u_ctrl_hsuart: Add HSUART control module

RMNET driver can use this hsuart control module
for sending and receiving the control information.

CRs-Fixed: 355162
Change-Id: Ib7735ae0492ca80b0d41d5abb24aab569dfea86d
Signed-off-by: Chiranjeevi Velempati <cvelempa@codeaurora.org>
diff --git a/drivers/usb/gadget/u_ctrl_hsuart.c b/drivers/usb/gadget/u_ctrl_hsuart.c
new file mode 100644
index 0000000..7102d81
--- /dev/null
+++ b/drivers/usb/gadget/u_ctrl_hsuart.c
@@ -0,0 +1,576 @@
+/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/termios.h>
+#include <linux/debugfs.h>
+#include <linux/smux.h>
+
+#include <mach/usb_gadget_xport.h>
+
+#define CH_OPENED 0
+#define CH_READY 1
+
+static unsigned int num_ctrl_ports;
+
+static const char *ghsuart_ctrl_names[] = {
+	"SMUX_RMNET_CTL_HSUART"
+};
+
+struct ghsuart_ctrl_port {
+	/* port */
+	unsigned port_num;
+	/* gadget */
+	enum gadget_type gtype;
+	spinlock_t port_lock;
+	void *port_usb;
+	/* work queue*/
+	struct workqueue_struct	*wq;
+	struct work_struct connect_w;
+	struct work_struct disconnect_w;
+	/*ctrl pkt response cb*/
+	int (*send_cpkt_response)(void *g, void *buf, size_t len);
+	void *ctxt;
+	unsigned int ch_id;
+	/* flow control bits */
+	unsigned long flags;
+	int (*send_pkt)(void *, void *, size_t actual);
+	/* Channel status */
+	unsigned long channel_sts;
+	/* control bits */
+	unsigned cbits_tomodem;
+	/* counters */
+	unsigned long to_modem;
+	unsigned long to_host;
+	unsigned long drp_cpkt_cnt;
+};
+
+static struct {
+	struct ghsuart_ctrl_port	*port;
+	struct platform_driver	pdrv;
+} ghsuart_ctrl_ports[NUM_HSUART_PORTS];
+
+static int ghsuart_ctrl_receive(void *dev, void *buf, size_t actual);
+
+static void smux_control_event(void *priv, int event_type, const void *metadata)
+{
+	struct grmnet		*gr = NULL;
+	struct ghsuart_ctrl_port	*port = priv;
+	void			*buf;
+	unsigned long		flags;
+	size_t			len;
+
+	switch (event_type) {
+	case SMUX_CONNECTED:
+		spin_lock_irqsave(&port->port_lock, flags);
+		if (!port->port_usb) {
+			spin_unlock_irqrestore(&port->port_lock, flags);
+			return;
+		}
+		spin_unlock_irqrestore(&port->port_lock, flags);
+		set_bit(CH_OPENED, &port->channel_sts);
+		if (port->gtype == USB_GADGET_RMNET) {
+			gr = port->port_usb;
+			if (gr && gr->connect)
+				gr->connect(gr);
+		}
+		break;
+	case SMUX_DISCONNECTED:
+		clear_bit(CH_OPENED, &port->channel_sts);
+		break;
+	case SMUX_READ_DONE:
+		len = ((struct smux_meta_read *)metadata)->len;
+		buf = ((struct smux_meta_read *)metadata)->buffer;
+		ghsuart_ctrl_receive(port, buf, len);
+		break;
+	case SMUX_READ_FAIL:
+		buf = ((struct smux_meta_read *)metadata)->buffer;
+		kfree(buf);
+		break;
+	case SMUX_WRITE_DONE:
+	case SMUX_WRITE_FAIL:
+		buf = ((struct smux_meta_write *)metadata)->buffer;
