* Patch by Daniel Engström, 13 Nov 2002:
Add support for i386 architecture and AMD SC520 board
* Patch by Pierre Aubert, 12 Nov 2002:
Add support for DOS filesystem and booting from DOS floppy disk
diff --git a/lib_i386/ic/sc520_asm.S b/lib_i386/ic/sc520_asm.S
new file mode 100644
index 0000000..72110c4
--- /dev/null
+++ b/lib_i386/ic/sc520_asm.S
@@ -0,0 +1,530 @@
+/*
+ * (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
+ */
+
+/*
+ * =============================================================================
+ *
+ * Copyright 1999 Advanced Micro Devices, Inc.
+ *
+ * This software is the property of Advanced Micro Devices, Inc (AMD) which
+ * specifically grants the user the right to modify, use and distribute this
+ * software provided this COPYRIGHT NOTICE is not removed or altered. All
+ * other rights are reserved by AMD.
+ *
+ * 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 INFORMAITON) 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.
+ *
+ * So that all may benefit from your experience, please report any problems
+ * or suggestions about this software back to AMD. Please include your name,
+ * company, telephone number, AMD product requiring support and question or
+ * problem encountered.
+ *
+ * Advanced Micro Devices, Inc. Worldwide support and contact
+ * Embedded Processor Division information available at:
+ * Systems Engineering epd.support@amd.com
+ * 5204 E. Ben White Blvd. -or-
+ * Austin, TX 78741 http://www.amd.com/html/support/techsup.html
+ * ============================================================================
+ */
+
+
+/*******************************************************************************
+ * AUTHOR : Buddy Fey - Original.
+ *******************************************************************************
+ */
+
+
+/*******************************************************************************
+ * 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
+ *******************************************************************************
+ */
+
+.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 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) */
+
+
+ /*
+ * initialize dram controller registers
+ */
+.globl mem_init
+mem_init:
+ xorw %ax,%ax
+ movl $DBCTL, %edi
+fs movb %al, (%edi) /* disable write buffer */
+
+ movl $ECCCTL, %edi
+fs movb %al, (%edi) /* disable ECC */
+
+ movl $DRCTMCTL, %edi
+ movb $0x1E,%al /* Set SDRAM timing for slowest */
+fs 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 */
+fs movl %eax, (%edi)
+
+ movl $DRCCFG, %edi /* setup */
+ movw $0xbbbb,%ax /* dram config register for */
+fs movw %ax, (%edi)
+
+ /*
+ * issue a NOP to all DRAMs
+ */
+ movl $DRCCTL, %edi /* setup DRAM control register with */
+ movb $0x1,%al /* Disable refresh,disable write buffer */
+fs movb %al, (%edi)
+ movl $CACHELINESZ, %esi /* just a dummy address to write for */
+fs movw %ax, (%esi)
+ /*
+ * delay for 100 usec? 200?
+ * ******this is a cludge for now *************
+ */
+ movw $100,%cx
+sizdelay:
+ loop sizdelay /* we need 100 usec here */
+ /***********************************************/
+
+ /*
+ * issue all banks precharge
+ */
+ movb $0x2,%al /* All banks precharge */
+fs movb %al, (%edi)
+fs movw %ax, (%esi)
+
+ /*
+ * issue 2 auto refreshes to all banks
+ */
+ movb $0x4,%al /* Auto refresh cmd */
+fs movb %al, (%edi)
+ movw $2,%cx
+refresh1:
+fs movw %ax, (%esi)
+ loop refresh1
+
+ /*
+ * issue LOAD MODE REGISTER command
+ */
+ movb $0x3,%al /* Load mode register cmd */
+fs movb %al, (%edi)
+fs movw %ax, (%esi)
+
+ /*
+ * issue 8 more auto refreshes to all banks
+ */
+ movb $0x4,%al /* Auto refresh cmd */
+fs movb %al, (%edi)
+ movw $8,%cx
+refresh2:
+fs movw %ax, (%esi)
+ loop refresh2
+
+ /*
+ * set control register to NORMAL mode
+ */
+ movb $0x0,%al /* Normal mode value */
+fs 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) */
+fs movl %eax, (%esi) /* write max col pattern at max col adr */
+fs 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 */
+fs movl %eax, (%esi) /* write 10 col pattern @ 10 col wrap adr */
