Johan Hovold | 9059389 | 2010-08-19 00:13:48 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Atmel SAM Boot Assistant (SAM-BA) driver |
| 3 | * |
| 4 | * Copyright (C) 2010 Johan Hovold <jhovold@gmail.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License version |
| 8 | * 2 as published by the Free Software Foundation. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/tty.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/moduleparam.h> |
| 15 | #include <linux/usb.h> |
| 16 | #include <linux/usb/serial.h> |
| 17 | |
| 18 | |
| 19 | #define DRIVER_VERSION "v1.0" |
| 20 | #define DRIVER_AUTHOR "Johan Hovold <jhovold@gmail.com>" |
| 21 | #define DRIVER_DESC "Atmel SAM Boot Assistant (SAM-BA) driver" |
| 22 | |
| 23 | #define SAMBA_VENDOR_ID 0x3eb |
| 24 | #define SAMBA_PRODUCT_ID 0x6124 |
| 25 | |
| 26 | |
| 27 | static int debug; |
| 28 | |
| 29 | static const struct usb_device_id id_table[] = { |
| 30 | /* |
| 31 | * NOTE: Only match the CDC Data interface. |
| 32 | */ |
| 33 | { USB_DEVICE_AND_INTERFACE_INFO(SAMBA_VENDOR_ID, SAMBA_PRODUCT_ID, |
| 34 | USB_CLASS_CDC_DATA, 0, 0) }, |
| 35 | { } |
| 36 | }; |
| 37 | MODULE_DEVICE_TABLE(usb, id_table); |
| 38 | |
| 39 | static struct usb_driver samba_driver = { |
| 40 | .name = "sam-ba", |
| 41 | .probe = usb_serial_probe, |
| 42 | .disconnect = usb_serial_disconnect, |
| 43 | .id_table = id_table, |
| 44 | .no_dynamic_id = 1, |
| 45 | }; |
| 46 | |
| 47 | |
| 48 | /* |
| 49 | * NOTE: The SAM-BA firmware cannot handle merged write requests so we cannot |
| 50 | * use the generic write implementation (which uses the port write fifo). |
| 51 | */ |
| 52 | static int samba_write(struct tty_struct *tty, struct usb_serial_port *port, |
| 53 | const unsigned char *buf, int count) |
| 54 | { |
| 55 | struct urb *urb; |
| 56 | unsigned long flags; |
| 57 | int result; |
| 58 | int i; |
| 59 | |
| 60 | if (!count) |
| 61 | return 0; |
| 62 | |
| 63 | count = min_t(int, count, port->bulk_out_size); |
| 64 | |
| 65 | spin_lock_irqsave(&port->lock, flags); |
| 66 | if (!port->write_urbs_free) { |
| 67 | spin_unlock_irqrestore(&port->lock, flags); |
| 68 | return 0; |
| 69 | } |
| 70 | i = find_first_bit(&port->write_urbs_free, |
| 71 | ARRAY_SIZE(port->write_urbs)); |
| 72 | __clear_bit(i, &port->write_urbs_free); |
| 73 | port->tx_bytes += count; |
| 74 | spin_unlock_irqrestore(&port->lock, flags); |
| 75 | |
| 76 | urb = port->write_urbs[i]; |
| 77 | memcpy(urb->transfer_buffer, buf, count); |
| 78 | urb->transfer_buffer_length = count; |
| 79 | usb_serial_debug_data(debug, &port->dev, __func__, count, |
| 80 | urb->transfer_buffer); |
| 81 | result = usb_submit_urb(urb, GFP_ATOMIC); |
| 82 | if (result) { |
| 83 | dev_err(&port->dev, "%s - error submitting urb: %d\n", |
| 84 | __func__, result); |
| 85 | spin_lock_irqsave(&port->lock, flags); |
| 86 | __set_bit(i, &port->write_urbs_free); |
| 87 | port->tx_bytes -= count; |
| 88 | spin_unlock_irqrestore(&port->lock, flags); |
| 89 | |
| 90 | return result; |
| 91 | } |
| 92 | |
| 93 | return count; |
| 94 | } |
| 95 | |
| 96 | static int samba_write_room(struct tty_struct *tty) |
| 97 | { |
| 98 | struct usb_serial_port *port = tty->driver_data; |
| 99 | unsigned long flags; |
| 100 | unsigned long free; |
| 101 | int count; |
