patch-2.4.5 linux/arch/ppc/boot/prep/head.S

• Lines: 249
• Date: Thu May 24 15:02:07 2001
• Orig file: v2.4.4/linux/arch/ppc/boot/prep/head.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.4/linux/arch/ppc/boot/prep/head.S linux/arch/ppc/boot/prep/head.S
@@ -0,0 +1,248 @@
+/*
+ * BK Id: SCCS/s.head.S 1.8 05/18/01 06:20:29 patch
+ */
+#include "../../kernel/ppc_defs.h"
+#include "../../kernel/ppc_asm.tmpl"
+#include <asm/processor.h>
+#include <asm/cache.h>
+
+	.text
+
+/*
+ * Boot loader philosophy:
+ *      ROM loads us to some arbitrary location
+ *      Move the boot code to the link address (8M)
+ *      Call decompress_kernel()
+ *         Relocate the initrd, zimage and residual data to 8M
+ *         Decompress the kernel to 0
+ *      Jump to the kernel entry
+ *            -- Cort
+ */
+	.globl	start
+start:
+	bl	start_
+start_:
+	mr	r11,r3		/* Save pointer to residual/board data */
+	mr      r25,r5          /* Save OFW pointer */
+	li	r3,MSR_IP	/* Establish default MSR value */
+	mtmsr	r3
+
+/* check if we need to relocate ourselves to the link addr or were we
+   loaded there to begin with -- Cort */
+	lis	r4,start@h
+	ori	r4,r4,start@l
+	mflr	r3
+	subi	r3,r3,4		/* we get the nip, not the ip of the branch */
+	mr	r8,r3
+	cmp	0,r3,r4
+	bne	1010f
+/* compute size of whole image in words.  this should be moved to
+ * start_ldr() -- Cort
+ */
+	lis	r4,start@h
+	ori	r4,r4,start@l
+	lis	r5,end@h
+	ori	r5,r5,end@l
+	addi	r5,r5,3		/* round up */
+	sub	r5,r5,r4
+	srwi	r5,r5,2
+	mr	r7,r5
+	b	start_ldr
+1010:
+/* 
+ * no matter where we're loaded, move ourselves to -Ttext address
+ */
+relocate:
+	mflr	r3		/* Compute code bias */
+	subi	r3,r3,4
+	mr	r8,r3
+	lis	r4,start@h
+	ori	r4,r4,start@l
+	lis	r5,end@h
+	ori	r5,r5,end@l
+	addi	r5,r5,3			/* Round up - just in case */
+	sub	r5,r5,r4		/* Compute # longwords to move */
+	srwi	r5,r5,2
+	mtctr	r5
+	mr	r7,r5
+	li	r6,0
+	subi	r3,r3,4			/* Set up for loop */
+	subi	r4,r4,4
+00:	lwzu	r5,4(r3)
+	stwu	r5,4(r4)
+	xor	r6,r6,r5
+	bdnz	00b
+  	lis	r3,start_ldr@h
+	ori	r3,r3,start_ldr@l
+	mtlr	r3			/* Easiest way to do an absolute jump */
+	blr
+start_ldr:
+/* Clear all of BSS */
+	lis	r3,edata@h
+	ori	r3,r3,edata@l
+	lis	r4,end@h
+	ori	r4,r4,end@l
+	subi	r3,r3,4
+	subi	r4,r4,4
+	li	r0,0
+50:	stwu	r0,4(r3)
+	cmp	0,r3,r4
+	bne	50b
+90:	mr	r9,r1			/* Save old stack pointer (in case it matters) */
+	lis	r1,.stack@h
+	ori	r1,r1,.stack@l
+	addi	r1,r1,4096*2
+	subi	r1,r1,256
+	li	r2,0x000F		/* Mask pointer to 16-byte boundary */
+	andc	r1,r1,r2
+/* Run loader */
+	mr	r3,r8			/* Load point */
+	mr	r4,r7			/* Program length */
+	mr	r5,r6			/* Checksum */
+	mr	r6,r11			/* Residual data */
+	mr      r7,r25                  /* OFW interfaces */
