xref: /rk3399_rockchip-uboot/drivers/usb/gadget/storage_common.c (revision 18188f579f8222fe41bba5751e421795bd78312e)

/*
 * storage_common.c -- Common definitions for mass storage functionality
 *
 * Copyright (C) 2003-2008 Alan Stern
 * Copyeight (C) 2009 Samsung Electronics
 * Author: Michal Nazarewicz (m.nazarewicz@samsung.com)
 *
 * Ported to u-boot:
 * Andrzej Pietrasiewicz <andrzej.p@samsung.com>
 *
 * Code refactoring & cleanup:
 * Łukasz Majewski <l.majewski@samsung.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */


/*
 * This file requires the following identifiers used in USB strings to
 * be defined (each of type pointer to char):
 *  - fsg_string_manufacturer -- name of the manufacturer
 *  - fsg_string_product      -- name of the product
 *  - fsg_string_serial       -- product's serial
 *  - fsg_string_config       -- name of the configuration
 *  - fsg_string_interface    -- name of the interface
 * The first four are only needed when FSG_DESCRIPTORS_DEVICE_STRINGS
 * macro is defined prior to including this file.
 */

/*
 * When FSG_NO_INTR_EP is defined fsg_fs_intr_in_desc and
 * fsg_hs_intr_in_desc objects as well as
 * FSG_FS_FUNCTION_PRE_EP_ENTRIES and FSG_HS_FUNCTION_PRE_EP_ENTRIES
 * macros are not defined.
 *
 * When FSG_NO_DEVICE_STRINGS is defined FSG_STRING_MANUFACTURER,
 * FSG_STRING_PRODUCT, FSG_STRING_SERIAL and FSG_STRING_CONFIG are not
 * defined (as well as corresponding entries in string tables are
 * missing) and FSG_STRING_INTERFACE has value of zero.
 *
 * When FSG_NO_OTG is defined fsg_otg_desc won't be defined.
 */

/*
 * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included
 * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN
 * characters rather then a pointer to void.
 */


/* #include <asm/unaligned.h> */


/*
 * Thanks to NetChip Technologies for donating this product ID.
 *
 * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */
#define FSG_VENDOR_ID	0x0525	/* NetChip */
#define FSG_PRODUCT_ID	0xa4a5	/* Linux-USB File-backed Storage Gadget */

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

#ifndef DEBUG
#undef VERBOSE_DEBUG
#undef DUMP_MSGS
#endif /* !DEBUG */

#ifdef VERBOSE_DEBUG
#define VLDBG	LDBG
#else
#define VLDBG(lun, fmt, args...) do { } while (0)
#endif /* VERBOSE_DEBUG */

/*
#define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
#define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
#define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
#define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
*/

#define LDBG(lun, fmt, args...) do { } while (0)
#define LERROR(lun, fmt, args...) do { } while (0)
#define LWARN(lun, fmt, args...) do { } while (0)
#define LINFO(lun, fmt, args...) do { } while (0)

/*
 * Keep those macros in sync with those in
 * include/linux/usb/composite.h or else GCC will complain.  If they
 * are identical (the same names of arguments, white spaces in the
 * same places) GCC will allow redefinition otherwise (even if some
 * white space is removed or added) warning will be issued.
 *
 * Those macros are needed here because File Storage Gadget does not
 * include the composite.h header.  For composite gadgets those macros
 * are redundant since composite.h is included any way.
 *
 * One could check whether those macros are already defined (which
 * would indicate composite.h had been included) or not (which would
 * indicate we were in FSG) but this is not done because a warning is
 * desired if definitions here differ from the ones in composite.h.
 *
 * We want the definitions to match and be the same in File Storage
 * Gadget as well as Mass Storage Function (and so composite gadgets
 * using MSF).  If someone changes them in composite.h it will produce
 * a warning in this file when building MSF.
 */

#define DBG(d, fmt, args...)     debug(fmt , ## args)
#define VDBG(d, fmt, args...)    debug(fmt , ## args)
/* #define ERROR(d, fmt, args...)   printf(fmt , ## args) */
/* #define WARNING(d, fmt, args...) printf(fmt , ## args) */
/* #define INFO(d, fmt, args...)    printf(fmt , ## args) */

/* #define DBG(d, fmt, args...)     do { } while (0) */
/* #define VDBG(d, fmt, args...)    do { } while (0) */
#define ERROR(d, fmt, args...)   do { } while (0)
#define WARNING(d, fmt, args...) do { } while (0)
#define INFO(d, fmt, args...)    do { } while (0)

#ifdef DUMP_MSGS

/* dump_msg(fsg, const char * label, const u8 * buf, unsigned length); */
# define dump_msg(fsg, label, buf, length) do {                         \
	if (length < 512) {						\
		DBG(fsg, "%s, length %u:\n", label, length);		\
		print_hex_dump("", DUMP_PREFIX_OFFSET,	\
			       16, 1, buf, length, 0);			\
	}								\
} while (0)

