firmware: qcom: scm: Add qcom_scm_set_warm_boot_addr function

A core can be powered down for cpuidle or when it is hotplugged off. In
either case, the warmboot return address would be different. Allow
setting the warmboot address for a specific cpu, optimize and write to
the firmware, if the address is different than the previously set
address.

Export qcom_scm_set_warm_boot_addr function move the warm boot flags to
implementation.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Kumar Gala <galak@codeaurora.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index c953cc38918f..4d8ede4807ac 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -1,4 +1,5 @@
 /* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ * Copyright (C) 2015 Linaro Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -39,6 +40,23 @@
 #define QCOM_SCM_FLAG_COLDBOOT_CPU2     0x08
 #define QCOM_SCM_FLAG_COLDBOOT_CPU3     0x20
 
+#define QCOM_SCM_FLAG_WARMBOOT_CPU0     0x04
+#define QCOM_SCM_FLAG_WARMBOOT_CPU1     0x02
+#define QCOM_SCM_FLAG_WARMBOOT_CPU2     0x10
+#define QCOM_SCM_FLAG_WARMBOOT_CPU3     0x40
+
+struct qcom_scm_entry {
+        int flag;
+        void *entry;
+};
+
+static struct qcom_scm_entry qcom_scm_wb[] = {
+        { .flag = QCOM_SCM_FLAG_WARMBOOT_CPU0 },
+        { .flag = QCOM_SCM_FLAG_WARMBOOT_CPU1 },
+        { .flag = QCOM_SCM_FLAG_WARMBOOT_CPU2 },
+        { .flag = QCOM_SCM_FLAG_WARMBOOT_CPU3 },
+};
+
 static DEFINE_MUTEX(qcom_scm_lock);
 
 /**
@@ -379,3 +397,41 @@ int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
         return qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
 }
 EXPORT_SYMBOL(qcom_scm_set_cold_boot_addr);
+
+/**
+ * qcom_scm_set_warm_boot_addr() - Set the warm boot address for cpus
+ * @entry: Entry point function for the cpus
+ * @cpus: The cpumask of cpus that will use the entry point
+ *
+ * Set the Linux entry point for the SCM to transfer control to when coming
+ * out of a power down. CPU power down may be executed on cpuidle or hotplug.
+ */
+int qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
+{
+        int ret;
+        int flags = 0;
+        int cpu;
+
+        /*
+         * Reassign only if we are switching from hotplug entry point
+         * to cpuidle entry point or vice versa.
+         */
+        for_each_cpu(cpu, cpus) {
+                if (entry == qcom_scm_wb[cpu].entry)
+                        continue;
+                flags |= qcom_scm_wb[cpu].flag;
+        }
+
+        /* No change in entry function */
+        if (!flags)
+                return 0;
+
+        ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
+        if (!ret) {
+                for_each_cpu(cpu, cpus)
+                        qcom_scm_wb[cpu].entry = entry;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(qcom_scm_set_warm_boot_addr);