+fs 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 */
+fs movl %eax, (%esi) /* write 9 col pattern @ 9 col wrap adr */
+fs 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 */
+fs movl %eax, (%esi) /* write min col pattern @ min col adr */
+fs 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) */
+fs movl %eax, (%esi) /* write max row pattern at max row adr */
+fs 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 */
+fs movl %eax, (%esi) /* write 13 row pattern @ 13 row wrap adr */
+fs 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 */
+fs movl %eax, (%esi) /* write 12 row pattern @ 12 row wrap adr */
+fs 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 */
+fs movl %eax, (%edi) /* write 11 row pattern @ 11 row wrap adr */
+fs 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) */
+fs movl %eax, (%edi) /* write 10 row pattern @ 10 row wrap adr */
+fs 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 */
+fs 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 $8,%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 */
+fs 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 */
+fs 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 $3,%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 */
+ /*
+ * issue all banks precharge
+ */
+bad_reint:
+ movl $DRCCTL, %esi /* setup DRAM control register with */
+ movb $0x2,%al /* All banks precharge */
+fs movb %al, (%esi)
+ movl $CACHELINESZ, %esi /* address to init read buffer */
+fs movw %ax, (%esi)
+
+ /*
+ * update ENDING ADDRESS REGISTER
+ */
+ movl $DRCBENDADR, %edi /* DRAM ending address register */
+ movl %ecx,%ebx
+ addl %ebx, %edi
+fs movb %dh, (%edi)
+ /*
+ * update CONFIG REGISTER
+ */
+ xorb %dh,%dh
+ movw $0x00f,%bx
+ movw %cx,%ax
+ shlw $2,%ax
+ xchgw %cx,%ax
+ shlw %cl,%dx
+ shlw %cl,%bx
+ notw %bx
+ xchgw %cx,%ax
+ movl $DRCCFG, %edi
+fs mov (%edi), %ax
+ andw %bx,%ax
+ orw %dx,%ax
+fs movw %ax, (%edi)
+ jcxz cleanup
+
+ decw %cx
+ movl %ecx,%ebx
+ movl $DRCBENDADR, %edi /* DRAM ending address register */
+ movb $0xff,%al
+ addl %ebx, %edi
+fs movb %al, (%edi)
+ /*
+ * set control register to NORMAL mode
+ */
+ movl $DRCCTL, %esi /* setup DRAM control register with */
+ movb $0x0,%al /* Normal mode value */
+fs movb %al, (%esi)
+ movl $CACHELINESZ, %esi /* address to init read buffer */
+fs movw %ax, (%esi)
+ jmp nextbank
+
+cleanup:
+ movl $DRCBENDADR, %edi /* DRAM ending address register */
+ movw $4,%cx
+ xorw %ax,%ax
+cleanuplp:
+fs movb (%edi), %al
+ orb %al,%al
+ jz emptybank
+
+ addb %ah,%al
+ jns nottoomuch
+
+ movb $0x7f,%al
+nottoomuch:
+ movb %al,%ah
+ orb $0x80,%al
+fs movb %al, (%edi)
+emptybank:
+ incl %edi
+ loop cleanuplp
+
+#if defined(CFG_SDRAM_CAS_LATENCY_2T) || defined(CFG_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 CFG_SDRAM_CAS_LATENCY_2T
+ andb $0xef, %al
+#endif
+#ifdef CFG_SDRAM_CAS_LATENCY_3T
+ orb $0x10, %al
+#endif
+ movb %al, (%edi)
+#endif
+ movl $DRCCTL, %edi /* DRAM Control register */
+ movb $0x3,%al /* Load mode register cmd */
+fs movb %al, (%edi)
+fs movw %ax, (%esi)
+
+
+ movl $DRCCTL, %edi /* DRAM Control register */
+ movb $0x18,%al /* Enable refresh and NORMAL mode */
+fs movb %al, (%edi)
+
+ jmp dram_done
+
+bad_ram:
+ xorl %edx,%edx
+ xorl %edi,%edi
+ jmp bad_reint
+
+dram_done:
+
+ /* readback DRCBENDADR and return the number
+ * of available ram bytes in %eax */
+
+ movl $DRCBENDADR, %edi /* DRAM ending address register */
+
+ movl (%edi), %eax
+ movl %eax, %ecx
+ andl $0x80000000, %ecx
+ jz bank2
+ andl $0x7f000000, %eax
+ shrl $2, %eax
+ movl %eax, %ebx
+
+bank2: movl (%edi), %eax
+ movl %eax, %ecx
+ andl $0x00800000, %ecx
+ jz bank1
+ andl $0x007f0000, %eax
+ shll $6, %eax
+ movl %eax, %ebx
+
+bank1: movl (%edi), %eax
+ movl %eax, %ecx
+ andl $0x00008000, %ecx
+ jz bank0
+ andl $0x00007f00, %eax
+ shll $14, %eax
+ movl %eax, %ebx
+
+bank0: movl (%edi), %eax
+ movl %eax, %ecx
+ andl $0x00000080, %ecx
+ jz done
+ andl $0x0000007f, %eax
+ shll $22, %eax
+ movl %eax, %ebx
+
+done: movl %ebx, %eax
+
+ jmp *%ebp