| 102 | int room; |
| 103 | |
| 104 | spin_lock_irqsave(&port->lock, flags); |
| 105 | free = port->write_urbs_free; |
| 106 | spin_unlock_irqrestore(&port->lock, flags); |
| 107 | |
| 108 | count = hweight_long(free); |
| 109 | room = count * port->bulk_out_size; |
| 110 | |
| 111 | dbg("%s - returns %d", __func__, room); |
| 112 | |
| 113 | return room; |
| 114 | } |
| 115 | |
| 116 | static int samba_chars_in_buffer(struct tty_struct *tty) |
| 117 | { |
| 118 | struct usb_serial_port *port = tty->driver_data; |
| 119 | unsigned long flags; |
| 120 | int chars; |
| 121 | |
| 122 | spin_lock_irqsave(&port->lock, flags); |
| 123 | chars = port->tx_bytes; |
| 124 | spin_unlock_irqrestore(&port->lock, flags); |
| 125 | |
| 126 | dbg("%s - returns %d", __func__, chars); |
| 127 | |
| 128 | return chars; |
| 129 | } |
| 130 | |
| 131 | static void samba_write_bulk_callback(struct urb *urb) |
| 132 | { |
| 133 | struct usb_serial_port *port = urb->context; |
| 134 | unsigned long flags; |
| 135 | int i; |
| 136 | |
| 137 | dbg("%s - port %d", __func__, port->number); |
| 138 | |
| 139 | for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) { |
| 140 | if (port->write_urbs[i] == urb) |
| 141 | break; |
| 142 | } |
| 143 | spin_lock_irqsave(&port->lock, flags); |
| 144 | __set_bit(i, &port->write_urbs_free); |
| 145 | port->tx_bytes -= urb->transfer_buffer_length; |
| 146 | spin_unlock_irqrestore(&port->lock, flags); |
| 147 | |
| 148 | if (urb->status) |
| 149 | dbg("%s - non-zero urb status: %d", __func__, urb->status); |
| 150 | |
| 151 | usb_serial_port_softint(port); |
| 152 | } |
| 153 | |
| 154 | static struct usb_serial_driver samba_device = { |
| 155 | .driver = { |
| 156 | .owner = THIS_MODULE, |
| 157 | .name = "sam-ba", |
| 158 | }, |
| 159 | .usb_driver = &samba_driver, |
| 160 | .id_table = id_table, |
| 161 | .num_ports = 1, |
| 162 | .bulk_in_size = 512, |
| 163 | .bulk_out_size = 2048, |
| 164 | .write = samba_write, |
| 165 | .write_room = samba_write_room, |
| 166 | .chars_in_buffer = samba_chars_in_buffer, |
| 167 | .write_bulk_callback = samba_write_bulk_callback, |
| 168 | .throttle = usb_serial_generic_throttle, |
| 169 | .unthrottle = usb_serial_generic_unthrottle, |
| 170 | }; |
| 171 | |
| 172 | static int __init samba_init(void) |
| 173 | { |
| 174 | int retval; |
| 175 | |
| 176 | retval = usb_serial_register(&samba_device); |
| 177 | if (retval) |
| 178 | return retval; |
| 179 | |
| 180 | retval = usb_register(&samba_driver); |
| 181 | if (retval) { |
| 182 | usb_serial_deregister(&samba_device); |
| 183 | return retval; |
| 184 | } |
| 185 | |
| 186 | printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ": " |
| 187 | DRIVER_DESC "\n"); |
| 188 | return 0; |
| 189 | } |
| 190 | |
| 191 | static void __exit samba_exit(void) |
| 192 | { |
| 193 | usb_deregister(&samba_driver); |
| 194 | usb_serial_deregister(&samba_device); |
| 195 | } |
| 196 | |
| 197 | module_init(samba_init); |
| 198 | module_exit(samba_exit); |
| 199 | |
| 200 | MODULE_AUTHOR(DRIVER_AUTHOR); |
| 201 | MODULE_DESCRIPTION(DRIVER_DESC); |
| 202 | MODULE_VERSION(DRIVER_VERSION); |
| 203 | MODULE_LICENSE("GPL"); |
| 204 | |
| 205 | module_param(debug, bool, S_IRUGO | S_IWUSR); |
| 206 | MODULE_PARM_DESC(debug, "Enable verbose debugging messages"); |