modem: Add M6718 IPC SPI driver net interface

Adds the net device interface from the modem to userspace.

ST-Ericsson ID: 369397
ST-Ericsson FOSS-OUT ID: STETL-FOSS-OUT-12224
ST-Ericsson Linux next: NA

Change-Id: Ib1cafdc1558305d808870b0fdafa8e7029ec5a6b
Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/36494
Reviewed-by: QATOOLS
Reviewed-by: QABUILD
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

4 files changed, 437 insertions, 2 deletions

diff --git a/drivers/modem/m6718_spi/modem_driver.c b/drivers/modem/m6718_spi/modem_driver.c
index d85e6943c23..623a9191d27 100644
--- a/drivers/modem/m6718_spi/modem_driver.c
+++ b/drivers/modem/m6718_spi/modem_driver.c
@@ -13,9 +13,15 @@
 #include <linux/spi/spi.h>
 #include <linux/modem/modem_client.h>
 #include <linux/modem/m6718_spi/modem_driver.h>
+#include <linux/modem/m6718_spi/modem_net.h>
 #include <linux/modem/m6718_spi/modem_char.h>
 #include "modem_protocol.h"
 
+#ifdef CONFIG_PHONET
+static void phonet_rcv_tasklet_func(unsigned long);
+static struct tasklet_struct phonet_rcv_tasklet;
+#endif
+
 static struct modem_spi_dev modem_driver_data = {
 	.dev = NULL,
 	.ndev = NULL,
@@ -37,6 +43,10 @@ static struct modem_spi_dev modem_driver_data = {
  *
  * Special handling is given to slave-loopback channels where the data is simply
  * sent back to the modem on the same channel.
+ *
+ * Special handling is given to the ISI channel when PHONET is enabled - the
+ * phonet tasklet is scheduled in order to pump the received data through the
+ * net device interface.
  */
 int modem_m6718_spi_receive(struct spi_device *sdev, u8 channel,
 	u32 len, void *data)
@@ -95,10 +105,37 @@ int modem_m6718_spi_receive(struct spi_device *sdev, u8 channel,
 		dev_err(&sdev->dev, "failed to queue frame!");
 		return ret;
 	}
+
+#ifdef CONFIG_PHONET
+	if (channel == MODEM_M6718_SPI_CHN_ISI &&
+		modem_driver_data.netdev_flag_up)
+		tasklet_schedule(&phonet_rcv_tasklet);
+#endif
 	return ret;
 }
 EXPORT_SYMBOL_GPL(modem_m6718_spi_receive);
 
+static void phonet_rcv_tasklet_func(unsigned long unused)
+{
+	ssize_t result;
+
+	dev_dbg(modem_driver_data.dev, "receiving frames for phonet\n");
+	/* continue receiving while there are frames in the queue */
+	for (;;) {
+		result = modem_net_receive(modem_driver_data.ndev);
+		if (result == 0) {
+			dev_dbg(modem_driver_data.dev,
+				"queue is empty, finished receiving\n");
+			break;
+		}
+		if (result < 0) {
+			dev_err(modem_driver_data.dev,
+				"failed to receive frame from queue!\n");
+			break;
+		}
+	}
+}
+
 static int spi_probe(struct spi_device *sdev)
 {
 	int result = 0;
@@ -133,9 +170,22 @@ static int spi_probe(struct spi_device *sdev)
 				"failed to initialise char interface\n");
 			goto rollback_modem_get;
 		}
+
+		result = modem_net_init(&modem_driver_data);
+		if (result < 0) {
+			dev_err(&sdev->dev,
+				"failed to initialse net interface\n");
+			goto rollback_isa_init;
+		}
+
+#ifdef CONFIG_PHONET
+		tasklet_init(&phonet_rcv_tasklet, phonet_rcv_tasklet_func, 0);
+#endif
 	}
 	return result;
 
