4 files changed, 268 insertions, 0 deletions
diff --git a/drivers/firmware/scmi/Kconfig b/drivers/firmware/scmi/Kconfig
new file mode 100644
index 0000000000..57e2ebbe42
--- /dev/null
+++ b/drivers/firmware/scmi/Kconfig
@@ -0,0 +1,17 @@
+config SCMI_FIRMWARE
+	bool "Enable SCMI support"
+	select FIRMWARE
+	select OF_TRANSLATE
+	depends on SANDBOX
+	help
+	  System Control and Management Interface (SCMI) is a communication
+	  protocol that defines standard interfaces for power, performance
+	  and system management. The SCMI specification is available at
+	  https://developer.arm.com/architectures/system-architectures/software-standards/scmi
+
+	  An SCMI agent communicates with a related SCMI server firmware
+	  located in another sub-system, as a companion micro controller
+	  or a companion host in the CPU system.
+
+	  Communications between agent (client) and the SCMI server are
+	  based on message exchange.
diff --git a/drivers/firmware/scmi/Makefile b/drivers/firmware/scmi/Makefile
new file mode 100644
index 0000000000..336ea1f2a3
--- /dev/null
+++ b/drivers/firmware/scmi/Makefile
@@ -0,0 +1,2 @@
+obj-y	+= scmi_agent-uclass.o
+obj-$(CONFIG_SANDBOX)		+= sandbox-scmi_agent.o
diff --git a/drivers/firmware/scmi/sandbox-scmi_agent.c b/drivers/firmware/scmi/sandbox-scmi_agent.c
new file mode 100644
index 0000000000..3179438aab
--- /dev/null
+++ b/drivers/firmware/scmi/sandbox-scmi_agent.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <malloc.h>
+#include <scmi_agent.h>
+#include <scmi_agent-uclass.h>
+#include <scmi_protocols.h>
+#include <asm/io.h>
+#include <asm/scmi_test.h>
+#include <dm/device_compat.h>
+
+/*
+ * The sandbox SCMI agent driver simulates to some extend a SCMI message
+ * processing. It simulates few of the SCMI services for some of the
+ * SCMI protocols embedded in U-Boot. Currently none.
+ *
+ * This driver simulates 2 SCMI agents for test purpose.
+ *
+ * This Driver exports sandbox_scmi_service_ct() for the test sequence to
+ * get the state of the simulated services (clock state, rate, ...) and
+ * check back-end device state reflects the request send through the
+ * various uclass devices, currently nothing.
+ */
+
+#define SANDBOX_SCMI_AGENT_COUNT	2
+
+/* The list saves to simulted end devices references for test purpose */
+struct sandbox_scmi_agent *sandbox_scmi_agent_list[SANDBOX_SCMI_AGENT_COUNT];
+
+static struct sandbox_scmi_service sandbox_scmi_service_state = {
+	.agent = sandbox_scmi_agent_list,
+	.agent_count = SANDBOX_SCMI_AGENT_COUNT,
+};
+
+struct sandbox_scmi_service *sandbox_scmi_service_ctx(void)
+{
+	return &sandbox_scmi_service_state;
+}
+
+static void debug_print_agent_state(struct udevice *dev, char *str)
+{
+	struct sandbox_scmi_agent *agent = dev_get_priv(dev);
+
+	dev_dbg(dev, "Dump sandbox_scmi_agent %u: %s\n", agent->idx, str);
+};
+
+static int sandbox_scmi_test_process_msg(struct udevice *dev,
+					 struct scmi_msg *msg)
+{
+	switch (msg->protocol_id) {
+	case SCMI_PROTOCOL_ID_BASE:
+	case SCMI_PROTOCOL_ID_POWER_DOMAIN:
+	case SCMI_PROTOCOL_ID_SYSTEM:
+	case SCMI_PROTOCOL_ID_PERF:
+	case SCMI_PROTOCOL_ID_CLOCK:
+	case SCMI_PROTOCOL_ID_SENSOR:
+	case SCMI_PROTOCOL_ID_RESET_DOMAIN:
+		*(u32 *)msg->out_msg = SCMI_NOT_SUPPORTED;
+		return 0;
+	default:
+		break;
+	}
+
+	dev_err(dev, "%s(%s): Unhandled protocol_id %#x/message_id %#x\n",
+		__func__, dev->name, msg->protocol_id, msg->message_id);
+
+	if (msg->out_msg_sz < sizeof(u32))
+		return -EINVAL;
+
+	/* Intentionnaly report unhandled IDs through the SCMI return code */
+	*(u32 *)msg->out_msg = SCMI_PROTOCOL_ERROR;
+	return 0;
+}
+
+static int sandbox_scmi_test_remove(struct udevice *dev)
+{
+	struct sandbox_scmi_agent *agent = dev_get_priv(dev);
+
+	debug_print_agent_state(dev, "removed");
+
+	/* We only need to dereference the agent in the context */
+	sandbox_scmi_service_ctx()->agent[agent->idx] = NULL;
+
+	return 0;
+}
+
+static int sandbox_scmi_test_probe(struct udevice *dev)
+{
