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| author | Nathan Ringo <nathan@remexre.com> | 2024-02-25 02:26:14 -0600 |
|---|---|---|
| committer | Nathan Ringo <nathan@remexre.com> | 2024-02-25 10:59:52 -0600 |
| commit | f36676cda57e0228d76ef9b9c798b1e1d1d0e5e6 (patch) | |
| tree | c708133638b4376995f1be6cae802a328ca2dc1a /boards/qemu-virt/qemu-virt.s | |
| parent | b5dcf57c317715a4339e0b4a0bf61ec5e8e94ca0 (diff) | |
[boards/qemu-virt] Adds a strict flush routine.
This writes to the UART, ignoring any notion of readiness. This will
probably need to be reworked once a real UART driver exists that is used
by this platform.
Diffstat (limited to 'boards/qemu-virt/qemu-virt.s')
| -rw-r--r-- | boards/qemu-virt/qemu-virt.s | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/boards/qemu-virt/qemu-virt.s b/boards/qemu-virt/qemu-virt.s index 4628564..a2618d2 100644 --- a/boards/qemu-virt/qemu-virt.s +++ b/boards/qemu-virt/qemu-virt.s @@ -1,26 +1,54 @@ .section .text.start .extern main +.extern CONSOLE_STRICT_FLUSH .global _start +.type _start, STT_FUNC _start: # Have harts other than 0 spin until hart0 wakes them up. csrr a0, mhartid c.bnez a0, wait_for_hart0 + # Set up console_strict_flush. + la t0, console_strict_flush + la t1, CONSOLE_STRICT_FLUSH + sd t0, (t1) + # Set up hart0's stack. la sp, hart0_initial_stack_top # Call hart0_boot with the address of the DeviceTree. - c.mv a1, a0 + c.mv a0, a1 call hart0_boot - # Fall through to a spin loop. +.size _start, . - _start + +.type halt, STT_FUNC halt: j halt +.size halt, . - halt + +.section .text + +.type console_strict_flush, STT_FUNC +console_strict_flush: + li t0, 0x10000000 +1: + c.beqz a1, 2f + lb t1, (a0) + sb t1, (t0) + addi a0, a0, 1 + addi a1, a1, -1 + j 1b +2: + ret +.size console_strict_flush, . - console_strict_flush .section .text +.type wait_for_hart0, STT_FUNC wait_for_hart0: # TODO j halt +.size wait_for_hart0, . - wait_for_hart0 |