Add new driver to access the SAM-BA boot application of Atmel AT91SAM
devices.
The SAM-BA firmware cannot handle merged write requests so we cannot use
the generic write implementation (which uses the port write fifo).
Tested with the SAM-BA 2.10 tools and an Atmel at91sam9260-ek.
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
Hi,
I confirmed my suspicion that it was the merged write requests which made
SAM-BA no longer work with the generic driver (i.e. it has been broken since
the introduction of the write fifo).
Here is instead a new SAM-BA driver which does not merge writes and that uses
larger transfer buffers (appropriate for the task at hand -- in-system
programming).
Thanks,
Johan
drivers/usb/serial/Kconfig | 9 ++
drivers/usb/serial/Makefile | 1 +
drivers/usb/serial/sam-ba.c | 206 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 216 insertions(+), 0 deletions(-)
create mode 100644 drivers/usb/serial/sam-ba.c
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index bd8aab0..64e27c1 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -527,6 +527,15 @@ config USB_SERIAL_SAFE_PADDED
bool "USB Secure Encapsulated Driver - Padded"
depends on USB_SERIAL_SAFE
+config USB_SERIAL_SAMBA
+ tristate "USB Atmel SAM Boot Assistant (SAM-BA) driver"
+ help
+ Say Y here if you want to access the SAM-BA boot application of an
+ Atmel AT91SAM device.
+
+ To compile this driver as a module, choose M here: the
+ module will be called sam-ba.
+
config USB_SERIAL_SIEMENS_MPI
tristate "USB Siemens MPI driver"
help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index e54c728..91c3afb 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_USB_SERIAL_PL2303) += pl2303.o
obj-$(CONFIG_USB_SERIAL_QCAUX) += qcaux.o
obj-$(CONFIG_USB_SERIAL_QUALCOMM) += qcserial.o
obj-$(CONFIG_USB_SERIAL_SAFE) += safe_serial.o
+obj-$(CONFIG_USB_SERIAL_SAMBA) += sam-ba.o
obj-$(CONFIG_USB_SERIAL_SIEMENS_MPI) += siemens_mpi.o
obj-$(CONFIG_USB_SERIAL_SIERRAWIRELESS) += sierra.o
obj-$(CONFIG_USB_SERIAL_SPCP8X5) += spcp8x5.o
diff --git a/drivers/usb/serial/sam-ba.c b/drivers/usb/serial/sam-ba.c
new file mode 100644
index 0000000..e3bba64
--- /dev/null
+++ b/drivers/usb/serial/sam-ba.c
@@ -0,0 +1,206 @@
+/*
+ * Atmel SAM Boot Assistant (SAM-BA) driver
+ *
+ * Copyright (C) 2010 Johan Hovold <jhovold@xxxxxxxxx>
+ *
+ * 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@xxxxxxxxx>"
+#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");
--
1.7.2
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