From eaa3bcb06aed1ac1d6d9e3edd3b5f72ea57a6ac0 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 17 Mar 2010 23:06:08 +0100 Subject: [PATCH] USB: serial: generalise write buffer preparation Generalise write buffer preparation. This allows for drivers to manipulate (e.g. add headers) to bulk out data before it is sent. This adds a new function pointer to usb_serial_driver: int (*prepare_write_buffer)(struct usb_serial_port *port, void **dest, size_t size, const void *src, size_t count); The function is generic and can be used with either kfifo-based or multi-urb writes: If *dest is NULL the implementation should allocate dest. If src is NULL the implementation should use the port write fifo. If not set, a generic implementation is used which simply uses memcpy or kfifo_out. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/generic.c | 47 ++++++++++++++++++++++++--------- drivers/usb/serial/usb-serial.c | 1 + include/linux/usb/serial.h | 5 ++++ 3 files changed, 40 insertions(+), 13 deletions(-) diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c index ad4823bbfa19..1a134f9c64f3 100644 --- a/drivers/usb/serial/generic.c +++ b/drivers/usb/serial/generic.c @@ -167,12 +167,35 @@ void usb_serial_generic_close(struct usb_serial_port *port) } EXPORT_SYMBOL_GPL(usb_serial_generic_close); +int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, + void **dest, size_t size, const void *src, size_t count) +{ + if (!*dest) { + size = count; + *dest = kmalloc(count, GFP_ATOMIC); + if (!*dest) { + dev_err(&port->dev, "%s - could not allocate buffer\n", + __func__); + return -ENOMEM; + } + } + if (src) { + count = size; + memcpy(*dest, src, size); + } else { + count = kfifo_out_locked(&port->write_fifo, *dest, size, + &port->lock); + } + return count; +} +EXPORT_SYMBOL_GPL(usb_serial_generic_prepare_write_buffer); + static int usb_serial_multi_urb_write(struct tty_struct *tty, struct usb_serial_port *port, const unsigned char *buf, int count) { unsigned long flags; struct urb *urb; - unsigned char *buffer; + void *buffer; int status; spin_lock_irqsave(&port->lock, flags); @@ -191,16 +214,14 @@ static int usb_serial_multi_urb_write(struct tty_struct *tty, goto err_urb; } + buffer = NULL; count = min_t(int, count, PAGE_SIZE); - buffer = kmalloc(count, GFP_ATOMIC); - if (!buffer) { - dev_err(&port->dev, "%s - could not allocate buffer\n", - __func__); - status = -ENOMEM; + count = port->serial->type->prepare_write_buffer(port, &buffer, 0, + buf, count); + if (count < 0) { + status = count; goto err_buf; } - - memcpy(buffer, buf, count); usb_serial_debug_data(debug, &port->dev, __func__, count, buffer); usb_fill_bulk_urb(urb, port->serial->dev, usb_sndbulkpipe(port->serial->dev, @@ -242,7 +263,6 @@ err_urb: */ static int usb_serial_generic_write_start(struct usb_serial_port *port) { - unsigned char *data; int result; int count; unsigned long flags; @@ -255,10 +275,11 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port) port->write_urb_busy = 1; spin_unlock_irqrestore(&port->lock, flags); - data = port->write_urb->transfer_buffer; - count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock); - usb_serial_debug_data(debug, &port->dev, __func__, count, data); - + count = port->serial->type->prepare_write_buffer(port, + &port->write_urb->transfer_buffer, + port->bulk_out_size, NULL, 0); + usb_serial_debug_data(debug, &port->dev, __func__, + count, port->write_urb->transfer_buffer); port->write_urb->transfer_buffer_length = count; /* send the data out the bulk port */ diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 1b924425089f..8249fd8381fb 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -1299,6 +1299,7 @@ static void fixup_generic(struct usb_serial_driver *device) set_to_generic_if_null(device, disconnect); set_to_generic_if_null(device, release); set_to_generic_if_null(device, process_read_urb); + set_to_generic_if_null(device, prepare_write_buffer); } int usb_serial_register(struct usb_serial_driver *driver) diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h index 2a3283761600..a4c99ea390e7 100644 --- a/include/linux/usb/serial.h +++ b/include/linux/usb/serial.h @@ -277,6 +277,9 @@ struct usb_serial_driver { void (*write_bulk_callback)(struct urb *urb); /* Called by the generic read bulk callback */ void (*process_read_urb)(struct urb *urb); + /* Called by the generic write implementation */ + int (*prepare_write_buffer)(struct usb_serial_port *port, + void **dest, size_t size, const void *src, size_t count); }; #define to_usb_serial_driver(d) \ container_of(d, struct usb_serial_driver, driver) @@ -329,6 +332,8 @@ extern void usb_serial_generic_deregister(void); extern int usb_serial_generic_submit_read_urb(struct usb_serial_port *port, gfp_t mem_flags); extern void usb_serial_generic_process_read_urb(struct urb *urb); +extern int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, + void **dest, size_t size, const void *src, size_t count); extern int usb_serial_handle_sysrq_char(struct tty_struct *tty, struct usb_serial_port *port, unsigned int ch); -- 2.20.1