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Get ram size from the configuration device

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git-svn-id: svn://coreboot.org/openbios/openbios-devel@322 f158a5a8-5612-0410-a976-696ce0be7e32
This commit is contained in:
Blue Swirl
2008-12-23 20:36:45 +00:00
parent 4858cabb9b
commit f7e2ff3e4c
2 changed files with 24 additions and 34 deletions
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55
arch/ppc/qemu/start.S
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@@ -356,42 +356,29 @@ GLOBL(flush_icache_range):
isync
blr
/* compute RAM size
*
* Exception vectors are beween 0x00000000 and 0x00004000
* RAM size is limited to 2 MB (0x80000000)
* MMIO and IO are after 0x80000000.
* ROM is at 0xfff00000
* so we can scan from 0x4000 to 0x80000000
*
*/
/* Get RAM size from Qemu configuration device */
#define CFG_ADDR 0xf0000510
#define FW_CFG_RAM_SIZE 0x03
compute_ramsize:
li r3, 0x4000 /* start address */
/* how many pages between 0x4000 and 0x80000000 */
lis r4, 0x0007
ori r4, r4, 0xfffc
mtctr r4
/* pattern to write in memory */
lis r4, 0x55aa
ori r4, r4, 0x55aa
memloop:
/* store and re-read pattern */
stw r4, 0(r3)
sync
lwz r0, 0(r3)
cmpw cr7, r0, r4
bne cr7, exit_memloop
addi r3, r3, 4096 /* add page size */
bdnz memloop
exit_memloop:
blr
lis r9,HA(CFG_ADDR)
ori r9,r9,LO(CFG_ADDR)
li r0,FW_CFG_RAM_SIZE
sth r0,0(r9)
lis r9,HA(CFG_ADDR + 2)
ori r9,r9,LO(CFG_ADDR + 2)
lbz r1,0(r9)
lbz r0,0(r9)
slwi r0,r0,8
or r1,r1,r0
lbz r0,0(r9)
slwi r0,r0,16
or r1,r1,r0
lbz r0,0(r9)
slwi r0,r0,24
or r3,r1,r0
blr
/* Hard reset vector */
.section .romentry,"ax"