+		kfree(buf);
+		break;
+	case SMUX_LOW_WM_HIT:
+	case SMUX_HIGH_WM_HIT:
+	case SMUX_TIOCM_UPDATE:
+		break;
+	default:
+		pr_err("%s Event %d not supported\n", __func__, event_type);
+	};
+}
+
+static int rx_control_buffer(void *priv, void **pkt_priv, void **buffer,
+			int size)
+{
+	void *rx_buf;
+
+	rx_buf = kmalloc(size, GFP_KERNEL);
+	if (!rx_buf)
+		return -EAGAIN;
+	*buffer = rx_buf;
+	*pkt_priv = NULL;
+
+	return 0;
+}
+
+static int ghsuart_ctrl_receive(void *dev, void *buf, size_t actual)
+{
+	struct ghsuart_ctrl_port	*port = dev;
+	int retval = 0;
+
+	pr_debug_ratelimited("%s: read complete bytes read: %d\n",
+			__func__, actual);
+
+	/* send it to USB here */
+	if (port && port->send_cpkt_response) {
+		retval = port->send_cpkt_response(port->port_usb, buf, actual);
+		port->to_host++;
+	}
+	kfree(buf);
+	return retval;
+}
+
+static int
+ghsuart_send_cpkt_tomodem(u8 portno, void *buf, size_t len)
+{
+	void			*cbuf;
+	struct ghsuart_ctrl_port	*port;
+	int			ret;
+
+	if (portno >= num_ctrl_ports) {
+		pr_err("%s: Invalid portno#%d\n", __func__, portno);
+		return -ENODEV;
+	}
+
+	port = ghsuart_ctrl_ports[portno].port;
+	if (!port) {
+		pr_err("%s: port is null\n", __func__);
+		return -ENODEV;
+	}
+	/* drop cpkt if ch is not open */
+	if (!test_bit(CH_OPENED, &port->channel_sts)) {
+		port->drp_cpkt_cnt++;
+		return 0;
+	}
+	cbuf = kmalloc(len, GFP_ATOMIC);
+	if (!cbuf)
+		return -ENOMEM;
+
+	memcpy(cbuf, buf, len);
+
+	pr_debug("%s: ctrl_pkt:%d bytes\n", __func__, len);
+
+	ret = msm_smux_write(port->ch_id, port, (void *)cbuf, len);
+	if (ret < 0) {
+		pr_err_ratelimited("%s: write error:%d\n",
+				__func__, ret);
+		port->drp_cpkt_cnt++;
+		kfree(cbuf);
+		return ret;
+	}
+	port->to_modem++;
+
+	return 0;
+}
+
+static void
+ghsuart_send_cbits_tomodem(void *gptr, u8 portno, int cbits)
+{
+	struct ghsuart_ctrl_port	*port;
+
+	if (portno >= num_ctrl_ports || !gptr) {
+		pr_err("%s: Invalid portno#%d\n", __func__, portno);
+		return;
+	}
+
+	port = ghsuart_ctrl_ports[portno].port;
+	if (!port) {
+		pr_err("%s: port is null\n", __func__);
+		return;
+	}
+
+	if (cbits == port->cbits_tomodem)
+		return;
+
+	port->cbits_tomodem = cbits;
+
+	if (!test_bit(CH_OPENED, &port->channel_sts))
+		return;
+
+	pr_debug("%s: ctrl_tomodem:%d\n", __func__, cbits);
+	/* Send the control bits to the Modem */
+	msm_smux_tiocm_set(port->ch_id, cbits, ~cbits);
+}
+
+static void ghsuart_ctrl_connect_w(struct work_struct *w)
+{
+	struct ghsuart_ctrl_port	*port =
+			container_of(w, struct ghsuart_ctrl_port, connect_w);
+	int			retval;
+
+	if (!port || !test_bit(CH_READY, &port->channel_sts))
+		return;
+
+	pr_debug("%s: port:%p\n", __func__, port);
+
+	retval = msm_smux_open(port->ch_id, port->ctxt, smux_control_event,
