arch/i386/cpu/sc520/sc520_asm.S

/*
 * (C) Copyright 2002
 * Daniel Engström, Omicron Ceti AB <daniel@omicron.se>.
 *
 * 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
 */

/* This file is largely based on code obtned from AMD. AMD's original
 * copyright is included below
 */

/*		TITLE	SIZER - Aspen DRAM Sizing Routine.
 * =============================================================================
 *
 *  Copyright 1999 Advanced Micro Devices, Inc.
 * You may redistribute this program and/or modify this program 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 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.
 *
 * THE MATERIALS ARE PROVIDED "AS IS" WITHOUT ANY EXPRESS OR IMPLIED WARRANTY
 * OF ANY KIND INCLUDING WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT OF
 * THIRD-PARTY INTELLECTUAL PROPERTY, OR FITNESS FOR ANY PARTICULAR PURPOSE.
 * IN NO EVENT SHALL AMD OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER
 * (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS
 * INTERRUPTION, LOSS OF INFORMATION) ARISING OUT OF THE USE OF OR INABILITY
 * TO USE THE MATERIALS, EVEN IF AMD HAS BEEN ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES.  BECAUSE SOME JURSIDICTIONS PROHIBIT THE EXCLUSION OR
 * LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES, THE ABOVE
 * LIMITATION MAY NOT APPLY TO YOU.
 *
 * AMD does not assume any responsibility for any errors that may appear in
 * the Materials nor any responsibility to support or update the Materials.
 * AMD retains the right to make changes to its test specifications at any
 * time, without notice.
 * ==============================================================================
 */

/*
 ******************************************************************************
 *
 *  FILE        : sizer.asm - SDRAM DIMM Sizing Algorithm
 *
 *
 *
 *  FUNCTIONS   : sizemem() - jumped to, not called.  To be executed after
 *                reset to determine the size of the SDRAM DIMMs. Initializes
 *		 the memory subsystem.
 *
 *
 *  AUTHOR      : Buddy Fey - Original.
 *
 *
 *  DESCRIPTION : Performs sizing on SDRAM DIMMs on ASPEN processor.
 *                NOTE: This is a small memory model version
 *
 *
 *  INPUTS      : BP contains return address offset
 *		 CACHE is assumed to be disabled.
 *		 The FS segment limit has already been set to big real mode
 *		 (full 32-bit addressing capability)
 *
 *
 *  OUTPUTS     : None
 *
 *
 *  REG USE     :  ax,bx,cx,dx,di,si,bp, fs
 *
 *
 *  REVISION    : See PVCS info below
 *
 *
 *  TEST PLAN CROSS REFERENCE:
 *
 *
 * $Workfile: $
 * $Revision: 1.2 $
 * $Date: 1999/09/22 12:49:33 $
 * $Author: chipf $
 * $Log: sizer.asm $
 * Revision 1.2  1999/09/22 12:49:33  chipf
 * Add legal header
 *
 *******************************************************************************
 */


/*******************************************************************************
 *       FUNCTIONAL DESCRIPTION:
 * This routine is called to autodetect the geometry of the DRAM.
 *
 * This routine is called to determine the number of column bits for the DRAM
 * devices in this external bank. This routine assumes that the external bank
 * has been configured for an 11-bit column and for 4 internal banks. This gives
 * us the maximum address reach in memory. By writing a test value to the max
 * address and locating where it aliases to, we can determine the number of valid
 * column bits.
 *
 * This routine is called to determine the number of internal banks each DRAM
 * device has. The external bank (under test) is configured for maximum reach
 * with 11-bit columns and 4 internal banks. This routine will write to a max
 * address (BA1 and BA0 = 1) and then read from an address with BA1=0 to see if
 * that column is a "don't care". If BA1 does not affect write/read of data,
 * then this device has only 2 internal banks.
 *
 * This routine is called to determine the ending address for this external
 * bank of SDRAM. We write to a max address with a data value and then disable
 * row address bits looking for "don't care" locations. Each "don't care" bit
 * represents a dividing of the maximum density (128M) by 2. By dividing the
 * maximum of 32 4M chunks in an external bank down by all the "don't care" bits
 * determined during sizing, we set the proper density.
 *
 * WARNINGS.
 * bp must be preserved because it is used for return linkage.
 *
 * EXIT
 * nothing returned - but the memory subsystem is enabled
 *******************************************************************************
 */

