commit b94396c7dde699c17e81e087aadafda125f86856
author Samuel Holland <samuel.holland@sifive.com> Mon Mar 18 07:49:28 2024 -0700
committer Anup Patel <anup@brainfault.org> Fri Apr 05 17:34:24 2024 +0530
tree b77c4085afbe2f261cf956d5b50db1ac7f1bd62a
parent 5c9a73565f5e6d07cf30ecd7fa511d872050bd2c

lib: utils/timer: Optimize current hart scratch access

The address of the local scratch area is stored in each hart's mscratch
CSR. It is more efficient to read the CSR than to compute the address
from the hart ID.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/timer/aclint_mtimer.c

diff --git a/lib/utils/timer/aclint_mtimer.c b/lib/utils/timer/aclint_mtimer.c
index 271e625..9acb26e 100644
--- a/lib/utils/timer/aclint_mtimer.c
+++ b/lib/utils/timer/aclint_mtimer.c
@@ -72,14 +72,10 @@
 static void mtimer_event_stop(void)
 {
 	u32 target_hart = current_hartid();
-	struct sbi_scratch *scratch;
+	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 	struct aclint_mtimer_data *mt;
 	u64 *time_cmp;
 
-	scratch = sbi_hartid_to_scratch(target_hart);
-	if (!scratch)
-		return;
-
 	mt = mtimer_get_hart_data_ptr(scratch);
 	if (!mt)
 		return;
@@ -92,14 +88,10 @@
 static void mtimer_event_start(u64 next_event)
 {
 	u32 target_hart = current_hartid();
-	struct sbi_scratch *scratch;
+	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 	struct aclint_mtimer_data *mt;
 	u64 *time_cmp;
 
-	scratch = sbi_hartid_to_scratch(target_hart);
-	if (!scratch)
-		return;
-
 	mt = mtimer_get_hart_data_ptr(scratch);
 	if (!mt)
 		return;
@@ -155,13 +147,9 @@
 {
 	u64 *mt_time_cmp;
 	u32 target_hart = current_hartid();
-	struct sbi_scratch *scratch;
+	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 	struct aclint_mtimer_data *mt;
 
-	scratch = sbi_hartid_to_scratch(target_hart);
-	if (!scratch)
-		return SBI_ENOENT;
-
 	mt = mtimer_get_hart_data_ptr(scratch);
 	if (!mt)
 		return SBI_ENODEV;