+rollback_isa_init:
+	modem_isa_exit(&modem_driver_data);
 rollback_modem_get:
 	modem_put(modem_driver_data.modem);
 rollback_protocol_init:
@@ -147,6 +197,7 @@ rollback:
 static int __exit spi_remove(struct spi_device *sdev)
 {
 	modem_protocol_exit();
+	modem_net_exit(&modem_driver_data);
 	modem_isa_exit(&modem_driver_data);
 	return 0;
 }
@@ -167,7 +218,7 @@ static int spi_suspend(struct spi_device *sdev, pm_message_t mesg)
 	busy = modem_protocol_is_busy(sdev);
 	dev_dbg(&sdev->dev, "suspend called, protocol busy:%d\n", busy);
 	if (!busy)
-		return 0;
+		return modem_net_suspend(modem_driver_data.ndev);
 	else
 		return -EBUSY;
 }
@@ -179,7 +230,7 @@ static int spi_suspend(struct spi_device *sdev, pm_message_t mesg)
 static int spi_resume(struct spi_device *sdev)
 {
 	dev_dbg(&sdev->dev, "resume called\n");
-	return 0;
+	return modem_net_resume(modem_driver_data.ndev);
 }
 #endif /* CONFIG_PM */
 
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index c1d8099a34e..a0f2484368b 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -73,4 +73,5 @@ obj-$(CONFIG_HYPERV_NET) += hyperv/
 