#include <config.h>

.section .text
.equ            DRCCTL,     0x0fffef010   /* DRAM control register */
.equ            DRCTMCTL,   0x0fffef012   /* DRAM timing control register */
.equ            DRCCFG,     0x0fffef014   /* DRAM bank configuration register */
.equ            DRCBENDADR, 0x0fffef018   /* DRAM bank ending address register */
.equ            ECCCTL,     0x0fffef020   /* DRAM ECC control register */
.equ            ECCINT,     0x0fffefd18   /* DRAM ECC nmi-INT mapping */
.equ            DBCTL,      0x0fffef040   /* DRAM buffer control register */

.equ            CACHELINESZ, 0x00000010   /* size of our cache line (read buffer) */
.equ            COL11_ADR,  0x0e001e00    /* 11 col addrs */
.equ            COL10_ADR,  0x0e000e00    /* 10 col addrs */
.equ            COL09_ADR,  0x0e000600    /*  9 col addrs */
.equ            COL08_ADR,  0x0e000200    /*  8 col addrs */
.equ            ROW14_ADR,  0x0f000000    /* 14 row addrs */
.equ            ROW13_ADR,  0x07000000    /* 13 row addrs */
.equ            ROW12_ADR,  0x03000000    /* 12 row addrs */
.equ            ROW11_ADR,  0x01000000    /* 11 row addrs/also bank switch */
.equ            ROW10_ADR,  0x00000000    /* 10 row addrs/also bank switch */
.equ            COL11_DATA, 0x0b0b0b0b    /* 11 col addrs */
.equ            COL10_DATA, 0x0a0a0a0a    /* 10 col data */
.equ            COL09_DATA, 0x09090909    /*  9 col data */
.equ            COL08_DATA, 0x08080808    /*  8 col data */
.equ            ROW14_DATA, 0x3f3f3f3f    /* 14 row data (MASK) */
.equ            ROW13_DATA, 0x1f1f1f1f    /* 13 row data (MASK) */
.equ            ROW12_DATA, 0x0f0f0f0f    /* 12 row data (MASK) */
.equ            ROW11_DATA, 0x07070707    /* 11 row data/also bank switch (MASK) */
.equ            ROW10_DATA, 0xaaaaaaaa    /* 10 row data/also bank switch (MASK) */

.globl mem_init
mem_init:
	/* initialize dram controller registers */
	xorw	%ax, %ax
	movl	$DBCTL, %edi
	movb	%al, (%edi)		/* disable write buffer */

	movl	$ECCCTL, %edi
	movb	%al, (%edi)		/* disable ECC */

	movl	$DRCTMCTL, %edi
	movb	$0x1e, %al		/* Set SDRAM timing for slowest */
	movb	%al, (%edi)

	/* setup loop to do 4 external banks starting with bank 3 */
	movl	$0xff000000, %eax	/* enable last bank and setup */
	movl	$DRCBENDADR, %edi	/* ending address register */
	movl	%eax, (%edi)

	movl	$DRCCFG, %edi		/* setup */
	movw	$0xbbbb, %ax		/* dram config register for  */
	movw	%ax, (%edi)

	/* issue a NOP to all DRAMs */
	movl	$DRCCTL, %edi		/* setup DRAM control register with */
	movb	$0x01, %al		/* Disable refresh,disable write buffer */
	movb	%al, (%edi)
	movl	$CACHELINESZ, %esi	/* just a dummy address to write for */
	movw	%ax, (%esi)

	/* delay for 100 usec? */
	movw	$100, %cx
sizdelay:
	loop	sizdelay

	/* issue all banks precharge */
	movb	$0x02, %al
	movb	%al, (%edi)
	movw	%ax, (%esi)

	/* issue 2 auto refreshes to all banks */
	movb	$0x04, %al	/* Auto refresh cmd */
	movb	%al, (%edi)
	movw	$0x02, %cx
refresh1:
	movw	%ax, (%esi)
	loop	refresh1

	/* issue LOAD MODE REGISTER command */
	movb	$0x03, %al	/* Load mode register cmd */
	movb	%al, (%edi)
	movw	%ax, (%esi)

	/* issue 8 more auto refreshes to all banks */
	movb	$0x04, %al	/* Auto refresh cmd */
	movb	%al, (%edi)
	movw	$0x0008, %cx
refresh2:
	movw	%ax, (%esi)
	loop	refresh2

