[PATCH 09/18] dbtr: Read triggers should not read HW trigger if not mapped

[Nicholas Piggin]

When no hardware trigger is mapped to a dbtr trig idx there is logically
no hardware trigger to be read. The mapped status can be tested in the
tstate word, so callers understand this.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 lib/sbi/sbi_dbtr.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/lib/sbi/sbi_dbtr.c b/lib/sbi/sbi_dbtr.c
index a2c45061..6efd5435 100644
--- a/lib/sbi/sbi_dbtr.c
+++ b/lib/sbi/sbi_dbtr.c
@@ -577,14 +577,26 @@ int sbi_dbtr_read_trig(unsigned long smode,
 	for_each_trig_entry(shmem_base, trig_count, typeof(*entry), entry) {
 		xmit = &entry->data;
 		trig = INDEX_TO_TRIGGER((_idx + trig_idx_base));
-		csr_write(CSR_TSELECT, trig->index);
-		trig->tdata1 = csr_read(CSR_TDATA1);
-		trig->tdata2 = csr_read(CSR_TDATA2);
-		trig->tdata3 = csr_read(CSR_TDATA3);
+
 		xmit->tstate = cpu_to_lle(trig->state);
-		xmit->tdata1 = cpu_to_lle(trig->tdata1);
-		xmit->tdata2 = cpu_to_lle(trig->tdata2);
-		xmit->tdata3 = cpu_to_lle(trig->tdata3);
+		if (trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)) {
+			csr_write(CSR_TSELECT, trig->index);
+			trig->tdata1 = csr_read(CSR_TDATA1);
+			trig->tdata2 = csr_read(CSR_TDATA2);
+			trig->tdata3 = csr_read(CSR_TDATA3);
+			xmit->tdata1 = cpu_to_lle(trig->tdata1);
+			xmit->tdata2 = cpu_to_lle(trig->tdata2);
+			xmit->tdata3 = cpu_to_lle(trig->tdata3);
+		} else {
+			/*
+			 * If the trig idx does not have a HW trigger
+			 * assigned then just return zeroes in tdata
+			 * words.
+			 */
+			xmit->tdata1 = 0;
+			xmit->tdata2 = 0;
+			xmit->tdata3 = 0;
+		}
 	}
 	sbi_hart_protection_unmap_range((unsigned long)shmem_base,
 					trig_count * sizeof(*entry));
-- 
2.51.0