USB: g_file_storage: add CD-ROM emulation (12aae68a) · Commits · e / devices / android_kernel_teracube_2e

drivers/usb/gadget/file_storage.c

+154 −22

Original line number	Diff line number	Diff line
		/*
		* file_storage.c -- File-backed USB Storage Gadget, for USB development
		*
		* Copyright (C) 2003-2007 Alan Stern
		* Copyright (C) 2003-2008 Alan Stern
		* All rights reserved.
		*
		* Redistribution and use in source and binary forms, with or without
		@@ -38,16 +38,17 @@

		/*
		* The File-backed Storage Gadget acts as a USB Mass Storage device,
		* appearing to the host as a disk drive. In addition to providing an
		* example of a genuinely useful gadget driver for a USB device, it also
		* illustrates a technique of double-buffering for increased throughput.
		* Last but not least, it gives an easy way to probe the behavior of the
		* Mass Storage drivers in a USB host.
		* appearing to the host as a disk drive or as a CD-ROM drive. In addition
		* to providing an example of a genuinely useful gadget driver for a USB
		* device, it also illustrates a technique of double-buffering for increased
		* throughput. Last but not least, it gives an easy way to probe the
		* behavior of the Mass Storage drivers in a USB host.
		*
		* Backing storage is provided by a regular file or a block device, specified
		* by the "file" module parameter. Access can be limited to read-only by
		* setting the optional "ro" module parameter. The gadget will indicate that
		* it has removable media if the optional "removable" module parameter is set.
		* setting the optional "ro" module parameter. (For CD-ROM emulation,
		* access is always read-only.) The gadget will indicate that it has
		* removable media if the optional "removable" module parameter is set.
		*
		* The gadget supports the Control-Bulk (CB), Control-Bulk-Interrupt (CBI),
		* and Bulk-Only (also known as Bulk-Bulk-Bulk or BBB) transports, selected
		@@ -64,7 +65,12 @@
		* The default number of LUNs is taken from the number of "file" elements;
		* it is 1 if "file" is not given. If "removable" is not set then a backing
		* file must be specified for each LUN. If it is set, then an unspecified
		* or empty backing filename means the LUN's medium is not loaded.
		* or empty backing filename means the LUN's medium is not loaded. Ideally
		* each LUN would be settable independently as a disk drive or a CD-ROM
		* drive, but currently all LUNs have to be the same type. The CD-ROM
		* emulation includes a single data track and no audio tracks; hence there
		* need be only one backing file per LUN. Note also that the CD-ROM block
		* length is set to 512 rather than the more common value 2048.
		*
		* Requirements are modest; only a bulk-in and a bulk-out endpoint are
		* needed (an interrupt-out endpoint is also needed for CBI). The memory
		@@ -91,6 +97,8 @@
		* USB device controller (usually true),
		* boolean to permit the driver to halt
		* bulk endpoints
		* cdrom Default false, boolean for whether to emulate
		* a CD-ROM drive
		* transport=XXX Default BBB, transport name (CB, CBI, or BBB)
		* protocol=YYY Default SCSI, protocol name (RBC, 8020 or
		* ATAPI, QIC, UFI, 8070, or SCSI;
		@@ -103,15 +111,16 @@
		* PAGE_CACHE_SIZE)
		*
		* If CONFIG_USB_FILE_STORAGE_TEST is not set, only the "file", "ro",
		* "removable", "luns", and "stall" options are available; default values
		* are used for everything else.
		* "removable", "luns", "stall", and "cdrom" options are available; default
		* values are used for everything else.
		*
		* The pathnames of the backing files and the ro settings are available in
		* the attribute files "file" and "ro" in the lun<n> subdirectory of the
		* gadget's sysfs directory. If the "removable" option is set, writing to
		* these files will simulate ejecting/loading the medium (writing an empty
		* line means eject) and adjusting a write-enable tab. Changes to the ro
		* setting are not allowed when the medium is loaded.
		* setting are not allowed when the medium is loaded or if CD-ROM emulation
		* is being used.
		*
		* This gadget driver is heavily based on "Gadget Zero" by David Brownell.
		* The driver's SCSI command interface was based on the "Information
		@@ -261,7 +270,7 @@

		#define DRIVER_DESC "File-backed Storage Gadget"
		#define DRIVER_NAME "g_file_storage"
		#define DRIVER_VERSION "7 August 2007"
		#define DRIVER_VERSION "20 November 2008"

		static const char longname[] = DRIVER_DESC;
		static const char shortname[] = DRIVER_NAME;
		@@ -341,6 +350,7 @@ static struct {

		int removable;
		int can_stall;
		int cdrom;

		char *transport_parm;
		char *protocol_parm;
		@@ -359,6 +369,7 @@ static struct {
		.protocol_parm = "SCSI",
		.removable = 0,
		.can_stall = 1,
		.cdrom = 0,
		.vendor = DRIVER_VENDOR_ID,
		.product = DRIVER_PRODUCT_ID,
		.release = 0xffff, // Use controller chip type
		@@ -382,6 +393,9 @@ MODULE_PARM_DESC(removable, "true to simulate removable media");
		module_param_named(stall, mod_data.can_stall, bool, S_IRUGO);
		MODULE_PARM_DESC(stall, "false to prevent bulk stalls");

		module_param_named(cdrom, mod_data.cdrom, bool, S_IRUGO);
		MODULE_PARM_DESC(cdrom, "true to emulate cdrom instead of disk");


