW 10
+#define SEND_QUEUE_HIGH 100
+#define CAIF_SENDING 1 /* Bit 1 = 0x02*/
+#define CAIF_FLOW_OFF_SENT 4 /* Bit 4 = 0x10 */
+#define MAX_WRITE_CHUNK 4096
+#define ON 1
+#define OFF 0
+#define CAIF_MAX_MTU 4096
+
+static DEFINE_SPINLOCK(ser_lock);
+static LIST_HEAD(ser_list);
+static LIST_HEAD(ser_release_list);
+
+static bool ser_loop;
+module_param(ser_loop, bool, 0444);
+MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
+
+static bool ser_use_stx = true;
+module_param(ser_use_stx, bool, 0444);
+MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
+
+static bool ser_use_fcs = true;
+
+module_param(ser_use_fcs, bool, 0444);
+MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
+
+static int ser_write_chunk = MAX_WRITE_CHUNK;
+module_param(ser_write_chunk, int, 0444);
+
+MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");
+
+static struct dentry *debugfsdir;
+
+static int caif_net_open(struct net_device *dev);
+static int caif_net_close(struct net_device *dev);
+
+struct ser_device {
+ struct caif_dev_common common;
+ struct list_head node;
+ struct net_device *dev;
+ struct sk_buff_head head;
+ struct tty_struct *tty;
+ bool tx_started;
+ unsigned long state;
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *debugfs_tty_dir;
+ struct debugfs_blob_wrapper tx_blob;
+ struct debugfs_blob_wrapper rx_blob;
+ u8 rx_data[128];
+ u8 tx_data[128];
+ u8 tty_status;
+
+#endif
+};
+
+static void caifdev_setup(struct net_device *dev);
+static void ldisc_tx_wakeup(struct tty_struct *tty);
+#ifdef CONFIG_DEBUG_FS
+static inline void update_tty_status(struct ser_device *ser)
+{
+ ser->tty_status =
+ ser->tty->flow.stopped << 5 |
+ ser->tty->flow.tco_stopped << 3 |
+ ser->tty->ctrl.packet << 2;
+}
+static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
+{
+ ser->debugfs_tty_dir = debugfs_create_dir(tty->name, debugfsdir);
+
+ debugfs_create_blob("last_tx_msg", 0400, ser->debugfs_tty_dir,
+ &ser->tx_blob);
+
+ debugfs_create_blob("last_rx_msg", 0400, ser->debugfs_tty_dir,
+ &ser->rx_blob);
+
+ debugfs_create_xul("ser_state", 0400, ser->debugfs_tty_dir,
+ &ser->state);
+
+ debugfs_create_x8("tty_status", 0400, ser->debugfs_tty_dir,
+ &ser->tty_status);
+
+ ser->tx_blob.data = ser->tx_data;
+ ser->tx_blob.size = 0;
+ ser->rx_blob.data = ser->rx_data;
+ ser->rx_blob.size = 0;
+}
+
+static inline void debugfs_deinit(struct ser_device *ser)
+{
+ debugfs_remove_recursive(ser->debugfs_tty_dir);
+}
+
+static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
+{
+ if (size > sizeof(ser->rx_data))
+ size = sizeof(ser->rx_data);
+ memcpy(ser->rx_data, data, size);
+ ser->rx_blob.data = ser->rx_data;
+ ser->rx_blob.size = size;
+}
+
+static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
+{
+ if (size > sizeof(ser->tx_data))
+ size = sizeof(ser->tx_data);
+ memcpy(ser->tx_data, data, size);
+ ser->tx_blob.data = ser->tx_data;
+ ser->tx_blob.size = size;
+}
+#else
+static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
+{
+}
+
+static inline void debugfs_deinit(struct ser_device *ser)
+{
+}
+
+static inline void update_tty_status(struct ser_device *ser)
+{
+}
+
+static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
+{
+}
+
+static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
+{
+}
+
+#endif
+
+static void ldisc_receive(struct tty_struct *tty, const u8 *data,
+ const char *flags, int count)
+{
+ struct sk_buff *skb = NULL;
+ struct ser_device *ser;
+ int ret;
+
+ ser = tty->disc_data;
+
+ /*
+ * NOTE: flags may contain information about break or overrun.
+ * This is not yet handled.
+ */
+
+
+ /*
+ * Workaround for garbage at start of transmission,
+ * only enable if STX handling is not enabled.
