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ub.c
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/*
* The low performance USB storage driver (ub).
*
* Copyright (c) 1999, 2000 Matthew Dharm ([email protected])
* Copyright (C) 2004 Pete Zaitcev ([email protected])
*
* This work is a part of Linux kernel, is derived from it,
* and is not licensed separately. See file COPYING for details.
*
* TODO (sorted by decreasing priority)
* -- Kill first_open (Al Viro fixed the block layer now)
* -- Do resets with usb_device_reset (needs a thread context, use khubd)
* -- set readonly flag for CDs, set removable flag for CF readers
* -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
* -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
* -- verify the 13 conditions and do bulk resets
* -- kill last_pipe and simply do two-state clearing on both pipes
* -- verify protocol (bulk) from USB descriptors (maybe...)
* -- highmem
* -- move top_sense and work_bcs into separate allocations (if they survive)
* for cache purists and esoteric architectures.
* -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
* -- prune comments, they are too volumnous
* -- Exterminate P3 printks
* -- Resove XXX's
* -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
* -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/blkdev.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/timer.h>
#include <scsi/scsi.h>
#define DRV_NAME "ub"
#define DEVFS_NAME DRV_NAME
#define UB_MAJOR 180
/*
* The command state machine is the key model for understanding of this driver.
*
* The general rule is that all transitions are done towards the bottom
* of the diagram, thus preventing any loops.
*
* An exception to that is how the STAT state is handled. A counter allows it
* to be re-entered along the path marked with [C].
*
* +--------+
* ! INIT !
* +--------+
* !
* ub_scsi_cmd_start fails ->--------------------------------------\
* ! !
* V !
* +--------+ !
* ! CMD ! !
* +--------+ !
* ! +--------+ !
* was -EPIPE -->-------------------------------->! CLEAR ! !
* ! +--------+ !
* ! ! !
* was error -->------------------------------------- ! --------->\
* ! ! !
* /--<-- cmd->dir == NONE ? ! !
* ! ! ! !
* ! V ! !
* ! +--------+ ! !
* ! ! DATA ! ! !
* ! +--------+ ! !
* ! ! +---------+ ! !
* ! was -EPIPE -->--------------->! CLR2STS ! ! !
* ! ! +---------+ ! !
* ! ! ! ! !
* ! ! was error -->---- ! --------->\
* ! was error -->--------------------- ! ------------- ! --------->\
* ! ! ! ! !
* ! V ! ! !
* \--->+--------+ ! ! !
* ! STAT !<--------------------------/ ! !
* /--->+--------+ ! !
* ! ! ! !
* [C] was -EPIPE -->-----------\ ! !
* ! ! ! ! !
* +<---- len == 0 ! ! !
* ! ! ! ! !
* ! was error -->--------------------------------------!---------->\
* ! ! ! ! !
* +<---- bad CSW ! ! !
* +<---- bad tag ! ! !
* ! ! V ! !
* ! ! +--------+ ! !
* ! ! ! CLRRS ! ! !
* ! ! +--------+ ! !
* ! ! ! ! !
* \------- ! --------------------[C]--------\ ! !
* ! ! ! !
* cmd->error---\ +--------+ ! !
* ! +--------------->! SENSE !<----------/ !
* STAT_FAIL----/ +--------+ !
* ! ! V
* ! V +--------+
* \--------------------------------\--------------------->! DONE !
* +--------+
*/
/*
* Definitions which have to be scattered once we understand the layout better.
*/
/* Transport (despite PR in the name) */
#define US_PR_BULK 0x50 /* bulk only */
/* Protocol */
#define US_SC_SCSI 0x06 /* Transparent */
/*
* This many LUNs per USB device.
* Every one of them takes a host, see UB_MAX_HOSTS.