	/* set control register to NORMAL mode */
	movb	$0x00, %al	/* Normal mode value */
	movb	%al, (%edi)

	/*
	 * size dram starting with external bank 3
	 * moving to external bank 0
	 */
	movl	$0x3, %ecx	/* start with external bank 3 */

nextbank:

	/* write col 11 wrap adr */
	movl	$COL11_ADR, %esi	/* set address to max col (11) wrap addr */
	movl	$COL11_DATA, %eax	/* pattern for max supported columns(11) */
	movl	%eax, (%esi)		/* write max col pattern at max col adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write col 10 wrap adr */
	movl	$COL10_ADR, %esi	/* set address to 10 col wrap address */
	movl	$COL10_DATA, %eax	/* pattern for 10 col wrap */
	movl	%eax, (%esi)		/* write 10 col pattern @ 10 col wrap adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write col 9 wrap adr */
	movl	$COL09_ADR, %esi	/* set address to 9 col wrap address */
	movl	$COL09_DATA, %eax	/* pattern for 9 col wrap */
	movl	%eax, (%esi)		/* write 9 col pattern @ 9 col wrap adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write col 8 wrap adr */
	movl	$COL08_ADR, %esi	/* set address to min(8) col wrap address */
	movl	$COL08_DATA, %eax	/* pattern for min (8) col wrap */
	movl	%eax, (%esi)		/* write min col pattern @ min col adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write row 14 wrap adr */
	movl	$ROW14_ADR, %esi	/* set address to max row (14) wrap addr */
	movl	$ROW14_DATA, %eax	/* pattern for max supported rows(14) */
	movl	%eax, (%esi)		/* write max row pattern at max row adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write row 13 wrap adr */
	movl	$ROW13_ADR, %esi	/* set address to 13 row wrap address */
	movl	$ROW13_DATA, %eax	/* pattern for 13 row wrap */
	movl	%eax, (%esi)		/* write 13 row pattern @ 13 row wrap adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write row 12 wrap adr */
	movl	$ROW12_ADR, %esi	/* set address to 12 row wrap address */
	movl	$ROW12_DATA, %eax	/* pattern for 12 row wrap */
	movl	%eax, (%esi)		/* write 12 row pattern @ 12 row wrap adr */
	movl	(%esi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/* write row 11 wrap adr */
	movl	$ROW11_ADR, %edi	/* set address to 11 row wrap address */
	movl	$ROW11_DATA, %eax	/* pattern for 11 row wrap */
	movl	%eax, (%edi)		/* write 11 row pattern @ 11 row wrap adr */
	movl	(%edi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/*
	 * write row 10 wrap adr --- this write is really to determine
	 * number of banks
	 */
	movl	$ROW10_ADR, %edi	/* set address to 10 row wrap address */
	movl	$ROW10_DATA, %eax	/* pattern for 10 row wrap (AA) */
	movl	%eax, (%edi)		/* write 10 row pattern @ 10 row wrap adr */
	movl	(%edi), %ebx		/* optional read */
	cmpl	%ebx, %eax		/* to verify write */
	jnz	bad_ram			/* this ram is bad */

	/*
	 * read data @ row 12 wrap adr to determine  * banks,
	 * and read data @ row 14 wrap adr to determine  * rows.
	 * if data @ row 12 wrap adr is not AA, 11 or 12 we have bad RAM.
	 * if data @ row 12 wrap == AA, we only have 2 banks, NOT 4
	 * if data @ row 12 wrap == 11 or 12, we have 4 banks,
	 */
	xorw	%di, %di		/* value for 2 banks in DI */
	movl	(%esi), %ebx		/* read from 12 row wrap to check banks */
					/* (esi is setup from the write to row 12 wrap) */
	cmpl	%ebx, %eax		/* check for AA pattern  (eax holds the aa pattern) */
	jz	only2			/* if pattern == AA, we only have 2 banks */

	/* 4 banks */

	movw	$0x008, %di		/* value for 4 banks in DI (BNK_CNT bit) */
	cmpl	$ROW11_DATA, %ebx	/* only other legitimate values are 11 */
	jz	only2
	cmpl	$ROW12_DATA, %ebx	/* and 12 */
	jnz	bad_ram			/* its bad if not 11 or 12! */

