From 03fcf4dbb27736e5a2d05b550bc34366b9047ada Mon Sep 17 00:00:00 2001
From: Quantum <thomasmuller336@gmail.com>
Date: Wed, 26 Jan 2022 18:16:29 -0500
Subject: [PATCH] OpenSBI: Added HSM(Hart State Management) extension

---
 kernel/drivers/opensbi/extensions/hsm.cpp     | 58 +++++++++++++++++++
 .../opensbi/include/opensbi/extensions/hsm.h  | 32 ++++++++++
 kernel/drivers/opensbi/meson.build            |  3 +-
 3 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 kernel/drivers/opensbi/extensions/hsm.cpp
 create mode 100644 kernel/drivers/opensbi/include/opensbi/extensions/hsm.h

diff --git a/kernel/drivers/opensbi/extensions/hsm.cpp b/kernel/drivers/opensbi/extensions/hsm.cpp
new file mode 100644
index 0000000..d0f7d2d
--- /dev/null
+++ b/kernel/drivers/opensbi/extensions/hsm.cpp
@@ -0,0 +1,58 @@
+#include "opensbi/extensions/hsm.h"
+
+namespace drivers {
+namespace opensbi::hsm {
+
+    namespace {
+        enum class ExtensionId {
+            HSM = 0x48534D
+        };
+
+        enum class FunctionId {
+            HART_START,
+            HART_STOP,
+            HART_GET_STATUS,
+            HART_SUSPEND
+        };
+    }
+
+    SbiRet set_hsm(
+            unsigned long hartid,
+            unsigned long start_addr,
+            unsigned long opaque) {
+        return ecall(
+            static_cast<sbiword_t>(ExtensionId::HSM),
+            static_cast<sbiword_t>(FunctionId::HART_START),
+            hartid,
+            start_addr,
+            opaque);
+    }
+
+    SbiRet hart_stop() {
+        return ecall(
+            static_cast<sbiword_t>(ExtensionId::HSM),
+            static_cast<sbiword_t>(FunctionId::HART_STOP));
+    }
+
+    SbiRet hart_get_status(unsigned long hartid) {
+        return ecall(
+            static_cast<sbiword_t>(ExtensionId::HSM),
+            static_cast<sbiword_t>(FunctionId::HART_GET_STATUS),
+            hartid);
+    }
+
+    SbiRet hart_suspend(
+            SuspendType suspend_type,
+            unsigned long resume_addr,
+            unsigned long opaque) {
+        return ecall(
+            static_cast<sbiword_t>(ExtensionId::HSM),
+            static_cast<sbiword_t>(FunctionId::HART_SUSPEND),
+            static_cast<uint32_t>(suspend_type),
+            resume_addr,
+            opaque);
+    }
+
+}  // End namespace opensbi::hsm
+}  // End namespace drivers
+
diff --git a/kernel/drivers/opensbi/include/opensbi/extensions/hsm.h b/kernel/drivers/opensbi/include/opensbi/extensions/hsm.h
new file mode 100644
index 0000000..bcf2918
--- /dev/null
+++ b/kernel/drivers/opensbi/include/opensbi/extensions/hsm.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include "opensbi/opensbi.h"
+
+namespace drivers {
+namespace opensbi::hsm {
+
+    enum class SuspendType : uint32_t {
+        RETENTIVE = 0,
+        // 0x00000001 - 0x0FFFFFFF: Reserved
+        // 0x10000000 - 0x7FFFFFFF: Platform specific retentive
+        NON_RETENTIVE = 0x80000000
+        // 0x80000001 - 0x8FFFFFFF: Reserved
+        // 0x90000000 - 0xFFFFFFFF: Platform specific non-retentive
+    };
+
+    SbiRet hart_start(
+            unsigned long hartid,
+            unsigned long start_addr,
+            unsigned long opaque);
+
+    SbiRet hart_stop();
+
+    SbiRet hart_get_status(unsigned long hartid);
+
+    SbiRet hart_suspend(
+            SuspendType suspend_type,
+            unsigned long resume_addr,
+            unsigned long opaque);
+
+}  // End namespace opensbi::hsm
+}  // End namespace drivers
diff --git a/kernel/drivers/opensbi/meson.build b/kernel/drivers/opensbi/meson.build
index c01bed1..9156f91 100644
--- a/kernel/drivers/opensbi/meson.build
+++ b/kernel/drivers/opensbi/meson.build
@@ -5,7 +5,8 @@ kernel_sources += [
         'extensions/base.cpp',
         'extensions/timer.cpp',
         'extensions/ipi.cpp',
-        'extensions/rfence.cpp'
+        'extensions/rfence.cpp',
+        'extensions/hsm.cpp'
     ),
 ]