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/* A fake 'bios' which does nothing but move a kernel image
* to RAM address zero and then starts that...
*/
#include <bsp/residual.h>
#define LD_CACHE_LINE_SIZE 5
#define INIT_STACK (0x100 - 16) /* 16-byte/svr4 aligned */
/* These offsets must correspond to declaration in qemu_fakeres.c */
#define DAT_LEN 0
#define RES_OFF 4
#define CMD_OFF 8
#define CMD_LEN 12
#define IMG_ADR 16
/* Non-volatile registers */
#define OBASE 30
#define PCID 25
#define PCIA 26
#define PCI_MAX_DEV 32
#define BA_OPCODE(tgt) ((18<<(31-5)) | 2 | ((tgt) & 0x03fffffc))
.global fake_data
.global res_set_memsz
.global _start
_start:
lis 1, INIT_STACK@h
ori 1,1,INIT_STACK@l
/* qemu 0.14.1 has the wrong exception prefix for 74xx CPUs
* (bug 811683). Work around this by putting a stub at 0x00000X00
* which simply jumps to high memory. We only need the SC exception
* for now.
*/
lis 3, BA_OPCODE(0xfff00000)@h
ori 3, 3, BA_OPCODE(0xfff00000)@l
li 4, 0x0c00
add 3, 3, 4
stw 3, 0(4)
dcbf 0, 4
icbi 0, 4
bl pci_irq_set
/* copy residual to RAM and fix up;
* this routine returns a pointer to
* a 'fake_data' struct. If reading
* NVRAM failed then the return value
* points to a fall-back version in
* ROM...
*/
bl res_copy
/* fake_data pointer to R29 */
mr 29, 3
/* Load up R3..R5 with PreP mandated
* values (R3: residual, R4: kernel image,
* R5: OpenFirmware PTR (or NULL).
*/
/* load R3 with residual pointer */
lwz 3, RES_OFF(29)
add 3, 3, 29
/* load R4 with image address */
lwz 4, IMG_ADR(29)
/* load R5 with zero (OFW = NULL) */
li 5, 0
/* EXTENSION: R6 = cmdline start */
lwz 6, CMD_OFF(29)
add 6, 6, 29
/* EXTENSION: R7 = cmdline end */
lwz 7, CMD_LEN(29)
add 7, 7, 6
/* jump to image address */
mtctr 4
bctr
.org 0x100
b _start
.org 0x110
template:
mfsrr0 30
mfsrr1 31
1: b 1b
template_end:
.org 0xc00
b monitor
.org 0x4000
codemove: /* src/dst are cache-aligned */
addi 5,5,(1<<LD_CACHE_LINE_SIZE)-1
srwi 5,5,LD_CACHE_LINE_SIZE
addi 3,3,-4
addi 4,4,-4
1:
li 0, (1<<LD_CACHE_LINE_SIZE)
mtctr 0
2:
lwzu 0, 4(3)
stwu 0, 4(4)
bdnz 2b
dcbf 0,4
icbi 0,4
addic. 5,5,-1
bne 1b
blr
cpexc:
lis 3,template@h
ori 3,3,template@l
li 5,template_end-template
b codemove
monitor:
stwu 1,-16(1)
stw OBASE, 8(1)
lis OBASE, 0x80000000@h
cmplwi 10,0x63 /* enter_monitor -> RESET */
bne 10f
hwreset:
li 3,1
stb 3,0x92(OBASE)
1: b 1b
10: cmplwi 10,0x1d /* .NETCTRL -> ignore */
bne 10f
b ret_from_mon
10: b hwreset /* unknown -> RESET */
ret_from_mon:
lwz OBASE,8(1)
lwz 1,0(1)
rfi
rcb:
stwbrx 3, 0, PCIA
lbzx 3, 0, PCID
blr
wcb:
stwbrx 3, 0, PCIA
stbx 4, 0, PCID
blr
rcd:
stwbrx 3, 0, PCIA
lwbrx 3, 0, PCID
blr
/* fixup pci interrupt line register according to what
* qemu does: line = ((pin-1) + slot_no) & 1 ? 11 : 9;
*/
pci_irq_set:
/* set up stack frame */
stwu 1, -32(1)
mflr 0
stw 0, 32+4(1)
/* load counter with # of PCI devs */
li 0, PCI_MAX_DEV
mtctr 0
/* save non-volatile registers we use
* in stack frame
*/
stw 20, 8(1)
stw PCIA, 12(1)
stw PCID, 16(1)
/* load non-volatile registers with
* intended values.
*/
lis 20, 0x80000000@h /* key for slot # 0 */
lis PCIA, 0x80000cf8@h /* PCI config space address reg */
ori PCIA, PCIA, 0x80000cf8@l
addi PCID, PCIA, 4 /* PCI config space data reg */
/* loop over all slots and fix up PCI IRQ LINE */
1:
mr 3, 20
bl rcd
addi 3, 3, 1
cmplwi 3, 0 /* slot empty (= -1 + 1 = 0) ? */
beq 2f
addi 3, 20, 0x3d
bl rcb
cmplwi 3, 0
beq 2f
slwi 4, 3, 11
addi 3, 20, 0x3c
xor 4, 4, 3 /* bit 11 = slot # + irq_num [zero-based] + 1 */
andi. 4, 4, 0x0800
li 4, 11
beq 3f
li 4, 9
3:
bl wcb
2:
addi 20, 20, 0x0800 /* next slot */
bdnz 1b
/* restore and return */
lwz 20, 32+4(1)
mtlr 20
lwz PCID, 16(1)
lwz PCIA, 12(1)
lwz 20, 8(1)
lwz 1, 0(1)
blr
.section .romentry, "ax"
b _start
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