[Skiboot] [PATCH v3 16/18] fadump: Add support to trigger memory preserving IPL on BMC system

[Vasant Hegde]

On FSP based system we call 'attn' instruction. FSP detects attention and
initiates memory preserving IPL. On BMC system we have to call SBE s0
interrupt to initiate memory preserving IPL.

This patch adds support to call s0 interrupt.
Sequence :
  - s0 interrupt on slave chip SBE
  - s0 interrupt on master chip SBE

Note:
  - This patch enables MPIPL support on witherspoon only. We will enable
    on other BMC systems later.
  - It uses xscom node to detect master and slave chip. So that we can
    trigger early MPIPL (even before initializing SBE driver).
  - At present we do not have a proper way to detect SBE is alive or not.
    So we wait for predefined time and then call normal reboot.

Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
---
 hw/ipmi/ipmi-attn.c            |  1 +
 hw/sbe-p9.c                    | 54 ++++++++++++++++++++++++++++++++++++++++++
 include/sbe-p9.h               | 10 ++++++++
 platforms/astbmc/witherspoon.c |  3 ++-
 4 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/hw/ipmi/ipmi-attn.c b/hw/ipmi/ipmi-attn.c
index 8ff872c62..ed52e45ca 100644
--- a/hw/ipmi/ipmi-attn.c
+++ b/hw/ipmi/ipmi-attn.c
@@ -19,6 +19,7 @@
 #include <pel.h>
 #include <platform.h>
 #include <processor.h>
+#include <sbe-p9.h>
 #include <skiboot.h>
 #include <stack.h>
 #include <timebase.h>
diff --git a/hw/sbe-p9.c b/hw/sbe-p9.c
index 12d9e97ff..627ef428a 100644
--- a/hw/sbe-p9.c
+++ b/hw/sbe-p9.c
@@ -48,6 +48,7 @@
 
 #include <chip.h>
 #include <errorlog.h>
+#include <ipmi.h>
 #include <lock.h>
 #include <opal.h>
 #include <sbe-p9.h>
@@ -931,3 +932,56 @@ void p9_sbe_init(void)
 	/* Initiate SBE timeout poller */
 	opal_add_poller(p9_sbe_timeout_poll, NULL);
 }
+
+/* Terminate and initiate MPIPL */
+void __attribute__((noreturn)) p9_sbe_terminate(const char *msg)
+{
+	uint32_t chip_id;
+	uint32_t primary_chip = -1;
+	int rc, waited = 0;
+	struct dt_node *xn;
+
+	dt_for_each_compatible(dt_root, xn, "ibm,xscom") {
+		chip_id = dt_get_chip_id(xn);
+
+		if (dt_has_node_property(xn, "primary", NULL)) {
+			primary_chip = chip_id;
+			continue;;
+		}
+
+		rc = xscom_write(chip_id,
+				 SBE_CONTROL_REG_RW, SBE_CONTROL_REG_S0);
+		/* Initiate normal reboot */
+		if (rc) {
+			prlog(PR_ERR, "Failed to write S0 interrupt [chip id = %x]\n",
+			      chip_id);
+			goto out_reboot;
+		}
+	}
+
+	if (primary_chip == -1) {
+		prlog(PR_ERR, "Master chip ID not found.\n");
+		goto out_reboot;
+	}
+
+	/* Write S0 interrupt on master SBE */
+	rc = xscom_write(primary_chip,
+			 SBE_CONTROL_REG_RW, SBE_CONTROL_REG_S0);
+	/* Initiate normal reboot */
+	if (rc) {
+		prlog(PR_ERR, "Failed to write S0 interrupt [chip id = %x]\n",
+		      primary_chip);
+		goto out_reboot;
+	}
+
+	/* XXX We do not have a way to detect SBE state. Hence wait for max
+	 *     time SBE takes to respond and then trigger normal reboot.
+	 */
+	while (waited <= SBE_CMD_TIMEOUT_MAX) {
+		time_wait_ms(100);
+		waited += 100;
+	}
+
+out_reboot:
+	ipmi_terminate(msg);
+}
diff --git a/include/sbe-p9.h b/include/sbe-p9.h
index 7101dc700..14d7a3af4 100644
--- a/include/sbe-p9.h
+++ b/include/sbe-p9.h
@@ -103,6 +103,13 @@
 #define SBE_HOST_TIMER_EXPIRY		PPC_BIT(14)
 #define SBE_HOST_RESPONSE_MASK		(PPC_BITMASK(0, 4) | SBE_HOST_TIMER_EXPIRY)
 
+/* SBE Control Register */
+#define SBE_CONTROL_REG_RW		0x00050008
+
+/* SBE interrupt s0/s1 bits */
+#define SBE_CONTROL_REG_S0		PPC_BIT(14)
+#define SBE_CONTROL_REG_S1		PPC_BIT(15)
+
 /* SBE Target Type */
 #define SBE_TARGET_TYPE_PROC		0x00
 #define SBE_TARGET_TYPE_EX		0x01
@@ -243,4 +250,7 @@ extern void p9_sbe_update_timer_expiry(uint64_t new_target);
 /* Send skiboot relocated base address to SBE */
 extern void p9_sbe_send_relocated_base(uint64_t val);
 
+/* Terminate and trigger MPIPL */
+extern void __attribute__((noreturn)) p9_sbe_terminate(const char *msg);
+
 #endif	/* __SBE_P9_H */
diff --git a/platforms/astbmc/witherspoon.c b/platforms/astbmc/witherspoon.c
index cb09eefe0..30ec73157 100644
--- a/platforms/astbmc/witherspoon.c
+++ b/platforms/astbmc/witherspoon.c
@@ -27,6 +27,7 @@
 #include <pci.h>
 #include <pci-slot.h>
 #include <phb4.h>
+#include <sbe-p9.h>
 
 #include "astbmc.h"
 
@@ -166,7 +167,7 @@ DECLARE_PLATFORM(witherspoon) = {
 	.cec_reboot             = astbmc_ipmi_reboot,
 	.elog_commit		= ipmi_elog_commit,
 	.exit			= ipmi_wdt_final_reset,
-	.terminate		= ipmi_terminate,
+	.terminate		= p9_sbe_terminate,
 
 	.pci_get_slot_info	= dt_slot_get_slot_info,
 };
-- 
2.14.3