/* * scsi.c Copyright (C) 1992 Drew Eckhardt * generic mid-level SCSI driver by * Drew Eckhardt * * <drew@colorado.edu> */ #include <linux/config.h> #ifdef CONFIG_SCSI #include <asm/system.h> #include <linux/sched.h> #include <linux/timer.h> #include <linux/string.h> #include "scsi.h" #include "hosts.h" #ifdef CONFIG_BLK_DEV_SD #include "sd.h" #endif #ifdef CONFIG_BLK_DEV_ST #include "st.h" #endif /* static const char RCSid[] = "$Header: /usr/src/linux/kernel/blk_drv/scsi/RCS/scsi.c,v 1.1 1992/04/24 18:01:50 root Exp root $"; */ #define INTERNAL_ERROR (printk ("Internal error in file %s, line %s.\n", __FILE__, __LINE__), panic("")) static void scsi_done (int host, int result); static void update_timeout (void); static int time_start; static int time_elapsed; /* global variables : NR_SCSI_DEVICES is the number of SCSI devices we have detected, scsi_devices an array of these specifing the address for each (host, id, LUN) */ int NR_SCSI_DEVICES=0; Scsi_Device scsi_devices[MAX_SCSI_DEVICE]; #define SENSE_LENGTH 255 /* As the scsi do command functions are inteligent, and may need to redo a command, we need to keep track of the last command executed on each one. */ #define WAS_RESET 0x01 #define WAS_TIMEDOUT 0x02 #define WAS_SENSE 0x04 #define IS_RESETTING 0x08 static Scsi_Cmnd last_cmnd[MAX_SCSI_HOSTS]; static int last_reset[MAX_SCSI_HOSTS]; /* This is the number of clock ticks we should wait before we time out and abort the command. This is for where the scsi.c module generates the command, not where it originates from a higher level, in which case the timeout is specified there. ABORT_TIMEOUT and RESET_TIMEOUT are the timeouts for RESET and ABORT respectively. */ #ifdef DEBUG #define SCSI_TIMEOUT 500 #else #define SCSI_TIMEOUT 100 #endif #ifdef DEBUG #define SENSE_TIMEOUT SCSI_TIMEOUT #define ABORT_TIMEOUT SCSI_TIMEOUT #define RESET_TIMEOUT SCSI_TIMEOUT #else #define SENSE_TIMEOUT 50 #define RESET_TIMEOUT 50 #define ABORT_TIMEOUT 50 #define MIN_RESET_DELAY 25 #endif /* As the actual SCSI command runs in the background, we must set up a flag that tells scan_scsis() when the result it has is valid. scan_scsis can set the_result to -1, and watch for it to become the actual return code for that call. the scan_scsis_done function() is our user specified completion function that is passed on to the scsi_do_cmd() function. */ static int the_result; static unsigned char sense_buffer[SENSE_LENGTH]; static void scan_scsis_done (int host, int result) { #ifdef DEBUG printk ("scan_scsis_done(%d, %06x\n\r", host, result); #endif the_result = result; } /* Detecting SCSI devices : We scan all present host adapter's busses, from ID 0 to ID 6. We use the INQUIRY command, determine device type, and pass the ID / lun address of all sequential devices to the tape driver, all random devices to the disk driver. */ static void scan_scsis (void) { int host_nr , dev, lun, type, maxed; static unsigned char scsi_cmd [12]; static unsigned char scsi_result [256]; for (host_nr = 0; host_nr < MAX_SCSI_HOSTS; ++host_nr) if (scsi_hosts[host_nr].present) { for (dev = 0; dev < 7; ++dev) if (scsi_hosts[host_nr].this_id != dev) #ifdef MULTI_LUN for (lun = 0; lun < 8; ++lun) { #else { lun = 0; #endif /* Build an INQUIRY command block. */ scsi_cmd[0] = INQUIRY; scsi_cmd[1] = (lun << 5) & 0xe0; scsi_cmd[2] = 0; scsi_cmd[3] = 