ref: b7af62b250e5dff30320a181ca9d53ab5a7c276d
dir: /os/port/devftl.c/
/*
* basic Flash Translation Layer driver
* see for instance the Intel technical paper
* ``Understanding the Flash Translation Layer (FTL) Specification''
* Order number 297816-001 (online at www.intel.com)
*
* a public driver by David Hinds, dhinds@allegro.stanford.edu
* further helps with some details.
*
* this driver uses the common simplification of never storing
* the VBM on the medium (a waste of precious flash!) but
* rather building it on the fly as the block maps are read.
*
* Plan 9 driver (c) 1997 by C H Forsyth (forsyth@terzarima.net)
* This driver may be used or adapted by anyone for any non-commercial purpose.
*
* adapted for Inferno 1998 by C H Forsyth, Vita Nuova Limited, York, England (forsyth@vitanuova.com)
*
* TO DO:
* check error handling details for get/put flash
* bad block handling
* reserved space in formatted size
* possibly block size as parameter
*/
#include "u.h"
#include "../port/lib.h"
#include "../port/error.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "kernel.h"
typedef struct Ftl Ftl;
typedef struct Merase Merase;
typedef struct Terase Terase;
enum {
Eshift = 18, /* 2^18=256k; log2(eraseunit) */
Flashseg = 1<<Eshift,
Bshift = 9, /* 2^9=512 */
Bsize = 1<<Bshift,
BAMoffset = 0x100,
Nolimit = ~0,
USABLEPCT = 95, /* release only this % to client */
FTLDEBUG = 0,
NPART = 4,
};
/* erase unit header (defined by FTL specification) */
struct Merase {
uchar linktuple[5];
uchar orgtuple[10];
uchar nxfer;
uchar nerase[4];
uchar id[2];
uchar bshift;
uchar eshift;
uchar pstart[2];
uchar nunits[2];
uchar psize[4];
uchar vbmbase[4];
uchar nvbm[2];
uchar flags;
uchar code;
uchar serial[4];
uchar altoffset[4];
uchar bamoffset[4];
uchar rsv2[12];
};
#define ERASEHDRLEN 64
enum {
/* special unit IDs */
XferID = 0xffff,
XferBusy = 0x7fff,
/* special BAM addresses */
Bfree = 0xffffffff,
Bwriting = 0xfffffffe,
Bdeleted = 0,
/* block types */
TypeShift = 7,
BlockType = (1<<TypeShift)-1,
ControlBlock = 0x30,
DataBlock = 0x40,
ReplacePage = 0x60,
BadBlock = 0x70,
};
#define BTYPE(b) ((b) & BlockType)
#define BADDR(b) ((b) & ~BlockType)
#define BNO(va) (((ulong)(va))>>Bshift)
#define MKBAM(b,t) (((b)<<Bshift)|(t))
struct Terase {
int x;
int id;
ulong offset;
ulong bamoffset;
ulong nbam;
ulong* bam;
ulong bamx;
ulong nfree;
ulong nused;
ulong ndead;
ulong nbad;
ulong nerase;
};
struct Ftl {
QLock;
Ref;
Chan* flash;
Chan* flashctl;
ulong base; /* base of flash region */
ulong size; /* size of flash region */
ulong segsize; /* size of flash segment (erase unit) */
int eshift; /* log2(erase-unit-size) */
int bshift; /* log2(bsize) */
int bsize;
int nunit; /* number of segments (erase units) */
Terase** unit;
int lastx; /* index in unit of last allocation */
int xfer; /* index in unit of current transfer unit (-1 if none) */
ulong nfree; /* total free space in blocks */
ulong nblock; /* total space in blocks */
ulong rwlimit; /* user-visible block limit (`formatted size') */
ulong* vbm; /* virtual block map */
ulong fstart; /* address of first block of data in a segment */
int trace; /* (debugging) trace of read/write actions */
int detach; /* free Ftl on last close */
/* scavenging variables */
QLock wantq;
Rendez wantr;
Rendez workr;
int needspace;
int hasproc;
int npart; /* over and above ftldata */
struct {
ulong start, size;
ulong rwlimit;