+ */
+ if (!ser->common.use_stx && !ser->tx_started) {
+ dev_info(&ser->dev->dev,
+ "Bytes received before initial transmission -"
+ "bytes discarded.\n");
+ return;
+ }
+
+ BUG_ON(ser->dev == NULL);
+
+ /* Get a suitable caif packet and copy in data. */
+ skb = netdev_alloc_skb(ser->dev, count+1);
+ if (skb == NULL)
+ return;
+ skb_put_data(skb, data, count);
+
+ skb->protocol = htons(ETH_P_CAIF);
+ skb_reset_mac_header(skb);
+ debugfs_rx(ser, data, count);
+ /* Push received packet up the stack. */
+ ret = netif_rx(skb);
+ if (!ret) {
+ ser->dev->stats.rx_packets++;
+ ser->dev->stats.rx_bytes += count;
+ } else
+ ++ser->dev->stats.rx_dropped;
+ update_tty_status(ser);
+}
+
+static int handle_tx(struct ser_device *ser)
+{
+ struct tty_struct *tty;
+ struct sk_buff *skb;
+ int tty_wr, len, room;
+
+ tty = ser->tty;
+ ser->tx_started = true;
+
+ /* Enter critical section */
+ if (test_and_set_bit(CAIF_SENDING, &ser->state))
+ return 0;
+
+ /* skb_peek is safe because handle_tx is called after skb_queue_tail */
+ while ((skb = skb_peek(&ser->head)) != NULL) {
+
+ /* Make sure you don't write too much */
+ len = skb->len;
+ room = tty_write_room(tty);
+ if (!room)
+ break;
+ if (room > ser_write_chunk)
+ room = ser_write_chunk;
+ if (len > room)
+ len = room;
+
+ /* Write to tty or loopback */
+ if (!ser_loop) {
+ tty_wr = tty->ops->write(tty, skb->data, len);
+ update_tty_status(ser);
+ } else {
+ tty_wr = len;
+ ldisc_receive(tty, skb->data, NULL, len);
+ }
+ ser->dev->stats.tx_packets++;
+ ser->dev->stats.tx_bytes += tty_wr;
+
+ /* Error on TTY ?! */
+ if (tty_wr < 0)
+ goto error;
+ /* Reduce buffer written, and discard if empty */
+ skb_pull(skb, tty_wr);
+ if (skb->len == 0) {
+ struct sk_buff *tmp = skb_dequeue(&ser->head);
+ WARN_ON(tmp != skb);
+ dev_consume_skb_any(skb);
+ }
+ }
+ /* Send flow off if queue is empty */
+ if (ser->head.qlen <= SEND_QUEUE_LOW &&
+ test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
+ ser->common.flowctrl != NULL)
+ ser->common.flowctrl(ser->dev, ON);
+ clear_bit(CAIF_SENDING, &ser->state);
+ return 0;
+error:
+ clear_bit(CAIF_SENDING, &ser->state);
+ return tty_wr;
+}
+
+static netdev_tx_t caif_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct ser_device *ser;
+
+ ser = netdev_priv(dev);
+
+ /* Send flow off once, on high water mark */
+ if (ser->head.qlen > SEND_QUEUE_HIGH &&
+ !test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
+ ser->common.flowctrl != NULL)
+
+ ser->common.flowctrl(ser->dev, OFF);
+
+ skb_queue_tail(&ser->head, skb);
+ return handle_tx(ser);
+}
+
+
+static void ldisc_tx_wakeup(struct tty_struct *tty)
+{
+ struct ser_device *ser;
+
+ ser = tty->disc_data;
+ BUG_ON(ser == NULL);
+ WARN_ON(ser->tty != tty);
+ handle_tx(ser);
+}
+
+
+static void ser_release(struct work_struct *work)
+{
+ struct list_head list;
+ struct ser_device *ser, *tmp;
+
+ spin_lock(&ser_lock);
+ list_replace_init(&ser_release_list, &list);
+ spin_unlock(&ser_lock);
+
+ if (!list_empty(&list)) {
+ rtnl_lock();
+ list_for_each_entry_safe(ser, tmp, &list, node) {
+ dev_close(ser->dev);
+ unregister_netdevice(ser->dev);
+ debugfs_deinit(ser);
+ }
+ rtnl_unlock();
+ }
+}
+
+static DECLARE_WORK(ser_release_work, ser_release);
+
+static int ldisc_open(struct tty_struct *tty)
+{
+ struct ser_device *ser;
+ struct net_device *dev;
+ char name[64];
+ int result;
+
+ /* No write no play */
+ if (tty->ops->write == NULL)
+ return -EOPNOTSUPP;
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
+ return -EPERM;
+
+ /* release devices to avoid name collision */
+ ser_release(NULL);
+
+ result = snprintf(name, sizeof(name), "cf%s", tty->name);
+ if (result >= IFNAMSIZ)
+ return -EINVAL;
+ dev = alloc_netdev(sizeof(*ser), name, NET_NAME_UNKNOWN,
+ caifdev_setup);
+ if (!dev)
+ return -ENOMEM;
+
+ ser = netdev_priv(dev);
+ ser->tty = tty_kref_get(tty);
+ ser->dev = dev;
+ debugfs_init(ser, tty);
+ tty->receive_room = N_TTY_BUF_SIZE;
+ tty->disc_data = ser;
+ set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ rtnl_lock();
+ result = register_netdevice(dev);
+ if (result) {
+ tty_kref_put(tty);
+ rtnl_unlock();
+ free_netdev(dev);
+ return -ENODEV;
+ }
+
+ spin_lock(&ser_lock);
+ list_add(&ser->node, &ser_list);
+ spin_unlock(&ser_lock);
+ rtnl_unlock();
+ netif_stop_queue(dev);
+ update_tty_status(ser);
+ return 0;
+}
+
+static void ldisc_close(struct tty_struct *tty)
+{
+ struct ser_device *ser = tty->disc_data;
+
+ tty_kref_put(ser->tty);