#  define dump_cdb(fsg) do { } while (0)

#else

#  define dump_msg(fsg, /* const char * */ label, \
		   /* const u8 * */ buf, /* unsigned */ length) do { } while (0)

#  ifdef VERBOSE_DEBUG

#    define dump_cdb(fsg)						\
	print_hex_dump("SCSI CDB: ", DUMP_PREFIX_NONE,	\
		       16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)		\

#  else

#    define dump_cdb(fsg) do { } while (0)

#  endif /* VERBOSE_DEBUG */

#endif /* DUMP_MSGS */

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

/* 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 */
#define USB_PR_BULK	0x50		/* Bulk-only */

/* USB subclass value = the protocol encapsulation */
#define USB_SC_RBC	0x01		/* Reduced Block Commands (flash) */
#define USB_SC_8020	0x02		/* SFF-8020i, MMC-2, ATAPI (CD-ROM) */
#define USB_SC_QIC	0x03		/* QIC-157 (tape) */
#define USB_SC_UFI	0x04		/* UFI (floppy) */
#define USB_SC_8070	0x05		/* SFF-8070i (removable) */
#define USB_SC_SCSI	0x06		/* Transparent SCSI */

/* Bulk-only data structures */

/* Command Block Wrapper */
struct fsg_bulk_cb_wrap {
	__le32	Signature;		/* Contains 'USBC' */
	u32	Tag;			/* Unique per command id */
	__le32	DataTransferLength;	/* Size of the data */
	u8	Flags;			/* Direction in bit 7 */
	u8	Lun;			/* LUN (normally 0) */
	u8	Length;			/* Of the CDB, <= MAX_COMMAND_SIZE */
	u8	CDB[16];		/* Command Data Block */
};

#define USB_BULK_CB_WRAP_LEN	31
#define USB_BULK_CB_SIG		0x43425355	/* Spells out USBC */
#define USB_BULK_IN_FLAG	0x80

/* 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

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

/* 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_READ_HEADER			0x44
#define SC_READ_TOC			0x43
#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))

struct device_attribute { int i; };
#define ETOOSMALL	525

#include <usb_mass_storage.h>

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

struct fsg_lun {
	loff_t		file_length;
	loff_t		num_sectors;

	unsigned int	initially_ro:1;
	unsigned int	ro:1;
	unsigned int	removable:1;
	unsigned int	cdrom:1;
	unsigned int	prevent_medium_removal:1;
	unsigned int	registered:1;
	unsigned int	info_valid:1;
	unsigned int	nofua:1;

	u32		sense_data;
	u32		sense_data_info;
	u32		unit_attention_data;

	struct device	dev;
};

#define fsg_lun_is_open(curlun)	((curlun)->filp != NULL)
#if 0
static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
{
	return container_of(dev, struct fsg_lun, dev);
}
#endif

/* 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 FSG_NUM_BUFFERS	2

#if defined(CONFIG_USB_DWC3_GADGET) && defined(ROCKUSB_FSG_BUFLEN)
#define FSG_BUFLEN	((u32)ROCKUSB_FSG_BUFLEN)
#else
/* Default size of buffer length. */
#define FSG_BUFLEN	((u32)262144)
#endif

/* Maximal number of LUNs supported in mass storage function */
#define FSG_MAX_LUNS	8

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

struct fsg_buffhd {
#ifdef FSG_BUFFHD_STATIC_BUFFER
	char				buf[FSG_BUFLEN];
#else
	void				*buf;
#endif
	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;
	int				inreq_busy;
	struct usb_request		*outreq;
	int				outreq_busy;
};

enum fsg_state {
	/* This one isn't used anywhere */
	FSG_STATE_COMMAND_PHASE = -10,
	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
};

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

static inline u32 get_unaligned_be24(u8 *buf)
{
	return 0xffffff & (u32) get_unaligned_be32(buf - 1);
}

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

enum {
#ifndef FSG_NO_DEVICE_STRINGS
	FSG_STRING_MANUFACTURER	= 1,
	FSG_STRING_PRODUCT,
	FSG_STRING_SERIAL,
	FSG_STRING_CONFIG,
#endif
	FSG_STRING_INTERFACE
};

#ifndef FSG_NO_OTG
static struct usb_otg_descriptor
fsg_otg_desc = {
	.bLength =		sizeof fsg_otg_desc,
	.bDescriptorType =	USB_DT_OTG,

	.bmAttributes =		USB_OTG_SRP,
};
#endif

/* There is only one interface. */

static struct usb_interface_descriptor
fsg_intf_desc = {
	.bLength =		sizeof fsg_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() */
	.iInterface =		FSG_STRING_INTERFACE,
};

/*
 * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 * interrupt-in.
 */

static struct usb_endpoint_descriptor
fsg_fs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};

static struct usb_endpoint_descriptor
fsg_fs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};

#ifndef FSG_NO_INTR_EP

static struct usb_endpoint_descriptor
fsg_fs_intr_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	cpu_to_le16(2),
	.bInterval =		32,	/* frames -> 32 ms */
};

#ifndef FSG_NO_OTG
#  define FSG_FS_FUNCTION_PRE_EP_ENTRIES	2
#else
#  define FSG_FS_FUNCTION_PRE_EP_ENTRIES	1
#endif

