/*
* SCSI target kernel/user interface functions
*
* Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
* Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <linux/miscdevice.h>
#include <linux/file.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tgt.h>
#include <scsi/scsi_tgt_if.h>
#include <asm/cacheflush.h>
#include "scsi_tgt_priv.h"
#if TGT_RING_SIZE < PAGE_SIZE
# define TGT_RING_SIZE PAGE_SIZE
#endif
#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
struct tgt_ring {
u32 tr_idx;
unsigned long tr_pages[TGT_RING_PAGES];
spinlock_t tr_lock;
};
/* tx_ring : kernel->user, rx_ring : user->kernel */
static struct tgt_ring tx_ring, rx_ring;
static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);
static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
{
if (ring->tr_idx == TGT_MAX_EVENTS - 1)
ring->tr_idx = 0;
else
ring->tr_idx++;
}
static struct tgt_event *tgt_head_event(struct tgt_ring *ring, u32 idx)
{
u32 pidx, off;
pidx = idx / TGT_EVENT_PER_PAGE;
off = idx % TGT_EVENT_PER_PAGE;
return (struct tgt_event *)
(ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
}
static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
{
struct tgt_event *ev;
struct tgt_ring *ring = &tx_ring;
unsigned long flags;
int err = 0;
spin_lock_irqsave(&ring->tr_lock, flags);
ev = tgt_head_event(ring, ring->tr_idx);
if (!ev->hdr.status)
tgt_ring_idx_inc(ring);
else
err = -BUSY;
spin_unlock_irqrestore(&ring->tr_lock, flags);
if (err)
return err;
memcpy(ev, p, sizeof(*ev));
ev->hdr.type = type;
mb();
ev->hdr.status = 1;
flush_dcache_page(virt_to_page(ev));
wake_up_interruptible(&tgt_poll_wait);
return 0;
}
int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 tag)
{
struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
struct tgt_event ev;
int err;
memset(&ev, 0, sizeof(ev));
ev.p.cmd_req.host_no = shost->host_no;
ev.p.cmd_req.data_len = cmd->request_bufflen;
memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
ev.p.cmd_req.attribute = cmd->tag;
ev.p.cmd_req.tag = tag;
dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
ev.p.cmd_req.data_len, cmd->tag,
(unsigned long long) ev.p.cmd_req.tag);
err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
if (err)
eprintk("tx buf is full, could not send\n");
return err;
}
int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
{
struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
struct tgt_event ev;
int err;
memset(&ev, 0, sizeof(ev));
ev.p.cmd_done.host_no = shost->host_no;
ev.p.cmd_done.tag = tag;
ev.p.cmd_done.result = cmd->result;
dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
(unsigned long long) ev.p.cmd_req.tag,
ev.p.cmd_req.data_len, cmd->tag);
err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
if (err)
eprintk("tx buf is full, could not send\n");
return err;
}
int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
struct scsi_lun *scsilun, void *data)
{
struct tgt_event ev;
int err;
memset(&ev, 0, sizeof(ev));
ev.p.tsk_mgmt_req.host_no = host_no;
ev.p.tsk_mgmt_req.function = function;
ev.p.tsk_mgmt_req.tag = tag;
memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;
dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
(unsigned long long) ev.p.tsk_mgmt_req.mid);
err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
if (err)
eprintk("tx buf is full, could not send\n");
return err;
}
static int event_recv_msg(struct tgt_event *ev)
{
int err = 0;
switch (ev->hdr.type) {
case TGT_UEVENT_CMD_RSP:
err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
ev->p.cmd_rsp.tag,
ev->p.cmd_rsp.result,
ev->p.cmd_rsp.len,
ev->p.cmd_rsp.uaddr,
ev->p.cmd_rsp.rw);
break;
case TGT_UEVENT_TSK_MGMT_RSP:
err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
ev->p.tsk_mgmt_rsp.mid,
ev->p.tsk_mgmt_rsp.result);
break;
default:
eprintk("unknown type %d\n", ev->hdr.type);
err = -EINVAL;
}
return err;
}
static ssize_t tgt_write(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
struct tgt_event *ev;
struct tgt_ring *ring = &rx_ring;
while (1) {
ev = tgt_head_event(ring, ring->tr_idx);
/* do we need this? */
flush_dcache_page(virt_to_page(ev));
if (!ev->hdr.status)
break;
tgt_ring_idx_inc(ring);
event_recv_msg(ev);
ev->hdr.status = 0;
};
return count;
}
static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
{
struct tgt_event *ev;
struct tgt_ring *ring = &tx_ring;
unsigned long flags;
unsigned int mask = 0;
u32 idx;
poll_wait(file, &tgt_poll_wait, wait);
spin_lock_irqsave(&ring->tr_lock, flags);
idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
ev = tgt_head_event(ring, idx);
if (ev->hdr.status)
mask |= POLLIN | POLLRDNORM;
spin_unlock_irqrestore(&ring->tr_lock, flags);
return mask;
}
static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
struct tgt_ring *ring)
{
int i, err;
for (i = 0; i < TGT_RING_PAGES; i++) {
struct page *page = virt_to_page(ring->tr_pages[i]);
err = vm_insert_page(vma, addr, page);
if (err)
return err;
addr += PAGE_SIZE;
}
return 0;
}
static int tgt_mmap(struct file *filp, struct vm_area_struct *vma)
{
unsigned long addr;
int err;
if (vma->vm_pgoff)
return -EINVAL;
if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
eprintk("mmap size must be %lu, not %lu \n",
TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
return -EINVAL;
}
addr = vma->vm_start;
err = uspace_ring_map(vma, addr, &tx_ring);
if (err)
return err;
err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);
return err;
}
static int tgt_open(struct inode *inode, struct file *file)
{
tx_ring.tr_idx = rx_ring.tr_idx = 0;
return 0;
}
static const struct file_operations tgt_fops = {
.owner = THIS_MODULE,
.open = tgt_open,
.poll = tgt_poll,
.write = tgt_write,
.mmap = tgt_mmap,
};
static struct miscdevice tgt_miscdev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "tgt",
.fops = &tgt_fops,
};
static void tgt_ring_exit(struct tgt_ring *ring)
{
int i;
for (i = 0; i < TGT_RING_PAGES; i++)
free_page(ring->tr_pages[i]);
}
static int tgt_ring_init(struct tgt_ring *ring)
{
int i;
spin_lock_init(&ring->tr_lock);
for (i = 0; i < TGT_RING_PAGES; i++) {
ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
if (!ring->tr_pages[i]) {
eprintk("out of memory\n");
return -ENOMEM;
}
}
return 0;
}
void scsi_tgt_if_exit(void)
{
tgt_ring_exit(&tx_ring);
tgt_ring_exit(&rx_ring);
misc_deregister(&tgt_miscdev);
}
int scsi_tgt_if_init(void)
{
int err;
err = tgt_ring_init(&tx_ring);
if (err)
return err;
err = tgt_ring_init(&rx_ring);
if (err)
goto free_tx_ring;
err = misc_register(&tgt_miscdev);
if (err)
goto free_rx_ring;
return 0;
free_rx_ring:
tgt_ring_exit(&rx_ring);
free_tx_ring:
tgt_ring_exit(&tx_ring);
return err;
}