0; scsi_cmd[4] = 255; scsi_cmd[5] = 0; the_result = -1; #ifdef DEBUG memset ((void *) scsi_result , 0, 255); #endif scsi_do_cmd (host_nr, dev, (void *) scsi_cmd, (void *) scsi_result, 256, scan_scsis_done, SCSI_TIMEOUT, sense_buffer, 3); /* Wait for valid result */ while (the_result < 0); if (!the_result) { scsi_devices[NR_SCSI_DEVICES]. host_no = host_nr; scsi_devices[NR_SCSI_DEVICES]. id = dev; scsi_devices[NR_SCSI_DEVICES]. lun = lun; scsi_devices[NR_SCSI_DEVICES]. removable = (0x80 & scsi_result[1]) >> 7; /* Currently, all sequential devices are assumed to be tapes, all random devices disk, with the appropriate read only flags set for ROM / WORM treated as RO. */ switch (type = scsi_result[0]) { case TYPE_TAPE: case TYPE_DISK: scsi_devices[NR_SCSI_DEVICES].writeable = 1; break; case TYPE_WORM: case TYPE_ROM: scsi_devices[NR_SCSI_DEVICES].writeable = 0; break; default: type = -1; } scsi_devices[NR_SCSI_DEVICES].random = (type == TYPE_TAPE) ? 0 : 1; maxed = 0; switch (type) { case -1: break; case TYPE_TAPE: printk("Detected scsi tape at host %d, ID %d, lun %d \n", host_nr, dev, lun); #ifdef CONFIG_BLK_DEV_ST if (!(maxed = (NR_ST == MAX_ST))) scsi_tapes[NR_ST].device = &scsi_devices[NR_SCSI_DEVICES]; #endif default: printk("Detected scsi disk at host %d, ID %d, lun %d \n", host_nr, dev, lun); #ifdef CONFIG_BLK_DEV_SD if (!(maxed = (NR_SD >= MAX_SD))) rscsi_disks[NR_SD].device = &scsi_devices[NR_SCSI_DEVICES]; #endif } if (maxed) { printk ("Already have detected maximum number of SCSI %ss Unable to \n" "add drive at SCSI host %s, ID %d, LUN %d\n\r", (type == TYPE_TAPE) ? "tape" : "disk", scsi_hosts[host_nr].name, dev, lun); type = -1; break; } else if (type != -1) { if (type == TYPE_TAPE) #ifdef CONFIG_BLK_DEV_ST ++NR_ST; #else ; #endif else #ifdef CONFIG_BLK_DEV_SD ++NR_SD; #else ; #endif } ++NR_SCSI_DEVICES; } /* if result == DID_OK ends */ } /* for lun ends */ } /* if present */ printk("Detected " #ifdef CONFIG_BLK_DEV_SD "%d disk%s " #endif #ifdef CONFIG_BLK_DEV_ST "%d tape%s " #endif "total.\n", #ifdef CONFIG_BLK_DEV_SD NR_SD, (NR_SD != 1) ? "s" : "" #ifdef CONFIG_BLK_DEV_ST , #endif #endif #ifdef CONFIG_BLK_DEV_ST NR_ST, (NR_ST != 1) ? "s" : "" #endif ); } /* scan_scsis ends */ /* We handle the timeout differently if it happens when a reset, abort, etc are in process. */ static unsigned char internal_timeout[MAX_SCSI_HOSTS]; /* Flag bits for the internal_timeout array */ #define NORMAL_TIMEOUT 0 #define IN_ABORT 1 #define IN_RESET 2 /* This is our time out function, called when the timer expires for a given host adapter. It will attempt to abort the currently executing command, that failing perform a kernel panic. */ static void scsi_times_out (int host) { switch (internal_timeout[host] & (IN_ABORT | IN_RESET)) { case NORMAL_TIMEOUT: printk("SCSI host %d timed out - aborting command \r\n", host); if (!scsi_abort (host, DID_TIME_OUT)) return; case IN_ABORT: printk("SCSI host %d abort() timed out - reseting \r\n", host); if (!scsi_reset (host)) return; case IN_RESET: case (IN_ABORT | IN_RESET): printk("Unable to reset scsi host %d\r\n",host); panic(""); default: INTERNAL_ERROR; } } /* This is inline because we have stack problemes if we recurse to deeply. */ static void internal_cmnd (int host, unsigned char target, const void *cmnd , void *buffer, unsigned bufflen, void (*done)(int,int)) { int temp; #ifdef DEBUG_DELAY int clock; #endif if ((host < 0) || (host > MAX_SCSI_HOSTS)) panic ("Host number in internal_cmnd() is out of range.