char *name; /* nil if slot unused */
} part[NPART];
};
enum {
/* Ftl.detach */
Detached = 1, /* detach on close */
Deferred /* scavenger must free it */
};
/* little endian */
#define GET2(p) (((p)[1]<<8)|(p)[0])
#define GET4(p) (((((((p)[3]<<8)|(p)[2])<<8)|(p)[1])<<8)|(p)[0])
#define PUT2(p,v) (((p)[1]=(v)>>8),((p)[0]=(v)))
#define PUT4(p,v) (((p)[3]=(v)>>24),((p)[2]=(v)>>16),((p)[1]=(v)>>8),((p)[0]=(v)))
static Lock ftllock;
static Ftl *ftls;
static int ftlpct = USABLEPCT;
static ulong allocblk(Ftl*);
static int erasedetect(Ftl *ftl, ulong base, ulong size, ushort *pstart, ushort *nunits);
static void eraseflash(Ftl*, ulong);
static void erasefree(Terase*);
static void eraseinit(Ftl*, ulong, int, int);
static Terase* eraseload(Ftl*, int, ulong);
static void ftlfree(Ftl*);
static void getflash(Ftl*, void*, ulong, long);
static int mapblk(Ftl*, ulong, Terase**, ulong*);
static Ftl* mkftl(char*, ulong, ulong, int, char*);
static void putbam(Ftl*, Terase*, int, ulong);
static void putflash(Ftl*, ulong, void*, long);
static int scavenge(Ftl*);
enum {
Qdir,
Qctl,
Qdata,
};
#define DATAQID(q) ((q) >= Qdata && (q) <= Qdata + NPART)
static void
ftlpartcmd(Ftl *ftl, char **fields, int nfields)
{
ulong start, end;
char *p;
int n, newn;
/* name start [end] */
if(nfields < 2 || nfields > 3)
error(Ebadarg);
if(ftl->npart >= NPART)
error("table full");
if(strcmp(fields[0], "ctl") == 0 || strcmp(fields[0], "data") == 0)
error(Ebadarg);
newn = -1;
for(n = 0; n < NPART; n++){
if(ftl->part[n].name == nil){
if(newn < 0)
newn = n;
continue;
}
if(strcmp(fields[0], ftl->part[n].name + 3) == 0)
error(Ebadarg);
}
start = strtoul(fields[1], 0, 0);
if(nfields > 2)
end = strtoul(fields[2], 0, 0);
else
end = ftl->rwlimit * Bsize;
if(start >= end || start % Bsize || end % Bsize)
error(Ebadarg);
ftl->part[newn].start = start;
ftl->part[newn].size = end - start;
ftl->part[newn].rwlimit = end / Bsize;
free(ftl->part[newn].name);
p = malloc(strlen(fields[0]) + 3 + 1);
strcpy(p, "ftl");
strcat(p, fields[0]);
ftl->part[newn].name = p;
ftl->npart++;
}
static void
ftldelpartcmd(Ftl *ftl, char **fields, int nfields)
{
int n;
// name
if(nfields != 1)
error(Ebadarg);
for(n = 0; n < NPART; n++)
if(strcmp(fields[0], ftl->part[n].name + 3) == 0){
free(ftl->part[n].name);
ftl->part[n].name = nil;
ftl->npart--;
return;
}
error(Ebadarg);
}
static int
ftlgen(Chan *c, char*, Dirtab*, int, int i, Dir *dp)
{
int n;
switch(i){
case DEVDOTDOT:
devdir(c, (Qid){Qdir, 0, QTDIR}, "#X", 0, eve, 0555, dp);
break;
case 0:
devdir(c, (Qid){Qctl, 0, QTFILE}, "ftlctl", 0, eve, 0660, dp);
break;
case 1:
devdir(c, (Qid){Qdata, 0, QTFILE}, "ftldata", ftls ? ftls->rwlimit * Bsize : 0, eve, 0660, dp);
break;
default:
if(ftls == nil)
return -1;
i -= 2;
if(i >= ftls->npart)
return -1;
for(n = 0; n < NPART; n++)
if(ftls->part[n].name != nil){
if(i == 0)
break;
i--;
}
if(i != 0){
print("wierd\n");
return -1;
}
devdir(c, (Qid){Qdata + 1 + n, 0, QTFILE}, ftls->part[n].name, ftls->part[n].size, eve, 0660, dp);
}
return 1;
}
static Ftl *
ftlget(void)
{
Ftl *ftl;
lock(&ftllock);
ftl = ftls;
if(ftl != nil)
incref(ftl);
unlock(&ftllock);
return ftl;
}
static void
ftlput(Ftl *ftl)
{
if(ftl != nil){
lock(&ftllock);
if(decref(ftl) == 0 && ftl->detach == Detached){
ftls = nil;
if(ftl->hasproc){ /* no lock needed: can't change if ftl->ref==0 */
ftl->detach = Deferred;
wakeup(&ftl->workr);
}else
ftlfree(ftl);
}
