Fixed MTP to work with TWRP

Documentation/arm/SH-Mobile/vrl4.c

@@ -0,0 +1,170 @@
+/*
+ * vrl4 format generator
+ *
+ * Copyright (C) 2010 Simon Horman
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+/*
+ * usage: vrl4 < zImage > out
+ *	  dd if=out of=/dev/sdx bs=512 seek=1 # Write the image to sector 1
+ *
+ * Reads a zImage from stdin and writes a vrl4 image to stdout.
+ * In practice this means writing a padded vrl4 header to stdout followed
+ * by the zImage.
+ *
+ * The padding places the zImage at ALIGN bytes into the output.
+ * The vrl4 uses ALIGN + START_BASE as the start_address.
+ * This is where the mask ROM will jump to after verifying the header.
+ *
+ * The header sets copy_size to min(sizeof(zImage), MAX_BOOT_PROG_LEN) + ALIGN.
+ * That is, the mask ROM will load the padded header (ALIGN bytes)
+ * And then MAX_BOOT_PROG_LEN bytes of the image, or the entire image,
+ * whichever is smaller.
+ *
+ * The zImage is not modified in any way.
+ */
+
+#define _BSD_SOURCE
+#include <endian.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <errno.h>
+#include <tools/endian.h>
+
+struct hdr {
+	uint32_t magic1;
+	uint32_t reserved1;
+	uint32_t magic2;
+	uint32_t reserved2;
+	uint16_t copy_size;
+	uint16_t boot_options;
+	uint32_t reserved3;
+	uint32_t start_address;
+	uint32_t reserved4;
+	uint32_t reserved5;
+	char     reserved6[308];
+};
+
+#define DECLARE_HDR(h)					\
+	struct hdr (h) = {				\
+		.magic1 =	htole32(0xea000000),	\
+		.reserved1 =	htole32(0x56),		\
+		.magic2 =	htole32(0xe59ff008),	\
+		.reserved3 =	htole16(0x1) }
+
+/* Align to 512 bytes, the MMCIF sector size */
+#define ALIGN_BITS	9
+#define ALIGN		(1 << ALIGN_BITS)
+
+#define START_BASE	0xe55b0000
+
+/*
+ * With an alignment of 512 the header uses the first sector.
+ * There is a 128 sector (64kbyte) limit on the data loaded by the mask ROM.
+ * So there are 127 sectors left for the boot programme. But in practice
+ * Only a small portion of a zImage is needed, 16 sectors should be more
+ * than enough.
+ *
+ * Note that this sets how much of the zImage is copied by the mask ROM.
+ * The entire zImage is present after the header and is loaded
+ * by the code in the boot program (which is the first portion of the zImage).
+ */
+#define	MAX_BOOT_PROG_LEN (16 * 512)
+
+#define ROUND_UP(x)	((x + ALIGN - 1) & ~(ALIGN - 1))
+
+static ssize_t do_read(int fd, void *buf, size_t count)
+{
+	size_t offset = 0;
+	ssize_t l;
+
+	while (offset < count) {
+		l = read(fd, buf + offset, count - offset);
+		if (!l)
+			break;
+		if (l < 0) {
+			if (errno == EAGAIN || errno == EWOULDBLOCK)
+				continue;
+			perror("read");
+			return -1;
+		}
+		offset += l;
+	}
+
+	return offset;
+}
+
+static ssize_t do_write(int fd, const void *buf, size_t count)
+{
+	size_t offset = 0;
+	ssize_t l;
+
+	while (offset < count) {
+		l = write(fd, buf + offset, count - offset);
+		if (l < 0) {
+			if (errno == EAGAIN || errno == EWOULDBLOCK)
+				continue;
+			perror("write");
+			return -1;
+		}
+		offset += l;
+	}
+
+	return offset;
+}
+
+static ssize_t write_zero(int fd, size_t len)
+{
+	size_t i = len;
+
+	while (i--) {
+		const char x = 0;
+		if (do_write(fd, &x, 1) < 0)
+			return -1;
+	}
+
+	return len;
+}
+
+int main(void)
+{
+	DECLARE_HDR(hdr);
+	char boot_program[MAX_BOOT_PROG_LEN];
+	size_t aligned_hdr_len, alligned_prog_len;
+	ssize_t prog_len;
+
+	prog_len = do_read(0, boot_program, sizeof(boot_program));
+	if (prog_len <= 0)
+		return -1;
+
+	aligned_hdr_len = ROUND_UP(sizeof(hdr));
+	hdr.start_address = htole32(START_BASE + aligned_hdr_len);
+	alligned_prog_len = ROUND_UP(prog_len);
+	hdr.copy_size = htole16(aligned_hdr_len + alligned_prog_len);
+
+	if (do_write(1, &hdr, sizeof(hdr)) < 0)
+		return -1;
+	if (write_zero(1, aligned_hdr_len - sizeof(hdr)) < 0)
+		return -1;
+
+	if (do_write(1, boot_program, prog_len) < 0)
+		return 1;
+
+	/* Write out the rest of the kernel */
+	while (1) {
+		prog_len = do_read(0, boot_program, sizeof(boot_program));
+		if (prog_len < 0)
+			return 1;
+		if (prog_len == 0)
+			break;
+		if (do_write(1, boot_program, prog_len) < 0)
+			return 1;
+	}
+
+	return 0;
+}