From 6704216732e528ac99109b8bad401e60c68d6c22 Mon Sep 17 00:00:00 2001
From: Atish Patra <atish.patra@wdc.com>
Date: Fri, 6 Mar 2020 11:44:44 -0800
Subject: 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>
---
lib/sbi/sbi_hart.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 3de46a2..535fe19 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -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);
};
--
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