[Skiboot] [PATCH] SLW: Add init for power9 power management

[Akshay Adiga]

This patch adds new function to init core for power9 power management.
SPECIAL_WKUP_* SCOM registers, if set, can hold the cores from going into
idle states. Hence, clear PPM SPECIAL_WKUP_HYP_REG scom register for each
core during init.

Signed-off-by: Akshay Adiga <akshay.adiga at linux.vnet.ibm.com>
---
 hw/slw.c        | 53 ++++++++++++++++++++++++++++++++++++++++++++++-------
 include/xscom.h |  6 ++++++
 2 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/hw/slw.c b/hw/slw.c
index 1f59e83..3d94651 100644
--- a/hw/slw.c
+++ b/hw/slw.c
@@ -287,6 +287,34 @@ static bool slw_set_overrides(struct proc_chip *chip, struct cpu_thread *c)
 	return true;
 }
 
+static bool slw_set_overrides_p9(struct proc_chip *chip, struct cpu_thread *c)
+{
+	uint64_t tmp;
+	int rc;
+	uint32_t core = pir_to_core_id(c->pir);
+
+	/* Clear special wakeup bits that could hold power mgt */
+	rc = xscom_write(chip->id,
+			 XSCOM_ADDR_P9_EC_SLAVE(core, EC_PPM_SPECIAL_WKUP_HYP),
+			 0);
+	if (rc) {
+		log_simple_error(&e_info(OPAL_RC_SLW_SET),
+			"SLW: Failed to write EC_PPM_SPECIAL_WKUP_HYP\n");
+		return false;
+	}
+	/* Read back for debug */
+	rc = xscom_read(chip->id,
+			XSCOM_ADDR_P9_EC_SLAVE(core, EC_PPM_SPECIAL_WKUP_HYP),
+			&tmp);
+	prlog(PR_NOTICE, "SLW: EC_PPM_SPECIAL_WKUP_HYP read  0x%016llx\n", tmp);
+	rc = xscom_read(chip->id,
+			XSCOM_ADDR_P9_EC_SLAVE(core, EC_PPM_SPECIAL_WKUP_OTR),
+			&tmp);
+	if (tmp)
+		prlog(PR_WARNING, "SLW: EC_PPM_SPECIAL_WKUP_OTR read  0x%016llx\n", tmp);
+	return true;
+}
+
 #ifdef __HAVE_LIBPORE__
 static bool slw_unset_overrides(struct proc_chip *chip, struct cpu_thread *c)
 {
@@ -1085,6 +1113,16 @@ static void slw_patch_regs(struct proc_chip *chip)
 }
 #endif /* __HAVE_LIBPORE__ */
 
+static void slw_init_chip_p9(struct proc_chip *chip)
+{
+	struct cpu_thread *c;
+
+	prlog(PR_NOTICE, "SLW: Init chip 0x%x\n", chip->id);
+
+	/* At power ON setup inits for power-mgt */
+	for_each_available_core_in_chip(c, chip->id)
+		slw_set_overrides_p9(chip, c);
+}
 static void slw_init_chip(struct proc_chip *chip)
 {
 	int64_t rc;
@@ -1444,11 +1482,12 @@ void slw_init(void)
 {
 	struct proc_chip *chip;
 
-	if (proc_gen != proc_gen_p8)
-		return;
-
-	for_each_chip(chip)
-		slw_init_chip(chip);
-
-	slw_init_timer();
+	if (proc_gen == proc_gen_p8) {
+		for_each_chip(chip)
+			slw_init_chip(chip);
+		slw_init_timer();
+	} else if (proc_gen == proc_gen_p9) {
+		for_each_chip(chip)
+			slw_init_chip_p9(chip);
+	}
 }
diff --git a/include/xscom.h b/include/xscom.h
index bad9140..fae956d 100644
--- a/include/xscom.h
+++ b/include/xscom.h
@@ -143,6 +143,12 @@
 #define XSCOM_ADDR_P9_EC_SLAVE(core, addr) \
 	XSCOM_ADDR_P9_EC(core, (addr) | 0xf0000)
 
+/* Power 9 EC slave per-core power mgt slave registers */
+#define EC_PPM_SPECIAL_WKUP_OTR		0x010A
+#define EC_PPM_SPECIAL_WKUP_FSP		0x010B
+#define EC_PPM_SPECIAL_WKUP_OCC		0x010C
+#define EC_PPM_SPECIAL_WKUP_HYP		0x010D
+
 /************* XXXX Move these P8 only registers elswhere !!! ****************/
 
 /* Per core power mgt registers */
-- 
2.5.5