i2c: begin skeleton device driver framework

libraries/libstratosphere/source/i2c/i2c_client_api.cpp

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::i2c {
+
+    namespace {
+
+        constinit os::SdkMutex g_init_mutex;
+        constinit int g_initialize_count = 0;
+
+        constinit os::SdkMutex g_i2c_mutex;
+        std::shared_ptr<sf::IManager> g_i2c_manager;
+        constinit int g_i2c_count = 0;
+
+        constinit os::SdkMutex g_i2c_pcv_mutex;
+        std::shared_ptr<sf::IManager> g_i2c_pcv_manager;
+        constinit int g_i2c_pcv_count = 0;
+
+    }
+
+    void InitializeWith(std::shared_ptr<i2c::sf::IManager> &&sp, std::shared_ptr<i2c::sf::IManager> &&sp_pcv) {
+        std::scoped_lock lk(g_init_mutex);
+
+        AMS_ABORT_UNLESS(g_initialize_count == 0);
+
+        {
+            std::scoped_lock lk(g_i2c_mutex);
+            g_i2c_manager = std::move(sp);
+            AMS_ABORT_UNLESS(g_i2c_count == 0);
+            g_i2c_count = 1;
+        }
+
+        {
+            std::scoped_lock lk(g_i2c_pcv_mutex);
+            g_i2c_pcv_manager = std::move(sp);
+            AMS_ABORT_UNLESS(g_i2c_pcv_count == 0);
+            g_i2c_pcv_count = 1;
+        }
+
+        g_initialize_count = 1;
+    }
+
+    void InitializeEmpty() {
+        std::scoped_lock lk(g_init_mutex);
+
+        ++g_initialize_count;
+    }
+
+    void Finalize() {
+        std::scoped_lock lk(g_init_mutex);
+
+        AMS_ASSERT(g_initialize_count > 0);
+
+        if ((--g_initialize_count) == 0) {
+            {
+                std::scoped_lock lk(g_i2c_mutex);
+                AMS_ASSERT(g_i2c_count > 0);
+                if ((--g_i2c_count) == 0) {
+                    g_i2c_manager.reset();
+                }
+            }
+            {
+                std::scoped_lock lk(g_i2c_pcv_mutex);
+                AMS_ASSERT(g_i2c_pcv_count > 0);
+                if ((--g_i2c_pcv_count) == 0) {
+                    g_i2c_pcv_manager.reset();
+                }
+            }
+        }
+    }
+
+}