*/
#define UB_MAX_LUNS 9
/*
*/
#define UB_MINORS_PER_MAJOR 8
#define UB_MAX_CDB_SIZE 16 /* Corresponds to Bulk */
#define UB_SENSE_SIZE 18
/*
*/
/* command block wrapper */
struct bulk_cb_wrap {
__le32 Signature; /* contains 'USBC' */
u32 Tag; /* unique per command id */
__le32 DataTransferLength; /* size of data */
u8 Flags; /* direction in bit 0 */
u8 Lun; /* LUN */
u8 Length; /* of of the CDB */
u8 CDB[UB_MAX_CDB_SIZE]; /* max command */
};
#define US_BULK_CB_WRAP_LEN 31
#define US_BULK_CB_SIGN 0x43425355 /*spells out USBC */
#define US_BULK_FLAG_IN 1
#define US_BULK_FLAG_OUT 0
/* 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 US_BULK_CS_WRAP_LEN 13
#define US_BULK_CS_SIGN 0x53425355 /* spells out 'USBS' */
#define US_BULK_STAT_OK 0
#define US_BULK_STAT_FAIL 1
#define US_BULK_STAT_PHASE 2
/* bulk-only class specific requests */
#define US_BULK_RESET_REQUEST 0xff
#define US_BULK_GET_MAX_LUN 0xfe
/*
*/
struct ub_dev;
#define UB_MAX_REQ_SG 9 /* cdrecord requires 32KB and maybe a header */
#define UB_MAX_SECTORS 64
/*
* A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
* even if a webcam hogs the bus, but some devices need time to spin up.
*/
#define UB_URB_TIMEOUT (HZ*2)
#define UB_DATA_TIMEOUT (HZ*5) /* ZIP does spin-ups in the data phase */
#define UB_STAT_TIMEOUT (HZ*5) /* Same spinups and eject for a dataless cmd. */
#define UB_CTRL_TIMEOUT (HZ/2) /* 500ms ought to be enough to clear a stall */
/*
* An instance of a SCSI command in transit.
*/
#define UB_DIR_NONE 0
#define UB_DIR_READ 1
#define UB_DIR_ILLEGAL2 2
#define UB_DIR_WRITE 3
#define UB_DIR_CHAR(c) (((c)==UB_DIR_WRITE)? 'w': \
(((c)==UB_DIR_READ)? 'r': 'n'))
enum ub_scsi_cmd_state {
UB_CMDST_INIT, /* Initial state */
UB_CMDST_CMD, /* Command submitted */
UB_CMDST_DATA, /* Data phase */
UB_CMDST_CLR2STS, /* Clearing before requesting status */
UB_CMDST_STAT, /* Status phase */
UB_CMDST_CLEAR, /* Clearing a stall (halt, actually) */
UB_CMDST_CLRRS, /* Clearing before retrying status */
UB_CMDST_SENSE, /* Sending Request Sense */
UB_CMDST_DONE /* Final state */
};
static char *ub_scsi_cmd_stname[] = {
". ",
"Cmd",
"dat",
"c2s",
"sts",
"clr",
"crs",
"Sen",
"fin"
};
struct ub_scsi_cmd {
unsigned char cdb[UB_MAX_CDB_SIZE];
unsigned char cdb_len;
unsigned char dir; /* 0 - none, 1 - read, 3 - write. */
unsigned char trace_index;
enum ub_scsi_cmd_state state;
unsigned int tag;
struct ub_scsi_cmd *next;
int error; /* Return code - valid upon done */
unsigned int act_len; /* Return size */
unsigned char key, asc, ascq; /* May be valid if error==-EIO */
int stat_count; /* Retries getting status. */
unsigned int len; /* Requested length */
unsigned int current_sg;
unsigned int nsg; /* sgv[nsg] */
struct scatterlist sgv[UB_MAX_REQ_SG];
struct ub_lun *lun;
void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
void *back;
};
/*
*/
struct ub_capacity {
unsigned long nsec; /* Linux size - 512 byte sectors */
unsigned int bsize; /* Linux hardsect_size */
unsigned int bshift; /* Shift between 512 and hard sects */
};
/*
* The SCSI command tracing structure.
*/
#define SCMD_ST_HIST_SZ 8
#define SCMD_TRACE_SZ 63 /* Less than 4KB of 61-byte lines */
struct ub_scsi_cmd_trace {
int hcur;
unsigned int tag;
unsigned int req_size, act_size;
unsigned char op;
unsigned char dir;
unsigned char key, asc, ascq;
char st_hst[SCMD_ST_HIST_SZ];
};
struct ub_scsi_trace {
int cur;
struct ub_scsi_cmd_trace vec[SCMD_TRACE_SZ];
};
/*
* This is a direct take-off from linux/include/completion.h
* The difference is that I do not wait on this thing, just poll.
* When I want to wait (ub_probe), I just use the stock completion.