+				rx_control_buffer);
+	if (retval < 0) {
+		pr_err(" %s smux_open failed\n", __func__);
+		return;
+	}
+
+}
+
+int ghsuart_ctrl_connect(void *gptr, int port_num)
+{
+	struct ghsuart_ctrl_port	*port;
+	struct grmnet		*gr;
+	unsigned long		flags;
+
+	pr_debug("%s: port#%d\n", __func__, port_num);
+
+	if (port_num > num_ctrl_ports || !gptr) {
+		pr_err("%s: invalid portno#%d\n", __func__, port_num);
+		return -ENODEV;
+	}
+
+	port = ghsuart_ctrl_ports[port_num].port;
+	if (!port) {
+		pr_err("%s: port is null\n", __func__);
+		return -ENODEV;
+	}
+
+	spin_lock_irqsave(&port->port_lock, flags);
+
+	gr = gptr;
+	port->send_cpkt_response = gr->send_cpkt_response;
+	gr->send_encap_cmd = ghsuart_send_cpkt_tomodem;
+	gr->notify_modem = ghsuart_send_cbits_tomodem;
+
+	port->port_usb = gptr;
+	port->to_host = 0;
+	port->to_modem = 0;
+	port->drp_cpkt_cnt = 0;
+	spin_unlock_irqrestore(&port->port_lock, flags);
+
+	if (test_bit(CH_READY, &port->channel_sts))
+		queue_work(port->wq, &port->connect_w);
+
+	return 0;
+}
+
+static void ghsuart_ctrl_disconnect_w(struct work_struct *w)
+{
+	struct ghsuart_ctrl_port	*port =
+			container_of(w, struct ghsuart_ctrl_port, disconnect_w);
+
+	if (!test_bit(CH_OPENED, &port->channel_sts))
+		return;
+
+	msm_smux_close(port->ch_id);
+	clear_bit(CH_OPENED, &port->channel_sts);
+}
+
+void ghsuart_ctrl_disconnect(void *gptr, int port_num)
+{
+	struct gctrl_port	*port;
+	struct grmnet		*gr = NULL;
+	unsigned long		flags;
+
+	pr_debug("%s: port#%d\n", __func__, port_num);
+
+	if (port_num > num_ctrl_ports) {
+		pr_err("%s: invalid portno#%d\n", __func__, port_num);
+		return;
+	}
+
+	port = gctrl_ports[port_num].port;
+
+	if (!gptr || !port) {
+		pr_err("%s: grmnet port is null\n", __func__);
+		return;
+	}
+
+	gr = gptr;
+
+	spin_lock_irqsave(&port->port_lock, flags);
+	gr->send_encap_cmd = 0;
+	gr->notify_modem = 0;
+	port->cbits_tomodem = 0;
+	port->port_usb = 0;
+	port->send_cpkt_response = 0;
+	spin_unlock_irqrestore(&port->port_lock, flags);
+
+	queue_work(port->wq, &port->disconnect_w);
+}
+
+static int ghsuart_ctrl_probe(struct platform_device *pdev)
+{
+	struct ghsuart_ctrl_port	*port;
+	unsigned long		flags;
+
+	pr_debug("%s: name:%s\n", __func__, pdev->name);
+
+	port = ghsuart_ctrl_ports[pdev->id].port;
+	set_bit(CH_READY, &port->channel_sts);
+
+	/* if usb is online, start read */
+	spin_lock_irqsave(&port->port_lock, flags);
+	if (port->port_usb)
+		queue_work(port->wq, &port->connect_w);
+	spin_unlock_irqrestore(&port->port_lock, flags);
+
+	return 0;
+}
+
+static int ghsuart_ctrl_remove(struct platform_device *pdev)
+{
+	struct ghsuart_ctrl_port	*port;
+	struct grmnet		*gr = NULL;
+	unsigned long		flags;
+
+	pr_debug("%s: name:%s\n", __func__, pdev->name);