+
+ spin_lock(&ser_lock);
+ list_move(&ser->node, &ser_release_list);
+ spin_unlock(&ser_lock);
+ schedule_work(&ser_release_work);
+}
+
+/* The line discipline structure. */
+static struct tty_ldisc_ops caif_ldisc = {
+ .owner = THIS_MODULE,
+ .num = N_CAIF,
+ .name = "n_caif",
+ .open = ldisc_open,
+ .close = ldisc_close,
+ .receive_buf = ldisc_receive,
+ .write_wakeup = ldisc_tx_wakeup
+};
+
+static const struct net_device_ops netdev_ops = {
+ .ndo_open = caif_net_open,
+ .ndo_stop = caif_net_close,
+ .ndo_start_xmit = caif_xmit
+};
+
+static void caifdev_setup(struct net_device *dev)
+{
+ struct ser_device *serdev = netdev_priv(dev);
+
+ dev->features = 0;
+ dev->netdev_ops = &netdev_ops;
+ dev->type = ARPHRD_CAIF;
+ dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+ dev->mtu = CAIF_MAX_MTU;
+ dev->priv_flags |= IFF_NO_QUEUE;
+ dev->needs_free_netdev = true;
+ skb_queue_head_init(&serdev->head);
+ serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
+ serdev->common.use_frag = true;
+ serdev->common.use_stx = ser_use_stx;
+ serdev->common.use_fcs = ser_use_fcs;
+ serdev->dev = dev;
+}
+
+
+static int caif_net_open(struct net_device *dev)
+{
+ netif_wake_queue(dev);
+ return 0;
+}
+
+static int caif_net_close(struct net_device *dev)
+{
+ netif_stop_queue(dev);
+ return 0;
+}
+
+static int __init caif_ser_init(void)
+{
+ int ret;
+
+ ret = tty_register_ldisc(&caif_ldisc);
+ if (ret < 0)
+ pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF, ret);
+
+ debugfsdir = debugfs_create_dir("caif_serial", NULL);
+ return ret;
+}
+
+static void __exit caif_ser_exit(void)
+{
+ spin_lock(&ser_lock);
+ list_splice(&ser_list, &ser_release_list);
+ spin_unlock(&ser_lock);
+ ser_release(NULL);
+ cancel_work_sync(&ser_release_work);
+ tty_unregister_ldisc(&caif_ldisc);
+ debugfs_remove_recursive(debugfsdir);
+}
+
+module_init(caif_ser_init);
+module_exit(caif_ser_exit);
diff --git a/drivers/net/caif/caif_virtio.c b/drivers/net/caif/caif_virtio.c
new file mode 100644
index 000000000..0b0f234b0
--- /dev/null
+++ b/drivers/net/caif/caif_virtio.c
@@ -0,0 +1,792 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) ST-Ericsson AB 2013
+ * Authors: Vicram Arv
+ * Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no>
+ * Sjur Brendeland
+ */
+#include <linux/module.h>
+#include <linux/if_arp.h>
+#include <linux/virtio.h>
+#include <linux/vringh.h>
+#include <linux/debugfs.h>
+#include <linux/spinlock.h>
+#include <linux/genalloc.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_caif.h>
+#include <linux/virtio_ring.h>
+#include <linux/dma-mapping.h>
+#include <net/caif/caif_dev.h>
+#include <linux/virtio_config.h>
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Vicram Arv");
+MODULE_AUTHOR("Sjur Brendeland");
+MODULE_DESCRIPTION("Virtio CAIF Driver");
+
+/* NAPI schedule quota */
+#define CFV_DEFAULT_QUOTA 32
+
+/* Defaults used if virtio config space is unavailable */
+#define CFV_DEF_MTU_SIZE 4096
+#define CFV_DEF_HEADROOM 32
+#define CFV_DEF_TAILROOM 32
+
+/* Required IP header alignment */
+#define IP_HDR_ALIGN 4
+
+/* struct cfv_napi_contxt - NAPI context info
+ * @riov: IOV holding data read from the ring. Note that riov may
+ * still hold data when cfv_rx_poll() returns.
+ * @head: Last descriptor ID we received from vringh_getdesc_kern.
+ * We use this to put descriptor back on the used ring. USHRT_MAX is
+ * used to indicate invalid head-id.
+ */
+struct cfv_napi_context {
+ struct vringh_kiov riov;
+ unsigned short head;
+};
+
+/* struct cfv_stats - statistics for debugfs
+ * @rx_napi_complete: Number of NAPI completions (RX)
+ * @rx_napi_resched: Number of calls where the full quota was used (RX)
+ * @rx_nomem: Number of SKB alloc failures (RX)
+ * @rx_kicks: Number of RX kicks
+ * @tx_full_ring: Number times TX ring was full
+ * @tx_no_mem: Number of times TX went out of memory
+ * @tx_flow_on: Number of flow on (TX)
+ * @tx_kicks: Number of TX kicks
+ */
+struct cfv_stats {
+ u32 rx_napi_complete;
+ u32 rx_napi_resched;
+ u32 rx_nomem;
+ u32 rx_kicks;
+ u32 tx_full_ring;
+ u32 tx_no_mem;
+ u32 tx_flow_on;
+ u32 tx_kicks;
+};
+
+/* struct cfv_info - Caif Virtio control structure
+ * @cfdev: caif common header
+ * @vdev: Associated virtio device
+ * @vr_rx: rx/downlink host vring
+ * @vq_tx: tx/uplink virtqueue
+ * @ndev: CAIF link layer device
+ * @watermark_tx: indicates number of free descriptors we need
+ * to reopen the tx-queues after overload.