*
* Note that INIT_COMPLETION takes no lock. It is correct. But why
* in the bloody hell that thing takes struct instead of pointer to struct
* is quite beyond me. I just copied it from the stock completion.
*/
struct ub_completion {
unsigned int done;
spinlock_t lock;
};
static inline void ub_init_completion(struct ub_completion *x)
{
x->done = 0;
spin_lock_init(&x->lock);
}
#define UB_INIT_COMPLETION(x) ((x).done = 0)
static void ub_complete(struct ub_completion *x)
{
unsigned long flags;
spin_lock_irqsave(&x->lock, flags);
x->done++;
spin_unlock_irqrestore(&x->lock, flags);
}
static int ub_is_completed(struct ub_completion *x)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&x->lock, flags);
ret = x->done;
spin_unlock_irqrestore(&x->lock, flags);
return ret;
}
/*
*/
struct ub_scsi_cmd_queue {
int qlen, qmax;
struct ub_scsi_cmd *head, *tail;
};
/*
* The block device instance (one per LUN).
*/
struct ub_lun {
struct ub_dev *udev;
struct list_head link;
struct gendisk *disk;
int id; /* Host index */
int num; /* LUN number */
char name[16];
int changed; /* Media was changed */
int removable;
int readonly;
int first_open; /* Kludge. See ub_bd_open. */
/* Use Ingo's mempool if or when we have more than one command. */
/*
* Currently we never need more than one command for the whole device.
* However, giving every LUN a command is a cheap and automatic way
* to enforce fairness between them.
*/
int cmda[1];
struct ub_scsi_cmd cmdv[1];
struct ub_capacity capacity;
};
/*
* The USB device instance.
*/
struct ub_dev {
spinlock_t lock;
atomic_t poison; /* The USB device is disconnected */
int openc; /* protected by ub_lock! */
/* kref is too implicit for our taste */
unsigned int tagcnt;
char name[12];
struct usb_device *dev;
struct usb_interface *intf;
struct list_head luns;
unsigned int send_bulk_pipe; /* cached pipe values */
unsigned int recv_bulk_pipe;
unsigned int send_ctrl_pipe;
unsigned int recv_ctrl_pipe;
struct tasklet_struct tasklet;
struct ub_scsi_cmd_queue cmd_queue;
struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
unsigned char top_sense[UB_SENSE_SIZE];
struct ub_completion work_done;
struct urb work_urb;
struct timer_list work_timer;
int last_pipe; /* What might need clearing */
__le32 signature; /* Learned signature */
struct bulk_cb_wrap work_bcb;
struct bulk_cs_wrap work_bcs;
struct usb_ctrlrequest work_cr;
int sg_stat[6];
struct ub_scsi_trace tr;
};
/*
*/
static void ub_cleanup(struct ub_dev *sc);
static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
struct ub_scsi_cmd *cmd, struct request *rq);
static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
struct ub_scsi_cmd *cmd, struct request *rq);
static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_end_rq(struct request *rq, int uptodate);
static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
static void ub_scsi_action(unsigned long _dev);
static void ub_scsi_dispatch(struct ub_dev *sc);
static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
int stalled_pipe);
static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
struct ub_capacity *ret);
static int ub_probe_lun(struct ub_dev *sc, int lnum);
/*
*/
static struct usb_device_id ub_usb_ids[] = {
// { USB_DEVICE_VER(0x0781, 0x0002, 0x0009, 0x0009) }, /* SDDR-31 */
{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
{ }
};
MODULE_DEVICE_TABLE(usb, ub_usb_ids);
/*
* Find me a way to identify "next free minor" for add_disk(),
* and the array disappears the next day. However, the number of
* hosts has something to do with the naming and /proc/partitions.
* This has to be thought out in detail before changing.
* If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
*/
#define UB_MAX_HOSTS 26
static char ub_hostv[UB_MAX_HOSTS];
static DEFINE_SPINLOCK(ub_lock); /* Locks globals and ->openc */
/*
* The SCSI command tracing procedures.
