init.c

/* Initialization of the system and the HWRPB.

   Copyright (C) 2011 Richard Henderson

   This file is part of QEMU PALcode.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the text
   of the GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.  If not see
   <http://www.gnu.org/licenses/>.  */

#include <string.h>
#include <stddef.h>
#include "hwrpb.h"
#include "osf.h"
#include "ioport.h"
#include "uart.h"
#include "protos.h"
#include SYSTEM_H

#define PAGE_SHIFT	13
#define PAGE_SIZE	(1ul << PAGE_SHIFT)
#define PAGE_OFFSET	0xfffffc0000000000UL

#define VPTPTR		0xfffffffe00000000UL

#define PA(VA)		((unsigned long)(VA) & 0xfffffffffful)
#define VA(PA)		((void *)(PA) + PAGE_OFFSET)

#define HZ	1024

struct hwrpb_combine {
  struct hwrpb_struct hwrpb;
  struct percpu_struct processor[4];
  struct memdesc_struct md;
  struct memclust_struct mc[2];
  struct crb_struct crb;
  struct procdesc_struct proc_dispatch;
  struct procdesc_struct proc_fixup;
};

extern char stack[PAGE_SIZE] __attribute__((section(".sbss")));
extern char _end[] __attribute__((visibility("hidden"), nocommon));

struct pcb_struct pcb __attribute__((section(".sbss")));

static unsigned long page_dir[1024]
  __attribute__((aligned(PAGE_SIZE), section(".bss.page_dir")));

/* The HWRPB must be aligned because it is exported at INIT_HWRPB.  */
struct hwrpb_combine hwrpb __attribute__((aligned(PAGE_SIZE)));

void *last_alloc;
bool have_vga;

static void *
alloc (unsigned long size, unsigned long align)
{
  void *p = (void *)(((unsigned long)last_alloc + align - 1) & ~(align - 1));
  last_alloc = p + size;
  return memset (p, 0, size);
}

static inline unsigned long
pt_index(unsigned long addr, int level)
{
  return (addr >> (PAGE_SHIFT + (10 * level))) & 0x3ff;
}

static inline unsigned long
build_pte (void *page)
{
  unsigned long bits;

  bits = PA((unsigned long)page) << (32 - PAGE_SHIFT);
  bits += _PAGE_VALID | _PAGE_KRE | _PAGE_KWE;

  return bits;
}

static inline void *
pte_page (unsigned long pte)
{
  return VA(pte >> 32 << PAGE_SHIFT);
}

static void
set_pte (unsigned long addr, void *page)
{
  unsigned long *pt = page_dir;
  unsigned long index;

  index = pt_index(addr, 2);
  if (pt[index] != 0)
    pt = pte_page (pt[index]);
  else
    {
      unsigned long *npt = alloc(PAGE_SIZE, PAGE_SIZE);
      pt[index] = build_pte (npt);
      pt = npt;
    }

  index = pt_index(addr, 1);
  if (pt[index] != 0)
    pt = pte_page (pt[index]);
  else
    {
      unsigned long *npt = alloc(PAGE_SIZE, PAGE_SIZE);
      pt[index] = build_pte (npt);
      pt = npt;
    }

  index = pt_index(addr, 0);
  pt[index] = build_pte (page);
}

static void
init_page_table(void)
{
  /* Install the self-reference for the virtual page table base register.  */
  page_dir[pt_index(VPTPTR, 2)] = build_pte(page_dir);

  set_pte ((unsigned long)INIT_HWRPB, &hwrpb);
  
  /* ??? SRM maps some amount of memory at 0x20000000 for use by programs
     started from the console prompt.  Including the bootloader.  While
     we're emulating MILO, don't bother as we jump straight to the kernel
     loaded into KSEG.  */
}

static void
init_hwrpb (unsigned long memsize, unsigned long cpus)
{
  unsigned long pal_pages;
  unsigned long amask;
  unsigned long i;
  
  hwrpb.hwrpb.phys_addr = PA(&hwrpb);