+ * @tx_lock: protects vq_tx from concurrent use
+ * @tx_release_tasklet: Tasklet for freeing consumed TX buffers
+ * @napi: Napi context used in cfv_rx_poll()
+ * @ctx: Context data used in cfv_rx_poll()
+ * @tx_hr: transmit headroom
+ * @rx_hr: receive headroom
+ * @tx_tr: transmit tail room
+ * @rx_tr: receive tail room
+ * @mtu: transmit max size
+ * @mru: receive max size
+ * @allocsz: size of dma memory reserved for TX buffers
+ * @alloc_addr: virtual address to dma memory for TX buffers
+ * @alloc_dma: dma address to dma memory for TX buffers
+ * @genpool: Gen Pool used for allocating TX buffers
+ * @reserved_mem: Pointer to memory reserve allocated from genpool
+ * @reserved_size: Size of memory reserve allocated from genpool
+ * @stats: Statistics exposed in sysfs
+ * @debugfs: Debugfs dentry for statistic counters
+ */
+struct cfv_info {
+ struct caif_dev_common cfdev;
+ struct virtio_device *vdev;
+ struct vringh *vr_rx;
+ struct virtqueue *vq_tx;
+ struct net_device *ndev;
+ unsigned int watermark_tx;
+ /* Protect access to vq_tx */
+ spinlock_t tx_lock;
+ struct tasklet_struct tx_release_tasklet;
+ struct napi_struct napi;
+ struct cfv_napi_context ctx;
+ u16 tx_hr;
+ u16 rx_hr;
+ u16 tx_tr;
+ u16 rx_tr;
+ u32 mtu;
+ u32 mru;
+ size_t allocsz;
+ void *alloc_addr;
+ dma_addr_t alloc_dma;
+ struct gen_pool *genpool;
+ unsigned long reserved_mem;
+ size_t reserved_size;
+ struct cfv_stats stats;
+ struct dentry *debugfs;
+};
+
+/* struct buf_info - maintains transmit buffer data handle
+ * @size: size of transmit buffer
+ * @dma_handle: handle to allocated dma device memory area
+ * @vaddr: virtual address mapping to allocated memory area
+ */
+struct buf_info {
+ size_t size;
+ u8 *vaddr;
+};
+
+/* Called from virtio device, in IRQ context */
+static void cfv_release_cb(struct virtqueue *vq_tx)
+{
+ struct cfv_info *cfv = vq_tx->vdev->priv;
+
+ ++cfv->stats.tx_kicks;
+ tasklet_schedule(&cfv->tx_release_tasklet);
+}
+
+static void free_buf_info(struct cfv_info *cfv, struct buf_info *buf_info)
+{
+ if (!buf_info)
+ return;
+ gen_pool_free(cfv->genpool, (unsigned long) buf_info->vaddr,
+ buf_info->size);
+ kfree(buf_info);
+}
+
+/* This is invoked whenever the remote processor completed processing
+ * a TX msg we just sent, and the buffer is put back to the used ring.
+ */
+static void cfv_release_used_buf(struct virtqueue *vq_tx)
+{
+ struct cfv_info *cfv = vq_tx->vdev->priv;
+ unsigned long flags;
+
+ BUG_ON(vq_tx != cfv->vq_tx);
+
+ for (;;) {
+ unsigned int len;
+ struct buf_info *buf_info;
+
+ /* Get used buffer from used ring to recycle used descriptors */
+ spin_lock_irqsave(&cfv->tx_lock, flags);
+ buf_info = virtqueue_get_buf(vq_tx, &len);
+ spin_unlock_irqrestore(&cfv->tx_lock, flags);
+
+ /* Stop looping if there are no more buffers to free */
+ if (!buf_info)
+ break;
+
+ free_buf_info(cfv, buf_info);
+
+ /* watermark_tx indicates if we previously stopped the tx
+ * queues. If we have enough free stots in the virtio ring,
+ * re-establish memory reserved and open up tx queues.
+ */
+ if (cfv->vq_tx->num_free <= cfv->watermark_tx)
+ continue;
+
+ /* Re-establish memory reserve */
+ if (cfv->reserved_mem == 0 && cfv->genpool)
+ cfv->reserved_mem =
+ gen_pool_alloc(cfv->genpool,
+ cfv->reserved_size);
+
+ /* Open up the tx queues */
+ if (cfv->reserved_mem) {
+ cfv->watermark_tx =
+ virtqueue_get_vring_size(cfv->vq_tx);
+ netif_tx_wake_all_queues(cfv->ndev);
+ /* Buffers are recycled in cfv_netdev_tx, so
+ * disable notifications when queues are opened.
