risc-v/mpfs: clear IPIs at boot

Inter-processor interrupts (IPIs) are not cleared via mie/mip registers but rather, at the MPFS_CLINT_BASE + mhartid * 4 (a word or 4-byte offset for each hart). If there's an IPI waiting, the system will continue to boot altough it's expected to stay at the wfi loop waiting for the IPI. Signed-off-by: Eero Nurkkala <[email protected]>
apache · Nov 29, 2024 · 34f8599 · 34f8599
1 parent 834d189
commit 34f8599
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/arch/risc-v/src/mpfs/mpfs_head.S b/arch/risc-v/src/mpfs/mpfs_head.S
@@ -49,6 +49,14 @@ __start:
   csrw CSR_MIE, zero
   csrw CSR_MIP, zero
 
+  /* Clear all IPIs (above doesn't clear them) */
+
+  csrr a0, CSR_MHARTID
+  slli t1, a0, 2
+  li   t0, MPFS_CLINT_BASE
+  add  t1, t1, t0
+  sw   zero, 0(t1)
+
   /* Initialize the Machine Trap Vector */
 
   la   t0, __trap_vec