379 lines
8.6 KiB
C
379 lines
8.6 KiB
C
/*
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* Simulated SCSI driver.
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*
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* Copyright (C) 1999, 2001-2003 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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* Stephane Eranian <eranian@hpl.hp.com>
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*
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* 02/01/15 David Mosberger Updated for v2.5.1
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* 99/12/18 David Mosberger Added support for READ10/WRITE10 needed by linux v2.3.33
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*/
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#include <linux/blkdev.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/timer.h>
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#include <asm/irq.h>
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#include "hpsim_ssc.h"
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#include <scsi/scsi.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_host.h>
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#define DEBUG_SIMSCSI 0
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#define SIMSCSI_REQ_QUEUE_LEN 64
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#define DEFAULT_SIMSCSI_ROOT "/var/ski-disks/sd"
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/* Simulator system calls: */
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#define SSC_OPEN 50
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#define SSC_CLOSE 51
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#define SSC_READ 52
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#define SSC_WRITE 53
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#define SSC_GET_COMPLETION 54
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#define SSC_WAIT_COMPLETION 55
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#define SSC_WRITE_ACCESS 2
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#define SSC_READ_ACCESS 1
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#if DEBUG_SIMSCSI
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int simscsi_debug;
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# define DBG simscsi_debug
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#else
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# define DBG 0
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#endif
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static struct Scsi_Host *host;
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static void simscsi_interrupt (unsigned long val);
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static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
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struct disk_req {
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unsigned long addr;
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unsigned len;
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};
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struct disk_stat {
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int fd;
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unsigned count;
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};
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static int desc[16] = {
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};
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static struct queue_entry {
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struct scsi_cmnd *sc;
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} queue[SIMSCSI_REQ_QUEUE_LEN];
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static int rd, wr;
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static atomic_t num_reqs = ATOMIC_INIT(0);
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/* base name for default disks */
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static char *simscsi_root = DEFAULT_SIMSCSI_ROOT;
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#define MAX_ROOT_LEN 128
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/*
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* used to setup a new base for disk images
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* to use /foo/bar/disk[a-z] as disk images
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* you have to specify simscsi=/foo/bar/disk on the command line
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*/
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static int __init
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simscsi_setup (char *s)
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{
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/* XXX Fix me we may need to strcpy() ? */
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if (strlen(s) > MAX_ROOT_LEN) {
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printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
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simscsi_root);
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}
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simscsi_root = s;
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return 1;
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}
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__setup("simscsi=", simscsi_setup);
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static void
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simscsi_interrupt (unsigned long val)
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{
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struct scsi_cmnd *sc;
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while ((sc = queue[rd].sc) != NULL) {
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atomic_dec(&num_reqs);
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queue[rd].sc = NULL;
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if (DBG)
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printk("simscsi_interrupt: done with %ld\n", sc->serial_number);
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(*sc->scsi_done)(sc);
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rd = (rd + 1) % SIMSCSI_REQ_QUEUE_LEN;
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}
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}
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static int
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simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
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sector_t capacity, int ip[])
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{
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ip[0] = 64; /* heads */
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ip[1] = 32; /* sectors */
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ip[2] = capacity >> 11; /* cylinders */
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return 0;
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}
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static void
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simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
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{
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int i;
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struct scatterlist *sl;
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struct disk_stat stat;
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struct disk_req req;
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stat.fd = desc[sc->device->id];
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scsi_for_each_sg(sc, sl, scsi_sg_count(sc), i) {
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req.addr = __pa(sg_virt(sl));
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req.len = sl->length;
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if (DBG)
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printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
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mode == SSC_READ ? "read":"write", req.addr, offset,
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scsi_sg_count(sc) - i, sl->length);
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ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
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ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
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/* should not happen in our case */
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if (stat.count != req.len) {
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sc->result = DID_ERROR << 16;
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return;
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}
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offset += sl->length;
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}
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sc->result = GOOD;
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}
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/*
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* function handling both READ_6/WRITE_6 (non-scatter/gather mode)
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* commands.
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* Added 02/26/99 S.Eranian
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*/
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static void
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simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
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{
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unsigned long offset;
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offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
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simscsi_sg_readwrite(sc, mode, offset);
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}
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static size_t
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simscsi_get_disk_size (int fd)
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{
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struct disk_stat stat;
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size_t bit, sectors = 0;
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struct disk_req req;
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char buf[512];
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/*
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* This is a bit kludgey: the simulator doesn't provide a
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* direct way of determining the disk size, so we do a binary
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* search, assuming a maximum disk size of 128GB.