+ */
+ virtqueue_disable_cb(cfv->vq_tx);
+ ++cfv->stats.tx_flow_on;
+ } else {
+ /* if no memory reserve, wait for more free slots */
+ WARN_ON(cfv->watermark_tx >
+ virtqueue_get_vring_size(cfv->vq_tx));
+ cfv->watermark_tx +=
+ virtqueue_get_vring_size(cfv->vq_tx) / 4;
+ }
+ }
+}
+
+/* Allocate a SKB and copy packet data to it */
+static struct sk_buff *cfv_alloc_and_copy_skb(int *err,
+ struct cfv_info *cfv,
+ u8 *frm, u32 frm_len)
+{
+ struct sk_buff *skb;
+ u32 cfpkt_len, pad_len;
+
+ *err = 0;
+ /* Verify that packet size with down-link header and mtu size */
+ if (frm_len > cfv->mru || frm_len <= cfv->rx_hr + cfv->rx_tr) {
+ netdev_err(cfv->ndev,
+ "Invalid frmlen:%u mtu:%u hr:%d tr:%d\n",
+ frm_len, cfv->mru, cfv->rx_hr,
+ cfv->rx_tr);
+ *err = -EPROTO;
+ return NULL;
+ }
+
+ cfpkt_len = frm_len - (cfv->rx_hr + cfv->rx_tr);
+ pad_len = (unsigned long)(frm + cfv->rx_hr) & (IP_HDR_ALIGN - 1);
+
+ skb = netdev_alloc_skb(cfv->ndev, frm_len + pad_len);
+ if (!skb) {
+ *err = -ENOMEM;
+ return NULL;
+ }
+
+ skb_reserve(skb, cfv->rx_hr + pad_len);
+
+ skb_put_data(skb, frm + cfv->rx_hr, cfpkt_len);
+ return skb;
+}
+
+/* Get packets from the host vring */
+static int cfv_rx_poll(struct napi_struct *napi, int quota)
+{
+ struct cfv_info *cfv = container_of(napi, struct cfv_info, napi);
+ int rxcnt = 0;
+ int err = 0;
+ void *buf;
+ struct sk_buff *skb;
+ struct vringh_kiov *riov = &cfv->ctx.riov;
+ unsigned int skb_len;
+
+ do {
+ skb = NULL;
+
+ /* Put the previous iovec back on the used ring and
+ * fetch a new iovec if we have processed all elements.
+ */
+ if (riov->i == riov->used) {
+ if (cfv->ctx.head != USHRT_MAX) {
+ vringh_complete_kern(cfv->vr_rx,
+ cfv->ctx.head,
+ 0);
+ cfv->ctx.head = USHRT_MAX;
+ }
+
+ err = vringh_getdesc_kern(
+ cfv->vr_rx,
+ riov,
+ NULL,
+ &cfv->ctx.head,
+ GFP_ATOMIC);
+
+ if (err <= 0)
+ goto exit;
+ }
+
+ buf = phys_to_virt((unsigned long) riov->iov[riov->i].iov_base);
+ /* TODO: Add check on valid buffer address */
+
+ skb = cfv_alloc_and_copy_skb(&err, cfv, buf,
+ riov->iov[riov->i].iov_len);
+ if (unlikely(err))
+ goto exit;
+
+ /* Push received packet up the stack. */
+ skb_len = skb->len;
+ skb->protocol = htons(ETH_P_CAIF);
+ skb_reset_mac_header(skb);
+ skb->dev = cfv->ndev;
+ err = netif_receive_skb(skb);
+ if (unlikely(err)) {
+ ++cfv->ndev->stats.rx_dropped;
+ } else {
+ ++cfv->ndev->stats.rx_packets;
+ cfv->ndev->stats.rx_bytes += skb_len;
+ }
+
+ ++riov->i;
+ ++rxcnt;
+ } while (rxcnt < quota);
+
+ ++cfv->stats.rx_napi_resched;
+ goto out;
+
+exit:
+ switch (err) {
+ case 0:
+ ++cfv->stats.rx_napi_complete;
+
+ /* Really out of packets? (stolen from virtio_net)*/
+ napi_complete(napi);
+ if (unlikely(!vringh_notify_enable_kern(cfv->vr_rx)) &&
+ napi_schedule_prep(napi)) {
+ vringh_notify_disable_kern(cfv->vr_rx);
+ __napi_schedule(napi);
+ }
+ break;
+
+ case -ENOMEM:
+ ++cfv->stats.rx_nomem;
+ dev_kfree_skb(skb);
+ /* Stop NAPI poll on OOM, we hope to be polled later */
+ napi_complete(napi);
+ vringh_notify_enable_kern(cfv->vr_rx);
+ break;
+
+ default:
+ /* We're doomed, any modem fault is fatal */
+ netdev_warn(cfv->ndev, "Bad ring, disable device\n");
+ cfv->ndev->stats.rx_dropped = riov->used - riov->i;
+ napi_complete(napi);
+ vringh_notify_disable_kern(cfv->vr_rx);
+ netif_carrier_off(cfv->ndev);
+ break;
+ }
+out:
+ if (rxcnt && vringh_need_notify_kern(cfv->vr_rx) > 0)
+ vringh_notify(cfv->vr_rx);
+ return rxcnt;
+}
+
+static void cfv_recv(struct virtio_device *vdev, struct vringh *vr_rx)
+{
+ struct cfv_info *cfv = vdev->priv;
+
+ ++cfv->stats.rx_kicks;
+ vringh_notify_disable_kern(cfv->vr_rx);
+ napi_schedule(&cfv->napi);
+}
+
+static void cfv_destroy_genpool(struct cfv_info *cfv)
+{
+ if (cfv->alloc_addr)
+ dma_free_coherent(cfv->vdev->dev.parent->parent,
+ cfv->allocsz, cfv->alloc_addr,
+ cfv->alloc_dma);
+
+ if (!cfv->genpool)
+ return;
+ gen_pool_free(cfv->genpool, cfv->reserved_mem,
+ cfv->reserved_size);
+ gen_pool_destroy(cfv->genpool);
+ cfv->genpool = NULL;
+}
+
+static int cfv_create_genpool(struct cfv_info *cfv)
+{
+ int err;
+
+ /* dma_alloc can only allocate whole pages, and we need a more
+ * fine graned allocation so we use genpool. We ask for space needed
+ * by IP and a full ring. If the dma allcoation fails we retry with a
+ * smaller allocation size.
