cpu.c

嵌入式ARM的一些源代码

/*
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*
 * m8xx.c
 *
 * CPU specific code
 *
 * written or collected and sometimes rewritten by
 * Magnus Damm <[e-mail]>
 *
 * minor modifications by
 * Wolfgang Denk <[e-mail]>
 *
 * modified for 8260 by
 * Murray Jensen <[e-mail]>
 */

#include <ppcboot.h>
#include <command.h>
#include <mpc8260.h>
#include <asm/processor.h>
#include <asm/cpm_8260.h>

int
checkcpu(long clock)
{
  volatile immap_t *immap = (immap_t *)CFG_IMMR;
  uint pvr = get_pvr();
  uint immr, rev, k;
  char buf[32];

  if ((pvr >> 16) != 0x0081)
    return -1;	/* whoops! not an MPC8260 */
  rev = pvr & 0xff;

  immr = immap->im_memctl.memc_immr;
  if ((immr & IMMR_ISB_MSK) != CFG_IMMR)
    return -1;	/* whoops! someone moved the IMMR */

  printf("MPC8260 (REV %02x) ", rev);

  /*
   * the bottom 16 bits of the immr are the Part Number and Mask Number
   * (4-34); the 16 bits at PROFF_REVNUM (0x8af0) in dual port ram is the
   * RISC Microcode Revision Number (13-10).
   */
  k = (immr << 16) | *((ushort *)&immap->im_dprambase[PROFF_REVNUM]);

  switch(k) {
  default: printf("unknown (k=0x%08x)", k); break;
  }

  printf(" at %s MHz\n", strmhz(buf, clock));

  return 0;
}

/* ------------------------------------------------------------------------- */
/* configures a UPM by writing into the UPM RAM array			     */
/* uses bank 11 and physical address 0x80000000				     */

void
upmconfig(uint upm, uint *table, uint size)
{
  volatile immap_t      *immap = (immap_t *)CFG_IMMR;
  volatile memctl8260_t *memctl = &immap->im_memctl;
  volatile uchar	*dummy = (uchar *)0x80000000;
  uint i;

  /* first set up bank 11 to reference the correct UPM at a dummy address */

  memctl->memc_or11 = ORxU_AM_MSK;	/* set all AM bits */

  switch (upm) {

  case UPMA:
    memctl->memc_br11 = ((uint)dummy&BRx_BA_MSK)|BRx_PS_32|BRx_MS_UPMA|BRx_V;
    memctl->memc_mamr = MxMR_OP_WARR;
    break;

  case UPMB:
    memctl->memc_br11 = ((uint)dummy&BRx_BA_MSK)|BRx_PS_32|BRx_MS_UPMB|BRx_V;
    memctl->memc_mbmr = MxMR_OP_WARR;
    break;

  case UPMC:
    memctl->memc_br11 = ((uint)dummy&BRx_BA_MSK)|BRx_PS_32|BRx_MS_UPMC|BRx_V;
    memctl->memc_mcmr = MxMR_OP_WARR;
    break;

  default:
    panic("upmconfig passed invalid UPM number (%u)\n", upm);
    break;

  }

  /*
   * at this point, the dummy address is set up to access the selected UPM,
   * the MAD pointer is zero, and the MxMR OP is set for writing to RAM
   *
   * now we simply load the mdr with each word and poke the dummy address.
   * the MAD is incremented on each access.
   */

  for (i = 0; i < size; i++) {
    memctl->memc_mdr = table[i];
    *dummy = 0;
  }

  /* now kill bank 11 */
  memctl->memc_br11 = 0;
}

/* ------------------------------------------------------------------------- */

void
do_reset(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
{
	ulong msr, addr;

	volatile immap_t *immap = (immap_t *)CFG_IMMR;

	immap->im_clkrst.car_rmr = RMR_CSRE; /* Checkstop Reset enable */

	/* Interrupts and MMU off */
	__asm__ __volatile__ ("mfmsr    %0" : "=r"(msr) : );
	msr &= ~(MSR_EE|MSR_IR|MSR_DR);
	__asm__ __volatile__ ("mtmsr    %0" : : "r"(msr) );

	/*
	* Trying to execute the next instruction at a non-existing address
	* should cause a machine check, resulting in reset
	*/
#if 0
	addr = (ulong)-1;
#else
	/*
	 * -1 was actually a valid address on my system, so I got a
	 * Software Emulation exception instead of a Machine Check
	 * exception. Let's try to pick a better address...
	 */
	addr = CFG_MONITOR_BASE - sizeof (ulong);
#endif
	((void (*)(void ))addr)();

}

/* ------------------------------------------------------------------------- */

/*
 * We implement the delay by converting the delay (the number of
 * microseconds to wait) into a number of time base ticks; then we
 * watch the time base until it has incremented by that amount.
 */
void
udelay(unsigned long usec)
{
	ulong tbclk;
	ulong ticks;
	/* Pointer to initial global data area */
	init_data_t *idata =
		(init_data_t *)(CFG_INIT_RAM_ADDR+CFG_INIT_DATA_OFFSET);

	tbclk = (idata->cpu_clk + 3) / 4;
	ticks = ((usec * ((tbclk + 999) / 1000)) + 999) / 1000;

	wait_ticks (ticks);
}

/* ------------------------------------------------------------------------- */

#if defined(CONFIG_WATCHDOG)
void
watchdog_reset(void)
{
	int re_enable = disable_interrupts();
	reset_8260_watchdog((immap_t *)CFG_IMMR);
	if (re_enable) enable_interrupts();
}
#endif /* CONFIG_WATCHDOG */

/* ------------------------------------------------------------------------- */