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/*
 * arch/alpha/boot/bootp.c
 *
 * Copyright (C) 1997 Jay Estabrook
 *
 * This file is used for creating a bootp file for the Linux/AXP kernel
 *
 * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/version.h>
#include <linux/mm.h>
 
#include <asm/system.h>
#include <asm/console.h>
#include <asm/hwrpb.h>
#include <asm/pgtable.h>
#include <asm/io.h>
 
#include <stdarg.h>
 
#include "ksize.h"
 
extern int vsprintf(char *, const char *, va_list);
extern unsigned long switch_to_osf_pal(unsigned long nr,
	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
	unsigned long vptb, unsigned long *kstk);
 
int printk(const char * fmt, ...)
{
	va_list args;
	int i, j, written, remaining, num_nl;
	static char buf[1024];
	char * str;
 
	va_start(args, fmt);
	i = vsprintf(buf, fmt, args);
	va_end(args);
 
	/* expand \n into \r\n: */
 
	num_nl = 0;
	for (j = 0; j < i; ++j) {
	    if (buf[j] == '\n')
	    	++num_nl;
	}
	remaining = i + num_nl;
	for (j = i - 1; j >= 0; --j) {
	    buf[j + num_nl] = buf[j];
	    if (buf[j] == '\n') {
	    	--num_nl;
		buf[j + num_nl] = '\r';
	    }
	}
 
	str = buf;
	do {
	    written = puts(str, remaining);
	    remaining -= written;
	    str += written;
	} while (remaining > 0);
	return i;
}
 
#define hwrpb (*INIT_HWRPB)
 
/*
 * Find a physical address of a virtual object..
 *
 * This is easy using the virtual page table address.
 */
struct pcb_struct * find_pa(unsigned long *vptb, struct pcb_struct * pcb)
{
	unsigned long address = (unsigned long) pcb;
	unsigned long result;
 
	result = vptb[address >> 13];
	result >>= 32;
	result <<= 13;
	result |= address & 0x1fff;
	return (struct pcb_struct *) result;
}	
 
/*
 * This function moves into OSF/1 pal-code, and has a temporary
 * PCB for that. The kernel proper should replace this PCB with
 * the real one as soon as possible.
 *
 * The page table muckery in here depends on the fact that the boot
 * code has the L1 page table identity-map itself in the second PTE
 * in the L1 page table. Thus the L1-page is virtually addressable
 * itself (through three levels) at virtual address 0x200802000.
 *
 * As we don't want it there anyway, we also move the L1 self-map
 * up as high as we can, so that the last entry in the L1 page table
 * maps the page tables.
 *
 * As a result, the OSF/1 pal-code will instead use a virtual page table
 * map located at 0xffffffe00000000.
 */
#define pcb_va ((struct pcb_struct *) 0x20000000)
#define old_vptb (0x0000000200000000UL)
#define new_vptb (0xfffffffe00000000UL)
void pal_init(void)
{
	unsigned long i, rev, sum;
	unsigned long *L1, *l;
	struct percpu_struct * percpu;
	struct pcb_struct * pcb_pa;
 
	/* Find the level 1 page table and duplicate it in high memory */
	L1 = (unsigned long *) 0x200802000UL; /* (1<<33 | 1<<23 | 1<<13) */
	L1[1023] = L1[1];
 
	percpu = (struct percpu_struct *)
			(hwrpb.processor_offset + (unsigned long) &hwrpb),
 
	pcb_va->ksp = 0;
	pcb_va->usp = 0;
	pcb_va->ptbr = L1[1] >> 32;
	pcb_va->asn = 0;
	pcb_va->pcc = 0;
	pcb_va->unique = 0;
	pcb_va->flags = 1;
	pcb_pa = find_pa((unsigned long *) old_vptb, pcb_va);
	printk("Switching to OSF PAL-code .. ");
	/*
	 * a0 = 2 (OSF)
	 * a1 = return address, but we give the asm the vaddr of the PCB
	 * a2 = physical addr of PCB
	 * a3 = new virtual page table pointer
	 * a4 = KSP (but we give it 0, asm sets it)
	 */
	i = switch_to_osf_pal(
		2,
		pcb_va,
		pcb_pa,
		new_vptb,
		0);
	if (i) {
		printk("failed, code %ld\n", i);
		halt();
	}
	rev = percpu->pal_revision = percpu->palcode_avail[2];
 
	hwrpb.vptb = new_vptb;
 
	/* update checksum: */
	sum = 0;
	for (l = (unsigned long *) &hwrpb;
	     l < (unsigned long *) &hwrpb.chksum;
	     ++l)
		sum += *l;
	hwrpb.chksum = sum;
 
	printk("Ok (rev %lx)\n", rev);
	/* remove the old virtual page-table mapping */
	L1[1] = 0;
	flush_tlb_all();
}
 
static inline long load(unsigned long dst,
			unsigned long src,
			unsigned long count)
{
	extern void * memcpy(void *, const void *, size_t);
 
	memcpy((void *)dst, (void *)src, count);
	return count;
}
 
/*
 * Start the kernel.
 */
static void runkernel(void)
{
	__asm__ __volatile__(
		"bis %1,%1,$30\n\t"
		"bis %0,%0,$26\n\t"
		"ret ($26)"
		: /* no outputs: it doesn't even return */
		: "r" (START_ADDR),
		  "r" (PAGE_SIZE + INIT_STACK));
}
 
extern char _end;
#define KERNEL_ORIGIN \
	((((unsigned long)&_end) + 511) & ~511)
 
void start_kernel(void)
{
	static long i;
	static int nbytes;
	static char envval[256];
	char envbuf[256];
 
	printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n");
 
	if (hwrpb.pagesize != 8192) {
		printk("Expected 8kB pages, got %ldkB\n",
		       hwrpb.pagesize >> 10);
		return;
	}
	pal_init();
 
	nbytes = dispatch(CCB_GET_ENV, ENV_BOOTED_OSFLAGS,
			  envbuf, sizeof(envbuf));
	if (nbytes < 0 || nbytes >= sizeof(envbuf)) {
		nbytes = 0;
	}
 
	envbuf[nbytes] = '\0';
	memcpy(envval, envbuf, nbytes+1);
	printk("Loading the kernel...'%s'\n", envval);
 
	/* NOTE: *no* callbacks or printouts from here on out!!! */
 
	/*
	 * HACK alert:
	 *
	 * assume direct copy will fail due to overlap of virtual source
	 * and physical destination, so move it way high physical first,
	 * then move it back to its final resting place...
	 *
	 * this way could fail, too, but it works on the platforms *I* have
	 */
	i = load(START_ADDR+(4*KERNEL_SIZE), KERNEL_ORIGIN, KERNEL_SIZE);
        i = load(START_ADDR, START_ADDR+(4*KERNEL_SIZE), KERNEL_SIZE);
 
	strcpy((char*)ZERO_PAGE, envval);
 
	runkernel();
 
	for (i = 0 ; i < 0x100000000 ; i++)
		/* nothing */;
	halt();
}