[PATCH 02/13] lib: sbi: Detect AIA CSRs at boot-time

[Anup Patel]

We extend HART feature detection to discover AIA CSRs at boot-time.

Signed-off-by: Anup Patel <anup.patel at wdc.com>
Signed-off-by: Anup Patel <apatel at ventanamicro.com>
---
 include/sbi/sbi_hart.h |  4 +++-
 lib/sbi/sbi_hart.c     | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index d2db9d6..a83b45b 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -24,9 +24,11 @@ enum sbi_hart_features {
 	SBI_HART_HAS_SSCOFPMF = (1 << 3),
 	/** HART has timer csr implementation in hardware */
 	SBI_HART_HAS_TIME = (1 << 4),
+	/** HART has AIA local interrupt CSRs */
+	SBI_HART_HAS_AIA = (1 << 5),
 
 	/** Last index of Hart features*/
-	SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_TIME,
+	SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_AIA,
 };
 
 struct sbi_scratch;
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index d9a15d9..c16b395 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -283,6 +283,9 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
 	case SBI_HART_HAS_TIME:
 		fstr = "time";
 		break;
+	case SBI_HART_HAS_AIA:
+		fstr = "aia";
+		break;
 	default:
 		break;
 	}
@@ -506,6 +509,26 @@ __mhpm_skip:
 	csr_read_allowed(CSR_TIME, (unsigned long)&trap);
 	if (!trap.cause)
 		hfeatures->features |= SBI_HART_HAS_TIME;
+
+	/* Detect if hart has AIA local interrupt CSRs */
+	csr_read_allowed(CSR_MTOPI, (unsigned long)&trap);
+	if (trap.cause)
+		goto __aia_skip;
+	csr_read_allowed(CSR_MISELECT, (unsigned long)&trap);
+	if (trap.cause)
+		goto __aia_skip;
+	csr_write_allowed(CSR_MISELECT, (unsigned long)&trap, 0x30);
+	if (trap.cause)
+		goto __aia_skip;
+	val = csr_read_allowed(CSR_MIREG, (unsigned long)&trap);
+	if (trap.cause)
+		goto __aia_skip;
+	csr_write_allowed(CSR_MIREG, (unsigned long)&trap, val);
+	if (trap.cause)
+		goto __aia_skip;
+	hfeatures->features |= SBI_HART_HAS_AIA;
+__aia_skip:
+	return;
 }
 
 int sbi_hart_reinit(struct sbi_scratch *scratch)
-- 
2.25.1