[RFC PATCH 2/2] lib: sbi: add priority for reset handler

[Nikita Shubin]

From: Nikita Shubin <n.shubin at yadro.com>

Let's make system_reset_check returning priority instead of only
true/false. In that case 0 - means not supported, and anything above
means priority that makes existing reset handlers being used in first
place, unless it is decided to lower their priority.

The handler with the least priority wins.

Signed-off-by: Nikita Shubin <n.shubin at yadro.com>
---
 lib/sbi/sbi_system.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/lib/sbi/sbi_system.c b/lib/sbi/sbi_system.c
index 92bc0ac..a82c4ef 100644
--- a/lib/sbi/sbi_system.c
+++ b/lib/sbi/sbi_system.c
@@ -55,6 +55,8 @@ void __noreturn sbi_system_reset(u32 reset_type, u32 reset_reason)
 	struct sbi_domain *dom = sbi_domain_thishart_ptr();
 	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 	struct sbi_dlist *pos;
+	struct sbi_system_reset_device *reset_dev = 0;
+	int priority = 255;
 
 	/* Send HALT IPI to every hart other than the current hart */
 	while (!sbi_hsm_hart_interruptible_mask(dom, hbase, &hmask)) {
@@ -70,12 +72,22 @@ void __noreturn sbi_system_reset(u32 reset_type, u32 reset_reason)
 
 	/* Check each reset device registered for supported reset type */
 	sbi_list_for_each(pos, &(reset_devices_list)) {
-		struct sbi_system_reset_device *dev =
-			to_system_reset_device(pos);
-		if (dev->system_reset_check(reset_type, reset_reason))
-			dev->system_reset(reset_type, reset_reason);
+		struct sbi_system_reset_device *dev
+			= to_system_reset_device(pos);
+		int status = dev->system_reset_check(reset_type, reset_reason);
+
+		if (status == 0)
+			continue;
+
+		if (status < priority) {
+			reset_dev = dev;
+			priority = status;
+		}
 	}
 
+	if (reset_dev)
+		reset_dev->system_reset(reset_type, reset_reason);
+
 	/* If platform specific reset did not work then do sbi_exit() */
 	sbi_exit(scratch);
 }
-- 
2.31.1