unlock(&ftllock);
}
}
static Chan *
ftlattach(char *spec)
{
return devattach('X', spec);
}
static Walkqid*
ftlwalk(Chan *c, Chan *nc, char **name, int nname)
{
Walkqid *wq;
wq = devwalk(c, nc, name, nname, 0, 0, ftlgen);
if(wq != nil && wq->clone != nil && wq->clone != c)
if(DATAQID(wq->clone->qid.path))
wq->clone->aux = ftlget();
return wq;
}
static int
ftlstat(Chan *c, uchar *dp, int n)
{
return devstat(c, dp, n, 0, 0, ftlgen);
}
static Chan*
ftlopen(Chan *c, int omode)
{
Ftl *ftl;
omode = openmode(omode);
if(DATAQID(c->qid.path)){
ftl = ftls;
if(ftl == nil)
error(Enodev);
if(strcmp(up->env->user, eve)!=0)
error(Eperm);
}
else if(c->qid.path == Qctl){
if(strcmp(up->env->user, eve)!=0)
error(Eperm);
}
c = devopen(c, omode, 0, 0, ftlgen);
if(DATAQID(c->qid.path)){
c->aux = ftlget();
if(c->aux == nil)
error(Enodev);
}
return c;
}
static void
ftlclose(Chan *c)
{
if(DATAQID(c->qid.path) && (c->flag&COPEN) != 0)
ftlput((Ftl*)c->aux);
}
static long
ftlread(Chan *c, void *buf, long n, vlong offset)
{
Ftl *ftl;
Terase *e;
int nb;
uchar *a;
ulong pb;
if(c->qid.type & QTDIR)
return devdirread(c, buf, n, 0, 0, ftlgen);
if(DATAQID(c->qid.path)){
ulong rwlimit;
if(n <= 0 || n%Bsize || offset%Bsize)
error(Eio);
ftl = c->aux;
if(c->qid.path > Qdata){
int p = c->qid.path - Qdata - 1;
offset += ftl->part[p].start;
rwlimit = ftl->part[p].rwlimit;
}
else
rwlimit = ftl->rwlimit;
nb = n/Bsize;
offset /= Bsize;
if(offset >= rwlimit)
return 0;
if(offset+nb > rwlimit)
nb = rwlimit - offset;
a = buf;
for(n = 0; n < nb; n++){
qlock(ftl);
if(waserror()){
qunlock(ftl);
nexterror();
}
if(mapblk(ftl, offset+n, &e, &pb))
getflash(ftl, a, e->offset + pb*Bsize, Bsize);
else
memset(a, 0, Bsize);
poperror();
qunlock(ftl);
a += Bsize;
}
return a-(uchar*)buf;
}
if(c->qid.path != Qctl)
error(Egreg);
return 0;
}
static long
ftlwrite(Chan *c, void *buf, long n, vlong offset)
{
char cmd[64], *fields[6];
int ns, i, k, nb;
uchar *a;
Terase *e, *oe;
ulong ob, v, base, size, segsize;
Ftl *ftl;
if(n <= 0)
return 0;
if(DATAQID(c->qid.path)){
ulong rwlimit;
ftl = c->aux;
if(n <= 0 || n%Bsize || offset%Bsize)
error(Eio);
if(c->qid.path > Qdata){
int p = c->qid.path - Qdata - 1;
offset += ftl->part[p].start;
rwlimit = ftl->part[p].rwlimit;
}
else
rwlimit = ftl->rwlimit;
nb = n/Bsize;
offset /= Bsize;
if(offset >= rwlimit)
return 0;
if(offset+nb > rwlimit)
nb = rwlimit - offset;
a = buf;
for(n = 0; n < nb; n++){
ns = 0;
while((v = allocblk(ftl)) == 0)
if(!scavenge(ftl) || ++ns > 3){
static int stop;
if(stop < 3){
stop++;
print("ftl: flash memory full\n");
}
error("flash memory full");
}
qlock(ftl);
if(waserror()){
qunlock(ftl);
nexterror();
}
if(!mapblk(ftl, offset+n, &oe, &ob))
oe = nil;
e = ftl->unit[v>>16];
v &= 0xffff;
putflash(ftl, e->offset + v*Bsize, a, Bsize);
putbam(ftl, e, v, MKBAM(offset+n, DataBlock));
/* both old and new block references exist in this window (can't be closed?) */
ftl->vbm[offset+n] = (e->x<<16) | v;
if(oe != nil){
putbam(ftl, oe, ob, Bdeleted);
oe->ndead++;
}
poperror();
qunlock(ftl);
a += Bsize;
}
return a-(uchar*)buf;
}
else if(c->qid.path == Qctl){
if(n > sizeof(cmd)-1)
n = sizeof(cmd)-1;
memmove(cmd, buf, n);
cmd[n] = 0;
i = getfields(cmd, fields, 6, 1, " \t\n");
if(i <= 0)
error(Ebadarg);
if(i >= 2 && (strcmp(fields[0], "init") == 0 || strcmp(fields[0], "format") == 0)){
if(i > 2)
base = strtoul(fields[2], nil, 0);
else
base = 0; /* TO DO: hunt for signature */
