--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author: Sjur Brendeland / sjur.brandeland@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/init.h>
+#include <linux/version.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<sjur.brandeland@stericsson.com>");
+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
+
+/*This list is protected by the rtnl lock. */
+static LIST_HEAD(ser_list);
+
+static int ser_loop;
+module_param(ser_loop, bool, S_IRUGO);
+MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
+
+static int ser_use_stx = 1;
+module_param(ser_use_stx, bool, S_IRUGO);
+MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
+
+static int ser_use_fcs = 1;
+
+module_param(ser_use_fcs, bool, S_IRUGO);
+MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
+
+static int ser_write_chunk = MAX_WRITE_CHUNK;
+module_param(ser_write_chunk, int, S_IRUGO);
+
+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;
+ char *tty_name;
+#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->stopped << 5 |
+ ser->tty->hw_stopped << 4 |
+ ser->tty->flow_stopped << 3 |
+ ser->tty->packet << 2 |
+ ser->tty->low_latency << 1 |
+ ser->tty->warned;
+}
+static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
+{
+ ser->debugfs_tty_dir =
+ debugfs_create_dir(tty->name, debugfsdir);
+ if (!IS_ERR(ser->debugfs_tty_dir)) {
+ debugfs_create_blob("last_tx_msg", S_IRUSR,
+ ser->debugfs_tty_dir,
+ &ser->tx_blob);
+
+ debugfs_create_blob("last_rx_msg", S_IRUSR,
+ ser->debugfs_tty_dir,
+ &ser->rx_blob);
+
+ debugfs_create_x32("ser_state", S_IRUSR,
+ ser->debugfs_tty_dir,
+ (u32 *)&ser->state);
+
+ debugfs_create_x8("tty_status", S_IRUSR,
+ 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,
+ char *flags, int count)
+{
+ struct sk_buff *skb = NULL;
+ struct ser_device *ser;
+ int ret;
+ u8 *p;
+ 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);
+ BUG_ON(skb == NULL);
+ p = skb_put(skb, count);
+ memcpy(p, data, count);
+
+ skb->protocol = htons(ETH_P_CAIF);
+ skb_reset_mac_header(skb);
+ skb->dev = ser->dev;
+ debugfs_rx(ser, data, count);
+ /* Push received packet up the stack. */
+ ret = netif_rx_ni(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);
+ BUG_ON(tmp != skb);
+ if (in_interrupt())
+ dev_kfree_skb_irq(skb);
+ else
+ kfree_skb(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 int caif_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct ser_device *ser;
+ BUG_ON(dev == NULL);
+ 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);
+ BUG_ON(ser->tty != tty);
+ handle_tx(ser);
+}
+
+
+static int ldisc_open(struct tty_struct *tty)
+{
+ struct ser_device *ser;
+ struct net_device *dev;
+ char name[64];
+ int result;
+
+ sprintf(name, "cf%s", tty->name);
+ dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
+ ser = netdev_priv(dev);
+ ser->tty = 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) {
+ rtnl_unlock();
+ free_netdev(dev);
+ return -ENODEV;
+ }
+
+ list_add(&ser->node, &ser_list);
+ 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;
+ /* Remove may be called inside or outside of rtnl_lock */
+ int islocked = rtnl_is_locked();
+ if (!islocked)
+ rtnl_lock();
+ /* device is freed automagically by net-sysfs */
+ dev_close(ser->dev);
+ unregister_netdevice(ser->dev);
+ list_del(&ser->node);
+ debugfs_deinit(ser);
+ if (!islocked)
+ rtnl_unlock();
+}
+
+/* The line discipline structure. */
+static struct tty_ldisc_ops caif_ldisc = {
+ .owner = THIS_MODULE,
+ .magic = TTY_LDISC_MAGIC,
+ .name = "n_caif",
+ .open = ldisc_open,
+ .close = ldisc_close,
+ .receive_buf = ldisc_receive,
+ .write_wakeup = ldisc_tx_wakeup
+};
+
+static int register_ldisc(void)
+{
+ int result;
+ result = tty_register_ldisc(N_CAIF, &caif_ldisc);
+ if (result < 0) {
+ pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
+ result);
+ return result;
+ }
+ return result;
+}
+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->hard_header_len = CAIF_NEEDED_HEADROOM;
+ dev->tx_queue_len = 0;
+ dev->destructor = free_netdev;
+ 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)
+{
+ struct ser_device *ser;
+ ser = netdev_priv(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 = register_ldisc();
+ debugfsdir = debugfs_create_dir("caif_serial", NULL);
+ return ret;
+}
+
+static void __exit caif_ser_exit(void)
+{
+ struct ser_device *ser = NULL;
+ struct list_head *node;
+ struct list_head *_tmp;
+ list_for_each_safe(node, _tmp, &ser_list) {
+ ser = list_entry(node, struct ser_device, node);
+ dev_close(ser->dev);
+ unregister_netdevice(ser->dev);
+ list_del(node);
+ }
+ tty_unregister_ldisc(N_CAIF);
+ debugfs_remove_recursive(debugfsdir);
+}
+
+module_init(caif_ser_init);
+module_exit(caif_ser_exit);
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff