USB: unusual dev for Option N.V. ZeroCD modems

Many newer Option mobile broadband devices initially provide a
usb-storage "driver CD" device that's pretty useless on Linux since
any software on it most likely wouldn't be compatible with your
kernel or distro anyway.  Thus, by default just kill the driver
CD device by sending the SCSI 'rezero' command, but allow override
of the default behavior via usb-storage module parameter so users
can keep the ZeroCD device if they really want to.  Inspired by
the Sierra TruInstall patch.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Peter Henn <p.henn@option.com
Cc: Denis Joseph Barrow <D.Barow@option.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 147 insertions, 0 deletions

diff --git a/drivers/usb/storage/option_ms.c b/drivers/usb/storage/option_ms.c
new file mode 100644
index 000000000000..353f922939a4
--- /dev/null
+++ b/drivers/usb/storage/option_ms.c
@@ -0,0 +1,147 @@
+/*
+ * Driver for Option High Speed Mobile Devices.
+ *
+ *   (c) 2008 Dan Williams <dcbw@redhat.com>
+ *
+ * Inspiration taken from sierra_ms.c by Kevin Lloyd <klloyd@sierrawireless.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/usb.h>
+
+#include "usb.h"
+#include "transport.h"
+#include "option_ms.h"
+#include "debug.h"
+
+#define ZCD_FORCE_MODEM			0x01
+#define ZCD_ALLOW_MS 			0x02
+
+static unsigned int option_zero_cd = ZCD_FORCE_MODEM;
+module_param(option_zero_cd, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
+		 " 2=Allow CD-Rom");
+
+#define RESPONSE_LEN 1024
+
+static int option_rezero(struct us_data *us, int ep_in, int ep_out)
+{
+	const unsigned char rezero_msg[] = {
+	  0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
+	  0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
+	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+	};
+	char *buffer;
+	int result;
+
+	US_DEBUGP("Option MS: %s", "DEVICE MODE SWITCH\n");
+
+	buffer = kzalloc(RESPONSE_LEN, GFP_KERNEL);
+	if (buffer == NULL)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	memcpy(buffer, rezero_msg, sizeof (rezero_msg));
+	result = usb_stor_bulk_transfer_buf(us,
+			usb_sndbulkpipe(us->pusb_dev, ep_out),
+			buffer, sizeof (rezero_msg), NULL);
+	if (result != USB_STOR_XFER_GOOD) {
+		result = USB_STOR_XFER_ERROR;
+		goto out;
+	}
+
+	/* Some of the devices need to be asked for a response, but we don't
+	 * care what that response is.
+	 */
+	result = usb_stor_bulk_transfer_buf(us,
+			usb_sndbulkpipe(us->pusb_dev, ep_out),
+			buffer, RESPONSE_LEN, NULL);
+	result = USB_STOR_XFER_GOOD;
+
+out:
+	kfree(buffer);
+	return result;
+}
+
+int option_ms_init(struct us_data *us)
+{
+	struct usb_device *udev;
+	struct usb_interface *intf;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint = NULL;
+	u8 ep_in = 0, ep_out = 0;
+	int ep_in_size = 0, ep_out_size = 0;
+	int i, result;
+
+	udev = us->pusb_dev;
+	intf = us->pusb_intf;
+
+	/* Ensure it's really a ZeroCD device; devices that are already
+	 * in modem mode return 0xFF for class, subclass, and protocol.
+	 */
+	if (udev->descriptor.bDeviceClass != 0 ||
+	    udev->descriptor.bDeviceSubClass != 0 ||
+	    udev->descriptor.bDeviceProtocol != 0)
+		return USB_STOR_TRANSPORT_GOOD;
+
+	US_DEBUGP("Option MS: option_ms_init called\n");
+
+	/* Find the right mass storage interface */
+	iface_desc = intf->cur_altsetting;
+	if (iface_desc->desc.bInterfaceClass != 0x8 ||
+	    iface_desc->desc.bInterfaceSubClass != 0x6 ||
+	    iface_desc->desc.bInterfaceProtocol != 0x50) {
+		US_DEBUGP("Option MS: mass storage interface not found, no action "
+		          "required\n");
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	/* Find the mass storage bulk endpoints */
+	for (i = 0; i < iface_desc->desc.bNumEndpoints && (!ep_in_size || !ep_out_size); ++i) {
+		endpoint = &iface_desc->endpoint[i].desc;
+
+		if (usb_endpoint_is_bulk_in(endpoint)) {
+			ep_in = usb_endpoint_num(endpoint);
+			ep_in_size = le16_to_cpu(endpoint->wMaxPacketSize);
+		} else if (usb_endpoint_is_bulk_out(endpoint)) {
+			ep_out = usb_endpoint_num(endpoint);
+			ep_out_size = le16_to_cpu(endpoint->wMaxPacketSize);
+		}
+	}
+
+	/* Can't find the mass storage endpoints */
+	if (!ep_in_size || !ep_out_size) {
+		US_DEBUGP("Option MS: mass storage endpoints not found, no action "
+		          "required\n");
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	/* Force Modem mode */
+	if (option_zero_cd == ZCD_FORCE_MODEM) {
+		US_DEBUGP("Option MS: %s", "Forcing Modem Mode\n");
+		result = option_rezero(us, ep_in, ep_out);
+		if (result != USB_STOR_XFER_GOOD)
+			US_DEBUGP("Option MS: Failed to switch to modem mode.\n");
+		return -EIO;
+	} else if (option_zero_cd == ZCD_ALLOW_MS) {
+		/* Allow Mass Storage mode (keep CD-Rom) */
+		US_DEBUGP("Option MS: %s", "Allowing Mass Storage Mode if device"
+		          " requests it\n");
+	}
+
+	return USB_STOR_TRANSPORT_GOOD;
+}
+