[PATCH v2 08/34] media: iris: introduce state machine for iris core

[Dikshita Agarwal]

Introduces different states for core. State transitions
are defined, based on which they would be allowed/rejected/ignored.

IRIS_CORE_DEINIT - default state.
IRIS_CORE_INIT_WAIT -  wait state for video core to complete
initialization.
IRIS_CORE_INIT - core state with core initialized. FW loaded and
HW brought out of reset, shared queues established between host
driver and firmware.
IRIS_CORE_ERROR - error state.

            |
            v
       -----------
  +--->| DEINIT  |<---+
  |    -----------    |
  |         |         |
  |         v         |
  |    -----------    |
  |    |INIT_WAIT|    |
  |    -----------    |
  |      /     \      |
  |     /       \     |
  |    /         \    |
  |   v           v   v
 -----------   ----------.
 |  INIT   |-->|  ERROR |
 -----------   ----------.

Signed-off-by: Dikshita Agarwal <quic_dikshita@xxxxxxxxxxx>
---
 drivers/media/platform/qcom/vcodec/iris/Makefile   |  3 +-
 .../media/platform/qcom/vcodec/iris/iris_core.h    |  4 ++
 .../media/platform/qcom/vcodec/iris/iris_state.c   | 64 ++++++++++++++++++++++
 .../media/platform/qcom/vcodec/iris/iris_state.h   | 22 ++++++++
 4 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 drivers/media/platform/qcom/vcodec/iris/iris_state.c
 create mode 100644 drivers/media/platform/qcom/vcodec/iris/iris_state.h

diff --git a/drivers/media/platform/qcom/vcodec/iris/Makefile b/drivers/media/platform/qcom/vcodec/iris/Makefile
index 0748819..12a74de 100644
--- a/drivers/media/platform/qcom/vcodec/iris/Makefile
+++ b/drivers/media/platform/qcom/vcodec/iris/Makefile
@@ -1,4 +1,5 @@
 iris-objs += iris_probe.o \
-             resources.o
+             resources.o \
+             iris_state.o
 
 obj-$(CONFIG_VIDEO_QCOM_IRIS) += iris.o
diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_core.h b/drivers/media/platform/qcom/vcodec/iris/iris_core.h
index c2bc95d..56a5b7d 100644
--- a/drivers/media/platform/qcom/vcodec/iris/iris_core.h
+++ b/drivers/media/platform/qcom/vcodec/iris/iris_core.h
@@ -9,6 +9,8 @@
 #include <linux/types.h>
 #include <media/v4l2-device.h>
 
+#include "iris_state.h"
+
 /**
  * struct iris_core - holds core parameters valid for all instances
  *
@@ -27,6 +29,7 @@
  * @clk_count: count of iris clocks
  * @reset_tbl: table of iris reset clocks
  * @reset_count: count of iris reset clocks
+ * @state: current state of core
  */
 
 struct iris_core {
@@ -45,6 +48,7 @@ struct iris_core {
 	u32					clk_count;
 	struct reset_info			*reset_tbl;
 	u32					reset_count;
+	enum iris_core_state			state;
 };
 
 #endif
diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_state.c b/drivers/media/platform/qcom/vcodec/iris/iris_state.c
new file mode 100644
index 0000000..22557af
--- /dev/null
+++ b/drivers/media/platform/qcom/vcodec/iris/iris_state.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include "iris_core.h"
+#include "iris_state.h"
+
+#define IRIS_STATE(name)[IRIS_CORE_##name] = "CORE_"#name
+
+static const char * const core_state_names[] = {
+	IRIS_STATE(DEINIT),
+	IRIS_STATE(INIT_WAIT),
+	IRIS_STATE(INIT),
+	IRIS_STATE(ERROR),
+};
+
+#undef IRIS_STATE
+
+bool core_in_valid_state(struct iris_core *core)
+{
+	return core->state == IRIS_CORE_INIT ||
+		core->state == IRIS_CORE_INIT_WAIT;
+}
+
+static const char *core_state_name(enum iris_core_state state)
+{
+	if ((unsigned int)state < ARRAY_SIZE(core_state_names))
+		return core_state_names[state];
+
+	return "UNKNOWN_STATE";
+}
+
+static bool iris_allow_core_state_change(struct iris_core *core,
+					 enum iris_core_state req_state)
+{
+	if (core->state == IRIS_CORE_DEINIT)
+		return req_state == IRIS_CORE_INIT_WAIT || req_state == IRIS_CORE_ERROR;
+	else if (core->state == IRIS_CORE_INIT_WAIT)
+		return req_state == IRIS_CORE_INIT || req_state == IRIS_CORE_ERROR;
+	else if (core->state == IRIS_CORE_INIT)
+		return req_state == IRIS_CORE_DEINIT || req_state == IRIS_CORE_ERROR;
+	else if (core->state == IRIS_CORE_ERROR)
+		return req_state == IRIS_CORE_DEINIT;
+
+	dev_warn(core->dev, "core state change %s -> %s is not allowed\n",
+		 core_state_name(core->state), core_state_name(req_state));
+
+	return false;
+}
+
+int iris_change_core_state(struct iris_core *core,
+			   enum iris_core_state request_state)
+{
+	if (core->state == request_state)
+		return 0;
+
+	if (!iris_allow_core_state_change(core, request_state))
+		return -EINVAL;
+
+	core->state = request_state;
+
+	return 0;
+}
diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_state.h b/drivers/media/platform/qcom/vcodec/iris/iris_state.h
new file mode 100644
index 0000000..ee20842
--- /dev/null
+++ b/drivers/media/platform/qcom/vcodec/iris/iris_state.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _IRIS_STATE_H_
+#define _IRIS_STATE_H_
+
+struct iris_core;
+
+enum iris_core_state {
+	IRIS_CORE_DEINIT,
+	IRIS_CORE_INIT_WAIT,
+	IRIS_CORE_INIT,
+	IRIS_CORE_ERROR,
+};
+
+bool core_in_valid_state(struct iris_core *core);
+int iris_change_core_state(struct iris_core *core,
+			   enum iris_core_state request_state);
+
+#endif
-- 
2.7.4