20060303

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;
+}