* Patch by Daniel Engström, 13 Nov 2002:

  Add support for i386 architecture and AMD SC520 board

* Patch by Pierre Aubert, 12 Nov 2002:
  Add support for DOS filesystem and booting from DOS floppy disk

1 files changed, 276 insertions, 0 deletions

diff --git a/lib_i386/zimage.c b/lib_i386/zimage.c
new file mode 100644
index 0000000..190d46e
--- /dev/null
+++ b/lib_i386/zimage.c
@@ -0,0 +1,276 @@
+/*
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, daniel@omicron.se
+ * 
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/* 
+ * Linux i386 zImage and bzImage loading
+ * 
+ * based on the procdure described in 
+ * linux/Documentation/i386/boot.txt
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/ptrace.h>
+#include <asm/zimage.h>
+#include <asm/realmode.h>
+#include <asm/byteorder.h>
+
+/*
+ * Memory lay-out:
+ * 
+ * relative to setup_base (which is 0x90000 currently)
+ * 
+ *	0x0000-0x7FFF	Real mode kernel   
+ *	0x8000-0x8FFF	Stack and heap
+ *	0x9000-0x90FF	Kernel command line
+ */
+#define DEFAULT_SETUP_BASE  0x90000
+#define COMMAND_LINE_OFFSET 0x9000
+#define HEAP_END_OFFSET     0x8e00
+
+#define COMMAND_LINE_SIZE   2048
+
+static void build_command_line(char *command_line, int auto_boot)
+{
+	char *env_command_line;
+	
+	command_line[0] = '\0';
+	
+	env_command_line =  getenv("bootargs");
+	
+	/* set console= argument if we use a serial console */
+	if (NULL == strstr(env_command_line, "console=")) {
+		if (0==strcmp(getenv("stdout"), "serial")) {
+			
+			/* We seem to use serial console */
+			sprintf(command_line, "console=ttyS0,%s ", 
+				 getenv("baudrate"));
+		}
+	}
+	
+	if (auto_boot) {
+		strcat(command_line, "auto ");
+	}
+		
+	if (NULL != env_command_line) {
+		strcat(command_line, env_command_line);
+	} 
+	
+	
+	printf("Kernel command line: \"%s\"\n", command_line);
+}
+
+void *load_zimage(char *image, unsigned long kernel_size, 
+		  unsigned long initrd_addr, unsigned long initrd_size,
+		  int auto_boot)
+{
+        void *setup_base;
+	int setup_size;
+	int bootproto;
+	int big_image;
+	void *load_address;
+	
+	
+	setup_base = (void*)DEFAULT_SETUP_BASE;	/* base address for real-mode segment */
+	
+ 	if (KERNEL_MAGIC != *(u16*)(image + BOOT_FLAG_OFF)) {
+		printf("Error: Invalid kernel magic (found 0x%04x, expected 0xaa55)\n",
+		       *(u16*)(image + BOOT_FLAG_OFF));
+		return 0;
+	}
+	
+	
+	/* determine boot protocol version */
+	if (KERNEL_V2_MAGIC == *(u32*)(image+HEADER_OFF)) {
+		bootproto = *(u16*)(image+VERSION_OFF);
+	} else {
+		/* Very old kernel */
+		bootproto = 0x0100;
+	}
+	
+	/* determine size of setup */
+	if (0 == *(u8*)(image + SETUP_SECTS_OFF)) {
+		setup_size = 5 * 512;
+	} else {
+		setup_size = (*(u8*)(image + SETUP_SECTS_OFF) + 1) * 512;
+	}
+	
+	if (setup_size > SETUP_MAX_SIZE) {
+		printf("Error: Setup is too large (%d bytes)\n", setup_size);
+	}
+	
+	/* Determine image type */
+  	big_image = (bootproto >= 0x0200) && (*(u8*)(image + LOADFLAGS_OFF) & BIG_KERNEL_FLAG);
+	
+	/* Derermine load address */
+	load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR:ZIMAGE_LOAD_ADDR);
+			
+	/* load setup */
+	memmove(setup_base, image, setup_size);
+	
+	printf("Using boot protocol version %x.%02x\n", 
+	       (bootproto & 0xff00) >> 8, bootproto & 0xff);
+	
+	
+	if (bootproto == 0x0100) {		
+	
+		*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
+		*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET; 
+		
+		/* A very old kernel MUST have its real-mode code
+		 * loaded at 0x90000 */
+		
+		if ((u32)setup_base != 0x90000) {
+			/* Copy the real-mode kernel */
+			memmove((void*)0x90000, setup_base, setup_size);
