/*
   * arch/alpha/boot/main.c
   *
   * Copyright (C) 1994, 1995 Linus Torvalds
   *
   * This file is the bootloader for the Linux/AXP kernel
   */
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  #include <generated/utsrelease.h>
  #include <linux/mm.h>
  
  #include <asm/console.h>
  #include <asm/hwrpb.h>
  #include <asm/pgtable.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);
  struct hwrpb_struct *hwrpb = INIT_HWRPB;
  static struct pcb_struct pcb_va[1];
  
  /*
   * Find a physical address of a virtual object..
   *
   * This is easy using the virtual page table address.
   */
  
  static inline void *
  find_pa(unsigned long *vptb, void *ptr)
  {
  	unsigned long address = (unsigned long) ptr;
  	unsigned long result;
  
  	result = vptb[address >> 13];
  	result >>= 32;
  	result <<= 13;
  	result |= address & 0x1fff;
  	return (void *) 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.
   */
  
  #define VPTB	((unsigned long *) 0x200000000)
  #define L1	((unsigned long *) 0x200802000)
  
  void
  pal_init(void)
  {
  	unsigned long i, rev;
  	struct percpu_struct * percpu;
  	struct pcb_struct * pcb_pa;
  
  	/* Create the dummy PCB.  */
  	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_va->res1 = 0;
  	pcb_va->res2 = 0;
  	pcb_pa = find_pa(VPTB, pcb_va);
  
  	/*
  	 * 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 the asm sets it)
  	 */
  	srm_printk("Switching to OSF PAL-code .. ");
  
  	i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
  	if (i) {
  		srm_printk("failed, code %ld
  ", i);
  		__halt();
  	}
  
  	percpu = (struct percpu_struct *)
  		(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
  	rev = percpu->pal_revision = percpu->palcode_avail[2];
  
  	srm_printk("Ok (rev %lx)
  ", rev);
  
  	tbia(); /* do it directly in case we are SMP */
  }
  
  static inline long openboot(void)
  {
  	char bootdev[256];
  	long result;
  
  	result = callback_getenv(ENV_BOOTED_DEV, bootdev, 255);
  	if (result < 0)
  		return result;
  	return callback_open(bootdev, result & 255);
  }
  
  static inline long close(long dev)
  {
  	return callback_close(dev);
  }
  
  static inline long load(long dev, unsigned long addr, unsigned long count)
  {
  	char bootfile[256];
  	extern char _end;
  	long result, boot_size = &_end - (char *) BOOT_ADDR;
  
  	result = callback_getenv(ENV_BOOTED_FILE, bootfile, 255);
  	if (result < 0)
  		return result;
  	result &= 255;
  	bootfile[result] = '\0';
  	if (result)
  		srm_printk("Boot file specification (%s) not implemented
  ",
  		       bootfile);
  	return callback_read(dev, count, (void *)addr, boot_size/512 + 1);
  }
  
  /*
   * Start the kernel.
   */
  static void runkernel(void)
  {
  	__asm__ __volatile__(
  		"bis %1,%1,$30
  \t"
  		"bis %0,%0,$26
  \t"
  		"ret ($26)"
  		: /* no outputs: it doesn't even return */
  		: "r" (START_ADDR),
  		  "r" (PAGE_SIZE + INIT_STACK));
  }
  
  void start_kernel(void)
  {
  	long i;
  	long dev;
  	int nbytes;
  	char envval[256];
  
  	srm_printk("Linux/AXP bootloader for Linux " UTS_RELEASE "
  ");
  	if (INIT_HWRPB->pagesize != 8192) {
  		srm_printk("Expected 8kB pages, got %ldkB
  ", INIT_HWRPB->pagesize >> 10);
  		return;
  	}
  	pal_init();
  	dev = openboot();
  	if (dev < 0) {
  		srm_printk("Unable to open boot device: %016lx
  ", dev);
  		return;
  	}
  	dev &= 0xffffffff;
  	srm_printk("Loading vmlinux ...");
  	i = load(dev, START_ADDR, KERNEL_SIZE);
  	close(dev);
  	if (i != KERNEL_SIZE) {
  		srm_printk("Failed (%lx)
  ", i);
  		return;
  	}
  
  	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
  	if (nbytes < 0) {
  		nbytes = 0;
  	}
  	envval[nbytes] = '\0';
  	strcpy((char*)ZERO_PGE, envval);
  
  	srm_printk(" Ok
  Now booting the kernel
  ");
  	runkernel();
  	for (i = 0 ; i < 0x100000000 ; i++)
  		/* nothing */;
  	__halt();
  }