[Skiboot] [PATCH v2 03/12] opal: Query chip TOD status for a given topology.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

Query and update chip TOD status for both topologies. This helps to
identify which chip TOD is active master and which one is backup master.
During TOD error recovery this information will become very useful.

Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
---
 hw/chiptod.c |   41 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/hw/chiptod.c b/hw/chiptod.c
index fc62268..3ff110d 100644
--- a/hw/chiptod.c
+++ b/hw/chiptod.c
@@ -36,6 +36,8 @@
 /* -- TOD primary/secondary master/slave status register -- */
 #define TOD_STATUS			0x00040008
 #define   TOD_ST_TOPOLOGY_SELECT	PPC_BITMASK(0, 2)
+#define   TOD_ST_ACTIVE_MASTER		PPC_BIT(23)
+#define   TOD_ST_BACKUP_MASTER		PPC_BIT(24)
 
 /* TOD chip XSCOM addresses */
 #define TOD_TTYPE_0			0x00040011
@@ -111,9 +113,15 @@ enum chiptod_chip_role {
 	chiptod_chip_role_SDST,		/* Slave Drawer Slave TOD */
 };
 
+enum chiptod_chip_status {
+	chiptod_active_master = 0,	/* Chip TOD is Active master */
+	chiptod_backup_master = 1,	/* Chip TOD is backup master */
+};
+
 struct chiptod_chip_config_info {
 	int32_t id;				/* chip id */
 	enum chiptod_chip_role role;		/* Chip role */
+	enum chiptod_chip_status status;	/* active/backup/disabled */
 };
 
 static int32_t chiptod_primary = -1;
@@ -143,10 +151,13 @@ static struct lock chiptod_lock = LOCK_UNLOCKED;
 static void print_topo_info(enum chiptod_topology topo)
 {
 	const char *role[] = { "Unknown", "MDMT", "MDST", "SDMT", "SDST" };
+	const char *status[] = { "Unknown",
+		"Active Master", "Backup Master", "Backup Master Disabled" };
 
-	prlog(PR_DEBUG, "CHIPTOD:    chip id: %d, Role: %s\n",
+	prlog(PR_DEBUG, "CHIPTOD:    chip id: %d, Role: %s, Status: %s\n",
 				chiptod_topology_info[topo].id,
-				role[chiptod_topology_info[topo].role + 1]);
+				role[chiptod_topology_info[topo].role + 1],
+				status[chiptod_topology_info[topo].status + 1]);
 }
 
 static void print_topology_info(void)
@@ -232,11 +243,37 @@ chiptod_get_chip_role(enum chiptod_topology topology, int32_t chip_id)
 	return role;
 }
 
+static enum chiptod_chip_status _chiptod_get_chip_status(int32_t chip_id)
+{
+	uint64_t tod_status;
+	enum chiptod_chip_status status = -1;
+
+	if (xscom_read(chip_id, TOD_STATUS, &tod_status) != 0) {
+		prerror("CHIPTOD: XSCOM error reading TOD_STATUS reg\n");
+		goto out;
+	}
+
+	if (tod_status & TOD_ST_ACTIVE_MASTER)
+		status = chiptod_active_master;
+	else if (tod_status & TOD_ST_BACKUP_MASTER)
+		status = chiptod_backup_master;
+
+out:
+	return status;
+}
+
+static enum chiptod_chip_status
+chiptod_get_chip_status(enum chiptod_topology topology)
+{
+	return _chiptod_get_chip_status(chiptod_topology_info[topology].id);
+}
+
 static void chiptod_update_topology(enum chiptod_topology topo)
 {
 	int32_t chip_id = chiptod_topology_info[topo].id;
 
 	chiptod_topology_info[topo].role = chiptod_get_chip_role(topo, chip_id);
+	chiptod_topology_info[topo].status = chiptod_get_chip_status(topo);
 }
 
 static void chiptod_setup_base_tfmr(void)