file_storage.c

linux-2.6.15.6

/* Command Status Wrapper */
struct bulk_cs_wrap {
	__le32	Signature;		// Should = 'USBS'
	u32	Tag;			// Same as original command
	__le32	Residue;		// Amount not transferred
	u8	Status;			// See below
};

#define USB_BULK_CS_WRAP_LEN	13
#define USB_BULK_CS_SIG		0x53425355	// Spells out 'USBS'
#define USB_STATUS_PASS		0
#define USB_STATUS_FAIL		1
#define USB_STATUS_PHASE_ERROR	2

/* Bulk-only class specific requests */
#define USB_BULK_RESET_REQUEST		0xff
#define USB_BULK_GET_MAX_LUN_REQUEST	0xfe


/* CBI Interrupt data structure */
struct interrupt_data {
	u8	bType;
	u8	bValue;
};

#define CBI_INTERRUPT_DATA_LEN		2

/* CBI Accept Device-Specific Command request */
#define USB_CBI_ADSC_REQUEST		0x00


#define MAX_COMMAND_SIZE	16	// Length of a SCSI Command Data Block

/* SCSI commands that we recognize */
#define SC_FORMAT_UNIT			0x04
#define SC_INQUIRY			0x12
#define SC_MODE_SELECT_6		0x15
#define SC_MODE_SELECT_10		0x55
#define SC_MODE_SENSE_6			0x1a
#define SC_MODE_SENSE_10		0x5a
#define SC_PREVENT_ALLOW_MEDIUM_REMOVAL	0x1e
#define SC_READ_6			0x08
#define SC_READ_10			0x28
#define SC_READ_12			0xa8
#define SC_READ_CAPACITY		0x25
#define SC_READ_FORMAT_CAPACITIES	0x23
#define SC_RELEASE			0x17
#define SC_REQUEST_SENSE		0x03
#define SC_RESERVE			0x16
#define SC_SEND_DIAGNOSTIC		0x1d
#define SC_START_STOP_UNIT		0x1b
#define SC_SYNCHRONIZE_CACHE		0x35
#define SC_TEST_UNIT_READY		0x00
#define SC_VERIFY			0x2f
#define SC_WRITE_6			0x0a
#define SC_WRITE_10			0x2a
#define SC_WRITE_12			0xaa

/* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
#define SS_NO_SENSE				0
#define SS_COMMUNICATION_FAILURE		0x040800
#define SS_INVALID_COMMAND			0x052000
#define SS_INVALID_FIELD_IN_CDB			0x052400
#define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE	0x052100
#define SS_LOGICAL_UNIT_NOT_SUPPORTED		0x052500
#define SS_MEDIUM_NOT_PRESENT			0x023a00
#define SS_MEDIUM_REMOVAL_PREVENTED		0x055302
#define SS_NOT_READY_TO_READY_TRANSITION	0x062800
#define SS_RESET_OCCURRED			0x062900
#define SS_SAVING_PARAMETERS_NOT_SUPPORTED	0x053900
#define SS_UNRECOVERED_READ_ERROR		0x031100
#define SS_WRITE_ERROR				0x030c02
#define SS_WRITE_PROTECTED			0x072700

#define SK(x)		((u8) ((x) >> 16))	// Sense Key byte, etc.
#define ASC(x)		((u8) ((x) >> 8))
#define ASCQ(x)		((u8) (x))


/*-------------------------------------------------------------------------*/

/*
 * These definitions will permit the compiler to avoid generating code for
 * parts of the driver that aren't used in the non-TEST version.  Even gcc
 * can recognize when a test of a constant expression yields a dead code
 * path.
 */

#ifdef CONFIG_USB_FILE_STORAGE_TEST

#define transport_is_bbb()	(mod_data.transport_type == USB_PR_BULK)
#define transport_is_cbi()	(mod_data.transport_type == USB_PR_CBI)
#define protocol_is_scsi()	(mod_data.protocol_type == USB_SC_SCSI)

#else

#define transport_is_bbb()	1
#define transport_is_cbi()	0
#define protocol_is_scsi()	1

#endif /* CONFIG_USB_FILE_STORAGE_TEST */


struct lun {
	struct file	*filp;
	loff_t		file_length;
	loff_t		num_sectors;

	unsigned int	ro : 1;
	unsigned int	prevent_medium_removal : 1;
	unsigned int	registered : 1;

	u32		sense_data;
	u32		sense_data_info;
	u32		unit_attention_data;

	struct device	dev;
};

#define backing_file_is_open(curlun)	((curlun)->filp != NULL)

static inline struct lun *dev_to_lun(struct device *dev)
{
	return container_of(dev, struct lun, dev);
}


/* Big enough to hold our biggest descriptor */
#define EP0_BUFSIZE	256
#define DELAYED_STATUS	(EP0_BUFSIZE + 999)	// An impossibly large value