		/* In the non-TEST version, only the module parameters listed above
		* are available. */
		@@ -411,6 +425,10 @@ MODULE_PARM_DESC(buflen, "I/O buffer size");

		/-------------------------------------------------------------------------/

		/* SCSI device types */
		#define TYPE_DISK 0x00
		#define TYPE_CDROM 0x05

		/* USB protocol value = the transport method */
		#define USB_PR_CBI 0x00 // Control/Bulk/Interrupt
		#define USB_PR_CB 0x01 // Control/Bulk w/o interrupt
		@@ -487,6 +505,8 @@ struct interrupt_data {
		#define SC_READ_12 0xa8
		#define SC_READ_CAPACITY 0x25
		#define SC_READ_FORMAT_CAPACITIES 0x23
		#define SC_READ_HEADER 0x44
		#define SC_READ_TOC 0x43
		#define SC_RELEASE 0x17
		#define SC_REQUEST_SENSE 0x03
		#define SC_RESERVE 0x16
		@@ -2006,23 +2026,28 @@ static int do_inquiry(struct fsg_dev fsg, struct fsg_buffhd bh)
		u8 buf = (u8 ) bh->buf;

		static char vendor_id[] = "Linux ";
		static char product_id[] = "File-Stor Gadget";
		static char product_disk_id[] = "File-Stor Gadget";
		static char product_cdrom_id[] = "File-CD Gadget ";

		if (!fsg->curlun) { // Unsupported LUNs are okay
		fsg->bad_lun_okay = 1;
		memset(buf, 0, 36);
		buf[0] = 0x7f; // Unsupported, no device-type
		buf[4] = 31; // Additional length
		return 36;
		}

		memset(buf, 0, 8); // Non-removable, direct-access device
		memset(buf, 0, 8);
		buf[0] = (mod_data.cdrom ? TYPE_CDROM : TYPE_DISK);
		if (mod_data.removable)
		buf[1] = 0x80;
		buf[2] = 2; // ANSI SCSI level 2
		buf[3] = 2; // SCSI-2 INQUIRY data format
		buf[4] = 31; // Additional length
		// No special options
		sprintf(buf + 8, "%-8s%-16s%04x", vendor_id, product_id,
		sprintf(buf + 8, "%-8s%-16s%04x", vendor_id,
		(mod_data.cdrom ? product_cdrom_id :
		product_disk_id),
		mod_data.release);
		return 36;
		}
		@@ -2101,6 +2126,75 @@ static int do_read_capacity(struct fsg_dev fsg, struct fsg_buffhd bh)
		}


		static void store_cdrom_address(u8 *dest, int msf, u32 addr)
		{
		if (msf) {
		/* Convert to Minutes-Seconds-Frames */
		addr >>= 2; /* Convert to 2048-byte frames */
		addr += 275; / Lead-in occupies 2 seconds */
		dest[3] = addr % 75; /* Frames */
		addr /= 75;
		dest[2] = addr % 60; /* Seconds */
		addr /= 60;
		dest[1] = addr; /* Minutes */
		dest[0] = 0; /* Reserved */
		} else {
		/* Absolute sector */
		put_be32(dest, addr);
		}
		}

		static int do_read_header(struct fsg_dev fsg, struct fsg_buffhd bh)
		{
		struct lun *curlun = fsg->curlun;
		int msf = fsg->cmnd[1] & 0x02;
		u32 lba = get_be32(&fsg->cmnd[2]);
		u8 buf = (u8 ) bh->buf;

		if ((fsg->cmnd[1] & ~0x02) != 0) { /* Mask away MSF */
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
		}
		if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
		}

		memset(buf, 0, 8);
		buf[0] = 0x01; /* 2048 bytes of user data, rest is EC */
		store_cdrom_address(&buf[4], msf, lba);
		return 8;
		}


		static int do_read_toc(struct fsg_dev fsg, struct fsg_buffhd bh)
		{
		struct lun *curlun = fsg->curlun;
		int msf = fsg->cmnd[1] & 0x02;
		int start_track = fsg->cmnd[6];
		u8 buf = (u8 ) bh->buf;

		if ((fsg->cmnd[1] & ~0x02) != 0 \|\| /* Mask away MSF */
		start_track > 1) {
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
		}