if(i > 3)
size = strtoul(fields[3], nil, 0);
else
size = Nolimit;
if(i > 4)
segsize = strtoul(fields[4], nil, 0);
else
segsize = 0;
/* segsize must be power of two and size and base must be multiples of it
* if segsize is zero, then use whatever the device returns
*/
if(segsize != 0 && (segsize > size
|| segsize&(segsize-1)
|| (base != Nolimit && base&(segsize-1))
|| size == 0
|| (size != Nolimit && size&(segsize-1))))
error(Ebadarg);
if(segsize == 0)
k = 0;
else {
for(k=0; k<32 && (1<<k) != segsize; k++)
;
}
if(ftls != nil)
error(Einuse);
ftls = mkftl(fields[1], base, size, k, fields[0]);
}else if(strcmp(fields[0], "scavenge") == 0){
if(ftls != nil)
print("scavenge %d\n", scavenge(ftls));
}else if(strcmp(fields[0], "trace") == 0){
if(ftls != nil)
ftls->trace = i>1? strtol(fields[1], nil, 0): 1;
}else if(strcmp(fields[0], "detach") == 0){
if((ftl = ftlget()) != nil){
if(ftl->ref > 1){
ftlput(ftl);
error(Einuse);
}
ftl->detach = Detached;
ftlput(ftl);
}else
error(Enodev);
}else if(strcmp(fields[0], "part")==0){
if((ftl = ftlget()) != nil){
if(ftl->ref > 1){
ftlput(ftl);
error(Einuse);
}
if(waserror()){
ftlput(ftl);
nexterror();
}
ftlpartcmd(ftl, fields + 1, i - 1);
poperror();
ftlput(ftl);
}else
error(Enodev);
}else if(strcmp(fields[0], "delpart")==0){
if((ftl = ftlget()) != nil){
if(ftl->ref > 1){
ftlput(ftl);
error(Einuse);
}
if(waserror()){
ftlput(ftl);
nexterror();
}
ftldelpartcmd(ftls, fields + 1, i - 1);
poperror();
ftlput(ftl);
}else
error(Enodev);
}else if(i >= 2 && strcmp(fields[0], "pct")==0){
v = strtoul(fields[1], nil, 0);
if(v >= 50)
ftlpct = v;
}else
error(Ebadarg);
return n;
}
error(Egreg);
return 0; /* not reached */
}
static Chan *
ftlkopen(char *name, char *suffix, int mode)
{
Chan *c;
char *fn;
int fd;
if(suffix != nil && *suffix){
fn = smalloc(strlen(name)+strlen(suffix)+1);
if(fn == nil)
return nil;
strcpy(fn, name);
strcat(fn, suffix);
fd = kopen(fn, mode);
free(fn);
}else
fd = kopen(name, mode);
if(fd < 0)
return nil;
c = fdtochan(up->env->fgrp, fd, mode, 0, 1);
kclose(fd);
return c;
}
static ulong
ftlfsize(Chan *c)
{
uchar dbuf[STATFIXLEN+32*4];
Dir d;
int n;
n = devtab[c->type]->stat(c, dbuf, sizeof(dbuf));
if(convM2D(dbuf, n, &d, nil) == 0)
return 0;
return d.length;
}
static Ftl *
mkftl(char *fname, ulong base, ulong size, int eshift, char *op)
{
int i, j, nov, segblocks, n, badseg, old, valid;
ulong limit;
Terase *e;
Ftl *ftl;
char buf[64], *fields[8];
ulong ea;
Chan *statfd;
ftl = malloc(sizeof(*ftl));
if(ftl == nil)
error(Enomem);
e = nil;
if(waserror()){
ftlfree(ftl);
if(e)
free(e);
nexterror();
}
ftl->lastx = 0;
ftl->trace = 0;
ftl->flash = ftlkopen(fname, "", ORDWR);
if(ftl->flash == nil)
error(up->env->errstr);
ftl->flashctl = ftlkopen(fname, "ctl", ORDWR);
if(ftl->flashctl == nil)
error(up->env->errstr);
old = 1;
statfd = ftlkopen(fname, "stat", OREAD); /* old scheme */
if(statfd == nil){
statfd = ftl->flashctl; /* new just uses ctl */
old = 0;
}
statfd->offset = 0;
if((n = kchanio(statfd, buf, sizeof(buf), OREAD)) <= 0){
print("ftl: read stat/ctl failed: %s\n", up->env->errstr);
error(up->env->errstr);
}
if(n >= sizeof(buf))
n = sizeof(buf)-1;
buf[n] = 0;
if(statfd != ftl->flashctl)
cclose(statfd);
n = getfields(buf, fields, nelem(fields), 1, " \t\n");
ea = 0;
if(old){
if(n >= 4)
if((ea = strtoul(fields[3], nil, 16)) < 8*1024)
ea = 0; /* assume the format is wrong */
}else{