+ */
+ err = -ENOMEM;
+ cfv->allocsz = (virtqueue_get_vring_size(cfv->vq_tx) *
+ (ETH_DATA_LEN + cfv->tx_hr + cfv->tx_tr) * 11)/10;
+ if (cfv->allocsz <= (num_possible_cpus() + 1) * cfv->ndev->mtu)
+ return -EINVAL;
+
+ for (;;) {
+ if (cfv->allocsz <= num_possible_cpus() * cfv->ndev->mtu) {
+ netdev_info(cfv->ndev, "Not enough device memory\n");
+ return -ENOMEM;
+ }
+
+ cfv->alloc_addr = dma_alloc_coherent(
+ cfv->vdev->dev.parent->parent,
+ cfv->allocsz, &cfv->alloc_dma,
+ GFP_ATOMIC);
+ if (cfv->alloc_addr)
+ break;
+
+ cfv->allocsz = (cfv->allocsz * 3) >> 2;
+ }
+
+ netdev_dbg(cfv->ndev, "Allocated %zd bytes from dma-memory\n",
+ cfv->allocsz);
+
+ /* Allocate on 128 bytes boundaries (1 << 7)*/
+ cfv->genpool = gen_pool_create(7, -1);
+ if (!cfv->genpool)
+ goto err;
+
+ err = gen_pool_add_virt(cfv->genpool, (unsigned long)cfv->alloc_addr,
+ (phys_addr_t)virt_to_phys(cfv->alloc_addr),
+ cfv->allocsz, -1);
+ if (err)
+ goto err;
+
+ /* Reserve some memory for low memory situations. If we hit the roof
+ * in the memory pool, we stop TX flow and release the reserve.
+ */
+ cfv->reserved_size = num_possible_cpus() * cfv->ndev->mtu;
+ cfv->reserved_mem = gen_pool_alloc(cfv->genpool,
+ cfv->reserved_size);
+ if (!cfv->reserved_mem) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+ cfv->watermark_tx = virtqueue_get_vring_size(cfv->vq_tx);
+ return 0;
+err:
+ cfv_destroy_genpool(cfv);
+ return err;
+}
+
+/* Enable the CAIF interface and allocate the memory-pool */
+static int cfv_netdev_open(struct net_device *netdev)
+{
+ struct cfv_info *cfv = netdev_priv(netdev);
+
+ if (cfv_create_genpool(cfv))
+ return -ENOMEM;
+
+ netif_carrier_on(netdev);
+ napi_enable(&cfv->napi);
+
+ /* Schedule NAPI to read any pending packets */
+ napi_schedule(&cfv->napi);
+ return 0;
+}
+
+/* Disable the CAIF interface and free the memory-pool */
+static int cfv_netdev_close(struct net_device *netdev)
+{
+ struct cfv_info *cfv = netdev_priv(netdev);
+ unsigned long flags;
+ struct buf_info *buf_info;
+
+ /* Disable interrupts, queues and NAPI polling */
+ netif_carrier_off(netdev);
+ virtqueue_disable_cb(cfv->vq_tx);
+ vringh_notify_disable_kern(cfv->vr_rx);
+ napi_disable(&cfv->napi);
+
+ /* Release any TX buffers on both used and available rings */
+ cfv_release_used_buf(cfv->vq_tx);
+ spin_lock_irqsave(&cfv->tx_lock, flags);
+ while ((buf_info = virtqueue_detach_unused_buf(cfv->vq_tx)))
+ free_buf_info(cfv, buf_info);
+ spin_unlock_irqrestore(&cfv->tx_lock, flags);
+
+ /* Release all dma allocated memory and destroy the pool */
+ cfv_destroy_genpool(cfv);
+ return 0;
+}
+
+/* Allocate a buffer in dma-memory and copy skb to it */
+static struct buf_info *cfv_alloc_and_copy_to_shm(struct cfv_info *cfv,
+ struct sk_buff *skb,
+ struct scatterlist *sg)
+{
+ struct caif_payload_info *info = (void *)&skb->cb;
+ struct buf_info *buf_info = NULL;
+ u8 pad_len, hdr_ofs;
+
+ if (!cfv->genpool)
+ goto err;
+
+ if (unlikely(cfv->tx_hr + skb->len + cfv->tx_tr > cfv->mtu)) {
+ netdev_warn(cfv->ndev, "Invalid packet len (%d > %d)\n",
+ cfv->tx_hr + skb->len + cfv->tx_tr, cfv->mtu);
+ goto err;
+ }
+
+ buf_info = kmalloc(sizeof(struct buf_info), GFP_ATOMIC);
+ if (unlikely(!buf_info))
+ goto err;
+
+ /* Make the IP header aligned in the buffer */
+ hdr_ofs = cfv->tx_hr + info->hdr_len;
+ pad_len = hdr_ofs & (IP_HDR_ALIGN - 1);
+ buf_info->size = cfv->tx_hr + skb->len + cfv->tx_tr + pad_len;
+
+ /* allocate dma memory buffer */
+ buf_info->vaddr = (void *)gen_pool_alloc(cfv->genpool, buf_info->size);
+ if (unlikely(!buf_info->vaddr))
+ goto err;
+
+ /* copy skbuf contents to send buffer */
+ skb_copy_bits(skb, 0, buf_info->vaddr + cfv->tx_hr + pad_len, skb->len);
+ sg_init_one(sg, buf_info->vaddr + pad_len,
+ skb->len + cfv->tx_hr + cfv->rx_hr);
+
+ return buf_info;
+err:
+ kfree(buf_info);
+ return NULL;
+}
+
+/* Put the CAIF packet on the virtio ring and kick the receiver */
+static netdev_tx_t cfv_netdev_tx(struct sk_buff *skb, struct net_device *netdev)
+{
+ struct cfv_info *cfv = netdev_priv(netdev);
+ struct buf_info *buf_info;
+ struct scatterlist sg;
+ unsigned long flags;
+ bool flow_off = false;
+ int ret;
+
+ /* garbage collect released buffers */
+ cfv_release_used_buf(cfv->vq_tx);
+ spin_lock_irqsave(&cfv->tx_lock, flags);
+
+ /* Flow-off check takes into account number of cpus to make sure
+ * virtqueue will not be overfilled in any possible smp conditions.