 ifdef CONFIG_PHONET
 obj-$(CONFIG_U8500_SHRM) += u8500_shrm.o
+obj-$(CONFIG_MODEM_M6718_SPI) += m6718_modem_net.o
 endif
diff --git a/drivers/net/m6718_modem_net.c b/drivers/net/m6718_modem_net.c
new file mode 100644
index 00000000000..f64a775560b
--- /dev/null
+++ b/drivers/net/m6718_modem_net.c
@@ -0,0 +1,333 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *   based on u8500_shrm.c
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * M6718 modem net device interface.
+ */
+#include <linux/if_ether.h>
+#include <linux/netdevice.h>
+#include <linux/phonet.h>
+#include <linux/if_phonet.h>
+#include <linux/if_arp.h>
+#include <net/sock.h>
+#include <net/phonet/phonet.h>
+#include <net/phonet/pep.h>
+#include <linux/modem/m6718_spi/modem_net.h>
+#include <linux/modem/m6718_spi/modem_driver.h>
+#include <linux/modem/m6718_spi/modem_char.h>
+#include <linux/ratelimit.h>
+
+
+/**
+ * modem_net_receive() - receive data and copy to user space buffer
+ * @dev: pointer to the network device structure
+ *
+ * Copy data from ISI queue to the user space buffer.
+ */
+int modem_net_receive(struct net_device *dev)
+{
+	struct sk_buff *skb;
+	struct isa_device_context *isadev;
+	struct message_queue *q;
+	u32 msgsize;
+	u32 size = 0;
+	struct modem_spi_net_dev *net_iface_priv =
+		(struct modem_spi_net_dev *)netdev_priv(dev);
+	struct modem_spi_dev *modem_spi_dev = net_iface_priv->modem_spi_dev;
+
+	isadev = &modem_spi_dev->isa_context->isadev[MODEM_M6718_SPI_CHN_ISI];
+	q = &isadev->dl_queue;
+
+	spin_lock_bh(&q->update_lock);
+	if (list_empty(&q->msg_list)) {
+		spin_unlock_bh(&q->update_lock);
+		dev_dbg(modem_spi_dev->dev, "empty queue!\n");
+		return 0;
+	}
+	spin_unlock_bh(&q->update_lock);
+
+	msgsize = modem_isa_msg_size(q);
+	if (msgsize <= 0)
+		return msgsize;
+
+	/*
+	 * The packet has been retrieved from the transmission
+	 * medium. Build an skb around it, so upper layers can handle it
+	 */
+	skb = dev_alloc_skb(msgsize);
+	if (!skb) {
+		pr_notice_ratelimited("isa rx: low on mem - packet dropped\n");
+		dev->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+
+	if ((q->readptr + msgsize) >= q->size) {
+		size = (q->size - q->readptr);
+		/* copy first part of msg */
+		skb_copy_to_linear_data(skb,
+			(u8 *)(q->fifo_base + q->readptr), size);
+		skb_put(skb, size);
+
+		/* copy second part of msg at the top of fifo */
+		skb_copy_to_linear_data_offset(skb, size,
+				(u8 *)(q->fifo_base), (msgsize - size));
+		skb_put(skb, msgsize - size);
+
+	} else {
+		skb_copy_to_linear_data(skb,
+				(u8 *)(q->fifo_base + q->readptr), msgsize);
+		skb_put(skb, msgsize);
+	}
+
+	spin_lock_bh(&q->update_lock);
+	modem_isa_unqueue_msg(q);
+	spin_unlock_bh(&q->update_lock);
+
+	skb_reset_mac_header(skb);
+	__skb_pull(skb, dev->hard_header_len);
+	/* write metadata and then pass to the receive level */
+	skb->dev = dev;
+	skb->protocol = htons(ETH_P_PHONET);
+	skb->priority = 0;
+	skb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
+	if (likely(netif_rx_ni(skb) == NET_RX_SUCCESS)) {
+		dev->stats.rx_packets++;
+		dev->stats.rx_bytes += msgsize;
+	} else {
+		dev->stats.rx_dropped++;
+	}
+
+	return msgsize;
+}
+EXPORT_SYMBOL_GPL(modem_net_receive);
+
+static int netdev_isa_open(struct net_device *dev)
+{
+	struct modem_spi_net_dev *net_iface_priv =
+			(struct modem_spi_net_dev *)netdev_priv(dev);
+	struct modem_spi_dev *modem_spi_dev = net_iface_priv->modem_spi_dev;
+
+	modem_spi_dev->netdev_flag_up = 1;
+	if (!netif_carrier_ok(dev))
+		netif_carrier_on(dev);
+	netif_wake_queue(dev);
+	return 0;
+}
+
+static int netdev_isa_close(struct net_device *dev)
+{
+	struct modem_spi_net_dev *net_iface_priv =
+			(struct modem_spi_net_dev *)netdev_priv(dev);
+	struct modem_spi_dev *modem_spi_dev = net_iface_priv->modem_spi_dev;
+
