1 files changed, 115 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/head-shark.S b/arch/arm/boot/compressed/head-shark.S
new file mode 100644
index 0000000..848f60e
--- /dev/null
+++ b/arch/arm/boot/compressed/head-shark.S
@@ -0,0 +1,115 @@
+/* The head-file for the Shark
+ * by Alexander Schulz
+ *
+ * Does the following:
+ * - get the memory layout from firmware. This can only be done as long as the mmu
+ *   is still on.
+ * - switch the mmu off, so we have physical addresses
+ * - copy the kernel to 0x08508000. This is done to have a fixed address where the
+ *   C-parts (misc.c) are executed. This address must be known at compile-time,
+ *   but the load-address of the kernel depends on how much memory is installed.
+ * - Jump to this location.
+ * - Set r8 with 0, r7 with the architecture ID for head.S
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/assembler.h>
+	
+		.section	".start", "ax"
+
+		b	__beginning
+	
+__ofw_data:	.long	0				@ the number of memory blocks
+		.space  128				@ (startaddr,size) ...
+		.space  128				@ bootargs
+		.align
+
+__beginning:	mov	r4, r0				@ save the entry to the firmware
+
+		mov	r0, #0xC0			@ disable irq and fiq
+		mov	r1, r0
+		mrs	r3, cpsr
+		bic	r2, r3, r0
+		eor	r2, r2, r1
+		msr	cpsr_c, r2
+
+		mov	r0, r4				@ get the Memory layout from firmware
+		adr	r1, __ofw_data
+		add	r2, r1, #4
+		mov	lr, pc
+		b	ofw_init
+		mov	r1, #0
+
+		adr	r2, __mmu_off			@ calculate physical address
+		sub	r2, r2, #0xf0000000		@ openprom maps us at f000 virt, 0e50 phys
+		adr	r0, __ofw_data
+		ldr	r0, [r0, #4]
+		add	r2, r2, r0
+		add	r2, r2, #0x00500000
+
+		mrc	p15, 0, r3, c1, c0
+		bic	r3, r3, #0xC			@ Write Buffer and DCache
+		bic	r3, r3, #0x1000			@ ICache
+		mcr	p15, 0, r3, c1, c0		@ disabled
+
+		mov	r0, #0
+		mcr	p15, 0, r0, c7, c7		@ flush I,D caches on v4
+		mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer on v4
+		mcr	p15, 0, r0, c8, c7		@ flush I,D TLBs on v4
+
+		bic	r3, r3, #0x1			@ MMU
+		mcr	p15, 0, r3, c1, c0		@ disabled
+
+		mov	pc, r2
+
+__copy_target:	.long	0x08508000
+__copy_end:	.long	0x08608000
+		
+		.word	_start
+		.word	__bss_start
+
+		.align
+__temp_stack:	.space 128
+
+__mmu_off:
+		adr	r0, __ofw_data
+		ldr	r0, [r0, #4]
+		orr	r0, r0, #0x00600000
+	
+		ldr	r1, __copy_end
+		ldr	r3, __copy_target
+
+/* r0 = 0x0e600000 (current end of kernelcode)
+ * r3 = 0x08508000 (where it should begin)
+ * r1 = 0x08608000 (end of copying area, 1MB)
+ * The kernel is compressed, so 1 MB should be enough.
+ * copy the kernel to the beginning of physical memory
+ * We start from the highest address, so we can copy
+ * from 0x08500000 to 0x08508000 if we have only 8MB
+ */
+
+	
+__Copy:		ldr	r2, [r0], #-4
+		str	r2, [r1], #-4
+		teq	r1, r3
+		bne	__Copy
+		/* and jump to it */
+		adr	r2, __go_on
+		adr	r0, __ofw_data
+		ldr	r0, [r0, #4]
+		sub	r2, r2, r0
+		sub	r2, r2, #0x00500000
+		ldr	r0, __copy_target
+		add	r2, r2, r0
+		mov	pc, r2
+
+__go_on:
+		adr	sp, __temp_stack
+		add	sp, sp, #128
+		adr	r0, __ofw_data
+		mov	lr, pc
+		b	create_params
+	
+		mov	r8, #0
+		mov	r7, #15