lib: Check MSIP bit after returning from WFI

As per the RISC-V privilege specification, WFI can be implemented as
a NOP. Software should ensure that relevant interrupt pending bits
are set. Otherwise, loop back to WFI.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Atish Patra 2020-03-06 11:44:44 -08:00 committed by Anup Patel
parent e3f69fc1e9
commit 6704216732

View file

@ -385,7 +385,7 @@ static unsigned long coldboot_wait_bitmap = 0;
void sbi_hart_wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
{
unsigned long saved_mie;
unsigned long saved_mie, cmip;
const struct sbi_platform *plat = sbi_platform_ptr(scratch);
if ((sbi_platform_hart_count(plat) <= hartid) ||
@ -407,7 +407,10 @@ void sbi_hart_wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
/* Wait for coldboot to finish using WFI */
while (!coldboot_done) {
spin_unlock(&coldboot_lock);
wfi();
do {
wfi();
cmip = csr_read(CSR_MIP);
} while (!(cmip & MIP_MSIP));
spin_lock(&coldboot_lock);
};