#endif

static struct usb_descriptor_header *fsg_fs_function[] = {
#ifndef FSG_NO_OTG
	(struct usb_descriptor_header *) &fsg_otg_desc,
#endif
	(struct usb_descriptor_header *) &fsg_intf_desc,
	(struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
	(struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
#ifndef FSG_NO_INTR_EP
	(struct usb_descriptor_header *) &fsg_fs_intr_in_desc,
#endif
	NULL,
};

/*
 * USB 2.0 devices need to expose both high speed and full speed
 * descriptors, unless they only run at full speed.
 *
 * That means alternate endpoint descriptors (bigger packets)
 * and a "device qualifier" ... plus more construction options
 * for the configuration descriptor.
 */
static struct usb_endpoint_descriptor
fsg_hs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_endpoint_descriptor
fsg_hs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
	.bInterval =		1,	/* NAK every 1 uframe */
};

#ifndef FSG_NO_INTR_EP

static struct usb_endpoint_descriptor
fsg_hs_intr_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	cpu_to_le16(2),
	.bInterval =		9,	/* 2**(9-1) = 256 uframes -> 32 ms */
};

#ifndef FSG_NO_OTG
#  define FSG_HS_FUNCTION_PRE_EP_ENTRIES	2
#else
#  define FSG_HS_FUNCTION_PRE_EP_ENTRIES	1
#endif

#endif

static struct usb_descriptor_header *fsg_hs_function[] = {
#ifndef FSG_NO_OTG
	(struct usb_descriptor_header *) &fsg_otg_desc,
#endif
	(struct usb_descriptor_header *) &fsg_intf_desc,
	(struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
	(struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
#ifndef FSG_NO_INTR_EP
	(struct usb_descriptor_header *) &fsg_hs_intr_in_desc,
#endif
	NULL,
};

static struct usb_endpoint_descriptor
fsg_ss_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor
fsg_ss_bulk_in_comp_desc = {
	.bLength		= sizeof(fsg_ss_bulk_in_comp_desc),
	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
	/* .bMaxBurst		= DYNAMIC, */
};

static struct usb_endpoint_descriptor
fsg_ss_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor
fsg_ss_bulk_out_comp_desc = {
	.bLength		= sizeof(fsg_ss_bulk_out_comp_desc),
	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
	/* .bMaxBurst		= DYNAMIC, */
};

/* Maxpacket and other transfer characteristics vary by speed. */
static struct usb_endpoint_descriptor *
fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
	    struct usb_endpoint_descriptor *hs,
	    struct usb_endpoint_descriptor *ss,
	    struct usb_ss_ep_comp_descriptor *comp_desc,
	    struct usb_ep *ep)
{
	struct usb_endpoint_descriptor *speed_desc = NULL;

	/* select desired speed */
	switch (g->speed) {
	case USB_SPEED_SUPER:
		if (gadget_is_superspeed(g)) {
			speed_desc = ss;
			ep->comp_desc = comp_desc;
			break;
		}
		/* else: Fall trough */
	case USB_SPEED_HIGH:
		if (gadget_is_dualspeed(g)) {
			speed_desc = hs;
			break;
		}
		/* else: fall through */
	default:
		speed_desc = fs;
	}

	/*
	 * Config the ep maxpacket according to the right descriptors
	 * for a given endpoint.
	 */
	ep->maxpacket = usb_endpoint_maxp(speed_desc) & USB_ENDPOINT_MAXP_MASK;

	return speed_desc;
}

/* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
static struct usb_string		fsg_strings[] = {
#ifndef FSG_NO_DEVICE_STRINGS
	{FSG_STRING_MANUFACTURER,	fsg_string_manufacturer},
	{FSG_STRING_PRODUCT,		fsg_string_product},
	{FSG_STRING_SERIAL,		fsg_string_serial},
	{FSG_STRING_CONFIG,		fsg_string_config},
#endif
	{FSG_STRING_INTERFACE,		fsg_string_interface},
	{}
};

static struct usb_gadget_strings	fsg_stringtab = {
	.language	= 0x0409,		/* en-us */
	.strings	= fsg_strings,
};

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

/*
 * If the next two routines are called while the gadget is registered,
 * the caller must own fsg->filesem for writing.
 */

static int fsg_lun_open(struct fsg_lun *curlun, unsigned int num_sectors,
			const char *filename)
{
	int				ro;

	/* R/W if we can, R/O if we must */
	ro = curlun->initially_ro;

	curlun->ro = ro;
	curlun->file_length = num_sectors << 9;
	curlun->num_sectors = num_sectors;
	debug("open backing file: %s\n", filename);

	return 0;
}

static void fsg_lun_close(struct fsg_lun *curlun)
{
}

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

/*
 * Sync the file data, don't bother with the metadata.
 * This code was copied from fs/buffer.c:sys_fdatasync().
 */
static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
{
	return 0;
}

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 += 2*75;		/* 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_unaligned_be32(addr, dest);
	}
}

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