flash.S

.cfi_sections .debug_frame

.section .data._setup_is25lp
.global _setup_is25lp
.cfi_startproc
_setup_is25lp:
    li  a1, 0x10014000  // QSPI0 base address

    // Disable mapped region
    sw  zero,96(a1)  // fctrl.en = 0

    // Construct ffmt value for 4 dummy cycles
    li  a2, 0x00BB1447

    beqz a0, 2f

    // We need to set 8 dummy cycles instead of 4.
    // Issue a "Set Read Parameters" command.

    li  a0,2
    sw  a0,24(a1)  // csmode = HOLD
    li  a0,0xC0
    sw  a0,72(a1)  // txdata = 0xC0
    li  a0,0xF0
    sw  a0,72(a1)  // txdata = 0xF0
    sw  zero,24(a1)  // csmode = AUTO

    // Discard two response bytes
1:  lw  a0,76(a1)
    bltz a0,1b
1:  lw  a0,76(a1)
    bltz a0,1b

    addi a2,a2,0x40  // ffmt: 4 -> 8 dummy cycles
2:
    sw  a2,100(a1)  // Write ffmt

    // Enable mapped region
    li  a0, 1
    sw	a0,96(a1)  // fctrl.en = 1
    ret


.cfi_endproc
.size _setup_is25lp, . - _setup_is25lp