/* Number of buffers we will use.  2 is enough for double-buffering */
#define NUM_BUFFERS	2

enum fsg_buffer_state {
	BUF_STATE_EMPTY = 0,
	BUF_STATE_FULL,
	BUF_STATE_BUSY
};

struct fsg_buffhd {
	void				*buf;
	dma_addr_t			dma;
	volatile enum fsg_buffer_state	state;
	struct fsg_buffhd		*next;

	/* The NetChip 2280 is faster, and handles some protocol faults
	 * better, if we don't submit any short bulk-out read requests.
	 * So we will record the intended request length here. */
	unsigned int			bulk_out_intended_length;

	struct usb_request		*inreq;
	volatile int			inreq_busy;
	struct usb_request		*outreq;
	volatile int			outreq_busy;
};

enum fsg_state {
	FSG_STATE_COMMAND_PHASE = -10,		// This one isn't used anywhere
	FSG_STATE_DATA_PHASE,
	FSG_STATE_STATUS_PHASE,

	FSG_STATE_IDLE = 0,
	FSG_STATE_ABORT_BULK_OUT,
	FSG_STATE_RESET,
	FSG_STATE_INTERFACE_CHANGE,
	FSG_STATE_CONFIG_CHANGE,
	FSG_STATE_DISCONNECT,
	FSG_STATE_EXIT,
	FSG_STATE_TERMINATED
};

enum data_direction {
	DATA_DIR_UNKNOWN = 0,
	DATA_DIR_FROM_HOST,
	DATA_DIR_TO_HOST,
	DATA_DIR_NONE
};

struct fsg_dev {
	/* lock protects: state, all the req_busy's, and cbbuf_cmnd */
	spinlock_t		lock;
	struct usb_gadget	*gadget;

	/* filesem protects: backing files in use */
	struct rw_semaphore	filesem;

	struct usb_ep		*ep0;		// Handy copy of gadget->ep0
	struct usb_request	*ep0req;	// For control responses
	volatile unsigned int	ep0_req_tag;
	const char		*ep0req_name;

	struct usb_request	*intreq;	// For interrupt responses
	volatile int		intreq_busy;
	struct fsg_buffhd	*intr_buffhd;

 	unsigned int		bulk_out_maxpacket;
	enum fsg_state		state;		// For exception handling
	unsigned int		exception_req_tag;

	u8			config, new_config;

	unsigned int		running : 1;
	unsigned int		bulk_in_enabled : 1;
	unsigned int		bulk_out_enabled : 1;
	unsigned int		intr_in_enabled : 1;
	unsigned int		phase_error : 1;
	unsigned int		short_packet_received : 1;
	unsigned int		bad_lun_okay : 1;

	unsigned long		atomic_bitflags;
#define REGISTERED		0
#define CLEAR_BULK_HALTS	1
#define SUSPENDED		2

	struct usb_ep		*bulk_in;
	struct usb_ep		*bulk_out;
	struct usb_ep		*intr_in;

	struct fsg_buffhd	*next_buffhd_to_fill;
	struct fsg_buffhd	*next_buffhd_to_drain;
	struct fsg_buffhd	buffhds[NUM_BUFFERS];

	wait_queue_head_t	thread_wqh;
	int			thread_wakeup_needed;
	struct completion	thread_notifier;
	struct task_struct	*thread_task;
	sigset_t		thread_signal_mask;

	int			cmnd_size;
	u8			cmnd[MAX_COMMAND_SIZE];
	enum data_direction	data_dir;
	u32			data_size;
	u32			data_size_from_cmnd;
	u32			tag;
	unsigned int		lun;
	u32			residue;
	u32			usb_amount_left;

	/* The CB protocol offers no way for a host to know when a command
	 * has completed.  As a result the next command may arrive early,
	 * and we will still have to handle it.  For that reason we need
	 * a buffer to store new commands when using CB (or CBI, which
	 * does not oblige a host to wait for command completion either). */
	int			cbbuf_cmnd_size;
	u8			cbbuf_cmnd[MAX_COMMAND_SIZE];

	unsigned int		nluns;
	struct lun		*luns;
	struct lun		*curlun;
	struct completion	lun_released;
};

typedef void (*fsg_routine_t)(struct fsg_dev *);

static int inline exception_in_progress(struct fsg_dev *fsg)
{
	return (fsg->state > FSG_STATE_IDLE);
}

/* Make bulk-out requests be divisible by the maxpacket size */
static void inline set_bulk_out_req_length(struct fsg_dev *fsg,
		struct fsg_buffhd *bh, unsigned int length)
{
	unsigned int	rem;

	bh->bulk_out_intended_length = length;
	rem = length % fsg->bulk_out_maxpacket;
	if (rem > 0)
		length += fsg->bulk_out_maxpacket - rem;
	bh->outreq->length = length;
}

static struct fsg_dev			*the_fsg;
static struct usb_gadget_driver		fsg_driver;

static void	close_backing_file(struct lun *curlun);
static void	close_all_backing_files(struct fsg_dev *fsg);