if(n >= 7)
if((ea = strtoul(fields[6], nil, 0)) < 2*1024)
ea = 0; /* assume the format is wrong */
}
if(ea != 0){
for(i=0; i < 32 && (1<<i) != ea; i++)
;
if(eshift && i != eshift)
print("ftl: overriding erasesize %d with %d\n", 1 << eshift, 1 << i);
eshift = i;
if(FTLDEBUG)
print("ftl: e=%lud eshift=%d\n", ea, i);
}
if(eshift == 0)
error("no erasesize");
limit = ftlfsize(ftl->flash);
if(limit == 0)
error("no space for flash translation");
ftl->segsize = 1 << eshift;
if(base == Nolimit){
ushort pstart, nunits;
erasedetect(ftl, 0, limit, &pstart, &nunits);
base = pstart * ftl->segsize;
size = nunits * ftl->segsize;
print("ftl: partition in %s at 0x%.8lux, length 0x%.8lux\n", fname, base, size);
} else if(size == Nolimit)
size = limit-base;
if(base >= limit || size > limit || base+size > limit || eshift < 8 || (1<<eshift) > size){
print("ftl: bad: base=%#lux limit=%#lux size=%ld eshift=%d\n", base, limit, size, eshift);
error("bad flash space parameters");
}
if(FTLDEBUG)
print("%s flash %s #%lux:#%lux limit #%lux\n", op, fname, base, size, limit);
ftl->base = base;
ftl->size = size;
ftl->bshift = Bshift;
ftl->bsize = Bsize;
ftl->eshift = eshift;
ftl->nunit = size>>eshift;
nov = ((ftl->segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; /* number of overhead blocks per segment (header, and BAM itself) */
ftl->fstart = nov;
segblocks = ftl->segsize/Bsize - nov;
ftl->nblock = ftl->nunit*segblocks;
if(ftl->nblock > 0x10000){
/* oops - too many blocks */
ftl->nunit = 0x10000 / segblocks;
ftl->nblock = ftl->nunit * segblocks;
size = ftl->nunit * ftl->segsize;
ftl->size = size;
print("ftl: too many blocks - limiting to %ld bytes %d units %lud blocks\n",
size, ftl->nunit, ftl->nblock);
}
ftl->vbm = malloc(ftl->nblock*sizeof(*ftl->vbm));
ftl->unit = malloc(ftl->nunit*sizeof(*ftl->unit));
if(ftl->vbm == nil || ftl->unit == nil)
error(Enomem);
if(strcmp(op, "format") == 0){
for(i=0; i<ftl->nunit-1; i++)
eraseinit(ftl, i*ftl->segsize, i, 1);
eraseinit(ftl, i*ftl->segsize, XferID, 1);
}
badseg = -1;
ftl->xfer = -1;
valid = 0;
for(i=0; i<ftl->nunit; i++){
e = eraseload(ftl, i, i*ftl->segsize);
if(e == nil){
print("ftl: logical segment %d: bad format\n", i);
if(badseg == -1)
badseg = i;
else
badseg = -2;
continue;
}
if(e->id == XferBusy){
e->nerase++;
eraseinit(ftl, e->offset, XferID, e->nerase);
e->id = XferID;
}
for(j=0; j<ftl->nunit; j++)
if(ftl->unit[j] != nil && ftl->unit[j]->id == e->id){
print("ftl: duplicate erase unit #%x\n", e->id);
erasefree(e);
e = nil;
break;
}
if(e){
valid++;
ftl->unit[e->x] = e;
if(e->id == XferID)
ftl->xfer = e->x;
if(FTLDEBUG)
print("ftl: unit %d:#%x used %lud free %lud dead %lud bad %lud nerase %lud\n",
e->x, e->id, e->nused, e->nfree, e->ndead, e->nbad, e->nerase);
e = nil;
USED(e);
}
}
if(badseg >= 0){
if(ftl->xfer >= 0)
error("invalid ftl format");
i = badseg;
eraseinit(ftl, i*ftl->segsize, XferID, 1);
e = eraseload(ftl, i, i*ftl->segsize);
if(e == nil)
error("bad ftl format");
ftl->unit[e->x] = e;
ftl->xfer = e->x;
print("ftl: recovered transfer unit %d\n", e->x);
valid++;
e = nil;
USED(e);
}
if(ftl->xfer < 0 && valid <= 0 || ftl->xfer >= 0 && valid <= 1)
error("no valid flash data units");
if(ftl->xfer < 0)
error("ftl: no transfer unit: device is WORM\n");
else
ftl->nblock -= segblocks; /* discount transfer segment */
if(ftl->nblock >= 1000)
ftl->rwlimit = ftl->nblock-100; /* TO DO: variable reserve */