+
+	port = ghsuart_ctrl_ports[pdev->id].port;
+
+	spin_lock_irqsave(&port->port_lock, flags);
+	if (!port->port_usb) {
+		spin_unlock_irqrestore(&port->port_lock, flags);
+		goto not_ready;
+	}
+
+	gr = port->port_usb;
+
+	spin_unlock_irqrestore(&port->port_lock, flags);
+
+	if (gr && gr->disconnect)
+		gr->disconnect(gr);
+
+	clear_bit(CH_OPENED, &port->channel_sts);
+not_ready:
+	clear_bit(CH_READY, &port->channel_sts);
+
+	return 0;
+}
+
+static void ghsuart_ctrl_port_free(int portno)
+{
+	struct ghsuart_ctrl_port	*port = ghsuart_ctrl_ports[portno].port;
+	struct platform_driver	*pdrv = &gctrl_ports[portno].pdrv;
+
+	destroy_workqueue(port->wq);
+	if (pdrv)
+		platform_driver_unregister(pdrv);
+	kfree(port);
+}
+
+static int ghsuart_ctrl_port_alloc(int portno, enum gadget_type gtype)
+{
+	struct ghsuart_ctrl_port	*port;
+	struct platform_driver	*pdrv;
+	int err;
+
+	port = kzalloc(sizeof(struct ghsuart_ctrl_port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	port->wq = create_singlethread_workqueue(ghsuart_ctrl_names[portno]);
+	if (!port->wq) {
+		pr_err("%s: Unable to create workqueue:%s\n",
+			__func__, ghsuart_ctrl_names[portno]);
+		kfree(port);
+		return -ENOMEM;
+	}
+
+	port->port_num = portno;
+	port->gtype = gtype;
+
+	spin_lock_init(&port->port_lock);
+
+	INIT_WORK(&port->connect_w, ghsuart_ctrl_connect_w);
+	INIT_WORK(&port->disconnect_w, ghsuart_ctrl_disconnect_w);
+
+	port->ch_id = SMUX_USB_RMNET_CTL_0;
+	port->ctxt = port;
+	port->send_pkt = ghsuart_ctrl_receive;
+	ghsuart_ctrl_ports[portno].port = port;
+
+	pdrv = &ghsuart_ctrl_ports[portno].pdrv;
+	pdrv->probe = ghsuart_ctrl_probe;
+	pdrv->remove = ghsuart_ctrl_remove;
+	pdrv->driver.name = ghsuart_ctrl_names[portno];
+	pdrv->driver.owner = THIS_MODULE;
+
+	err = platform_driver_register(pdrv);
+	if (unlikely(err < 0))
+		return err;
+	pr_debug("%s: port:%p portno:%d\n", __func__, port, portno);
+
+	return 0;
+}
+
+int ghsuart_ctrl_setup(unsigned int num_ports, enum gadget_type gtype)
+{
+	int	first_port_id = num_ctrl_ports;
+	int	total_num_ports = num_ports + num_ctrl_ports;
+	int	i;
+	int	ret = 0;
+
+	if (!num_ports || total_num_ports > NUM_HSUART_PORTS) {
+		pr_err("%s: Invalid num of ports count:%d\n",
+				__func__, num_ports);
+		return -EINVAL;
+	}
+
+	pr_debug("%s: requested ports:%d\n", __func__, num_ports);
+
+	for (i = first_port_id; i < (first_port_id + num_ports); i++) {
+
+		num_ctrl_ports++;
+		ret = ghsuart_ctrl_port_alloc(i, gtype);
+		if (ret) {
+			num_ctrl_ports--;
+			pr_err("%s: Unable to alloc port:%d\n", __func__, i);
+			goto free_ports;
+		}
+	}
+
+	return first_port_id;
+
+free_ports:
+	for (i = first_port_id; i < num_ctrl_ports; i++)
+		ghsuart_ctrl_port_free(i);
