fix modules_install via NFS

Rafael reported:

I get the following error from 'make modules_install' on my test boxes:

  HOSTCC  firmware/ihex2fw
/home/rafael/src/linux-2.6/firmware/ihex2fw.c:268: fatal error: opening dependency file firmware/.ihex2fw.d: Read-only file system
compilation terminated.
make[3]: *** [firmware/ihex2fw] Error 1
make[2]: *** [_modinst_post] Error 2
make[1]: *** [sub-make] Error 2
make: *** [all] Error 2

where the configuration is that the kernel is compiled on a build box
with 'make O=<destdir> -j5' and then <destdir> is mounted over NFS read-only by
each test box (full path to this directory is the same on the build box and on
the test boxes).  Then, I cd into <destdir>, run 'make modules_install' and get
the error above.

The issue turns out to be that we when we install firmware pick
up the list of firmware blobs from firmware/Makefile.
And this triggers the Makefile rules to update ihex2fw.

There were two solutions for this issue:
1) Move the list of firmware blobs to a separate file
2) Avoid ihex2fw rebuild by moving it to scripts

As I seriously beleive that the list of firmware blobs should be
done in a fundamental different way solution 2) was selected.

Reported-and-tested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: David Woodhouse <dwmw2@infradead.org>

3 files changed, 271 insertions, 1 deletions

diff --git a/scripts/.gitignore b/scripts/.gitignore
index b939fbd..09e2406 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,6 +1,7 @@
 #
 # Generated files
 #
+ihex2fw
 conmakehash
 kallsyms
 pnmtologo
diff --git a/scripts/Makefile b/scripts/Makefile
index aafdf06..035182e 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -2,11 +2,12 @@
 # scripts contains sources for various helper programs used throughout
 # the kernel for the build process.
 # ---------------------------------------------------------------------------
+# ihex2fw:       Parser/loader for IHEX formatted data
 # kallsyms:      Find all symbols in vmlinux
 # pnmttologo:    Convert pnm files to logo files
-# conmakehash:   Create chartable
 # conmakehash:	 Create arrays for initializing the kernel console tables
 