*/
static void ub_cmdtr_new(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
int n;
struct ub_scsi_cmd_trace *t;
if ((n = sc->tr.cur + 1) == SCMD_TRACE_SZ) n = 0;
t = &sc->tr.vec[n];
memset(t, 0, sizeof(struct ub_scsi_cmd_trace));
t->tag = cmd->tag;
t->op = cmd->cdb[0];
t->dir = cmd->dir;
t->req_size = cmd->len;
t->st_hst[0] = cmd->state;
sc->tr.cur = n;
cmd->trace_index = n;
}
static void ub_cmdtr_state(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
int n;
struct ub_scsi_cmd_trace *t;
t = &sc->tr.vec[cmd->trace_index];
if (t->tag == cmd->tag) {
if ((n = t->hcur + 1) == SCMD_ST_HIST_SZ) n = 0;
t->st_hst[n] = cmd->state;
t->hcur = n;
}
}
static void ub_cmdtr_act_len(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
struct ub_scsi_cmd_trace *t;
t = &sc->tr.vec[cmd->trace_index];
if (t->tag == cmd->tag)
t->act_size = cmd->act_len;
}
static void ub_cmdtr_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
unsigned char *sense)
{
struct ub_scsi_cmd_trace *t;
t = &sc->tr.vec[cmd->trace_index];
if (t->tag == cmd->tag) {
t->key = sense[2] & 0x0F;
t->asc = sense[12];
t->ascq = sense[13];
}
}
static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr,
char *page)
{
struct usb_interface *intf;
struct ub_dev *sc;
struct list_head *p;
struct ub_lun *lun;
int cnt;
unsigned long flags;
int nc, nh;
int i, j;
struct ub_scsi_cmd_trace *t;
intf = to_usb_interface(dev);
sc = usb_get_intfdata(intf);
if (sc == NULL)
return 0;
cnt = 0;
spin_lock_irqsave(&sc->lock, flags);
cnt += sprintf(page + cnt,
"qlen %d qmax %d\n",
sc->cmd_queue.qlen, sc->cmd_queue.qmax);
cnt += sprintf(page + cnt,
"sg %d %d %d %d %d .. %d\n",
sc->sg_stat[0],
sc->sg_stat[1],
sc->sg_stat[2],
sc->sg_stat[3],
sc->sg_stat[4],
sc->sg_stat[5]);
list_for_each (p, &sc->luns) {
lun = list_entry(p, struct ub_lun, link);
cnt += sprintf(page + cnt,
"lun %u changed %d removable %d readonly %d\n",
lun->num, lun->changed, lun->removable, lun->readonly);
}
if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
for (j = 0; j < SCMD_TRACE_SZ; j++) {
t = &sc->tr.vec[nc];
cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
if (t->op == REQUEST_SENSE) {
cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
t->key, t->asc, t->ascq);
} else {
cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
cnt += sprintf(page + cnt, " [%5d %5d]",
t->req_size, t->act_size);
}
if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
cnt += sprintf(page + cnt, " %s",
ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
if (++nh == SCMD_ST_HIST_SZ) nh = 0;
}
cnt += sprintf(page + cnt, "\n");
if (++nc == SCMD_TRACE_SZ) nc = 0;
}
spin_unlock_irqrestore(&sc->lock, flags);
return cnt;
}
static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
/*
* The id allocator.
*
* This also stores the host for indexing by minor, which is somewhat dirty.
*/
static int ub_id_get(void)
{
unsigned long flags;
int i;
spin_lock_irqsave(&ub_lock, flags);
for (i = 0; i < UB_MAX_HOSTS; i++) {
if (ub_hostv[i] == 0) {
ub_hostv[i] = 1;
spin_unlock_irqrestore(&ub_lock, flags);
return i;
}
}
spin_unlock_irqrestore(&ub_lock, flags);
return -1;
}
static void ub_id_put(int id)
{
unsigned long flags;
if (id < 0 || id >= UB_MAX_HOSTS) {
printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
return;
}
spin_lock_irqsave(&ub_lock, flags);
if (ub_hostv[id] == 0) {
spin_unlock_irqrestore(&ub_lock, flags);
printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
return;
}
ub_hostv[id] = 0;
spin_unlock_irqrestore(&ub_lock, flags);
}
/*
* Downcount for deallocation. This rides on two assumptions:
* - once something is poisoned, its refcount cannot grow
* - opens cannot happen at this time (del_gendisk was done)
* If the above is true, we can drop the lock, which we need for
* blk_cleanup_queue(): the silly thing may attempt to sleep.
