Add support for Das U-Boot boot images

Notes:
Wed Mar 20 18:07:44 EDT 2013 geoff
    Do you really need u-boot-format images?
    What's wrong with ELF?
    
    There are other changes to the loaders in progress.
    This will have to wait until those are published
    in any case.

Wed Mar 20 19:27:22 PDT 2013 stallion
    uImages are the preferred header when using U-Boot (even Linux
    has added support for uImages).  The format is simpler than
    ELF and has some nice relocation properties that does away with
    the usual jump-around-the-header dance at boot.

    I have submitted a patch upstream to the U-Boot folks to treat
    Plan 9 as a first-class citizen:
        http://patchwork.ozlabs.org/patch/229459/

    I don't mind waiting; I've already sent a message to Charles
    mentioning the work.  Hopefully others find this useful.

Tue Apr 2 23:10:12 PDT 2013 stallion
    Merged with latest ELF changes.

Thu Jul 4 22:34:14 PDT 2013 stallion
    Genericized support for u-boot images in libmach.


Reference: /n/sources/patch/maybe/arm-uboot
Date: Sun Mar 17 08:36:06 CET 2013
Signed-off-by: sstallion@gmail.com
Reviewed-by: geoff

--- /sys/include/bootexec.h	Fri Jul  5 06:47:36 2013
+++ /sys/include/bootexec.h	Fri Jul  5 07:30:21 2013
@@ -135,3 +135,19 @@
 	struct coffsect ibsss;
 	struct coffsect icomments;
 };
+
+struct ubootexec
+{
+	ulong	umagic;		/* image magic */
+	ulong	hcrc;		/* header checksum */
+	ulong	time;		/* timestamp */
+	ulong	size;		/* data size */
+	ulong	load;		/* load address */
+	ulong	ep;		/* entry point */
+	ulong	dcrc;		/* data checksum */
+	uchar	os;		/* operating system */
+	uchar	arch;		/* architecture */
+	uchar	type;		/* image type */
+	uchar	comp;		/* compression */
+	uchar	name[32];	/* image name */
+};
--- /sys/src/cmd/5l/asm.c	Fri Jul  5 06:52:02 2013
+++ /sys/src/cmd/5l/asm.c	Fri Jul  5 07:30:32 2013
@@ -1,9 +1,43 @@
 #include	"l.h"
+#include	<flate.h>
 
 long	OFFSET;
 
 static Prog *PP;
 
+ulong
+crc32(char *name, int len, vlong off)
+{
+	uchar buf[MAXIO];
+	int fd, n;
+	ulong crc;
+	static ulong *crctab;
+
+	if(crctab == nil)
+		crctab = mkcrctab(0xedb88320);
+	fd = open(name, OREAD);
+	if(fd < 0) {
+		diag("cannot open %s: %r", name);
+		errorexit();
+	}
+	seek(fd, off, 0);
+	crc = 0;
+	while(len > 0) {
+		n = len;
+		if(n > sizeof buf)
+			n = sizeof buf;
+		n = read(fd, buf, n);
+		if(n < 0) {
+			diag("cannot read %s: %r", name);
+			errorexit();
+		}
+		crc = blockcrc(crctab, crc, buf, n);
+		len -= n;
+	}
+	close(fd);
+	return crc;
+}
+
 long
 entryvalue(void)
 {
@@ -89,6 +123,10 @@
 		OFFSET = rnd(HEADR+textsize, 4096);
 		seek(cout, OFFSET, 0);
 		break;
+	case 8:
+		OFFSET = rnd(textsize, INITRND)+HEADR;
+		seek(cout, OFFSET, 0);
+		break;
 	}
 	if(dlm){
 		char buf[8];
@@ -114,6 +152,7 @@
 		case 1:
 		case 4:
 		case 5:
+		case 8:
 			debug['s'] = 1;
 			break;
 		case 2:
@@ -218,6 +257,33 @@
 	case 7:	/* elf */
 		debug['S'] = 1;			/* symbol table */
 		elf32(ARM, ELFDATA2LSB, 0, nil);
+		break;
+	case 8:	/* u-boot image */
+		t = rnd(textsize, INITRND)+datsize;
+		lput(0x27051956);		/* image magic */
+		lput(0);			/* header checksum */
+		lput(time(nil));		/* timestamp */
+		lput(t);			/* data size */
+		lput(INITTEXT);			/* load address */
+		lput(entryvalue());		/* entry point */
+		lput(0);			/* data checksum */
+		cput(23);			/* os = Plan 9 */
+		cput(2);			/* arch = ARM */
+		cput(2);			/* type = OS Kernel Image */
+		cput(0);			/* compression = none */
+		strnput(outfile, 32);		/* image name */
+		cflush();
+
+		/* calculate data checksum */
+		OFFSET = 24;
+		seek(cout, OFFSET, 0);
+		lput(crc32(outfile, t, HEADR));
+		cflush();
+
+		/* calculate header checksum */
+		OFFSET = 4;
+		seek(cout, OFFSET, 0);
+		lput(crc32(outfile, HEADR, 0));
 		break;
 	}
 	cflush();
--- /sys/src/cmd/5l/obj.c	Fri Jul  5 06:51:11 2013
+++ /sys/src/cmd/5l/obj.c	Fri Jul  5 06:51:13 2013
@@ -24,6 +24,7 @@
  *	-H5 -T0xC0008010 -R1024		is ipaq
  *	-H6 -R4096			no header with segments padded to pages
  *	-H7				is elf
+ *	-H8				is u-boot image
  */
 