+	bl	decompress_kernel
+	
+	/* changed to use r3 (as firmware does) for kernel
+	   as ptr to residual -- Cort*/
+	lis	r6,cmd_line@h
+	ori	r6,r6,cmd_line@l
+	lwz	r6, 0(r6)
+	subi	r7,r6,1
+00:	lbzu	r2,1(r7)
+	cmpi	0,r2,0
+	bne	00b
+
+	/* r4,r5 have initrd_start, size */
+	lis	r2,initrd_start@h
+	ori	r2,r2,initrd_start@l
+	lwz	r4,0(r2)
+	lis	r2,initrd_end@h
+	ori	r2,r2,initrd_end@l
+	lwz	r5,0(r2)
+
+
+	/* tell kernel we're prep */
+	/* 
+	 * get start address of kernel code which is stored as a coff
+	 * entry.  see boot/head.S -- Cort 
+	 */
+	li	r9,0x4
+	mtlr	r9
+	lis	r10,0xdeadc0de@h
+	ori	r10,r10,0xdeadc0de@l
+	li	r9,0
+	stw	r10,0(r9)
+/*
+ * The Radstone firmware maps PCI memory at 0xc0000000 using BAT2
+ * so disable BATs before setting this to avoid a clash
+ */
+	li      r8,0
+	mtspr   DBAT0U,r8
+	mtspr   DBAT1U,r8
+	mtspr   DBAT2U,r8
+	mtspr   DBAT3U,r8
+	mtspr   IBAT0U,r8
+	mtspr   IBAT1U,r8
+	mtspr   IBAT2U,r8
+	mtspr   IBAT3U,r8
+
+	blr
+hang:
+	b	hang	
+
+/*
+ * Delay for a number of microseconds
+ * -- Use the BUS timer (assumes 66MHz)
+ */
+	.globl	udelay
+udelay:		
+	mfspr	r4,PVR
+	srwi	r4,r4,16
+	cmpi	0,r4,1		/* 601 ? */
+	bne	.udelay_not_601
+00:	li	r0,86	/* Instructions / microsecond? */
+	mtctr	r0
+10:	addi	r0,r0,0 /* NOP */
+	bdnz	10b
+	subic.	r3,r3,1
+	bne	00b
+	blr
+
+.udelay_not_601:		
+	mulli	r4,r3,1000	/* nanoseconds */
+	addi	r4,r4,59
+	li	r5,60
+	divw	r4,r4,r5	/* BUS ticks */
+1:	mftbu	r5
+	mftb	r6
+	mftbu	r7
+	cmp	0,r5,r7
+	bne	1b		/* Get [synced] base time */
+	addc	r9,r6,r4	/* Compute end time */
+	addze	r8,r5
+2:	mftbu	r5
+	cmp	0,r5,r8
+	blt	2b
+	bgt	3f
+	mftb	r6
+	cmp	0,r6,r9
+	blt	2b
+3:	blr		
+
+.globl _get_HID0
+_get_HID0:		
+	mfspr	r3,HID0
+	blr
+
+.globl _put_HID0
+_put_HID0:		
+	mtspr	HID0,r3
+	blr
+		
+.globl _get_MSR
+_get_MSR:		
+	mfmsr	r3
+	blr
+	
+.globl _put_MSR
+_put_MSR:		
+	mtmsr	r3
+	blr
+
+/*
+ * Flush instruction cache
+ * *** I'm really paranoid here!
+ */
+_GLOBAL(flush_instruction_cache)
+	mflr	r5
+	bl	flush_data_cache
+	mfspr	r3,HID0	/* Caches are controlled by this register */
+	li	r4,0
+	ori	r4,r4,(HID0_ICE|HID0_ICFI)
+	or	r3,r3,r4	/* Need to enable+invalidate to clear */
+	mtspr	HID0,r3
+	andc	r3,r3,r4
+	ori	r3,r3,HID0_ICE	/* Enable cache */
+	mtspr	HID0,r3
+	mtlr	r5
+	blr
+	
+#define NUM_CACHE_LINES 128*8
+#define CACHE_LINE_SIZE 32 
+#define cache_flush_buffer 0x1000
+
+/*
+ * Flush data cache
+ * *** I'm really paranoid here!
+ */
+_GLOBAL(flush_data_cache)
+	lis	r3,cache_flush_buffer@h
+	ori	r3,r3,cache_flush_buffer@l
+	li	r4,NUM_CACHE_LINES
+	mtctr	r4
+00:	lwz	r4,0(r3)
+	addi	r3,r3,CACHE_LINE_SIZE	/* Next line, please */
+	bdnz	00b	
+10:	blr
+	.comm	.stack,4096*2,4