+		num_ctrl_ports = first_port_id;
+	return ret;
+}
+
+#define DEBUG_BUF_SIZE	1024
+static ssize_t ghsuart_ctrl_read_stats(struct file *file, char __user *ubuf,
+		size_t count, loff_t *ppos)
+{
+	struct ghsuart_ctrl_port	*port;
+	char			*buf;
+	unsigned long		flags;
+	int			ret;
+	int			i;
+	int			temp = 0;
+
+	buf = kzalloc(sizeof(char) * DEBUG_BUF_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	for (i = 0; i < num_ctrl_ports; i++) {
+		port = ghsuart_ctrl_ports[i].port;
+		if (!port)
+			continue;
+		spin_lock_irqsave(&port->port_lock, flags);
+
+		temp += scnprintf(buf + temp, DEBUG_BUF_SIZE - temp,
+				"#PORT:%d port: %p\n"
+				"to_usbhost:    %lu\n"
+				"to_modem:      %lu\n"
+				"cpkt_drp_cnt:  %lu\n"
+				"DTR:           %s\n",
+				i, port,
+				port->to_host, port->to_modem,
+				port->drp_cpkt_cnt,
+				port->cbits_tomodem ? "HIGH" : "LOW");
+
+		spin_unlock_irqrestore(&port->port_lock, flags);
+	}
+
+	ret = simple_read_from_buffer(ubuf, count, ppos, buf, temp);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t ghsuart_ctrl_reset_stats(struct file *file,
+	const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct ghsuart_ctrl_port	*port;
+	int			i;
+	unsigned long		flags;
+
+	for (i = 0; i < num_ctrl_ports; i++) {
+		port = ghsuart_ctrl_ports[i].port;
+		if (!port)
+			continue;
+
+		spin_lock_irqsave(&port->port_lock, flags);
+		port->to_host = 0;
+		port->to_modem = 0;
+		port->drp_cpkt_cnt = 0;
+		spin_unlock_irqrestore(&port->port_lock, flags);
+	}
+	return count;
+}
+
+static const struct file_operations ghsuart_ctrl_stats_ops = {
+	.read = ghsuart_ctrl_read_stats,
+	.write = ghsuart_ctrl_reset_stats,
+};
+
+static struct dentry	*ghsuart_ctrl_dent;
+static int ghsuart_ctrl_debugfs_init(void)
+{
+	struct dentry	*ghsuart_ctrl_dfile;
+
+	ghsuart_ctrl_dent = debugfs_create_dir("ghsuart_ctrl_xport", 0);
+	if (!ghsuart_ctrl_dent || IS_ERR(ghsuart_ctrl_dent))
+		return -ENODEV;
+
+	ghsuart_ctrl_dfile =
+		debugfs_create_file("status", S_IRUGO | S_IWUSR,
+				ghsuart_ctrl_dent, 0, &gctrl_stats_ops);
+	if (!ghsuart_ctrl_dfile || IS_ERR(ghsuart_ctrl_dfile)) {
+		debugfs_remove(ghsuart_ctrl_dent);
+		ghsuart_ctrl_dent = NULL;
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static void ghsuart_ctrl_debugfs_exit(void)
+{
+	debugfs_remove_recursive(ghsuart_ctrl_dent);
+}
+
+static int __init ghsuart_ctrl_init(void)
+{
+	int ret;
+
+	ret = ghsuart_ctrl_debugfs_init();
+	if (ret) {
+		pr_debug("mode debugfs file is not available\n");
+		return ret;
+	}
+	return 0;
+}
+module_init(ghsuart_ctrl_init);
+
+static void __exit ghsuart_ctrl_exit(void)
+{
+	ghsuart_ctrl_debugfs_exit();
+}
+module_exit(ghsuart_ctrl_exit);
+
+MODULE_DESCRIPTION("HSUART control xport for RmNet");
+MODULE_LICENSE("GPL v2");