\n"); /* We will wait MIN_RESET_DELAY clock ticks after the last reset so we can avoid the drive not being ready. */ temp = last_reset[host]; while (jiffies < temp); host_timeout[host] = last_cmnd[host].timeout_per_command; update_timeout(); /* We will use a queued command if possible, otherwise we will emulate the queing and calling of completion function ourselves. */ #ifdef DEBUG printk("internal_cmnd (host = %d, target = %d, command = %08x, buffer = %08x, \n" "bufflen = %d, done = %08x)\n", host, target, cmnd, buffer, bufflen, done); #endif if (scsi_hosts[host].can_queue) { #ifdef DEBUG printk("queuecommand : routine at %08x\n", scsi_hosts[host].queuecommand); #endif scsi_hosts[host].queuecommand (target, cmnd, buffer, bufflen, done); } else { #ifdef DEBUG printk("command() : routine at %08x\n", scsi_hosts[host].command); #endif temp=scsi_hosts[host].command (target, cmnd, buffer, bufflen); #ifdef DEBUG_DELAY clock = jiffies + 400; while (jiffies < clock); printk("done(host = %d, result = %04x) : routine at %08x\n", host, temp, done); #endif done(host, temp); } #ifdef DEBUG printk("leaving internal_cmnd()\n"); #endif } static void scsi_request_sense (int host, unsigned char target, unsigned char lun) { cli(); host_timeout[host] = SENSE_TIMEOUT; update_timeout(); last_cmnd[host].flags |= WAS_SENSE; sti(); last_cmnd[host].sense_cmnd[1] = lun << 5; internal_cmnd (host, target, (void *) last_cmnd[host].sense_cmnd, (void *) last_cmnd[host].sense_buffer, SENSE_LENGTH, scsi_done); } /* scsi_do_cmd sends all the commands out to the low-level driver. It handles the specifics required for each low level driver - ie queued or non queud. It also prevents conflicts when different high level drivers go for the same host at the same time. */ void scsi_do_cmd (int host, unsigned char target, const void *cmnd , void *buffer, unsigned bufflen, void (*done)(int,int), int timeout, unsigned char *sense_buffer, int retries ) { int ok = 0; #ifdef DEBUG int i; printk ("scsi_do_cmd (host = %d, target = %d, buffer =%08x, " "bufflen = %d, done = %08x, timeout = %d, retries = %d)\n" "command : " , host, target, buffer, bufflen, done, timeout, retries); for (i = 0; i < 10; ++i) printk ("%02x ", ((unsigned char *) cmnd)[i]); printk("\n"); #endif if ((host >= MAX_SCSI_HOSTS) || !scsi_hosts[host].present) { printk ("Invalid or not present host number. %d\n", host); panic(""); } /* We must prevent reentrancy to the lowlevel host driver. This prevents it - we enter a loop until the host we want to talk to is not busy. Race conditions are prevented, as interrupts are disabled inbetween the time we check for the host being not busy, and the time we mark it busy ourselves. */ do { cli(); if (host_busy[host]) { sti(); #ifdef DEBUG printk("Host %d is busy.