	/* fall through */
only2:
 /*
  * validate row mask
  */
	movl	$ROW14_ADR, %esi	/* set address back to max row wrap addr */
	movl	(%esi), %eax		/* read actual number of rows @ row14 adr */

	cmpl	$ROW11_DATA, %eax	/* row must be greater than 11 pattern */
	jb	bad_ram

	cmpl	$ROW14_DATA, %eax	/* and row must be less than 14 pattern */
	ja	bad_ram

	cmpb	%ah, %al		/* verify all 4 bytes of dword same */
	jnz	bad_ram
	movl	%eax, %ebx
	shrl	$16, %ebx
	cmpw	%bx, %ax
	jnz	bad_ram

	/*
	 * read col 11 wrap adr for real column data value
	 */
	movl	$COL11_ADR, %esi	/* set address to max col (11) wrap addr */
	movl	(%esi), %eax		/* read real col number at max col adr */

	/*
	 * validate column data
	 */
	cmpl	$COL08_DATA, %eax	/* col must be greater than 8 pattern */
	jb	bad_ram

	cmpl	$COL11_DATA, %eax	/* and row must be less than 11 pattern */
	ja	bad_ram

	subl	$COL08_DATA, %eax	/* normalize column data to zero */
	jc	bad_ram
	cmpb	%ah, %al		/* verify all 4 bytes of dword equal */
	jnz	bad_ram
	movl	%eax, %edx
	shrl	$16, %edx
	cmpw	%dx, %ax
	jnz	bad_ram

	/*
	 * merge bank and col data together
	 */
	addw	%di, %dx		/* merge of bank and col info in dl */

	/*
	 * fix ending addr mask based upon col info
	 */
	movb	$0x03, %al
	subb	%dh, %al		/* dh contains the overflow from the bank/col merge  */
	movb	%bl, %dh		/* bl contains the row mask (aa, 07, 0f, 1f or 3f) */
	xchgw	%cx, %ax		/* cx = ax = 3 or 2 depending on 2 or 4 bank device */
	shrb	%cl, %dh
	incb	%dh			/* ending addr is 1 greater than real end */
	xchgw	%cx, %ax		/* cx is bank number again */

bad_reint:
	/*
	 * issue all banks precharge
	 */
	movl	$DRCCTL, %esi		/* setup DRAM control register with */
	movb	$0x02, %al		/* All banks precharge */
	movb	%al, (%esi)
	movl	$CACHELINESZ, %esi	/* address to init read buffer */
	movw	%ax, (%esi)

	/*
	 * update ENDING ADDRESS REGISTER
	 */
	movl	$DRCBENDADR, %edi	/* DRAM ending address register */
	movl	%ecx, %ebx
	addl	%ebx, %edi
	movb	%dh, (%edi)

	/*
	 * update CONFIG REGISTER
	 */
	xorb	%dh, %dh
	movw	$0x000f, %bx
	movw	%cx, %ax
	shlw	$2, %ax
	xchgw	%cx, %ax
	shlw	%cl, %dx
	shlw	%cl, %bx
	notw	%bx
	xchgw	%cx, %ax
	movl	$DRCCFG, %edi
	movw	(%edi), %ax
	andw	%bx, %ax
	orw	%dx, %ax
	movw	%ax, (%edi)
	jcxz	cleanup

	decw	%cx
	movl	%ecx, %ebx
	movl	$DRCBENDADR, %edi	/* DRAM ending address register */
	movb	$0xff, %al
	addl	%ebx, %edi
	movb	%al, (%edi)

	/*
	 * set control register to NORMAL mode
	 */
	movl	$DRCCTL, %esi		/* setup DRAM control register with */
	movb	$0x00, %al		/* Normal mode value */
	movb	%al, (%esi)
	movl	$CACHELINESZ, %esi	/* address to init read buffer */
	movw	%ax, (%esi)
	jmp	nextbank

cleanup:
	movl	$DRCBENDADR, %edi	/* DRAM ending address register  */
	movw	$0x04, %cx
	xorw	%ax, %ax
cleanuplp:
	movb	(%edi), %al
	orb	%al, %al
	jz	emptybank

	addb	%ah, %al
	jns	nottoomuch

	movb	$0x7f, %al
nottoomuch:
	movb	%al, %ah
	orb	$0x80, %al
	movb	%al, (%edi)
emptybank:
	incl	%edi
	loop	cleanuplp

