retrieve firmware arguments

kern/mips/startup.S

@@ -31,6 +31,7 @@ __start:
 _start:
 start:	
 	bal codestart
+base:	
 	. = _start + GRUB_KERNEL_CPU_COMPRESSED_SIZE
 compressed_size:
 	.long 0
@@ -41,8 +42,69 @@ total_module_size:
 kernel_image_size:	
 	.long	0
 codestart:
-	/* Decompress the payload. */
+	/* Save our base.  */
 	move $s0, $ra
+
+	/* Parse arguments. Has to be done before relocation.
+	So need to do it in asm.  */
+#ifdef GRUB_MACHINE_MIPS_YEELOONG
+	/* $a2 has the environment.  */
+	move $t0, $a2
+argcont:	
+	lw $t1, 0($t0)
+	beq $t1, $zero, argdone
+#define DO_PARSE(str, reg) \
+	addiu $t2, $s0, (str-base);\
+	bal parsestr;\
+	beq $v0, $zero, 1f;\
+	move reg, $v0;\
+	b 2f;\
+1:	
+	DO_PARSE (busclockstr, $s2)
+	DO_PARSE (cpuclockstr, $s3)
+	DO_PARSE (memsizestr, $s4)
+	DO_PARSE (highmemsizestr, $s5)
+2:	
+	addiu $t0, $t0, 4
+	b argcont
+parsestr:
+	move $v0, $zero
+	move $t3, $t1
+3:	
+	lb $t4, 0($t2)
+	lb $t5, 0($t3)
+	addiu $t2, $t2, 1
+	addiu $t3, $t3, 1
+	beq $t5, $zero, 1f
+	beq $t5, $t4, 3b
+	bne $t4, $zero, 1f
+
+	addiu $t3, $t3, 0xffff
+digcont:	
+	lb $t5, 0($t3)
+	/* Substract '0' from digit.  */
+	addiu $t5, $t5, 0xffd0
+	bltz $t5, 1f
+	addiu $t4, $t5, 0xfff7
+	bgtz $t4, 1f
+	/* Multiply $v0 by 10 with bitshifts. */
+	sll $v0, $v0, 1
+	sll $t4, $v0, 2
+	addu $v0, $v0, $t4
+	addu $v0, $v0, $t5
+	addiu $t3, $t3, 1
+	b digcont
+1:
+	jr $ra
+busclockstr:	.asciiz "busclock="
+cpuclockstr:	.asciiz "cpuclock="
+memsizestr:	.asciiz "memsize="
+highmemsizestr:	.asciiz "highmemsize="
+	.p2align 2
+argdone:
+#endif
+
+	/* Decompress the payload. */
 	addiu $a0, $s0, GRUB_KERNEL_CPU_RAW_SIZE - BASE_ADDR
 	lui $a1, %hi(compressed)
 	addiu $a1, %lo(compressed)
@@ -50,7 +112,8 @@ codestart:
 	move $s1, $a1
 
 	/* $a0 contains source compressed address, $a1 is destination,
-	   $a2 is compressed size. FIXME: put LZMA here. Don't clober $s0, $s1.
+	   $a2 is compressed size. FIXME: put LZMA here. Don't clober $s0,
+	   $s1, $s2, $s3, $s4 and $s5.
 	   On return $v0 contains uncompressed size.
 	*/
 	move $v0, $a2
@@ -84,9 +147,27 @@ VARIABLE(grub_prefix)
 	 */
 
 	. = _start + GRUB_KERNEL_CPU_DATA_END
-
+#ifdef GRUB_MACHINE_MIPS_YEELOONG
+VARIABLE (grub_arch_busclock)
+	.long 0
+VARIABLE (grub_arch_cpuclock)
+	.long 0
+VARIABLE (grub_arch_memsize)
+	.long 0
+VARIABLE (grub_arch_highmemsize)
+	.long 0
+#endif
 cont:
 
+#ifdef GRUB_MACHINE_MIPS_YEELOONG
+	lui $t1, %hi(grub_arch_busclock)
+	addiu $t1, %lo(grub_arch_busclock)
+	sw $s2, 0($t1)
+	sw $s3, 4($t1)
+	sw $s4, 8($t1)
+	sw $s5, 12($t1)
+#endif
+
 	/* Move the modules out of BSS.  */
 	lui $t1, %hi(_start)
 	addiu $t1, %lo(_start)