else
ftl->rwlimit = ftl->nblock*ftlpct/100;
poperror();
return ftl;
}
static void
ftlfree(Ftl *ftl)
{
int i, n;
if(ftl != nil){
if(ftl->flashctl != nil)
cclose(ftl->flashctl);
if(ftl->flash != nil)
cclose(ftl->flash);
if(ftl->unit){
for(i = 0; i < ftl->nunit; i++)
erasefree(ftl->unit[i]);
free(ftl->unit);
}
free(ftl->vbm);
for(n = 0; n < NPART; n++)
free(ftl->part[n].name);
free(ftl);
}
}
/*
* this simple greedy algorithm weighted by nerase does seem to lead
* to even wear of erase units (cf. the eNVy file system)
*/
static Terase *
bestcopy(Ftl *ftl)
{
Terase *e, *be;
int i;
be = nil;
for(i=0; i<ftl->nunit; i++)
if((e = ftl->unit[i]) != nil && e->id != XferID && e->id != XferBusy && e->ndead+e->nbad &&
(be == nil || e->nerase <= be->nerase && e->ndead >= be->ndead))
be = e;
return be;
}
static int
copyunit(Ftl *ftl, Terase *from, Terase *to)
{
int i, nb;
uchar id[2];
ulong *bam;
uchar *buf;
ulong v, bno;
if(FTLDEBUG || ftl->trace)
print("ftl: copying %d (#%lux) to #%lux\n", from->id, from->offset, to->offset);
to->nbam = 0;
free(to->bam);
to->bam = nil;
bam = nil;
buf = malloc(Bsize);
if(buf == nil)
return 0;
if(waserror()){
free(buf);
free(bam);
return 0;
}
PUT2(id, XferBusy);
putflash(ftl, to->offset+offsetof(Merase,id[0]), id, 2);
/* make new BAM */
nb = from->nbam*sizeof(*to->bam);
bam = malloc(nb);
if(bam == nil)
error(Enomem);
memmove(bam, from->bam, nb);
to->nused = 0;
to->nbad = 0;
to->nfree = 0;
to->ndead = 0;
for(i = 0; i < from->nbam; i++)
switch(bam[i]){
case Bwriting:
case Bdeleted:
case Bfree:
bam[i] = Bfree;
to->nfree++;
break;
default:
switch(bam[i]&BlockType){
default:
case BadBlock: /* it isn't necessarily bad in this unit */
to->nfree++;
bam[i] = Bfree;
break;
case DataBlock:
case ReplacePage:
v = bam[i];
bno = BNO(v & ~BlockType);
if(i < ftl->fstart || bno >= ftl->nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%lux\n", from->x, from->id, i, v);
to->nfree++;
bam[i] = Bfree;
break;
}
getflash(ftl, buf, from->offset+i*Bsize, Bsize);
putflash(ftl, to->offset+i*Bsize, buf, Bsize);
to->nused++;
break;
case ControlBlock:
to->nused++;
break;
}
}
for(i=0; i<from->nbam; i++){
uchar *p = (uchar*)&bam[i];
v = bam[i];
if(v != Bfree && ftl->trace > 1)
print("to[%d]=#%lux\n", i, v);
PUT4(p, v);
}
putflash(ftl, to->bamoffset, bam, nb); /* BUG: PUT4 */
for(i=0; i<from->nbam; i++){
uchar *p = (uchar*)&bam[i];
v = bam[i];
PUT4(p, v);
}
to->id = from->id;
PUT2(id, to->id);
putflash(ftl, to->offset+offsetof(Merase,id[0]), id, 2);
to->nbam = from->nbam;
to->bam = bam;
ftl->nfree += to->nfree - from->nfree;
poperror();
free(buf);
return 1;
}
static int
mustscavenge(void *a)
{
return ((Ftl*)a)->needspace || ((Ftl*)a)->detach == Deferred;
}
static int
donescavenge(void *a)
{
return ((Ftl*)a)->needspace == 0;
}
static void
scavengeproc(void *arg)
{
Ftl *ftl;
int i;
Terase *e, *ne;
ftl = arg;
if(waserror()){
print("ftl: kproc noted\n");
pexit("ftldeath", 0);
}
for(;;){
sleep(&ftl->workr, mustscavenge, ftl);
if(ftl->detach == Deferred){
ftlfree(ftl);
pexit("", 0);
}
if(FTLDEBUG || ftl->trace)
print("ftl: scavenge %ld\n", ftl->nfree);
qlock(ftl);
if(waserror()){
qunlock(ftl);
nexterror();
}
e = bestcopy(ftl);
if(e == nil || ftl->xfer < 0 || (ne = ftl->unit[ftl->xfer]) == nil || ne->id != XferID || e == ne)
goto Fail;
if(copyunit(ftl, e, ne)){
i = ne->x; ne->x = e->x; e->x = i;
ftl->unit[ne->x] = ne;
ftl->unit[e->x] = e;