  /* Yes, the 'HWRPB' magic is in big-endian byte ordering.  */
  hwrpb.hwrpb.id = ( (long)'H' << 56
		   | (long)'W' << 48
		   | (long)'R' << 40
		   | (long)'P' << 32
		   | (long)'B' << 24);

  hwrpb.hwrpb.size = sizeof(struct hwrpb_struct);

  ((int *)hwrpb.hwrpb.ssn)[0] = ( 'Q' << 0
				| 'E' << 8
				| 'M' << 16
				| 'U' << 24);

  amask = ~__builtin_alpha_amask(-1);
  switch (__builtin_alpha_implver())
    {
    case 0: /* EV4 */
      hwrpb.hwrpb.cpuid = EV4_CPU;
      hwrpb.hwrpb.max_asn = 63;
      break;

    case 1: /* EV5 */
      hwrpb.hwrpb.cpuid
	= ((amask & 0x101) == 0x101 ? PCA56_CPU		/* MAX+BWX */
	   : amask & 1 ? EV56_CPU			/* BWX */
	   : EV5_CPU);
      hwrpb.hwrpb.max_asn = 127;
      break;

    case 2: /* EV6 */
      hwrpb.hwrpb.cpuid = (amask & 4 ? EV67_CPU : EV6_CPU);  /* CIX */
      hwrpb.hwrpb.max_asn = 255;
      break;
    }

  hwrpb.hwrpb.pagesize = PAGE_SIZE;
  hwrpb.hwrpb.pa_bits = 40;
  hwrpb.hwrpb.sys_type = SYS_TYPE;
  hwrpb.hwrpb.sys_variation = SYS_VARIATION;
  hwrpb.hwrpb.sys_revision = SYS_REVISION;
  for (i = 0; i < cpus; ++i)
    {
      /* ??? Look up these bits.  Snagging the value examined by the kernel. */
      hwrpb.processor[i].flags = 0x1cc;
      hwrpb.processor[i].type = hwrpb.hwrpb.cpuid;
    }

  hwrpb.hwrpb.intr_freq = HZ * 4096;
  hwrpb.hwrpb.cycle_freq = 250000000;	/* QEMU architects 250MHz.  */

  hwrpb.hwrpb.vptb = VPTPTR;

  hwrpb.hwrpb.nr_processors = cpus;
  hwrpb.hwrpb.processor_size = sizeof(struct percpu_struct);
  hwrpb.hwrpb.processor_offset = offsetof(struct hwrpb_combine, processor);

  hwrpb.hwrpb.mddt_offset = offsetof(struct hwrpb_combine, md);
  hwrpb.md.numclusters = 2;

  pal_pages = (PA(last_alloc) + PAGE_SIZE - 1) >> PAGE_SHIFT;

  hwrpb.mc[0].numpages = pal_pages;
  hwrpb.mc[0].usage = 1;
  hwrpb.mc[1].start_pfn = pal_pages;
  hwrpb.mc[1].numpages = (memsize >> PAGE_SHIFT) - pal_pages;

  hwrpb.hwrpb.crb_offset = offsetof(struct hwrpb_combine, crb);
  hwrpb.crb.dispatch_va = &hwrpb.proc_dispatch;
  hwrpb.crb.dispatch_pa = PA(&hwrpb.proc_dispatch);
  hwrpb.crb.fixup_va = &hwrpb.proc_fixup;
  hwrpb.crb.fixup_pa = PA(&hwrpb.proc_fixup);
  hwrpb.crb.map_entries = 1;
  hwrpb.crb.map_pages = 1;
  hwrpb.crb.map[0].va = &hwrpb;
  hwrpb.crb.map[0].pa = PA(&hwrpb);
  hwrpb.crb.map[0].count = 1;

  /* See crb.c for how we match the VMS calling conventions to Unix.  */
  hwrpb.proc_dispatch.address = (unsigned long)crb_dispatch;
  hwrpb.proc_fixup.address = (unsigned long)crb_fixup;

  hwrpb_update_checksum(&hwrpb.hwrpb);
}

static void
init_pcb (void)
{
  pcb.ksp = (unsigned long)stack + sizeof(stack);
  pcb.ptbr = PA(page_dir) >> PAGE_SHIFT;
  pcb.flags = 1; /* FEN */
}

static void
init_i8259 (void)
{
  /* ??? MILO initializes the PIC as edge triggered; I do not know how SRM
     initializes them.  However, Linux seems to expect that these are level
     triggered.  That may be a kernel bug, but level triggers are more
     reliable anyway so lets go with that.  */