* [Actually, it never needs to sleep for us, but it calls might_sleep()]
*/
static void ub_put(struct ub_dev *sc)
{
unsigned long flags;
spin_lock_irqsave(&ub_lock, flags);
--sc->openc;
if (sc->openc == 0 && atomic_read(&sc->poison)) {
spin_unlock_irqrestore(&ub_lock, flags);
ub_cleanup(sc);
} else {
spin_unlock_irqrestore(&ub_lock, flags);
}
}
/*
* Final cleanup and deallocation.
*/
static void ub_cleanup(struct ub_dev *sc)
{
struct list_head *p;
struct ub_lun *lun;
request_queue_t *q;
while (!list_empty(&sc->luns)) {
p = sc->luns.next;
lun = list_entry(p, struct ub_lun, link);
list_del(p);
/* I don't think queue can be NULL. But... Stolen from sx8.c */
if ((q = lun->disk->queue) != NULL)
blk_cleanup_queue(q);
/*
* If we zero disk->private_data BEFORE put_disk, we have
* to check for NULL all over the place in open, release,
* check_media and revalidate, because the block level
* semaphore is well inside the put_disk.
* But we cannot zero after the call, because *disk is gone.
* The sd.c is blatantly racy in this area.
*/
/* disk->private_data = NULL; */
put_disk(lun->disk);
lun->disk = NULL;
ub_id_put(lun->id);
kfree(lun);
}
kfree(sc);
}
/*
* The "command allocator".
*/
static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
{
struct ub_scsi_cmd *ret;
if (lun->cmda[0])
return NULL;
ret = &lun->cmdv[0];
lun->cmda[0] = 1;
return ret;
}
static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
{
if (cmd != &lun->cmdv[0]) {
printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
lun->name, cmd);
return;
}
if (!lun->cmda[0]) {
printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
return;
}
lun->cmda[0] = 0;
}
/*
* The command queue.
*/
static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
if (t->qlen++ == 0) {
t->head = cmd;
t->tail = cmd;
} else {
t->tail->next = cmd;
t->tail = cmd;
}
if (t->qlen > t->qmax)
t->qmax = t->qlen;
}
static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
if (t->qlen++ == 0) {
t->head = cmd;
t->tail = cmd;
} else {
cmd->next = t->head;
t->head = cmd;
}
if (t->qlen > t->qmax)
t->qmax = t->qlen;
}
static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
{
struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
struct ub_scsi_cmd *cmd;
if (t->qlen == 0)
return NULL;
if (--t->qlen == 0)
t->tail = NULL;
cmd = t->head;
t->head = cmd->next;
cmd->next = NULL;
return cmd;
}
#define ub_cmdq_peek(sc) ((sc)->cmd_queue.head)
/*
* The request function is our main entry point
*/
static void ub_request_fn(request_queue_t *q)
{
struct ub_lun *lun = q->queuedata;
struct request *rq;
while ((rq = elv_next_request(q)) != NULL) {
if (ub_request_fn_1(lun, rq) != 0) {
blk_stop_queue(q);
break;
}
}
}
static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
{
struct ub_dev *sc = lun->udev;
struct ub_scsi_cmd *cmd;
int rc;
if (atomic_read(&sc->poison) || lun->changed) {
blkdev_dequeue_request(rq);
ub_end_rq(rq, 0);
return 0;
}
if ((cmd = ub_get_cmd(lun)) == NULL)
return -1;
memset(cmd, 0, sizeof(struct ub_scsi_cmd));
blkdev_dequeue_request(rq);
if (blk_pc_request(rq)) {
rc = ub_cmd_build_packet(sc, lun, cmd, rq);
} else {
rc = ub_cmd_build_block(sc, lun, cmd, rq);
}
if (rc != 0) {
ub_put_cmd(lun, cmd);
ub_end_rq(rq, 0);
return 0;
}
cmd->state = UB_CMDST_INIT;
cmd->lun = lun;
cmd->done = ub_rw_cmd_done;
cmd->back = rq;
cmd->tag = sc->tagcnt++;
if (ub_submit_scsi(sc, cmd) != 0) {
ub_put_cmd(lun, cmd);
ub_end_rq(rq, 0);
return 0;
}
return 0;
}
static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
struct ub_scsi_cmd *cmd, struct request *rq)
{
int ub_dir;
int n_elem;
unsigned int block, nblks;
if (rq_data_dir(rq) == WRITE)
ub_dir = UB_DIR_WRITE;
else
ub_dir = UB_DIR_READ;
cmd->dir = ub_dir;
/*
* get scatterlist from block layer
*/
n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
if (n_elem <= 0) {
printk(KERN_INFO "%s: failed request map (%d)\n",
sc->name, n_elem); /* P3 */
return -1; /* request with no s/g entries? */
}
if (n_elem > UB_MAX_REQ_SG) { /* Paranoia */
printk(KERN_WARNING "%s: request with %d segments\n",
sc->name, n_elem);
return -1;
}
cmd->nsg = n_elem;
sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
/*
* build the command
*
* The call to blk_queue_hardsect_size() guarantees that request
* is aligned, but it is given in terms of 512 byte units, always.