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*/
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for (bit = (128UL << 30)/512; bit != 0; bit >>= 1) {
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req.addr = __pa(&buf);
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req.len = sizeof(buf);
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ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
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stat.fd = fd;
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ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
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if (stat.count == sizeof(buf))
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sectors |= bit;
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}
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return sectors - 1; /* return last valid sector number */
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}
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static void
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simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
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{
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unsigned long offset;
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offset = (((unsigned long)sc->cmnd[2] << 24)
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| ((unsigned long)sc->cmnd[3] << 16)
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| ((unsigned long)sc->cmnd[4] << 8)
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| ((unsigned long)sc->cmnd[5] << 0))*512UL;
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simscsi_sg_readwrite(sc, mode, offset);
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}
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static int
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simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
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{
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unsigned int target_id = sc->device->id;
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char fname[MAX_ROOT_LEN+16];
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size_t disk_size;
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char *buf;
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char localbuf[36];
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#if DEBUG_SIMSCSI
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register long sp asm ("sp");
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if (DBG)
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printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
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target_id, sc->cmnd[0], sc->serial_number, sp, done);
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#endif
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sc->result = DID_BAD_TARGET << 16;
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sc->scsi_done = done;
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if (target_id <= 15 && sc->device->lun == 0) {
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switch (sc->cmnd[0]) {
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case INQUIRY:
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if (scsi_bufflen(sc) < 35) {
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break;
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}
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sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
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desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
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0, 0, SSC_OPEN);
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if (desc[target_id] < 0) {
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/* disk doesn't exist... */
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break;
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}
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buf = localbuf;
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buf[0] = 0; /* magnetic disk */
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buf[1] = 0; /* not a removable medium */
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buf[2] = 2; /* SCSI-2 compliant device */
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buf[3] = 2; /* SCSI-2 response data format */
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buf[4] = 31; /* additional length (bytes) */
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buf[5] = 0; /* reserved */
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buf[6] = 0; /* reserved */
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buf[7] = 0; /* various flags */
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memcpy(buf + 8, "HP SIMULATED DISK 0.00", 28);
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scsi_sg_copy_from_buffer(sc, buf, 36);
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sc->result = GOOD;
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break;
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case TEST_UNIT_READY:
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sc->result = GOOD;
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break;
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case READ_6:
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if (desc[target_id] < 0 )
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break;
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simscsi_readwrite6(sc, SSC_READ);
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break;
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case READ_10:
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if (desc[target_id] < 0 )
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break;
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simscsi_readwrite10(sc, SSC_READ);
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break;
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case WRITE_6:
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if (desc[target_id] < 0)
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break;
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simscsi_readwrite6(sc, SSC_WRITE);
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break;
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case WRITE_10:
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if (desc[target_id] < 0)
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break;
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simscsi_readwrite10(sc, SSC_WRITE);
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break;
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case READ_CAPACITY:
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if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
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break;
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}
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buf = localbuf;
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disk_size = simscsi_get_disk_size(desc[target_id]);
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buf[0] = (disk_size >> 24) & 0xff;
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buf[1] = (disk_size >> 16) & 0xff;
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buf[2] = (disk_size >> 8) & 0xff;
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buf[3] = (disk_size >> 0) & 0xff;
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/* set block size of 512 bytes: */
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buf[4] = 0;
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buf[5] = 0;
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buf[6] = 2;
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buf[7] = 0;
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scsi_sg_copy_from_buffer(sc, buf, 8);
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sc->result = GOOD;
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break;
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case MODE_SENSE:
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case MODE_SENSE_10:
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/* sd.c uses this to determine whether disk does write-caching. */
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scsi_sg_copy_from_buffer(sc, (char *)empty_zero_page,
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PAGE_SIZE);
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sc->result = GOOD;
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break;
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case START_STOP:
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printk(KERN_ERR "START_STOP\n");
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break;
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default:
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panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
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}
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}
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if (sc->result == DID_BAD_TARGET) {
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sc->result |= DRIVER_SENSE << 24;
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sc->sense_buffer[0] = 0x70;
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sc->sense_buffer[2] = 0x00;
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}
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if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
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panic("Attempt to queue command while command is pending!!");
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}
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atomic_inc(&num_reqs);
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queue[wr].sc = sc;
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wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
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tasklet_schedule(&simscsi_tasklet);
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return 0;
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}
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static int
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simscsi_host_reset (struct scsi_cmnd *sc)
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{
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printk(KERN_ERR "simscsi_host_reset: not implemented\n");
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return 0;
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}
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static struct scsi_host_template driver_template = {
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.name = "simulated SCSI host adapter",
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.proc_name = "simscsi",
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.queuecommand = simscsi_queuecommand,
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.eh_host_reset_handler = simscsi_host_reset,
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.bios_param = simscsi_biosparam,
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.can_queue = SIMSCSI_REQ_QUEUE_LEN,
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.this_id = -1,
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.sg_tablesize = SG_ALL,
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.max_sectors = 1024,
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.cmd_per_lun = SIMSCSI_REQ_QUEUE_LEN,
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.use_clustering = DISABLE_CLUSTERING,
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};
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static int __init
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simscsi_init(void)
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{
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int error;
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host = scsi_host_alloc(&driver_template, 0);
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if (!host)
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return -ENOMEM;
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error = scsi_add_host(host, NULL);
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if (error)
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goto free_host;
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scsi_scan_host(host);
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return 0;
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free_host:
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scsi_host_put(host);
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return error;
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}
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static void __exit
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simscsi_exit(void)
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{
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scsi_remove_host(host);
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scsi_host_put(host);
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}
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module_init(simscsi_init);
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module_exit(simscsi_exit);
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