 void
@@ -222,6 +223,15 @@
 		if(INITRND == -1)
 			INITRND = 4;
 		break;
+	case 8:	/* u-boot image */
+		HEADR = 64L;
+		if(INITTEXT == -1)
+			INITTEXT = 0;
+		if(INITDAT == -1)
+			INITDAT = 0;
+		if(INITRND == -1)
+			INITRND = 4;
+		break; 
 	}
 	if (INITTEXTP == -1)
 		INITTEXTP = INITTEXT;
--- /sys/src/libmach/executable.c	Fri Jul  5 06:48:10 2013
+++ /sys/src/libmach/executable.c	Fri Jul  5 06:49:46 2013
@@ -22,6 +22,7 @@
 		struct mips4kexec;	/* bootexec.h */
 		struct sparcexec;	/* bootexec.h */
 		struct nextexec;	/* bootexec.h */
+		struct ubootexec;	/* bootexec.h */
 	} e;
 	long dummy;			/* padding to ensure extra long */
 } ExecHdr;
@@ -35,6 +36,7 @@
 static	int	adotout(int, Fhdr*, ExecHdr*);
 static	int	elfdotout(int, Fhdr*, ExecHdr*);
 static	int	armdotout(int, Fhdr*, ExecHdr*);
+static	int	uboot(int, Fhdr*, ExecHdr*);
 static	void	setsym(Fhdr*, long, long, long, vlong);
 static	void	setdata(Fhdr*, uvlong, long, vlong, long);
 static	void	settext(Fhdr*, uvlong, uvlong, long, vlong);
@@ -234,6 +236,15 @@
 		sizeof(Exec),
 		leswal,
 		armdotout },
+	{ 0x27051956,			/* any u-boot image */
+		"u-boot image",
+		nil,
+		FNONE,
+		0,
+		nil,
+		sizeof(struct ubootexec),
+		beswal,
+		uboot },
 	{ L_MAGIC,			/* alpha 7.out */
 		"alpha plan 9 executable",
 		"alpha plan 9 dlm",
@@ -871,6 +882,62 @@
 	return 1;
 }
 
+/*
+ *	u-boot bootable image
+ */
+static int
+uboot(int, Fhdr *fp, ExecHdr *hp)
+{
+	fp->txtaddr = hp->e.load;
+	fp->txtsz = hp->e.size;
+	switch(hp->e.arch) {
+	case 1:
+		mach = &malpha;
+		fp->type = FALPHA;
+		fp->name = "alpha u-boot image";
+		break;
+	case 2:
+		mach = &marm;
+		fp->type = FARM;
+		fp->name = "ARM u-boot image";
+		break;
+	case 3:
+		mach = &mi386;
+		fp->type = FI386;
+		fp->name = "386 u-boot image";
+		break;
+	case 5:
+		mach = &mmips;
+		fp->type = FMIPS;
+		fp->name = "mips u-boot image";
+		break;
+	case 7:
+		mach = &mpower;
+		fp->type = FPOWER;
+		fp->name = "power u-boot image";
+		break;
+	case 10:
+		mach = &msparc;
+		fp->type = FSPARC;
+		fp->name = "sparc u-boot image";
+		break;
+	case 11:
+		mach = &msparc64;
+		fp->type = FSPARC64;
+		fp->name = "sparc64 u-boot image";
+		break;
+	case 12:
+		mach = &m68020;
+		fp->type = F68020;
+		fp->name = "68020 u-boot image";
+		break;
+	default:
+		return 0;
+	}
+	fp->hdrsz = 0;			/* header stripped */
+	return 1;
+}
+
 static void
 settext(Fhdr *fp, uvlong e, uvlong a, long s, vlong off)
 {
@@ -899,7 +966,6 @@
 	fp->lnpcsz = lnpcsz;
 	fp->lnpcoff = fp->sppcoff+fp->sppcsz;
 }
-
 
 static uvlong
 _round(uvlong a, ulong b)