diff options
Diffstat (limited to 'drivers/usb/gadget/storage_common.c')
| -rw-r--r-- | drivers/usb/gadget/storage_common.c | 778 |
1 files changed, 778 insertions, 0 deletions
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c new file mode 100644 index 000000000000..868d8ee86756 --- /dev/null +++ b/drivers/usb/gadget/storage_common.c @@ -0,0 +1,778 @@ +/* + * 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) + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + + +/* + * 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) + +/* Keep those macros in sync with thos in + * include/linux/ubs/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. No + * checking if those symbols is defined is performed because warning + * is desired when those macros were defined by someone else to mean + * something else. */ +#define DBG(d, fmt, args...) dev_dbg(&(d)->gadget->dev , fmt , ## args) +#define VDBG(d, fmt, args...) dev_vdbg(&(d)->gadget->dev , fmt , ## args) +#define ERROR(d, fmt, args...) dev_err(&(d)->gadget->dev , fmt , ## args) +#define WARNING(d, fmt, args...) dev_warn(&(d)->gadget->dev , fmt , ## args) +#define INFO(d, fmt, args...) dev_info(&(d)->gadget->dev , fmt , ## args) + + + +#ifdef DUMP_MSGS + +# define dump_msg(fsg, /* const char * */ label, \ + /* const u8 * */ buf, /* unsigned */ length) do { \ + if (length < 512) { \ + DBG(fsg, "%s, length %u:\n", label, length); \ + print_hex_dump(KERN_DEBUG, "", 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(KERN_DEBUG, "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 fsg_lun { + struct file *filp; + 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; + + u32 sense_data; + u32 sense_data_info; + u32 unit_attention_data; + + struct device dev; +}; + +#define fsg_lun_is_open(curlun) ((curlun)->filp != NULL) + +static struct fsg_lun *fsg_lun_from_dev(struct device *dev) +{ + return container_of(dev, struct fsg_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 FSG_NUM_BUFFERS 2 + +/* Default size of buffer length. */ +#define FSG_BUFLEN ((u32)16384) + +/* 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 config 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, +}; + +/* 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) +{ + if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) + return hs; + return fs; +} + + +/* 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, const char *filename) +{ + int ro; + struct file *filp = NULL; + int rc = -EINVAL; + 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->initially_ro; + if (!ro) { + filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0); + if (-EROFS == PTR_ERR(filp)) + ro = 1; + } + if (ro) + filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0); + if (IS_ERR(filp)) { + LINFO(curlun, "unable to open backing file: %s\n", filename); + return PTR_ERR(filp); + } + + if (!(filp->f_mode & FMODE_WRITE)) + ro = 1; + + if (filp->f_path.dentry) + inode = filp->f_path.dentry->d_inode; + if (inode && S_ISBLK(inode->i_mode)) { + if (bdev_read_only(inode->i_bdev)) + ro = 1; + } else if (!inode || !S_ISREG(inode->i_mode)) { + LINFO(curlun, "invalid file type: %s\n", filename); + goto out; + } + + /* If we can't read the file, it's no good. + * If we can't write the file, use it read-only. */ + if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) { + LINFO(curlun, "file not readable: %s\n", filename); + goto out; + } + if (!(filp->f_op->write || filp->f_op->aio_write)) + ro = 1; + + size = i_size_read(inode->i_mapping->host); + if (size < 0) { + LINFO(curlun, "unable to find file size: %s\n", filename); + rc = (int) size; + goto out; + } + num_sectors = size >> 9; /* File size in 512-byte blocks */ + min_sectors = 1; + if (curlun->cdrom) { + num_sectors &= ~3; /* Reduce to a multiple of 2048 */ + min_sectors = 300*4; /* Smallest track is 300 frames */ + if (num_sectors >= 256*60*75*4) { + num_sectors = (256*60*75 - 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; + } + + get_file(filp); + curlun->ro = ro; + curlun->filp = filp; + curlun->file_length = size; + curlun->num_sectors = num_sectors; + LDBG(curlun, "open backing file: %s\n", filename); + rc = 0; + +out: + filp_close(filp, current->files); + return rc; +} + + +static void fsg_lun_close(struct fsg_lun *curlun) +{ + if (curlun->filp) { + LDBG(curlun, "close backing file\n"); + fput(curlun->filp); + curlun->filp = NULL; + } +} + + +/*-------------------------------------------------------------------------*/ + +/* 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) +{ + struct file *filp = curlun->filp; + + if (curlun->ro || !filp) + return 0; + return vfs_fsync(filp, filp->f_path.dentry, 1); +} + +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); + } +} + + +/*-------------------------------------------------------------------------*/ + + +static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct fsg_lun *curlun = fsg_lun_from_dev(dev); + + return sprintf(buf, "%d\n", fsg_lun_is_open(curlun) + ? curlun->ro + : curlun->initially_ro); +} + +static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct fsg_lun *curlun = fsg_lun_from_dev(dev); + struct rw_semaphore *filesem = dev_get_drvdata(dev); + char *p; + ssize_t rc; + + down_read(filesem); + if (fsg_lun_is_open(curlun)) { /* Get the complete pathname */ + p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1); + if (IS_ERR(p)) + rc = PTR_ERR(p); + else { + rc = strlen(p); + memmove(buf, p, rc); + buf[rc] = '\n'; /* Add a newline */ + buf[++rc] = 0; + } + } else { /* No file, return 0 bytes */ + *buf = 0; + rc = 0; + } + up_read(filesem); + return rc; +} + + +static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + ssize_t rc = count; + struct fsg_lun *curlun = fsg_lun_from_dev(dev); + struct rw_semaphore *filesem = dev_get_drvdata(dev); + int i; + + if (sscanf(buf, "%d", &i) != 1) + return -EINVAL; + + /* Allow the write-enable status to change only while the backing file + * is closed. */ + down_read(filesem); + if (fsg_lun_is_open(curlun)) { + LDBG(curlun, "read-only status change prevented\n"); + rc = -EBUSY; + } else { + curlun->ro = !!i; + curlun->initially_ro = !!i; + LDBG(curlun, "read-only status set to %d\n", curlun->ro); + } + up_read(filesem); + return rc; +} + +static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct fsg_lun *curlun = fsg_lun_from_dev(dev); + struct rw_semaphore *filesem = dev_get_drvdata(dev); + int rc = 0; + + if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) { + LDBG(curlun, "eject attempt prevented\n"); + return -EBUSY; /* "Door is locked" */ + } + + /* Remove a trailing newline */ + if (count > 0 && buf[count-1] == '\n') + ((char *) buf)[count-1] = 0; /* Ugh! */ + + /* Eject current medium */ + down_write(filesem); + if (fsg_lun_is_open(curlun)) { + fsg_lun_close(curlun); + curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT; + } + + /* Load new medium */ + if (count > 0 && buf[0]) { + rc = fsg_lun_open(curlun, buf); + if (rc == 0) + curlun->unit_attention_data = + SS_NOT_READY_TO_READY_TRANSITION; + } + up_write(filesem); + return (rc < 0 ? rc : count); +} |