  /* Initialize the slave PIC.  */
  outb(0x11, PORT_PIC2_CMD);	/* ICW1: edge trigger, cascade, ICW4 req */
  outb(0x08, PORT_PIC2_DATA);	/* ICW2: irq offset = 8 */
  outb(0x02, PORT_PIC2_DATA);	/* ICW3: slave ID 2 */
  outb(0x01, PORT_PIC2_DATA);	/* ICW4: not special nested, normal eoi */

  /* Initialize the master PIC.  */
  outb(0x11, PORT_PIC1_CMD);	/* ICW1 */
  outb(0x00, PORT_PIC1_DATA);	/* ICW2: irq offset = 0 */
  outb(0x04, PORT_PIC1_DATA);	/* ICW3: slave control INTC2 */
  outb(0x01, PORT_PIC1_DATA);	/* ICW4 */

  /* Initialize level triggers.  The CY82C693UB that's on real alpha
     hardware doesn't have this; this is a PIIX extension.  However,
     QEMU doesn't implement regular level triggers.  */
  outb(0xff, PORT_PIC2_ELCR);
  outb(0xff, PORT_PIC1_ELCR);

  /* Disable all interrupts.  */
  outb(0xff, PORT_PIC2_DATA);
  outb(0xff, PORT_PIC1_DATA);

  /* Non-specific EOI, clearing anything the might be pending.  */
  outb(0x20, PORT_PIC2_CMD);
  outb(0x20, PORT_PIC1_CMD);
}

static void __attribute__((noreturn))
swppal(void *entry, void *pcb)
{
  register int variant __asm__("$16") = 2;	/* OSF/1 PALcode */
  register void *pc __asm__("$17") = entry;
  register unsigned long pa_pcb __asm__("$18") = PA(pcb);
  register unsigned long vptptr __asm__("$19") = VPTPTR;

  asm("call_pal 0x0a" : : "r"(variant), "r"(pc), "r"(pa_pcb), "r"(vptptr));
  __builtin_unreachable ();
}

void
do_start(unsigned long memsize, void (*kernel_entry)(void), unsigned long cpus)
{
  last_alloc = _end;

  init_page_table();
  init_hwrpb(memsize, cpus);
  init_pcb();
  init_i8259();
  uart_init();
  ps2port_setup();
  pci_setup();
  vgahw_init();

  swppal(kernel_entry ? kernel_entry : do_console, &pcb);
}

void
do_start_wait(unsigned long cpuid)
{
  while (1)
    {
      /* Wait 1ms for the kernel to wake us.  */
      ndelay(1000000);

      if (hwrpb.hwrpb.rxrdy & (1ull << cpuid))
	{
	  /* ??? The only message I know of is "START\r\n".
	     I can't be bothered to verify more than 4 characters.  */
	  /* ??? The Linux kernel fills in, but does not require,
	     CPU_restart_data.  It just sets that to the same address
	     as CPU_restart itself.  Our swppal *does* put the PC into
	     $26 and $27, the latter of which the kernel does rely upon.  */

	  unsigned int len = hwrpb.processor[cpuid].ipc_buffer[0];
	  unsigned int msg = hwrpb.processor[cpuid].ipc_buffer[1];
	  void *CPU_restart = hwrpb.hwrpb.CPU_restart;
	  __sync_synchronize();
	  hwrpb.hwrpb.rxrdy = 0;

          if (len == 7 && msg == ('S' | 'T' << 8 | 'A' << 16 | 'R' << 24))
	    {
	      /* Set bootstrap in progress */
	      hwrpb.processor[cpuid].flags |= 1;
	      swppal(CPU_restart, hwrpb.processor[cpuid].hwpcb);
	    }
	}
    }
}