+ *
+ * Flow-on is triggered when sufficient buffers are freed
+ */
+ if (unlikely(cfv->vq_tx->num_free <= num_present_cpus())) {
+ flow_off = true;
+ cfv->stats.tx_full_ring++;
+ }
+
+ /* If we run out of memory, we release the memory reserve and retry
+ * allocation.
+ */
+ buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg);
+ if (unlikely(!buf_info)) {
+ cfv->stats.tx_no_mem++;
+ flow_off = true;
+
+ if (cfv->reserved_mem && cfv->genpool) {
+ gen_pool_free(cfv->genpool, cfv->reserved_mem,
+ cfv->reserved_size);
+ cfv->reserved_mem = 0;
+ buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg);
+ }
+ }
+
+ if (unlikely(flow_off)) {
+ /* Turn flow on when a 1/4 of the descriptors are released */
+ cfv->watermark_tx = virtqueue_get_vring_size(cfv->vq_tx) / 4;
+ /* Enable notifications of recycled TX buffers */
+ virtqueue_enable_cb(cfv->vq_tx);
+ netif_tx_stop_all_queues(netdev);
+ }
+
+ if (unlikely(!buf_info)) {
+ /* If the memory reserve does it's job, this shouldn't happen */
+ netdev_warn(cfv->ndev, "Out of gen_pool memory\n");
+ goto err;
+ }
+
+ ret = virtqueue_add_outbuf(cfv->vq_tx, &sg, 1, buf_info, GFP_ATOMIC);
+ if (unlikely((ret < 0))) {
+ /* If flow control works, this shouldn't happen */
+ netdev_warn(cfv->ndev, "Failed adding buffer to TX vring:%d\n",
+ ret);
+ goto err;
+ }
+
+ /* update netdev statistics */
+ cfv->ndev->stats.tx_packets++;
+ cfv->ndev->stats.tx_bytes += skb->len;
+ spin_unlock_irqrestore(&cfv->tx_lock, flags);
+
+ /* tell the remote processor it has a pending message to read */
+ virtqueue_kick(cfv->vq_tx);
+
+ dev_kfree_skb(skb);
+ return NETDEV_TX_OK;
+err:
+ spin_unlock_irqrestore(&cfv->tx_lock, flags);
+ cfv->ndev->stats.tx_dropped++;
+ free_buf_info(cfv, buf_info);
+ dev_kfree_skb(skb);
+ return NETDEV_TX_OK;
+}
+
+static void cfv_tx_release_tasklet(struct tasklet_struct *t)
+{
+ struct cfv_info *cfv = from_tasklet(cfv, t, tx_release_tasklet);
+ cfv_release_used_buf(cfv->vq_tx);
+}
+
+static const struct net_device_ops cfv_netdev_ops = {
+ .ndo_open = cfv_netdev_open,
+ .ndo_stop = cfv_netdev_close,
+ .ndo_start_xmit = cfv_netdev_tx,
+};
+
+static void cfv_netdev_setup(struct net_device *netdev)
+{
+ netdev->netdev_ops = &cfv_netdev_ops;
+ netdev->type = ARPHRD_CAIF;
+ netdev->tx_queue_len = 100;
+ netdev->flags = IFF_POINTOPOINT | IFF_NOARP;
+ netdev->mtu = CFV_DEF_MTU_SIZE;
+ netdev->needs_free_netdev = true;
+}
+
+/* Create debugfs counters for the device */
+static inline void debugfs_init(struct cfv_info *cfv)
+{
+ cfv->debugfs = debugfs_create_dir(netdev_name(cfv->ndev), NULL);
+
+ debugfs_create_u32("rx-napi-complete", 0400, cfv->debugfs,
+ &cfv->stats.rx_napi_complete);
+ debugfs_create_u32("rx-napi-resched", 0400, cfv->debugfs,
+ &cfv->stats.rx_napi_resched);
+ debugfs_create_u32("rx-nomem", 0400, cfv->debugfs,
+ &cfv->stats.rx_nomem);
+ debugfs_create_u32("rx-kicks", 0400, cfv->debugfs,
+ &cfv->stats.rx_kicks);
+ debugfs_create_u32("tx-full-ring", 0400, cfv->debugfs,
+ &cfv->stats.tx_full_ring);
+ debugfs_create_u32("tx-no-mem", 0400, cfv->debugfs,
+ &cfv->stats.tx_no_mem);
+ debugfs_create_u32("tx-kicks", 0400, cfv->debugfs,
+ &cfv->stats.tx_kicks);
+ debugfs_create_u32("tx-flow-on", 0400, cfv->debugfs,
+ &cfv->stats.tx_flow_on);
+}
+
+/* Setup CAIF for the a virtio device */
+static int cfv_probe(struct virtio_device *vdev)
+{
+ vq_callback_t *vq_cbs = cfv_release_cb;
+ vrh_callback_t *vrh_cbs = cfv_recv;
+ const char *names = "output";
+ const char *cfv_netdev_name = "cfvrt";