+			/* Copy the command line */
+			memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET, 
+			       COMMAND_LINE_SIZE);
+			
+			setup_base = (void*)0x90000;		 /* Relocated */
+		}
+		
+		/* It is recommended to clear memory up to the 32K mark */
+		memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size);
+	}
+	
+	if (bootproto >= 0x0200) {
+		*(u8*)(setup_base + TYPE_OF_LOADER_OFF) = 0xff;
+		printf("Linux kernel version %s\n", 
+		       (char*)(setup_base + SETUP_START_OFFSET + 
+			       *(u16*)(setup_base + START_SYS_OFF + 2)));
+		
+		if (initrd_addr) {
+			printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n",
+			       initrd_addr, initrd_size);
+			
+			*(u32*)(setup_base + RAMDISK_IMAGE_OFF) = initrd_addr;
+			*(u32*)(setup_base + RAMDISK_SIZE_OFF)=initrd_size;
+		}
+	}
+	
+	if (bootproto >= 0x0201) {
+		*(u16*)(setup_base + HEAP_END_PTR_OFF) = HEAP_END_OFFSET;
+		
+		/* CAN_USE_HEAP */
+		*(u8*)(setup_base + LOADFLAGS_OFF) = 
+			*(u8*)(setup_base + LOADFLAGS_OFF) | HEAP_FLAG;
+	}
+	
+	if (bootproto >= 0x0202) {
+		*(u32*)(setup_base + CMD_LINE_PTR_OFF) = (u32)setup_base + COMMAND_LINE_OFFSET;
+	} else if (bootproto >= 0x0200) {
+		*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
+		*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET; 
+		*(u16*)(setup_base + SETUP_MOVE_SIZE_OFF) = 0x9100;
+	}
+	
+
+	
+	if (big_image) {
+		if ((kernel_size - setup_size) > BZIMAGE_MAX_SIZE) { 
+			printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
+			       kernel_size - setup_size, BZIMAGE_MAX_SIZE);
+			return 0;
+		}
+		
+	} else if ((kernel_size - setup_size) > ZIMAGE_MAX_SIZE) {
+		printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
+		       kernel_size - setup_size, ZIMAGE_MAX_SIZE);
+		return 0;
+	}
+	
+	/* build command line at COMMAND_LINE_OFFSET */
+	build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);
+	
+        printf("Loading %czImage at address 0x%08x (%ld bytes)\n", big_image ? 'b' : ' ', 
+	       (u32)load_address, kernel_size - setup_size);
+
+	       
+	memmove(load_address, image + setup_size, kernel_size - setup_size);
+	
+	/* ready for booting */
+	return setup_base;
+}
+
+
+void boot_zimage(void *setup_base)
+{
+	struct pt_regs regs;
+	
+	memset(&regs, 0, sizeof(struct pt_regs));
+	regs.xds = (u32)setup_base >> 4;
+	regs.xss = 0x8e00;
+	regs.esp = 0x200;
+	regs.eflags = 0;
+	enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs, &regs);
+}
+
+
+image_header_t *fake_zimage_header(image_header_t *hdr, void *ptr, int size)
+{	
+	/* There is no way to know the size of a zImage ... *
+	 * so we assume that 2MB will be enough for now */
+#define ZIMAGE_SIZE 0x200000
+	
+	/* load a 1MB, the loaded will have to be moved to its final
+	 * position again later... */
+#define ZIMAGE_LOAD 0x100000
+	
+	ulong checksum;
+	
+ 	if (KERNEL_MAGIC != *(u16*)(ptr + BOOT_FLAG_OFF)) {
+		/* not a zImage or bzImage */
+		return NULL;
+	}
+
+	if (-1 == size) {
+		size = ZIMAGE_SIZE;
+	}
+#if 0	
+	checksum = crc32 (0, ptr, size);
+#else
+	checksum = 0;
+#endif		
+	memset(hdr, 0, sizeof(image_header_t));
+	
+	/* Build new header */
+	hdr->ih_magic = htonl(IH_MAGIC);
+	hdr->ih_time  = 0;
+	hdr->ih_size  = htonl(size);
+	hdr->ih_load  = htonl(ZIMAGE_LOAD);
+	hdr->ih_ep    = 0;
+	hdr->ih_dcrc  = htonl(checksum);
+	hdr->ih_os    = IH_OS_LINUX;
+	hdr->ih_arch  = IH_CPU_I386;
+	hdr->ih_type  = IH_TYPE_KERNEL;
+	hdr->ih_comp  = IH_COMP_NONE;
+
+	strncpy((char *)hdr->ih_name, "(none)", IH_NMLEN);
+
+	checksum = crc32(0,(const char *)hdr,sizeof(image_header_t));
+
+	hdr->ih_hcrc = htonl(checksum);
+	
+	return hdr;
+}