ftl->xfer = e->x;
e->id = XferID;
e->nbam = 0;
free(e->bam);
e->bam = nil;
e->bamx = 0;
e->nerase++;
eraseinit(ftl, e->offset, XferID, e->nerase);
}
Fail:
if(FTLDEBUG || ftl->trace)
print("ftl: end scavenge %ld\n", ftl->nfree);
ftl->needspace = 0;
wakeup(&ftl->wantr);
poperror();
qunlock(ftl);
}
}
static int
scavenge(Ftl *ftl)
{
if(ftl->xfer < 0 || bestcopy(ftl) == nil)
return 0; /* you worm! */
qlock(ftl);
if(waserror()){
qunlock(ftl);
return 0;
}
if(!ftl->hasproc){
ftl->hasproc = 1;
kproc("ftl.scavenge", scavengeproc, ftl, 0);
}
ftl->needspace = 1;
wakeup(&ftl->workr);
poperror();
qunlock(ftl);
qlock(&ftl->wantq);
if(waserror()){
qunlock(&ftl->wantq);
nexterror();
}
while(ftl->needspace)
sleep(&ftl->wantr, donescavenge, ftl);
poperror();
qunlock(&ftl->wantq);
return ftl->nfree;
}
static void
putbam(Ftl *ftl, Terase *e, int n, ulong entry)
{
uchar b[4];
e->bam[n] = entry;
PUT4(b, entry);
putflash(ftl, e->bamoffset + n*4, b, 4);
}
static ulong
allocblk(Ftl *ftl)
{
Terase *e;
int i, j;
qlock(ftl);
i = ftl->lastx;
do{
e = ftl->unit[i];
if(e != nil && e->id != XferID && e->nfree){
ftl->lastx = i;
for(j=e->bamx; j<e->nbam; j++)
if(e->bam[j] == Bfree){
putbam(ftl, e, j, Bwriting);
ftl->nfree--;
e->nfree--;
e->bamx = j+1;
qunlock(ftl);
return (e->x<<16) | j;
}
e->nfree = 0;
qunlock(ftl);
print("ftl: unit %d:#%x nfree %ld but not free in BAM\n", e->x, e->id, e->nfree);
qlock(ftl);
}
if(++i >= ftl->nunit)
i = 0;
}while(i != ftl->lastx);
qunlock(ftl);
return 0;
}
static int
mapblk(Ftl *ftl, ulong bno, Terase **ep, ulong *bp)
{
ulong v;
int x;
if(bno < ftl->nblock){
v = ftl->vbm[bno];
if(v == 0 || v == ~0)
return 0;
x = v>>16;
if(x >= ftl->nunit || x == ftl->xfer || ftl->unit[x] == nil){
print("ftl: corrupt format: bad block mapping %lud -> unit #%x\n", bno, x);
return 0;
}
*ep = ftl->unit[x];
*bp = v & 0xFFFF;
return 1;
}
return 0;
}
static void
eraseinit(Ftl *ftl, ulong offset, int id, int nerase)
{
union {
Merase;
uchar block[ERASEHDRLEN];
} *m;
uchar *bam, *p;
int i, nov;
nov = ((ftl->segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; /* number of overhead blocks (header, and BAM itself) */
if(nov*Bsize >= ftl->segsize)
error("ftl -- too small for files");
eraseflash(ftl, offset);
m = malloc(sizeof(*m));
if(m == nil)
error(Enomem);
memset(m, 0xFF, sizeof(*m));
m->linktuple[0] = 0x13;
m->linktuple[1] = 0x3;
memmove(m->linktuple+2, "CIS", 3);
m->orgtuple[0] = 0x46;
m->orgtuple[1] = 0x57;
m->orgtuple[2] = 0x00;
memmove(m->orgtuple+3, "FTL100", 7);
m->nxfer = 1;
PUT4(m->nerase, nerase);
PUT2(m->id, id);
m->bshift = ftl->bshift;
m->eshift = ftl->eshift;
PUT2(m->pstart, ftl->base >> ftl->eshift);
PUT2(m->nunits, ftl->nunit);
PUT4(m->psize, ftl->size - nov*Bsize*ftl->nunit);
PUT4(m->vbmbase, 0xffffffff); /* we always calculate the VBM */
PUT2(m->nvbm, 0);
m->flags = 0;
m->code = 0xFF;
memmove(m->serial, "Inf1", 4);
PUT4(m->altoffset, 0);
PUT4(m->bamoffset, BAMoffset);
putflash(ftl, offset, m, ERASEHDRLEN);
free(m);
if(id == XferID)
return;
nov *= 4; /* now bytes of BAM */
bam = malloc(nov);
if(bam == nil)
error(Enomem);
for(i=0; i<nov; i += 4){
p = bam+i;
PUT4(p, ControlBlock); /* reserve them */
}
putflash(ftl, offset+BAMoffset, bam, nov);
free(bam);
}
static int
erasedetect(Ftl *ftl, ulong base, ulong size, ushort *pstart, ushort *nunits)
{
ulong o;
int rv;
union {
Merase;
uchar block[ERASEHDRLEN];
} *m;
m = malloc(sizeof(*m));