+ struct net_device *netdev;
+ struct cfv_info *cfv;
+ int err;
+
+ netdev = alloc_netdev(sizeof(struct cfv_info), cfv_netdev_name,
+ NET_NAME_UNKNOWN, cfv_netdev_setup);
+ if (!netdev)
+ return -ENOMEM;
+
+ cfv = netdev_priv(netdev);
+ cfv->vdev = vdev;
+ cfv->ndev = netdev;
+
+ spin_lock_init(&cfv->tx_lock);
+
+ /* Get the RX virtio ring. This is a "host side vring". */
+ err = -ENODEV;
+ if (!vdev->vringh_config || !vdev->vringh_config->find_vrhs)
+ goto err;
+
+ err = vdev->vringh_config->find_vrhs(vdev, 1, &cfv->vr_rx, &vrh_cbs);
+ if (err)
+ goto err;
+
+ /* Get the TX virtio ring. This is a "guest side vring". */
+ err = virtio_find_vqs(vdev, 1, &cfv->vq_tx, &vq_cbs, &names, NULL);
+ if (err)
+ goto err;
+
+ /* Get the CAIF configuration from virtio config space, if available */
+ if (vdev->config->get) {
+ virtio_cread(vdev, struct virtio_caif_transf_config, headroom,
+ &cfv->tx_hr);
+ virtio_cread(vdev, struct virtio_caif_transf_config, headroom,
+ &cfv->rx_hr);
+ virtio_cread(vdev, struct virtio_caif_transf_config, tailroom,
+ &cfv->tx_tr);
+ virtio_cread(vdev, struct virtio_caif_transf_config, tailroom,
+ &cfv->rx_tr);
+ virtio_cread(vdev, struct virtio_caif_transf_config, mtu,
+ &cfv->mtu);
+ virtio_cread(vdev, struct virtio_caif_transf_config, mtu,
+ &cfv->mru);
+ } else {
+ cfv->tx_hr = CFV_DEF_HEADROOM;
+ cfv->rx_hr = CFV_DEF_HEADROOM;
+ cfv->tx_tr = CFV_DEF_TAILROOM;
+ cfv->rx_tr = CFV_DEF_TAILROOM;
+ cfv->mtu = CFV_DEF_MTU_SIZE;
+ cfv->mru = CFV_DEF_MTU_SIZE;
+ }
+
+ netdev->needed_headroom = cfv->tx_hr;
+ netdev->needed_tailroom = cfv->tx_tr;
+
+ /* Disable buffer release interrupts unless we have stopped TX queues */
+ virtqueue_disable_cb(cfv->vq_tx);
+
+ netdev->mtu = cfv->mtu - cfv->tx_tr;
+ vdev->priv = cfv;
+
+ /* Initialize NAPI poll context data */
+ vringh_kiov_init(&cfv->ctx.riov, NULL, 0);
+ cfv->ctx.head = USHRT_MAX;
+ netif_napi_add_weight(netdev, &cfv->napi, cfv_rx_poll,
+ CFV_DEFAULT_QUOTA);
+
+ tasklet_setup(&cfv->tx_release_tasklet, cfv_tx_release_tasklet);
+
+ /* Carrier is off until netdevice is opened */
+ netif_carrier_off(netdev);
+
+ /* serialize netdev register + virtio_device_ready() with ndo_open() */
+ rtnl_lock();
+
+ /* register Netdev */
+ err = register_netdevice(netdev);
+ if (err) {
+ rtnl_unlock();
+ dev_err(&vdev->dev, "Unable to register netdev (%d)\n", err);
+ goto err;
+ }
+
+ virtio_device_ready(vdev);
+
+ rtnl_unlock();
+
+ debugfs_init(cfv);
+
+ return 0;
+err:
+ netdev_warn(cfv->ndev, "CAIF Virtio probe failed:%d\n", err);
+
+ if (cfv->vr_rx)
+ vdev->vringh_config->del_vrhs(cfv->vdev);
+ if (cfv->vdev)
+ vdev->config->del_vqs(cfv->vdev);
+ free_netdev(netdev);
+ return err;
+}
+
+static void cfv_remove(struct virtio_device *vdev)
+{
+ struct cfv_info *cfv = vdev->priv;
+
+ rtnl_lock();
+ dev_close(cfv->ndev);
+ rtnl_unlock();
+
+ tasklet_kill(&cfv->tx_release_tasklet);
+ debugfs_remove_recursive(cfv->debugfs);
+
+ vringh_kiov_cleanup(&cfv->ctx.riov);
+ virtio_reset_device(vdev);
+ vdev->vringh_config->del_vrhs(cfv->vdev);
+ cfv->vr_rx = NULL;
+ vdev->config->del_vqs(cfv->vdev);
+ unregister_netdev(cfv->ndev);
+}
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_CAIF, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static unsigned int features[] = {
+};
+
+static struct virtio_driver caif_virtio_driver = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = cfv_probe,
+ .remove = cfv_remove,
+};
+
+module_virtio_driver(caif_virtio_driver);
+MODULE_DEVICE_TABLE(virtio, id_table);