*/
block = rq->sector >> lun->capacity.bshift;
nblks = rq->nr_sectors >> lun->capacity.bshift;
cmd->cdb[0] = (ub_dir == UB_DIR_READ)? READ_10: WRITE_10;
/* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
cmd->cdb[2] = block >> 24;
cmd->cdb[3] = block >> 16;
cmd->cdb[4] = block >> 8;
cmd->cdb[5] = block;
cmd->cdb[7] = nblks >> 8;
cmd->cdb[8] = nblks;
cmd->cdb_len = 10;
cmd->len = rq->nr_sectors * 512;
return 0;
}
static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
struct ub_scsi_cmd *cmd, struct request *rq)
{
int n_elem;
if (rq->data_len == 0) {
cmd->dir = UB_DIR_NONE;
} else {
if (rq_data_dir(rq) == WRITE)
cmd->dir = UB_DIR_WRITE;
else
cmd->dir = UB_DIR_READ;
}
/*
* get scatterlist from block layer
*/
n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
if (n_elem < 0) {
printk(KERN_INFO "%s: failed request map (%d)\n",
sc->name, n_elem); /* P3 */
return -1;
}
if (n_elem > UB_MAX_REQ_SG) { /* Paranoia */
printk(KERN_WARNING "%s: request with %d segments\n",
sc->name, n_elem);
return -1;
}
cmd->nsg = n_elem;
sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
cmd->cdb_len = rq->cmd_len;
cmd->len = rq->data_len;
return 0;
}
static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
struct request *rq = cmd->back;
struct ub_lun *lun = cmd->lun;
int uptodate;
if (cmd->error == 0) {
uptodate = 1;
if (blk_pc_request(rq)) {
if (cmd->act_len >= rq->data_len)
rq->data_len = 0;
else
rq->data_len -= cmd->act_len;
}
} else {
uptodate = 0;
if (blk_pc_request(rq)) {
/* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
rq->sense_len = UB_SENSE_SIZE;
if (sc->top_sense[0] != 0)
rq->errors = SAM_STAT_CHECK_CONDITION;
else
rq->errors = DID_ERROR << 16;
}
}
ub_put_cmd(lun, cmd);
ub_end_rq(rq, uptodate);
blk_start_queue(lun->disk->queue);
}
static void ub_end_rq(struct request *rq, int uptodate)
{
int rc;
rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
// assert(rc == 0);
end_that_request_last(rq);
}
/*
* Submit a regular SCSI operation (not an auto-sense).
*
* The Iron Law of Good Submit Routine is:
* Zero return - callback is done, Nonzero return - callback is not done.
* No exceptions.
*
* Host is assumed locked.
*
* XXX We only support Bulk for the moment.
*/
static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
if (cmd->state != UB_CMDST_INIT ||
(cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
return -EINVAL;
}
ub_cmdq_add(sc, cmd);
/*
* We can call ub_scsi_dispatch(sc) right away here, but it's a little
* safer to jump to a tasklet, in case upper layers do something silly.
*/
tasklet_schedule(&sc->tasklet);
return 0;
}
/*
* Submit the first URB for the queued command.
* This function does not deal with queueing in any way.
*/
static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
struct bulk_cb_wrap *bcb;
int rc;
bcb = &sc->work_bcb;
/*
* ``If the allocation length is eighteen or greater, and a device
* server returns less than eithteen bytes of data, the application
* client should assume that the bytes not transferred would have been
* zeroes had the device server returned those bytes.''
*
* We zero sense for all commands so that when a packet request
* fails it does not return a stale sense.
*/
memset(&sc->top_sense, 0, UB_SENSE_SIZE);
/* set up the command wrapper */
bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
bcb->Tag = cmd->tag; /* Endianness is not important */