if(m == nil)
error(Enomem);
rv = 0;
for(o = base; o < base + size; o += ftl->segsize){
if(waserror())
continue;
getflash(ftl, m, o, ERASEHDRLEN);
poperror();
if(memcmp(m->orgtuple + 3, "FTL100", 7) == 0
&& memcmp(m->serial, "Inf1", 4) == 0){
*pstart = GET2(m->pstart);
*nunits = GET2(m->nunits);
rv = 1;
break;
}
}
free(m);
return rv;
}
static Terase *
eraseload(Ftl *ftl, int x, ulong offset)
{
union {
Merase;
uchar block[ERASEHDRLEN];
} *m;
Terase *e;
uchar *p;
int i, nbam;
ulong bno, v;
m = malloc(sizeof(*m));
if(m == nil)
error(Enomem);
if(waserror()){
free(m);
return nil;
}
getflash(ftl, m, offset, ERASEHDRLEN);
poperror();
if(memcmp(m->orgtuple+3, "FTL100", 7) != 0 ||
memcmp(m->serial, "Inf1", 4) != 0){
free(m);
print("%8.8lux: bad sig\n", offset);
return nil;
}
e = malloc(sizeof(*e));
if(e == nil){
free(m);
error(Enomem);
}
e->x = x;
e->id = GET2(m->id);
e->offset = offset;
e->bamoffset = GET4(m->bamoffset);
e->nerase = GET4(m->nerase);
free(m);
m = nil;
USED(m);
if(e->bamoffset != BAMoffset){
free(e);
print("%8.8lux: bad bamoffset %8.8lux\n", offset, e->bamoffset);
return nil;
}
e->bamoffset += offset;
if(e->id == XferID || e->id == XferBusy){
e->bam = nil;
e->nbam = 0;
return e;
}
nbam = ftl->segsize/Bsize;
e->bam = malloc(nbam*sizeof(*e->bam));
e->nbam = nbam;
if(waserror()){
free(e);
nexterror();
}
getflash(ftl, e->bam, e->bamoffset, nbam*4);
poperror();
/* scan BAM to build VBM */
e->bamx = 0;
for(i=0; i<nbam; i++){
p = (uchar*)&e->bam[i];
e->bam[i] = v = GET4(p);
if(v == Bwriting || v == Bdeleted)
e->ndead++;
else if(v == Bfree){
if(e->bamx == 0)
e->bamx = i;
e->nfree++;
ftl->nfree++;
}else{
switch(v & BlockType){
case ControlBlock:
break;
case DataBlock:
/* add to VBM */
if(v & (1<<31))
break; /* negative => VBM page, ignored */
bno = BNO(v & ~BlockType);
if(i < ftl->fstart || bno >= ftl->nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%lux\n", e->x, e->id, i, v);
e->nbad++;
break;
}
ftl->vbm[bno] = (e->x<<16) | i;
e->nused++;
break;
case ReplacePage:
/* replacement VBM page; ignored */
break;
default:
print("ftl: unit %d:#%x bad bam[%d]=%lux\n", e->x, e->id, i, v);
case BadBlock:
e->nbad++;
break;
}
}
}
return e;
}
static void
erasefree(Terase *e)
{
if(e){
free(e->bam);
free(e);
}
}
static void
eraseflash(Ftl *ftl, ulong offset)
{
char cmd[40];
offset += ftl->base;
if(FTLDEBUG || ftl->trace)
print("ftl: erase seg @#%lux\n", offset);
snprint(cmd, sizeof(cmd), "erase 0x%8.8lux", offset);
if(kchanio(ftl->flashctl, cmd, strlen(cmd), OWRITE) <= 0){
print("ftl: erase failed: %s\n", up->env->errstr);
error(up->env->errstr);
}
}
static void
putflash(Ftl *ftl, ulong offset, void *buf, long n)
{
offset += ftl->base;
if(ftl->trace)
print("ftl: write(#%lux, %ld)\n", offset, n);
ftl->flash->offset = offset;
if(kchanio(ftl->flash, buf, n, OWRITE) != n){
print("ftl: flash write error: %s\n", up->env->errstr);
error(up->env->errstr);
}
}
static void
getflash(Ftl *ftl, void *buf, ulong offset, long n)
{
offset += ftl->base;
if(ftl->trace)
print("ftl: read(#%lux, %ld)\n", offset, n);
ftl->flash->offset = offset;
if(kchanio(ftl->flash, buf, n, OREAD) != n){
print("ftl: flash read error %s\n", up->env->errstr);
error(up->env->errstr);
}
}
Dev ftldevtab = {
'X', /* TO DO */
"ftl",
devreset,
devinit,
devshutdown,
ftlattach,
ftlwalk,
ftlstat,
ftlopen,
devcreate,
ftlclose,
ftlread,
devbread,
ftlwrite,
devbwrite,
devremove,
devwstat,
};