+	modem_spi_dev->netdev_flag_up = 0;
+	netif_stop_queue(dev);
+	netif_carrier_off(dev);
+	return 0;
+}
+
+static int netdev_isa_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	struct if_phonet_req *req = (struct if_phonet_req *)ifr;
+
+	switch (cmd) {
+	case SIOCPNGAUTOCONF:
+		req->ifr_phonet_autoconf.device = PN_DEV_HOST;
+		return 0;
+	}
+	return -ENOIOCTLCMD;
+}
+
+static struct net_device_stats *netdev_isa_stats(struct net_device *dev)
+{
+	return &dev->stats;
+}
+
+/**
+ * netdev_isa_write() - write through the net interface
+ * @skb:	pointer to the socket buffer
+ * @dev:	pointer to the network device structure
+ *
+ * Copies data(ISI message) from the user buffer to the kernel buffer and
+ * schedule transfer thread to transmit the message to the modem via FIFO.
+ */
+static netdev_tx_t netdev_isa_write(struct sk_buff *skb, struct net_device *dev)
+{
+	int err;
+	int retval = 0;
+	struct modem_spi_net_dev *net_iface_priv =
+			(struct modem_spi_net_dev *)netdev_priv(dev);
+	struct modem_spi_dev *modem_spi_dev = net_iface_priv->modem_spi_dev;
+
+	/*
+	 * FIXME:
+	 * U8500 modem requires that Pipe created/enabled Indication should
+	 * be sent from the port corresponding to GPRS socket.
+	 * Also, the U8500 modem does not implement Pipe controller
+	 * which takes care of port manipulations for GPRS traffic.
+	 *
+	 * Now, APE has GPRS socket and the socket for sending
+	 * Indication msgs bound to different ports.
+	 * Phonet stack does not allow an indication msg to be sent
+	 * from GPRS socket, since Phonet stack assumes the presence
+	 * of Pipe controller in modem.
+	 *
+	 * So, due to lack of Pipe controller implementation in the
+	 * U8500 modem, carry out the port manipulation related to
+	 * GPRS traffic here.
+	 * Ideally, it should be done either by Pipe controller in
+	 * modem OR some implementation of Pipe controller on APE side
+	 */
+	if (skb->data[RESOURCE_ID_INDEX] == PN_PIPE) {
+		if ((skb->data[MSG_ID_INDEX] == PNS_PIPE_CREATED_IND) ||
+			(skb->data[MSG_ID_INDEX] == PNS_PIPE_ENABLED_IND) ||
+			(skb->data[MSG_ID_INDEX] == PNS_PIPE_DISABLED_IND))
+			skb->data[SRC_OBJ_INDEX] = skb->data[PIPE_HDL_INDEX];
+	}
+
+	spin_lock_bh(&modem_spi_dev->isa_context->common_tx_lock);
+	err = modem_m6718_spi_send(modem_spi_dev, MODEM_M6718_SPI_CHN_ISI,
+		skb->len, skb->data);
+	if (!err) {
+		dev->stats.tx_packets++;
+		dev->stats.tx_bytes += skb->len;
+		retval = NETDEV_TX_OK;
+		dev_kfree_skb(skb);
+	} else {
+		dev->stats.tx_dropped++;
+		retval = NETDEV_TX_BUSY;
+	}
+	spin_unlock_bh(&modem_spi_dev->isa_context->common_tx_lock);
+
+	return retval;
+}
+
+static const struct net_device_ops modem_netdev_ops = {
+	.ndo_open = netdev_isa_open,
+	.ndo_stop = netdev_isa_close,
+	.ndo_do_ioctl = netdev_isa_ioctl,
+	.ndo_start_xmit = netdev_isa_write,
+	.ndo_get_stats = netdev_isa_stats,
+};
+
+static void net_device_init(struct net_device *dev)
+{
+	struct modem_spi_net_dev *net_iface_priv;
+
+	dev->netdev_ops = &modem_netdev_ops;
+	dev->header_ops = &phonet_header_ops;
+	dev->type = ARPHRD_PHONET;
+	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+	dev->mtu = PHONET_MAX_MTU;
+	dev->hard_header_len = MODEM_HLEN;
+	dev->addr_len = PHONET_ALEN;
+	dev->tx_queue_len = PN_TX_QUEUE_LEN;
+	dev->destructor = free_netdev;
+	dev->dev_addr[0] = PN_LINK_ADDR;
+	net_iface_priv = netdev_priv(dev);
+	memset(net_iface_priv, 0 , sizeof(struct modem_spi_net_dev));
+}
+
+int modem_net_init(struct modem_spi_dev *modem_spi_dev)
+{
+	struct net_device *nw_device;
+	struct modem_spi_net_dev *net_iface_priv;
+	int err;
+	/*
+	 * keep the same net device name as U8500 to allow userspace clients
+	 * to remain unchanged and use the same interfaces
+	 */
+	char *devname = "shrm%d";
+
+	/* allocate the net device */
+	nw_device = modem_spi_dev->ndev =