/*-------------------------------------------------------------------------*/

#ifdef DUMP_MSGS

static void dump_msg(struct fsg_dev *fsg, const char *label,
		const u8 *buf, unsigned int length)
{
	unsigned int	start, num, i;
	char		line[52], *p;

	if (length >= 512)
		return;
	DBG(fsg, "%s, length %u:\n", label, length);

	start = 0;
	while (length > 0) {
		num = min(length, 16u);
		p = line;
		for (i = 0; i < num; ++i) {
			if (i == 8)
				*p++ = ' ';
			sprintf(p, " %02x", buf[i]);
			p += 3;
		}
		*p = 0;
		printk(KERN_DEBUG "%6x: %s\n", start, line);
		buf += num;
		start += num;
		length -= num;
	}
}

static void inline dump_cdb(struct fsg_dev *fsg)
{}

#else

static void inline dump_msg(struct fsg_dev *fsg, const char *label,
		const u8 *buf, unsigned int length)
{}

static void inline dump_cdb(struct fsg_dev *fsg)
{
	int	i;
	char	cmdbuf[3*MAX_COMMAND_SIZE + 1];

	for (i = 0; i < fsg->cmnd_size; ++i)
		sprintf(cmdbuf + i*3, " %02x", fsg->cmnd[i]);
	VDBG(fsg, "SCSI CDB: %s\n", cmdbuf);
}

#endif /* DUMP_MSGS */


static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
{
	const char	*name;

	if (ep == fsg->bulk_in)
		name = "bulk-in";
	else if (ep == fsg->bulk_out)
		name = "bulk-out";
	else
		name = ep->name;
	DBG(fsg, "%s set halt\n", name);
	return usb_ep_set_halt(ep);
}


/*-------------------------------------------------------------------------*/

/* Routines for unaligned data access */

static u16 inline get_be16(u8 *buf)
{
	return ((u16) buf[0] << 8) | ((u16) buf[1]);
}

static u32 inline get_be32(u8 *buf)
{
	return ((u32) buf[0] << 24) | ((u32) buf[1] << 16) |
			((u32) buf[2] << 8) | ((u32) buf[3]);
}

static void inline put_be16(u8 *buf, u16 val)
{
	buf[0] = val >> 8;
	buf[1] = val;
}

static void inline put_be32(u8 *buf, u32 val)
{
	buf[0] = val >> 24;
	buf[1] = val >> 16;
	buf[2] = val >> 8;
	buf[3] = val & 0xff;
}


/*-------------------------------------------------------------------------*/

/*
 * DESCRIPTORS ... most are static, but strings and (full) configuration
 * descriptors are built on demand.  Also the (static) config and interface
 * descriptors are adjusted during fsg_bind().
 */
#define STRING_MANUFACTURER	1
#define STRING_PRODUCT		2
#define STRING_SERIAL		3
#define STRING_CONFIG		4
#define STRING_INTERFACE	5

/* There is only one configuration. */
#define	CONFIG_VALUE		1

static struct usb_device_descriptor
device_desc = {
	.bLength =		sizeof device_desc,
	.bDescriptorType =	USB_DT_DEVICE,

	.bcdUSB =		__constant_cpu_to_le16(0x0200),
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,

	/* The next three values can be overridden by module parameters */
	.idVendor =		__constant_cpu_to_le16(DRIVER_VENDOR_ID),
	.idProduct =		__constant_cpu_to_le16(DRIVER_PRODUCT_ID),
	.bcdDevice =		__constant_cpu_to_le16(0xffff),

	.iManufacturer =	STRING_MANUFACTURER,
	.iProduct =		STRING_PRODUCT,
	.iSerialNumber =	STRING_SERIAL,
	.bNumConfigurations =	1,
};

static struct usb_config_descriptor
config_desc = {
	.bLength =		sizeof config_desc,
	.bDescriptorType =	USB_DT_CONFIG,

	/* wTotalLength computed by usb_gadget_config_buf() */
	.bNumInterfaces =	1,
	.bConfigurationValue =	CONFIG_VALUE,
	.iConfiguration =	STRING_CONFIG,
	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
	.bMaxPower =		1,	// self-powered
};

static struct usb_otg_descriptor
otg_desc = {
	.bLength =		sizeof(otg_desc),
	.bDescriptorType =	USB_DT_OTG,

	.bmAttributes =		USB_OTG_SRP,
};

/* There is only one interface. */

static struct usb_interface_descriptor
intf_desc = {
	.bLength =		sizeof intf_desc,
	.bDescriptorType =	USB_DT_INTERFACE,

	.bNumEndpoints =	2,		// Adjusted during fsg_bind()
	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
	.bInterfaceSubClass =	USB_SC_SCSI,	// Adjusted during fsg_bind()
	.bInterfaceProtocol =	USB_PR_BULK,	// Adjusted during fsg_bind()