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Simple ipl.S

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This commit is contained in:
Ronald G. Minnich 2000-12-08 01:00:34 +00:00
commit edbdd1c15d
1 changed files with 33 additions and 16 deletions
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49
src/northbridge/acer/m1631/ipl.S
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@ -1,4 +1,5 @@
/* wow, the acer way to to this hurts. So we do it our way:
#include <cpu/p5/macros.h>
/* wow, the usual way to to this hurts. So we do it our way:
* 32-bit test not needed.
*/
/* the MCR is 32-bits. You set it, it programs SDRAM.
@ -8,41 +9,42 @@
* ror it 16 bits, and as we grow the CAS, we just inc cs, and that will
* set the right value.
*/
#define INIT_MCR 0
xorl %edi, %edi
movl $INIT_MCR, %ecx
mov $0x6c, %al
CALL_SP PCI_WRITE($0x6c)
CALLSP(pci_write_dword)
rorl $16, %ecx
/* test 8 bit CAS */
clrb 0
movb $0, (%edi)
movb $1, 0x800
tstb 0
cmpb $0,(%edi)
jnz sizeram
inc %cl
movb $1, 0x1000
tstb 0
cmpb $0, (%edi)
jnz sizeram
inc %cl
movb $1, 0x2000
tstb 0
cmpb $0, (%edi)
jnz sizeram
inc %cl
sizeram:
rorl $16, %ecx
/* clear the 'no multi page' bit. */
andw $0xefff, %cx
mov $0x6c, %al
CALL_SP PCI_WRITE($0x6c)
CALLSP(pci_write_dword)
/* size is now in cx[19:16] */
/* now size the dram */
/* you had best have at least 32M; that's as small as we go */
/* rorr 20 the ecx value, to get row size into lsb */
clrb 0
movb $0, (%edi)
ror $20, %ecx
movl $0x400000, %esi
1:
movb $1, [esi]
movb $1, (%esi)
inc %cl
jz 1b
/* size is now in esi */
@ -51,23 +53,38 @@
/* set 4 banks. */
orb $1, %cl
mov $0x6c, %al
CALL_SP PCI_WRITE($0x6c)
CALLSP(pci_write_dword)
/* bank detect */
/* you don't need to even care how large CAS is.
* Just set 4-bank mode, and set non-zero numbers into a few places.
* if the byte at 0 changes, you have two banks. Trivial.
*/
clrb 0
movb $0, (%edi)
movb $1, 0x1000
movb $1, 0x2000
movb $1, 0x4000
tstb 0
cmpb $0, (%edi)
jz 1f /* only one bank */
orl $80000, %ecx
1:
/* clear 4 banks */
andb $0xfe, %cl
mov $0x6c, %al
CALL_SP PCI_WRITE($0x6c)
CALLSP(pci_write_dword)
/* at this point, dram slot 0 is up. we hope. */
/* now for flash ... */
/* NOTE: MUST NOT DESTROY %ecx! */
/* INPUT: %al, the register. %ecx, the write data */
pci_write_dword:
mov $0,%ah
mov $0x80000000,%edx
or %ax,%dx
mov %edx,%eax
mov $0x0cf8,%dx
outl %eax,%dx
mov $0x0fc,%dl
mov %ecx, %eax
outl %eax,%dx
RETSP