+hostprogs-y                      := ihex2fw
 hostprogs-$(CONFIG_KALLSYMS)     += kallsyms
 hostprogs-$(CONFIG_LOGO)         += pnmtologo
 hostprogs-$(CONFIG_VT)           += conmakehash
diff --git a/scripts/ihex2fw.c b/scripts/ihex2fw.c
new file mode 100644
index 0000000..8f7fdaa9
--- /dev/null
+++ b/scripts/ihex2fw.c
@@ -0,0 +1,268 @@
+/*
+ * Parser/loader for IHEX formatted data.
+ *
+ * Copyright © 2008 David Woodhouse <dwmw2@infradead.org>
+ * Copyright © 2005 Jan Harkes <jaharkes@cs.cmu.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#define _GNU_SOURCE
+#include <getopt.h>
+
+
+struct ihex_binrec {
+	struct ihex_binrec *next; /* not part of the real data structure */
+        uint32_t addr;
+        uint16_t len;
+        uint8_t data[];
+};
+
+/**
+ * nybble/hex are little helpers to parse hexadecimal numbers to a byte value
+ **/
+static uint8_t nybble(const uint8_t n)
+{
+       if      (n >= '0' && n <= '9') return n - '0';
+       else if (n >= 'A' && n <= 'F') return n - ('A' - 10);
+       else if (n >= 'a' && n <= 'f') return n - ('a' - 10);
+       return 0;
+}
+
+static uint8_t hex(const uint8_t *data, uint8_t *crc)
+{
+       uint8_t val = (nybble(data[0]) << 4) | nybble(data[1]);
+       *crc += val;
+       return val;
+}
+
+static int process_ihex(uint8_t *data, ssize_t size);
+static void file_record(struct ihex_binrec *record);
+static int output_records(int outfd);
+
+static int sort_records = 0;
+static int wide_records = 0;
+
+int usage(void)
+{
+	fprintf(stderr, "ihex2fw: Convert ihex files into binary "
+		"representation for use by Linux kernel\n");
+	fprintf(stderr, "usage: ihex2fw [<options>] <src.HEX> <dst.fw>\n");
+	fprintf(stderr, "       -w: wide records (16-bit length)\n");
+	fprintf(stderr, "       -s: sort records by address\n");
+	return 1;
+}
+
+int main(int argc, char **argv)
+{
+	int infd, outfd;
+	struct stat st;
+	uint8_t *data;
+	int opt;
+
+	while ((opt = getopt(argc, argv, "ws")) != -1) {
+		switch (opt) {
+		case 'w':
+			wide_records = 1;
+			break;
+		case 's':
+			sort_records = 1;
+			break;
+		default:
+			return usage();
+		}
+	}
+
+	if (optind + 2 != argc)
+		return usage();
+
+	if (!strcmp(argv[optind], "-"))
+	    infd = 0;
+	else
+		infd = open(argv[optind], O_RDONLY);
+	if (infd == -1) {
+		fprintf(stderr, "Failed to open source file: %s",
+			strerror(errno));
+		return usage();
+	}
+	if (fstat(infd, &st)) {
+		perror("stat");
+		return 1;
+	}
+	data = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, infd, 0);
+	if (data == MAP_FAILED) {
+		perror("mmap");
+		return 1;
+	}
+
+	if (!strcmp(argv[optind+1], "-"))
+	    outfd = 1;
+	else
+		outfd = open(argv[optind+1], O_TRUNC|O_CREAT|O_WRONLY, 0644);
+	if (outfd == -1) {
+		fprintf(stderr, "Failed to open destination file: %s",
+			strerror(errno));
+		return usage();
+	}
+	if (process_ihex(data, st.st_size))
+		return 1;
+
+	output_records(outfd);
+	return 0;
+}
+
+static int process_ihex(uint8_t *data, ssize_t size)
+{
+	struct ihex_binrec *record;
+	uint32_t offset = 0;
+	uint8_t type, crc = 0, crcbyte = 0;
+	int i, j;
+	int line = 1;
+	int len;
+
+	i = 0;
+next_record:
+	/* search for the start of record character */
+	while (i < size) {
+		if (data[i] == '\n') line++;
+		if (data[i++] == ':') break;
+	}
+
+	/* Minimum record length would be about 10 characters */
+	if (i + 10 > size) {
+		fprintf(stderr, "Can't find valid record at line %d\n", line);
+		return -EINVAL;
+	}
+
+	len = hex(data + i, &crc); i += 2;
+	if (wide_records) {
+		len <<= 8;
+		len += hex(data + i, &crc); i += 2;
+	}
+	record = malloc((sizeof (*record) + len + 3) & ~3);
+	if (!record) {
+		fprintf(stderr, "out of memory for records\n");
+		return -ENOMEM;
+	}
+	memset(record, 0, (sizeof(*record) + len + 3) & ~3);
+	record->len = len;
+
+	/* now check if we have enough data to read everything */
+	if (i + 8 + (record->len * 2) > size) {
+		fprintf(stderr, "Not enough data to read complete record at line %d\n",
+			line);
+		return -EINVAL;
+	}
+
+	record->addr  = hex(data + i, &crc) << 8; i += 2;
+	record->addr |= hex(data + i, &crc); i += 2;
+	type = hex(data + i, &crc); i += 2;
+
+	for (j = 0; j < record->len; j++, i += 2)
+		record->data[j] = hex(data + i, &crc);
+
+	/* check CRC */
+	crcbyte = hex(data + i, &crc); i += 2;
+	if (crc != 0) {
+		fprintf(stderr, "CRC failure at line %d: got 0x%X, expected 0x%X\n",
+			line, crcbyte, (unsigned char)(crcbyte-crc));
+		return -EINVAL;
+	}
+
+	/* Done reading the record */
+	switch (type) {
+	case 0:
+		/* old style EOF record? */
+		if (!record->len)
+			break;
+
+		record->addr += offset;
+		file_record(record);
+		goto next_record;
+
+	case 1: /* End-Of-File Record */
+		if (record->addr || record->len) {
+			fprintf(stderr, "Bad EOF record (type 01) format at line %d",
+				line);
+			return -EINVAL;
+		}
+		break;
+
+	case 2: /* Extended Segment Address Record (HEX86) */
+	case 4: /* Extended Linear Address Record (HEX386) */
+		if (record->addr || record->len != 2) {
+			fprintf(stderr, "Bad HEX86/HEX386 record (type %02X) at line %d\n",
+				type, line);
+			return -EINVAL;
+		}
+
+		/* We shouldn't really be using the offset for HEX86 because
+		 * the wraparound case is specified quite differently. */
+		offset = record->data[0] << 8 | record->data[1];
+		offset <<= (type == 2 ? 4 : 16);
+		goto next_record;
+
+	case 3: /* Start Segment Address Record */
+	case 5: /* Start Linear Address Record */
+		if (record->addr || record->len != 4) {
+			fprintf(stderr, "Bad Start Address record (type %02X) at line %d\n",
+				type, line);
+			return -EINVAL;
+		}
+
+		/* These records contain the CS/IP or EIP where execution
+		 * starts. Don't really know what to do with them. */
+		goto next_record;
+
+	default:
+		fprintf(stderr, "Unknown record (type %02X)\n", type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct ihex_binrec *records;
+
+static void file_record(struct ihex_binrec *record)
+{
+	struct ihex_binrec **p = &records;
+
+	while ((*p) && (!sort_records || (*p)->addr < record->addr))
+		p = &((*p)->next);
+
+	record->next = *p;
+	*p = record;
+}
+
+static int output_records(int outfd)
+{
+	unsigned char zeroes[6] = {0, 0, 0, 0, 0, 0};
+	struct ihex_binrec *p = records;
+
+	while (p) {
+		uint16_t writelen = (p->len + 9) & ~3;
+
+		p->addr = htonl(p->addr);
+		p->len = htons(p->len);
+		write(outfd, &p->addr, writelen);
+		p = p->next;
+	}
+	/* EOF record is zero length, since we don't bother to represent
+	   the type field in the binary version */
+	write(outfd, zeroes, 6);
+	return 0;
+}