[PATCH] lib: sbi: Fix PMP address bits detection

[Anup Patel]

From: Vasan VS <vasan.vs at gmail.com>

We should ensure that pmpcfg0.pmp0cfg is set to zero before using
pmpaddr0 CSR for detecting implemented PMP address bits.

Fixes: bf21632860b4 ("lib: sbi: Detect PMP granularity and number
of address bits")
Signed-off-by: Vasan VS <vasan.vs at gmail.com>
Signed-off-by: Anup Patel <anup.patel at wdc.com>
---
 lib/sbi/sbi_hart.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 8eb0c38..366066b 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -339,6 +339,10 @@ static unsigned long hart_pmp_get_allowed_addr(void)
 	unsigned long val = 0;
 	struct sbi_trap_info trap = {0};
 
+	csr_write_allowed(CSR_PMPCFG0, (ulong)&trap, 0);
+	if (trap.cause)
+		return 0;
+
 	csr_write_allowed(CSR_PMPADDR0, (ulong)&trap, PMP_ADDR_MASK);
 	if (!trap.cause) {
 		val = csr_read_allowed(CSR_PMPADDR0, (ulong)&trap);
-- 
2.25.1