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/*
* Atmel SAM Boot Assistant (SAM-BA) driver
*
* Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#define DRIVER_VERSION "v1.0"
#define DRIVER_AUTHOR "Johan Hovold <jhovold@gmail.com>"
#define DRIVER_DESC "Atmel SAM Boot Assistant (SAM-BA) driver"
#define SAMBA_VENDOR_ID 0x3eb
#define SAMBA_PRODUCT_ID 0x6124
static int debug;
static const struct usb_device_id id_table[] = {
/*
* NOTE: Only match the CDC Data interface.
*/
{ USB_DEVICE_AND_INTERFACE_INFO(SAMBA_VENDOR_ID, SAMBA_PRODUCT_ID,
USB_CLASS_CDC_DATA, 0, 0) },
{ }
};
MODULE_DEVICE_TABLE(usb, id_table);
static struct usb_driver samba_driver = {
.name = "sam-ba",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = id_table,
.no_dynamic_id = 1,
};
/*
* NOTE: The SAM-BA firmware cannot handle merged write requests so we cannot
* use the generic write implementation (which uses the port write fifo).
*/
static int samba_write(struct tty_struct *tty, struct usb_serial_port *port,
const unsigned char *buf, int count)
{
struct urb *urb;
unsigned long flags;
int result;
int i;
if (!count)
return 0;
count = min_t(int, count, port->bulk_out_size);
spin_lock_irqsave(&port->lock, flags);
if (!port->write_urbs_free) {
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
i = find_first_bit(&port->write_urbs_free,
ARRAY_SIZE(port->write_urbs));
__clear_bit(i, &port->write_urbs_free);
port->tx_bytes += count;
spin_unlock_irqrestore(&port->lock, flags);
urb = port->write_urbs[i];
memcpy(urb->transfer_buffer, buf, count);
urb->transfer_buffer_length = count;
usb_serial_debug_data(debug, &port->dev, __func__, count,
urb->transfer_buffer);
result = usb_submit_urb(urb, GFP_ATOMIC);
if (result) {
dev_err(&port->dev, "%s - error submitting urb: %d\n",
__func__, result);
spin_lock_irqsave(&port->lock, flags);
__set_bit(i, &port->write_urbs_free);
port->tx_bytes -= count;
spin_unlock_irqrestore(&port->lock, flags);
return result;
}
return count;
}
static int samba_write_room(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
unsigned long free;
int count;
int room;
spin_lock_irqsave(&port->lock, flags);
free = port->write_urbs_free;
spin_unlock_irqrestore(&port->lock, flags);
count = hweight_long(free);
room = count * port->bulk_out_size;
dbg("%s - returns %d", __func__, room);
return room;
}
static int samba_chars_in_buffer(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
int chars;
spin_lock_irqsave(&port->lock, flags);
chars = port->tx_bytes;
spin_unlock_irqrestore(&port->lock, flags);
dbg("%s - returns %d", __func__, chars);
return chars;
}
static void samba_write_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned long flags;
int i;
dbg("%s - port %d", __func__, port->number);
for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
if (port->write_urbs[i] == urb)
break;
}
spin_lock_irqsave(&port->lock, flags);
__set_bit(i, &port->write_urbs_free);
port->tx_bytes -= urb->transfer_buffer_length;
spin_unlock_irqrestore(&port->lock, flags);
if (urb->status)
dbg("%s - non-zero urb status: %d", __func__, urb->status);
usb_serial_port_softint(port);
}
static struct usb_serial_driver samba_device = {
.driver = {
.owner = THIS_MODULE,
.name = "sam-ba",
},
.usb_driver = &samba_driver,
.id_table = id_table,
.num_ports = 1,
.bulk_in_size = 512,
.bulk_out_size = 2048,
.write = samba_write,
.write_room = samba_write_room,
.chars_in_buffer = samba_chars_in_buffer,
.write_bulk_callback = samba_write_bulk_callback,
.throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle,
};
static int __init samba_init(void)
{
int retval;
retval = usb_serial_register(&samba_device);
if (retval)
return retval;
retval = usb_register(&samba_driver);
if (retval) {
usb_serial_deregister(&samba_device);
return retval;
}
printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ": "
DRIVER_DESC "\n");
return 0;
}
static void __exit samba_exit(void)
{
usb_deregister(&samba_driver);
usb_serial_deregister(&samba_device);
}
module_init(samba_init);
module_exit(samba_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable verbose debugging messages");
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