\n" ); #endif while (host_busy[host]); #ifdef DEBUG printk("Host %d is no longer busy."); #endif } else { host_busy[host] = 1; ok = 1; sti(); } } while (!ok); /* Our own function scsi_done (which marks the host as not busy, disables the timeout counter, etc) will be called by us or by the scsi_hosts[host].queuecommand() function needs to also call the completion function for the high level driver. */ memcpy ((void *) last_cmnd[host].cmnd , (void *) cmnd, 10); last_cmnd[host].host = host; last_cmnd[host].target = target; last_cmnd[host].lun = (last_cmnd[host].cmnd[1] >> 5); last_cmnd[host].bufflen = bufflen; last_cmnd[host].buffer = buffer; last_cmnd[host].sense_buffer = sense_buffer; last_cmnd[host].flags=0; last_cmnd[host].retries=0; last_cmnd[host].allowed=retries; last_cmnd[host].done = done; last_cmnd[host].timeout_per_command = timeout; /* Start the timer ticking. */ internal_timeout[host] = 0; internal_cmnd (host, target, cmnd , buffer, bufflen, scsi_done); #ifdef DEBUG printk ("Leaving scsi_do_cmd()\n"); #endif } /* The scsi_done() function disables the timeout timer for the scsi host, marks the host as not busy, and calls the user specified completion function for that host's current command. */ static void reset (int host) { #ifdef DEBUG printk("reset(%d)\n", host); #endif last_cmnd[host].flags |= (WAS_RESET | IS_RESETTING); scsi_reset(host); #ifdef DEBUG printk("performing request sense\n"); #endif scsi_request_sense (host, last_cmnd[host].target, last_cmnd[host].lun); } static int check_sense (int host) { if (((sense_buffer[0] & 0x70) >> 4) == 7) switch (sense_buffer[2] & 0xf) { case NO_SENSE: case RECOVERED_ERROR: return 0; case ABORTED_COMMAND: case NOT_READY: case UNIT_ATTENTION: return SUGGEST_RETRY; /* these three are not supported */ case COPY_ABORTED: case VOLUME_OVERFLOW: case MISCOMPARE: case MEDIUM_ERROR: return SUGGEST_REMAP; case BLANK_CHECK: case DATA_PROTECT: case HARDWARE_ERROR: case ILLEGAL_REQUEST: default: return SUGGEST_ABORT; } else return SUGGEST_RETRY; } static void scsi_done (int host, int result) { int status=0; int exit=0; int checked; int oldto; oldto = host_timeout[host]; host_timeout[host] = 0; update_timeout(); #define FINISHED 0 #define MAYREDO 1 #define REDO 3 #ifdef DEBUG printk("In scsi_done(host = %d, result = %06x)\n", host, result); #endif if (host > MAX_SCSI_HOSTS || host < 0) { host_timeout[host] = 0; update_timeout(); panic("scsi_done() called with invalid host number.\n"); } switch (host_byte(result)) { case DID_OK: if (last_cmnd[host].flags & IS_RESETTING) { last_cmnd[host].flags &= ~IS_RESETTING; status = REDO; break; } if (status_byte(result) && (last_cmnd[host].flags & WAS_SENSE)) { last_cmnd[host].flags &= ~WAS_SENSE; cli(); internal_timeout[host] &= ~SENSE_TIMEOUT; sti(); if (!(last_cmnd[host].flags & WAS_RESET)) reset(host); else { exit = (DRIVER_HARD | SUGGEST_ABORT); status = FINISHED; } } else switch(msg_byte(result)) { case COMMAND_COMPLETE: switch (status_byte(result)) { case GOOD: if (last_cmnd[host].flags & WAS_SENSE) { #ifdef DEBUG printk ("In scsi_done, GOOD status, COMMAND COMPLETE, parsing sense information.\n"); #endif last_cmnd[host].flags &= ~WAS_SENSE; cli(); internal_timeout[host] &= ~SENSE_TIMEOUT; sti(); switch (checked = check_sense(host)) { case 0: #ifdef DEBUG printk("NO SENSE. status = REDO\n"); #endif host_timeout[host] = oldto; update_timeout(); status = REDO; break; case SUGGEST_REMAP: case SUGGEST_RETRY: #ifdef DEBUG printk("SENSE SUGGEST REMAP or SUGGEST RETRY - status = MAYREDO\n"); #endif status = MAYREDO; exit = SUGGEST_RETRY; break; case SUGGEST_ABORT: #ifdef DEBUG printk("SENSE SUGGEST ABORT - status = FINISHED"); #endif status = FINISHED; exit = DRIVER_SENSE; break; default: printk ("Internal error %s %s \n", __FILE__, __LINE__); } } else { #ifdef DEBUG printk("COMMAND COMPLETE message returned, status = FINISHED. \n"); #endif exit = DRIVER_OK; status = FINISHED; } break; case CHECK_CONDITION: #ifdef DEBUG printk("CHECK CONDITION message returned, performing request sense.