[PATCH 06/29] powerpc/rtas: add rtas_activate_firmware()

[Nathan Lynch]

Provide a documented wrapper function for the ibm,activate-firmware
service, which must be called after a partition migration or
hibernation.

If the function is absent or the call fails, the OS will continue to
run normally with the current firmware, so there is no need to perform
any recovery. Just log it and continue.

Signed-off-by: Nathan Lynch <nathanl at linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h |  1 +
 arch/powerpc/kernel/rtas.c      | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index b43165fc6c2a..fdefe6a974eb 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -247,6 +247,7 @@ extern void __noreturn rtas_restart(char *cmd);
 extern void rtas_power_off(void);
 extern void __noreturn rtas_halt(void);
 extern void rtas_os_term(char *str);
+void rtas_activate_firmware(void);
 extern int rtas_get_sensor(int sensor, int index, int *state);
 extern int rtas_get_sensor_fast(int sensor, int index, int *state);
 extern int rtas_get_power_level(int powerdomain, int *level);
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 70c570269d7b..58bbd69a233f 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -961,6 +961,36 @@ int rtas_ibm_suspend_me_unsafe(u64 handle)
 }
 #endif
 
+/**
+ * rtas_activate_firmware() - Activate a new version of firmware.
+ *
+ * Activate a new version of partition firmware. The OS must call this
+ * after resuming from a partition hibernation or migration in order
+ * to maintain the ability to perform live firmware updates. It's not
+ * catastrophic for this method to be absent or to fail; just log the
+ * condition in that case.
+ *
+ * Context: This function may sleep.
+ */
+void rtas_activate_firmware(void)
+{
+	int token;
+	int fwrc;
+
+	token = rtas_token("ibm,activate-firmware");
+	if (token == RTAS_UNKNOWN_SERVICE) {
+		pr_notice("ibm,activate-firmware method unavailable\n");
+		return;
+	}
+
+	do {
+		fwrc = rtas_call(token, 0, 1, NULL);
+	} while (rtas_busy_delay(fwrc));
+
+	if (fwrc)
+		pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
+}
+
 /**
  * rtas_call_reentrant() - Used for reentrant rtas calls
  * @token:	Token for desired reentrant RTAS call
-- 
2.25.4