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#define CTRL_BASE 0xF001F000
#define XIP_BASE 0xE0040000
#define CTRL_DATA 0x00
#define CTRL_STATUS 0x04
#define CTRL_MODE 0x08
#define CTRL_RATE 0x20
#define CTRL_SS_SETUP 0x24
#define CTRL_SS_HOLD 0x28
#define CTRL_SS_DISABLE 0x2C
#define CTRL_XIP_CONFIG 0x40
#define CTRL_XIP_MODE 0x44
.global crtStart
.global main
#define CTRL x31
crtStart:
li x31, CTRL_BASE
sw x0, CTRL_MODE(CTRL)
li t0, 2
sw t0, CTRL_RATE(CTRL)
li t0, 4
sw t0, CTRL_SS_SETUP(CTRL)
sw t0, CTRL_SS_HOLD(CTRL)
sw t0, CTRL_SS_DISABLE(CTRL)
li a0, 0x880
call spiWrite
li a0, 0x181
call spiWrite
li a0, 0x183
call spiWrite
li a0, 0x800
call spiWrite
li t0, 0x00FF010B
sw t0, CTRL_XIP_MODE(CTRL)
li t0, 0x1
sw t0, CTRL_XIP_CONFIG(CTRL)
li t0, XIP_BASE
lw t1, (t0)
li t2, 0xFFFFFFFF
xor t3,t1,t2
beqz t3,retry
//if we are here we have read a value from flash which is not all ones
lw t2, (t0)
xor t3,t1,t2
bnez t3,retry
lw t2, (t0)
xor t3,t1,t2
bnez t3,retry
//if we are here we have read the same value 3 times, so flash seems good, lets's jump
jr t0
retry:
li a0, 0x800
call spiWrite
li t1,100000
loop:
addi t1,t1,-1
bnez t1, loop
j crtStart
spiWrite:
sw a0,CTRL_DATA(CTRL)
spiWrite_wait:
lw t0,CTRL_STATUS(CTRL)
slli t0,t0,0x10
beqz t0,spiWrite_wait
ret
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