diff options
Diffstat (limited to 'os/boot/mpc/flash.c')
| -rw-r--r-- | os/boot/mpc/flash.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/os/boot/mpc/flash.c b/os/boot/mpc/flash.c new file mode 100644 index 00000000..d05f638f --- /dev/null +++ b/os/boot/mpc/flash.c @@ -0,0 +1,212 @@ +#include "boot.h" + +typedef struct Flashdev Flashdev; +struct Flashdev { + uchar* base; + int size; + uchar* exec; + char* config; + int conflen; +}; + +enum { + FLASHSEG = 256*1024, + CONFIGLIM = FLASHSEG, + BOOTOFF = FLASHSEG, + BOOTLEN = 3*FLASHSEG, /* third segment might be filsys */ + /* rest of flash is free */ +}; + +static Flashdev flash; + +/* + * configuration data is written between the bootstrap and + * the end of region 0. the region ends with allocation descriptors + * of the following form: + * + * byte order is big endian + * + * the last valid region found that starts with the string "#plan9.ini\n" is plan9.ini + */ +typedef struct Flalloc Flalloc; +struct Flalloc { + ulong check; /* checksum of data, or ~0 */ + ulong base; /* base of region; ~0 if unallocated, 0 if deleted */ + uchar len[3]; + uchar tag; /* see below */ + uchar sig[4]; +}; + +enum { + /* tags */ + Tdead= 0, + Tboot= 0x01, /* space reserved for boot */ + Tconf= 0x02, /* configuration data */ + Tnone= 0xFF, + + Noval= ~0, +}; + +static char flashsig[] = {0xF1, 0xA5, 0x5A, 0x1F}; +static char conftag[] = "#plan9.ini\n"; + +static ulong +checksum(uchar* p, int n) +{ + ulong s; + + for(s=0; --n >= 0;) + s += *p++; + return s; +} + +static int +validptr(Flalloc *ap, uchar *p) +{ + return p > (uchar*)&end && p < (uchar*)ap; +} + +static int +flashcheck(Flalloc *ap, char **val, int *len) +{ + uchar *base; + int n; + + if(ap->base == Noval || ap->base >= FLASHSEG || ap->tag == Tnone) + return 0; + base = flash.base+ap->base; + if(!validptr(ap, base)) + return 0; + n = (((ap->len[0]<<8)|ap->len[1])<<8)|ap->len[2]; + if(n == 0xFFFFFF) + n = 0; + if(n < 0) + return 0; + if(n > 0 && !validptr(ap, base+n-1)) + return 0; + if(ap->check != Noval && checksum(base, n) != ap->check){ + print("flash: bad checksum\n"); + return 0; + } + *val = (char*)base; + *len = n; + return 1; +} + +int +flashinit(void) +{ + int len; + char *val; + Flalloc *ap; + void *addr; + long mbytes; + char type[20]; + + flash.base = 0; + flash.exec = 0; + flash.size = 0; + if(archflashreset(type, &addr, &mbytes) < 0){ + print("flash: flash not present or not enabled\n"); /* shouldn't happen */ + return 0; + } + flash.size = mbytes; + flash.base = addr; + flash.exec = flash.base + BOOTOFF; + flash.config = nil; + flash.conflen = 0; + + for(ap = (Flalloc*)(flash.base+CONFIGLIM)-1; memcmp(ap->sig, flashsig, 4) == 0; ap--){ + if(0) + print("conf #%8.8lux: #%x #%6.6lux\n", ap, ap->tag, ap->base); + if(ap->tag == Tconf && + flashcheck(ap, &val, &len) && + len >= sizeof(conftag)-1 && + memcmp(val, conftag, sizeof(conftag)-1) == 0){ + flash.config = val; + flash.conflen = len; + if(0) + print("flash: found config %8.8lux(%d):\n%s\n", val, len, val); + } + } + if(flash.config == nil) + print("flash: no config\n"); + else + print("flash config %8.8lux(%d):\n%s\n", flash.config, flash.conflen, flash.config); + if(issqueezed(flash.exec) == Q_MAGIC){ + print("flash: squeezed powerpc kernel installed\n"); + return 1<<0; + } + if(GLLONG(flash.exec) == Q_MAGIC){ + print("flash: unsqueezed powerpc kernel installed\n"); + return 1<<0; + } + flash.exec = 0; + print("flash: no powerpc kernel in Flash\n"); + return 0; +} + +char* +flashconfig(int) +{ + return flash.config; +} + +int +flashbootable(int) +{ + return flash.exec != nil && (issqueezed(flash.exec) || GLLONG(flash.exec) == Q_MAGIC); +} + +int +flashboot(int) +{ + ulong entry, addr; + void (*b)(void); + Exec *ep; + Block in; + long n; + uchar *p; + + if(flash.exec == 0) + return -1; + p = flash.exec; + if(GLLONG(p) == Q_MAGIC){ + /* unsqueezed: copy data and perhaps text, then jump to it */ + ep = (Exec*)p; + entry = PADDR(GLLONG(ep->entry)); + p += sizeof(Exec); + addr = entry; + n = GLLONG(ep->text); + if(addr != (ulong)p){ + memmove((void*)addr, p, n); + print("text: %8.8lux <- %8.8lux [%ld]\n", addr, p, n); + } + p += n; + if(entry >= FLASHMEM) + addr = 3*BY2PG; /* kernel text is in Flash, data in RAM */ + else + addr = PGROUND(addr+n); + n = GLLONG(ep->data); + memmove((void*)addr, p, n); + print("data: %8.8lux <- %8.8lux [%ld]\n", addr, p, n); + }else{ + in.data = p; + in.rp = in.data; + in.lim = p+BOOTLEN; + in.wp = in.lim; + n = unsqueezef(&in, &entry); + if(n < 0) + return -1; + } + print("entry=0x%lux\n", entry); + uartwait(); + scc2stop(); + /* + * Go to new code. It's up to the program to get its PC relocated to + * the right place. + */ + b = (void (*)(void))KADDR(PADDR(entry)); + (*b)(); + return -1; +} |