From 9a74a64ae08bfeda8dc366e931f5a60838d7bac0 Mon Sep 17 00:00:00 2001
From: Atish Patra <atish.patra@wdc.com>
Date: Fri, 20 Mar 2020 15:10:36 -0700
Subject: lib: Check MSIP bit after returning from WFI
Commit 71d2b837c46e (lib: Move all coldboot wait APIs to sbi_init.c)
caused a regression while moving the code from sbi_hart.c to sbi_init.c.
As per original commit text, WFI can be implemented as a NOP according
to the RISC-V privilege specification. Software should ensure that
relevant interrupt pending bits are set. Otherwise, loop back to WFI.
Fix the regression by applying the original patch to sbi_init.c.
Fixes: 71d2b837c46e ("lib: Move all coldboot wait APIs to sbi_init.c")
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
---
lib/sbi/sbi_init.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
index 2b9afb7..90ec64c 100644
--- a/lib/sbi/sbi_init.c
+++ b/lib/sbi/sbi_init.c
@@ -79,7 +79,7 @@ static struct sbi_hartmask coldboot_wait_hmask = { 0 };
static void 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);
/* Save MIE CSR */
@@ -97,7 +97,10 @@ static void 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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