+	static const char basename[] = "sandbox-scmi-agent@";
+	struct sandbox_scmi_agent *agent = dev_get_priv(dev);
+	const size_t basename_size = sizeof(basename) - 1;
+
+	if (strncmp(basename, dev->name, basename_size))
+		return -ENOENT;
+
+	switch (dev->name[basename_size]) {
+	case '0':
+		*agent = (struct sandbox_scmi_agent){
+			.idx = 0,
+		};
+		break;
+	case '1':
+		*agent = (struct sandbox_scmi_agent){
+			.idx = 1,
+		};
+		break;
+	default:
+		dev_err(dev, "%s(): Unexpected agent ID %s\n",
+			__func__, dev->name + basename_size);
+		return -ENOENT;
+	}
+
+	debug_print_agent_state(dev, "probed");
+
+	/* Save reference for tests purpose */
+	sandbox_scmi_service_ctx()->agent[agent->idx] = agent;
+
+	return 0;
+};
+
+static const struct udevice_id sandbox_scmi_test_ids[] = {
+	{ .compatible = "sandbox,scmi-agent" },
+	{ }
+};
+
+struct scmi_agent_ops sandbox_scmi_test_ops = {
+	.process_msg = sandbox_scmi_test_process_msg,
+};
+
+U_BOOT_DRIVER(sandbox_scmi_agent) = {
+	.name = "sandbox-scmi_agent",
+	.id = UCLASS_SCMI_AGENT,
+	.of_match = sandbox_scmi_test_ids,
+	.priv_auto_alloc_size = sizeof(struct sandbox_scmi_agent),
+	.probe = sandbox_scmi_test_probe,
+	.remove = sandbox_scmi_test_remove,
+	.ops = &sandbox_scmi_test_ops,
+};
diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
new file mode 100644
index 0000000000..67a6f907c9
--- /dev/null
+++ b/drivers/firmware/scmi/scmi_agent-uclass.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Linaro Limited.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <scmi_agent-uclass.h>
+#include <scmi_protocols.h>
+
+#include <dm/device-internal.h>
+#include <linux/compat.h>
+
+/**
+ * struct error_code - Helper structure for SCMI error code conversion
+ * @scmi:	SCMI error code
+ * @errno:	Related standard error number
+ */
+struct error_code {
+	int scmi;
+	int errno;
+};
+
+static const struct error_code scmi_linux_errmap[] = {
+	{ .scmi = SCMI_NOT_SUPPORTED, .errno = -EOPNOTSUPP, },
+	{ .scmi = SCMI_INVALID_PARAMETERS, .errno = -EINVAL, },
+	{ .scmi = SCMI_DENIED, .errno = -EACCES, },
+	{ .scmi = SCMI_NOT_FOUND, .errno = -ENOENT, },
+	{ .scmi = SCMI_OUT_OF_RANGE, .errno = -ERANGE, },
+	{ .scmi = SCMI_BUSY, .errno = -EBUSY, },
+	{ .scmi = SCMI_COMMS_ERROR, .errno = -ECOMM, },
+	{ .scmi = SCMI_GENERIC_ERROR, .errno = -EIO, },
+	{ .scmi = SCMI_HARDWARE_ERROR, .errno = -EREMOTEIO, },
+	{ .scmi = SCMI_PROTOCOL_ERROR, .errno = -EPROTO, },
+};
+
+int scmi_to_linux_errno(s32 scmi_code)
+{
+	int n;
+
+	if (!scmi_code)
+		return 0;
+
+	for (n = 0; n < ARRAY_SIZE(scmi_linux_errmap); n++)
+		if (scmi_code == scmi_linux_errmap[n].scmi)
+			return scmi_linux_errmap[1].errno;
+
+	return -EPROTO;
+}
+
+/*
+ * SCMI agent devices binds devices of various uclasses depeding on
+ * the FDT description. scmi_bind_protocol() is a generic bind sequence
+ * called by the uclass at bind stage, that is uclass post_bind.
+ */
+static int scmi_bind_protocols(struct udevice *dev)
+{
+	int ret = 0;
+	ofnode node;
+	struct driver *drv;
+
+	dev_for_each_subnode(node, dev) {
+		u32 protocol_id;
+
+		if (!ofnode_is_available(node))
+			continue;
+
+		if (ofnode_read_u32(node, "reg", &protocol_id))
+			continue;
+
+		switch (protocol_id) {
+		default:
+			dev_info(dev, "Ignore unsupported SCMI protocol %#x\n",
+				 protocol_id);
+			continue;
+		}
+
+		ret = device_bind_ofnode(dev, drv, ofnode_get_name(node),
+					 NULL, node, NULL);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static const struct scmi_agent_ops *transport_dev_ops(struct udevice *dev)
+{
+	return (const struct scmi_agent_ops *)dev->driver->ops;
+}
+
+int devm_scmi_process_msg(struct udevice *dev, struct scmi_msg *msg)
+{
+	const struct scmi_agent_ops *ops = transport_dev_ops(dev);
+
+	if (ops->process_msg)
+		return ops->process_msg(dev, msg);
+
+	return -EPROTONOSUPPORT;
+}
+
+UCLASS_DRIVER(scmi_agent) = {
+	.id		= UCLASS_SCMI_AGENT,
+	.name		= "scmi_agent",
+	.post_bind	= scmi_bind_protocols,
+};