\n"); #endif scsi_request_sense (host, last_cmnd[host].target, last_cmnd[host].lun); break; case CONDITION_GOOD: case INTERMEDIATE_GOOD: case INTERMEDIATE_C_GOOD: #ifdef DEBUG printk("CONDITION GOOD, INTERMEDIATE GOOD, or INTERMEDIATE CONDITION GOOD recieved and ignored. \n"); #endif break; case BUSY: #ifdef DEBUG printk("BUSY message returned, performing REDO"); #endif host_timeout[host] = oldto; update_timeout(); status = REDO; break; case RESERVATION_CONFLICT: reset(host); exit = DRIVER_SOFT | SUGGEST_ABORT; status = MAYREDO; break; default: printk ("Internal error %s %s \n" "status byte = %d \n", __FILE__, __LINE__, status_byte(result)); } break; default: panic ("unsupported message byte recieved."); } break; case DID_TIME_OUT: #ifdef DEBUG printk("Host returned DID_TIME_OUT - "); #endif if (last_cmnd[host].flags & WAS_TIMEDOUT) { #ifdef DEBUG printk("Aborting\n"); #endif exit = (DRIVER_TIMEOUT | SUGGEST_ABORT); } else { #ifdef DEBUG printk ("Retrying.\n"); #endif last_cmnd[host].flags |= WAS_TIMEDOUT; status = REDO; } break; case DID_BUS_BUSY: case DID_PARITY: status = REDO; break; case DID_NO_CONNECT: #ifdef DEBUG printk("Couldn't connect.\n"); #endif exit = (DRIVER_HARD | SUGGEST_ABORT); break; case DID_ERROR: status = MAYREDO; exit = (DRIVER_HARD | SUGGEST_ABORT); break; case DID_BAD_TARGET: case DID_ABORT: exit = (DRIVER_INVALID | SUGGEST_ABORT); break; default : exit = (DRIVER_ERROR | SUGGEST_DIE); } switch (status) { case FINISHED: break; case MAYREDO: #ifdef DEBUG printk("In MAYREDO, allowing %d retries, have %d\n\r", last_cmnd[host].allowed, last_cmnd[host].retries); #endif if ((++last_cmnd[host].retries) < last_cmnd[host].allowed) { if ((last_cmnd[host].retries >= (last_cmnd[host].allowed >> 1)) && !(last_cmnd[host].flags & WAS_RESET)) reset(host); break; } else { status = FINISHED; break; } /* fall through to REDO */ case REDO: if (last_cmnd[host].flags & WAS_SENSE) scsi_request_sense (host, last_cmnd[host].target, last_cmnd[host].lun); else internal_cmnd (host, last_cmnd[host].target, last_cmnd[host].cmnd, last_cmnd[host].buffer, last_cmnd[host].bufflen, scsi_done); break; default: INTERNAL_ERROR; } if (status == FINISHED) { #ifdef DEBUG printk("Calling done function - at address %08x\n", last_cmnd[host].done); #endif last_cmnd[host].done (host, (result | ((exit & 0xff) << 24))); host_busy[host] = 0; } #undef FINISHED #undef REDO #undef MAYREDO } /* The scsi_abort function interfaces with the abort() function of the host we are aborting, and causes the current command to not complete. The caller should deal with any error messages or status returned on the next call. This will not be called rentrantly for a given host. */ /* Since we're nice guys and specified that abort() and reset() can be non-reentrant. The internal_timeout flags are used for this. */ int scsi_abort (int host, int why) { int temp, oldto; while(1) { cli(); if (internal_timeout[host] & IN_ABORT) { sti(); while (internal_timeout[host] & IN_ABORT); } else { internal_timeout[host] |= IN_ABORT; host_timeout[host] = ABORT_TIMEOUT; update_timeout(); oldto = host_timeout[host]; sti(); if (!host_busy[host] || !scsi_hosts[host].abort(why)) temp = 0; else temp = 1; cli(); internal_timeout[host] &= ~IN_ABORT; host_timeout[host]=oldto; update_timeout(); sti(); return temp; } } } int scsi_reset (int host) { int temp, oldto; while (1) { cli(); if (internal_timeout[host] & IN_RESET) { sti(); while (internal_timeout[host] & IN_RESET); } else { oldto = host_timeout[host]; host_timeout[host] = RESET_TIMEOUT; update_timeout(); internal_timeout[host] |= IN_RESET; if (host_busy[host]) { sti(); if (!(last_cmnd[host].flags & IS_RESETTING) && !(internal_timeout[host] & IN_ABORT)) scsi_abort(host, DID_RESET); temp = scsi_hosts[host].reset(); } else { host_busy[host]=1; sti(); temp = scsi_hosts[host].reset(); last_reset[host] = jiffies; host_busy[host]=0; } cli(); host_timeout[host] = oldto; update_timeout(); internal_timeout[host] &= ~IN_RESET; sti(); return temp; } } } static void scsi_main_timeout(void) { /* We must not enter update_timeout with a timeout condition still pending. */ int i, timed_out; do { cli(); /* Find all timers such that they have 0 or negative (shouldn't happen) time remaining on them. */ for (i = timed_out = 0; i < MAX_SCSI_HOSTS; ++i) if (host_timeout[i] != 0 && host_timeout[i] <= time_elapsed) { sti(); host_timeout[i] = 0; scsi_times_out(i); ++timed_out; } update_timeout(); } while (timed_out); sti(); } /* These are used to keep track of things. */ static int time_start, time_elapsed; /* The strategy is to cause the timer code to call scsi_times_out() when the soonest timeout is pending. */ static void update_timeout(void) { int i, least, used; cli(); /* Figure out how much time has passed since the last time the timeouts were updated */ used = (time_start) ? (jiffies - time_start) : 0; /* Find out what is due to timeout soonest, and adjust all timeouts for the amount of time that has passed since the last time we called update_timeout. */ for (i = 0, least = 0xffffffff; i < MAX_SCSI_HOSTS; ++i) if (host_timeout[i] > 0 && (host_timeout[i] -= used) < least) least = host_timeout[i]; /* If something is due to timeout again, then we will set the next timeout interrupt to occur. Otherwise, timeouts are disabled. */ if (least != 0xffffffff) { time_start = jiffies; timer_table[SCSI_TIMER].expires = (time_elapsed = least) + jiffies; timer_active |= 1 << SCSI_TIMER; } else { timer_table[SCSI_TIMER].expires = time_start = time_elapsed = 0; timer_active &= ~(1 << SCSI_TIMER); } sti(); } /* scsi_dev_init() is our initialization routine, which inturn calls host initialization, bus scanning, and sd/st initialization routines. It should be called from main(). */ static unsigned char generic_sense[6] = {REQUEST_SENSE, 0,0,0, 255, 0}; void scsi_dev_init (void) { int i; #ifdef FOO_ON_YOU return; #endif timer_table[SCSI_TIMER].fn = scsi_main_timeout; timer_table[SCSI_TIMER].expires = 0; scsi_init(); /* initialize all hosts */ /* Set up sense command in each host structure. */ for (i = 0; i < MAX_SCSI_HOSTS; ++i) { memcpy ((void *) last_cmnd[i].sense_cmnd, (void *) generic_sense, 6); last_reset[i] = 0; } scan_scsis(); /* scan for scsi devices */ #ifdef CONFIG_BLK_DEV_SD sd_init(); /* init scsi disks */ #endif #ifdef CONFIG_BLK_DEV_ST st_init(); /* init scsi tapes */ #endif } #endif