/*
   * relocate_kernel.S - put the kernel image in place to boot
   * 2005.9.17 kogiidena@eggplant.ddo.jp
   *
   * LANDISK/sh4 is supported. Maybe, SH archtecture works well.
   *

   * 2009-03-18 Magnus Damm - Added Kexec Jump support
   *

   * This source code is licensed under the GNU General Public License,
   * Version 2.  See the file COPYING for more details.
   */

  #include <linux/linkage.h>

  #include <asm/addrspace.h>
  #include <asm/page.h>

  
  		.globl relocate_new_kernel
  relocate_new_kernel:
  	/* r4 = indirection_page   */
  	/* r5 = reboot_code_buffer */
  	/* r6 = start_address      */

  	mov.l	10f, r0		/* PAGE_SIZE */
  	add	r5, r0		/* setup new stack at end of control page */
  
  	/* save r15->r8 to new stack */
  	mov.l	r15, @-r0
  	mov	r0, r15
  	mov.l	r14, @-r15
  	mov.l	r13, @-r15
  	mov.l	r12, @-r15
  	mov.l	r11, @-r15
  	mov.l	r10, @-r15
  	mov.l	r9, @-r15
  	mov.l	r8, @-r15
  
  	/* save other random registers */
  	sts.l	macl, @-r15
  	sts.l	mach, @-r15
  	stc.l	gbr, @-r15
  	stc.l	ssr, @-r15
  	stc.l	sr, @-r15
  	sts.l	pr, @-r15
  	stc.l	spc, @-r15
  
  	/* switch to bank1 and save r7->r0 */
  	mov.l	12f, r9
  	stc	sr, r8
  	or	r9, r8
  	ldc	r8, sr
  	mov.l	r7, @-r15
  	mov.l	r6, @-r15
  	mov.l	r5, @-r15
  	mov.l	r4, @-r15
  	mov.l	r3, @-r15
  	mov.l	r2, @-r15
  	mov.l	r1, @-r15
  	mov.l	r0, @-r15
  
  	/* switch to bank0 and save r7->r0 */
  	mov.l	12f, r9
  	not	r9, r9
  	stc	sr, r8
  	and	r9, r8
  	ldc	r8, sr
  	mov.l	r7, @-r15
  	mov.l	r6, @-r15
  	mov.l	r5, @-r15
  	mov.l	r4, @-r15
  	mov.l	r3, @-r15
  	mov.l	r2, @-r15
  	mov.l	r1, @-r15
  	mov.l	r0, @-r15
  
  	mov.l	r4, @-r15	/* save indirection page again */
  
  	bsr	swap_pages	/* swap pages before jumping to new kernel */
  	 nop
  
  	mova	11f, r0
  	mov.l	r15, @r0	/* save pointer to stack */
  
  	jsr	@r6		/* hand over control to new kernel */
  	 nop
  
  	mov.l	11f, r15	/* get pointer to stack */
  	mov.l	@r15+, r4	/* restore r4 to get indirection page */

  	bsr	swap_pages	/* swap pages back to previous state */
  	 nop

  	/* make sure bank0 is active and restore r0->r7 */
  	mov.l	12f, r9
  	not	r9, r9
  	stc	sr, r8
  	and	r9, r8
  	ldc	r8, sr
  	mov.l	@r15+, r0
  	mov.l	@r15+, r1
  	mov.l	@r15+, r2
  	mov.l	@r15+, r3
  	mov.l	@r15+, r4
  	mov.l	@r15+, r5
  	mov.l	@r15+, r6
  	mov.l	@r15+, r7
  
  	/* switch to bank1 and restore r0->r7 */
  	mov.l	12f, r9
  	stc	sr, r8
  	or	r9, r8
  	ldc	r8, sr
  	mov.l	@r15+, r0
  	mov.l	@r15+, r1
  	mov.l	@r15+, r2
  	mov.l	@r15+, r3
  	mov.l	@r15+, r4
  	mov.l	@r15+, r5
  	mov.l	@r15+, r6
  	mov.l	@r15+, r7
  
  	/* switch back to bank0 */
  	mov.l	12f, r9
  	not	r9, r9
  	stc	sr, r8
  	and	r9, r8
  	ldc	r8, sr
  
  	/* restore other random registers */
  	ldc.l	@r15+, spc
  	lds.l	@r15+, pr
  	ldc.l	@r15+, sr
  	ldc.l	@r15+, ssr
  	ldc.l	@r15+, gbr
  	lds.l	@r15+, mach
  	lds.l	@r15+, macl
  
  	/* restore r8->r15 */
  	mov.l	@r15+, r8
  	mov.l	@r15+, r9
  	mov.l	@r15+, r10
  	mov.l	@r15+, r11
  	mov.l	@r15+, r12
  	mov.l	@r15+, r13
  	mov.l	@r15+, r14
  	mov.l	@r15+, r15
  	rts
  	 nop
  
  swap_pages:

  	bra	1f

  	 mov	r4,r0	  /* cmd = indirection_page */

  0:
  	mov.l	@r4+,r0	  /* cmd = *ind++ */

  1:	/* addr = cmd & 0xfffffff0 */

  	mov	r0,r2

  	mov	#-16,r1
  	and	r1,r2
  
  	/* if(cmd & IND_DESTINATION) dst = addr  */
  	tst	#1,r0
  	bt	2f
  	bra	0b

  	 mov	r2,r5

  
  2:	/* else if(cmd & IND_INDIRECTION) ind = addr  */
  	tst	#2,r0
  	bt	3f
  	bra	0b

  	 mov	r2,r4

  3:	/* else if(cmd & IND_DONE) return */

  	tst	#4,r0
  	bt	4f

  	rts
  	 nop

  
  4:	/* else if(cmd & IND_SOURCE) memcpy(dst,addr,PAGE_SIZE) */
  	tst	#8,r0
  	bt	0b

  	mov.l	10f,r3	  /* PAGE_SIZE */

  	shlr2	r3
  	shlr2	r3
  5:
  	dt	r3

  
  	/* regular kexec just overwrites the destination page
  	 * with the contents of the source page.
  	 * for the kexec jump case we need to swap the contents
  	 * of the pages.
  	 * to keep it simple swap the contents for both cases.
  	 */
  	mov.l	@(0, r2), r8
  	mov.l	@(0, r5), r1
  	mov.l	r8, @(0, r5)
  	mov.l	r1, @(0, r2)
  
  	mov.l	@(4, r2), r8
  	mov.l	@(4, r5), r1
  	mov.l	r8, @(4, r5)
  	mov.l	r1, @(4, r2)
  
  	mov.l	@(8, r2), r8
  	mov.l	@(8, r5), r1
  	mov.l	r8, @(8, r5)
  	mov.l	r1, @(8, r2)
  
  	mov.l	@(12, r2), r8
  	mov.l	@(12, r5), r1
  	mov.l	r8, @(12, r5)
  	mov.l	r1, @(12, r2)
  
  	add	#16,r5
  	add	#16,r2

  	bf	5b
  
  	bra	0b

  	 nop

  
  	.align 2
  10:
  	.long	PAGE_SIZE

  11:
  	.long	0
  12:
  	.long	0x20000000 ! RB=1

  
  relocate_new_kernel_end:
  
  	.globl relocate_new_kernel_size
  relocate_new_kernel_size:
  	.long relocate_new_kernel_end - relocate_new_kernel