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authorJason Wessel <jason.wessel@windriver.com>2009-05-11 16:24:09 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2009-06-16 00:44:45 -0400
commit98fcb5f78165b8a3d93870ad7afd4d9ebbb8b43a (patch)
treeed64298e8b6bf47ba9c57db298e732429f7f669e /drivers/usb/serial/usb_debug.c
parent87c1edd217a6742e48028db6664d7763de0449f6 (diff)
USB: serial: usb_debug,usb_generic_serial: implement sysrq and serial break
The usb_debug driver was modified to implement serial break handling by using a "magic" data packet comprised of the sequence: 0x00 0xff 0x01 0xfe 0x00 0xfe 0x01 0xff When the tty layer requests a serial break the usb_debug driver sends the magic packet. On the receiving side the magic packet is thrown away or a sysrq is activated depending on what kernel .config options have been set. The generic serial driver was modified as well as the usb serial headers to generically implement sysrq processing in the same way the non usb uart based drivers implement the sysrq handling. This will allow other usb serial devices to implement sysrq handling as desired. The new usb serial functions are named similarly and implemented similarly to the uart functions as follows: usb_serial_handle_break <-> uart_handle_break usb_serial_handle_sysrq_char <-> uart_handle_sysrq_char Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/serial/usb_debug.c')
-rw-r--r--drivers/usb/serial/usb_debug.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/usb/serial/usb_debug.c b/drivers/usb/serial/usb_debug.c
index a9427a8b8672..614800972dc3 100644
--- a/drivers/usb/serial/usb_debug.c
+++ b/drivers/usb/serial/usb_debug.c
@@ -17,6 +17,17 @@
17 17
18#define URB_DEBUG_MAX_IN_FLIGHT_URBS 4000 18#define URB_DEBUG_MAX_IN_FLIGHT_URBS 4000
19#define USB_DEBUG_MAX_PACKET_SIZE 8 19#define USB_DEBUG_MAX_PACKET_SIZE 8
20#define USB_DEBUG_BRK_SIZE 8
21static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
22 0x00,
23 0xff,
24 0x01,
25 0xfe,
26 0x00,
27 0xfe,
28 0x01,
29 0xff,
30};
20 31
21static struct usb_device_id id_table [] = { 32static struct usb_device_id id_table [] = {
22 { USB_DEVICE(0x0525, 0x127a) }, 33 { USB_DEVICE(0x0525, 0x127a) },
@@ -39,6 +50,32 @@ static int usb_debug_open(struct tty_struct *tty, struct usb_serial_port *port,
39 return usb_serial_generic_open(tty, port, filp); 50 return usb_serial_generic_open(tty, port, filp);
40} 51}
41 52
53/* This HW really does not support a serial break, so one will be
54 * emulated when ever the break state is set to true.
55 */
56static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
57{
58 struct usb_serial_port *port = tty->driver_data;
59 if (!break_state)
60 return;
61 usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
62}
63
64static void usb_debug_read_bulk_callback(struct urb *urb)
65{
66 struct usb_serial_port *port = urb->context;
67
68 if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
69 memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
70 USB_DEBUG_BRK_SIZE) == 0) {
71 usb_serial_handle_break(port);
72 usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
73 return;
74 }
75
76 usb_serial_generic_read_bulk_callback(urb);
77}
78
42static struct usb_serial_driver debug_device = { 79static struct usb_serial_driver debug_device = {
43 .driver = { 80 .driver = {
44 .owner = THIS_MODULE, 81 .owner = THIS_MODULE,
@@ -48,6 +85,8 @@ static struct usb_serial_driver debug_device = {
48 .num_ports = 1, 85 .num_ports = 1,
49 .open = usb_debug_open, 86 .open = usb_debug_open,
50 .max_in_flight_urbs = URB_DEBUG_MAX_IN_FLIGHT_URBS, 87 .max_in_flight_urbs = URB_DEBUG_MAX_IN_FLIGHT_URBS,
88 .break_ctl = usb_debug_break_ctl,
89 .read_bulk_callback = usb_debug_read_bulk_callback,
51}; 90};
52 91
53static int __init debug_init(void) 92static int __init debug_init(void)