+		alloc_netdev(sizeof(struct modem_spi_net_dev),
+			devname, net_device_init);
+	if (nw_device == NULL) {
+		dev_err(modem_spi_dev->dev,
+			"failed to allocate modem net device\n");
+		return -ENOMEM;
+	}
+	err = register_netdev(modem_spi_dev->ndev);
+	if (err) {
+		dev_err(modem_spi_dev->dev,
+			"failed to register modem net device: error %d\n", err);
+		free_netdev(modem_spi_dev->ndev);
+		return -ENODEV;
+	}
+	dev_dbg(modem_spi_dev->dev, "registered modem net device\n");
+
+	net_iface_priv = (struct modem_spi_net_dev *)netdev_priv(nw_device);
+	net_iface_priv->modem_spi_dev = modem_spi_dev;
+	net_iface_priv->iface_num = 0;
+	return err;
+}
+EXPORT_SYMBOL_GPL(modem_net_init);
+
+int modem_net_stop(struct net_device *dev)
+{
+	netif_stop_queue(dev);
+	return 0;
+}
+
+int modem_net_restart(struct net_device *dev)
+{
+	if (netif_queue_stopped(dev))
+		netif_wake_queue(dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(modem_net_restart);
+
+int modem_net_start(struct net_device *dev)
+{
+	struct modem_spi_net_dev *net_iface_priv =
+			(struct modem_spi_net_dev *)netdev_priv(dev);
+	struct modem_spi_dev *modem_spi_dev = net_iface_priv->modem_spi_dev;
+
+	if (!netif_carrier_ok(dev))
+		netif_carrier_on(dev);
+	netif_start_queue(dev);
+	modem_spi_dev->netdev_flag_up = 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(modem_net_start);
+
+int modem_net_suspend(struct net_device *dev)
+{
+	if (netif_running(dev)) {
+		netif_stop_queue(dev);
+		netif_carrier_off(dev);
+	}
+	netif_device_detach(dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(modem_net_suspend);
+
+int modem_net_resume(struct net_device *dev)
+{
+	netif_device_attach(dev);
+	if (netif_running(dev)) {
+		netif_carrier_on(dev);
+		netif_wake_queue(dev);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(modem_net_resume);
+
+void modem_net_exit(struct modem_spi_dev *modem_spi_dev)
+{
+	if (modem_spi_dev && modem_spi_dev->ndev) {
+		unregister_netdev(modem_spi_dev->ndev);
+		modem_spi_dev->ndev = NULL;
+		dev_dbg(modem_spi_dev->dev, "removed modem net device\n");
+	}
+}
+EXPORT_SYMBOL_GPL(modem_net_exit);
+
+MODULE_AUTHOR("Chris Blair <chris.blair@stericsson.com>");
+MODULE_DESCRIPTION("M6718 modem IPC net device interface");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/modem/m6718_spi/modem_net.h b/include/linux/modem/m6718_spi/modem_net.h
new file mode 100644
index 00000000000..521103bf006
--- /dev/null
+++ b/include/linux/modem/m6718_spi/modem_net.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *   based on shrm_net.h
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Modem IPC net device interface header.
+ */
+#ifndef _MODEM_NET_H_
+#define _MODEM_NET_H_
+
+#include <linux/modem/m6718_spi/modem_driver.h>
+
+#define MODEM_HLEN		(1)
+#define PHONET_ALEN		(1)
+
+#define PN_PIPE			(0xD9)
+#define PN_DEV_HOST		(0x00)
+#define PN_LINK_ADDR		(0x26)
+#define PN_TX_QUEUE_LEN		(3)
+
+#define RESOURCE_ID_INDEX	(3)
+#define SRC_OBJ_INDEX		(7)
+#define MSG_ID_INDEX		(9)
+#define PIPE_HDL_INDEX		(10)
+#define NETLINK_MODEM		(20)
+
+/**
+ * struct modem_spi_net_dev - modem net interface device information
+ * @modem_spi_dev:	pointer to the modem spi device information structure
+ * @iface_num:		flag used to indicate the up/down of netdev
+ */
+struct modem_spi_net_dev {
+	struct modem_spi_dev *modem_spi_dev;
+	unsigned int iface_num;
+};
+
+int modem_net_init(struct modem_spi_dev *modem_spi_dev);
+void modem_net_exit(struct modem_spi_dev *modem_spi_dev);
+
+int modem_net_receive(struct net_device *dev);
+int modem_net_suspend(struct net_device *dev);
+int modem_net_resume(struct net_device *dev);
+int modem_net_start(struct net_device *dev);
+int modem_net_restart(struct net_device *dev);
+int modem_net_stop(struct net_device *dev);
+
+#endif /* _MODEM_NET_H_ */