		memset(buf, 0, 20);
		buf[1] = (20-2); /* TOC data length */
		buf[2] = 1; /* First track number */
		buf[3] = 1; /* Last track number */
		buf[5] = 0x16; /* Data track, copying allowed */
		buf[6] = 0x01; /* Only track is number 1 */
		store_cdrom_address(&buf[8], msf, 0);

		buf[13] = 0x16; /* Lead-out track is data */
		buf[14] = 0xAA; /* Lead-out track number */
		store_cdrom_address(&buf[16], msf, curlun->num_sectors);
		return 20;
		}


		static int do_mode_sense(struct fsg_dev fsg, struct fsg_buffhd bh)
		{
		struct lun *curlun = fsg->curlun;
		@@ -2848,6 +2942,26 @@ static int do_scsi_command(struct fsg_dev *fsg)
		reply = do_read_capacity(fsg, bh);
		break;

		case SC_READ_HEADER:
		if (!mod_data.cdrom)
		goto unknown_cmnd;
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
		(3<<7) \| (0x1f<<1), 1,
		"READ HEADER")) == 0)
		reply = do_read_header(fsg, bh);
		break;

		case SC_READ_TOC:
		if (!mod_data.cdrom)
		goto unknown_cmnd;
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
		(7<<6) \| (1<<1), 1,
		"READ TOC")) == 0)
		reply = do_read_toc(fsg, bh);
		break;

		case SC_READ_FORMAT_CAPACITIES:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
		@@ -2933,6 +3047,7 @@ static int do_scsi_command(struct fsg_dev *fsg)
		// Fall through

		default:
		unknown_cmnd:
		fsg->data_size_from_cmnd = 0;
		sprintf(unknown, "Unknown x%02x", fsg->cmnd[0]);
		if ((reply = check_command(fsg, fsg->cmnd_size,
		@@ -3498,6 +3613,7 @@ static int open_backing_file(struct lun curlun, const char filename)
		struct inode *inode = NULL;
		loff_t size;
		loff_t num_sectors;
		loff_t min_sectors;

		/* R/W if we can, R/O if we must */
		ro = curlun->ro;
		@@ -3541,8 +3657,19 @@ static int open_backing_file(struct lun curlun, const char filename)
		rc = (int) size;
		goto out;
		}
		num_sectors = size >> 9; // File size in 512-byte sectors
		if (num_sectors == 0) {
		num_sectors = size >> 9; // File size in 512-byte blocks
		min_sectors = 1;
		if (mod_data.cdrom) {
		num_sectors &= ~3; // Reduce to a multiple of 2048
		min_sectors = 300*4; // Smallest track is 300 frames
		if (num_sectors >= 2566075*4) {
		num_sectors = (2566075 - 1) * 4;
		LINFO(curlun, "file too big: %s\n", filename);
		LINFO(curlun, "using only first %d blocks\n",
		(int) num_sectors);
		}
		}
		if (num_sectors < min_sectors) {
		LINFO(curlun, "file too small: %s\n", filename);
		rc = -ETOOSMALL;
		goto out;
		@@ -3845,9 +3972,12 @@ static int __init fsg_bind(struct usb_gadget *gadget)
		goto out;

		if (mod_data.removable) { // Enable the store_xxx attributes
		dev_attr_ro.attr.mode = dev_attr_file.attr.mode = 0644;
		dev_attr_ro.store = store_ro;
		dev_attr_file.attr.mode = 0644;
		dev_attr_file.store = store_file;
		if (!mod_data.cdrom) {
		dev_attr_ro.attr.mode = 0644;
		dev_attr_ro.store = store_ro;
		}
		}

		/* Find out how many LUNs there should be */
		@@ -3872,6 +4002,8 @@ static int __init fsg_bind(struct usb_gadget *gadget)
		for (i = 0; i < fsg->nluns; ++i) {
		curlun = &fsg->luns[i];
		curlun->ro = mod_data.ro[i];
		if (mod_data.cdrom)
		curlun->ro = 1;
		curlun->dev.release = lun_release;
		curlun->dev.parent = &gadget->dev;
		curlun->dev.driver = &fsg_driver.driver;
		@@ -4031,9 +4163,9 @@ static int __init fsg_bind(struct usb_gadget *gadget)
		mod_data.protocol_name, mod_data.protocol_type);
		DBG(fsg, "VendorID=x%04x, ProductID=x%04x, Release=x%04x\n",
		mod_data.vendor, mod_data.product, mod_data.release);
		DBG(fsg, "removable=%d, stall=%d, buflen=%u\n",
		DBG(fsg, "removable=%d, stall=%d, cdrom=%d, buflen=%u\n",
		mod_data.removable, mod_data.can_stall,
		mod_data.buflen);
		mod_data.cdrom, mod_data.buflen);
		DBG(fsg, "I/O thread pid: %d\n", task_pid_nr(fsg->thread_task));

		set_bit(REGISTERED, &fsg->atomic_bitflags);