#if defined CONFIG_SYS_SDRAM_DRCTMCTL
	/* just have your hardware desinger _GIVE_ you what you need here! */
	movl	$DRCTMCTL, %edi
	movb	$CONFIG_SYS_SDRAM_DRCTMCTL, %al
	movb	%al, (%edi)
#else
#if defined(CONFIG_SYS_SDRAM_CAS_LATENCY_2T) || defined(CONFIG_SYS_SDRAM_CAS_LATENCY_3T)
	/*
	 * Set the CAS latency now since it is hard to do
	 * when we run from the RAM
	 */
	movl	$DRCTMCTL, %edi	/* DRAM timing register */
	movb	(%edi), %al
#ifdef CONFIG_SYS_SDRAM_CAS_LATENCY_2T
	andb	$0xef, %al
#endif
#ifdef CONFIG_SYS_SDRAM_CAS_LATENCY_3T
	orb	$0x10, %al
#endif
	movb	%al, (%edi)
#endif
#endif
	movl	$DRCCTL, %edi	/* DRAM Control register */
	movb	$0x03, %al	/* Load mode register cmd */
	movb	%al, (%edi)
	movw	%ax, (%esi)


	movl	$DRCCTL, %edi	/* DRAM Control register */
	movb	$0x18, %al	/*  Enable refresh and NORMAL mode */
	movb	%al, (%edi)

	jmp	dram_done

bad_ram:
	xorl	%edx, %edx
	xorl	%edi, %edi
	jmp	bad_reint

dram_done:

#if CONFIG_SYS_SDRAM_ECC_ENABLE
	/*
	 * We are in the middle of an existing 'call' - Need to store the
	 * existing return address before making another 'call'
	 */
	movl	%ebp, %ebx

	/* Get the memory size */
	movl	$init_ecc, %ebp
	jmpl	get_mem_size

init_ecc:
	/* Restore the orignal return address */
	movl	%ebx, %ebp

	/* A nominal memory test: just a byte at each address line */
	movl	%eax, %ecx
	shrl	$0x1, %ecx
	movl	$0x1, %edi
memtest0:
	movb	$0xa5, (%edi)
	cmpb	$0xa5, (%edi)
	jne	out
	shrl	$0x1, %ecx
	andl	%ecx, %ecx
	jz	set_ecc
	shll	$0x1, %edi
	jmp	memtest0

set_ecc:
	/* clear all ram with a memset */
	movl	%eax, %ecx
	xorl	%esi, %esi
	xorl	%edi, %edi
	xorl	%eax, %eax
	shrl	$0x2, %ecx
	cld
	rep	stosl

	/* enable read, write buffers */
	movb	$0x11, %al
	movl	$DBCTL, %edi
	movb	%al, (%edi)

	/* enable NMI mapping for ECC */
	movl	$ECCINT, %edi
	movb	$0x10, %al
	movb	%al, (%edi)

	/* Turn on ECC */
	movl	$ECCCTL, %edi
	movb	$0x05, %al
	movb	%al,(%edi)
#endif

out:
	jmp	*%ebp

/*
 * Read and decode the sc520 DRCBENDADR MMCR and return the number of
 * available ram bytes in %eax
 */
.globl get_mem_size
get_mem_size:
	movl	$DRCBENDADR, %edi	/* DRAM ending address register */

bank0:	movl	(%edi), %eax
	movl	%eax, %ecx
	andl	$0x00000080, %ecx
	jz	bank1
	andl	$0x0000007f, %eax
	shll	$22, %eax
	movl	%eax, %ebx

bank1:	movl	(%edi), %eax
	movl	%eax, %ecx
	andl	$0x00008000, %ecx
	jz	bank2
	andl	$0x00007f00, %eax
	shll	$14, %eax
	movl	%eax, %ebx

bank2:	movl	(%edi), %eax
	movl	%eax, %ecx
	andl	$0x00800000, %ecx
	jz	bank3
	andl	$0x007f0000, %eax
	shll	$6, %eax
	movl	%eax, %ebx

bank3:	movl	(%edi), %eax
	movl	%eax, %ecx
	andl	$0x80000000, %ecx
	jz	done
	andl	$0x7f000000, %eax
	shrl	$2, %eax
	movl	%eax, %ebx

done:
	movl	%ebx, %eax
	jmp	*%ebp