reset: add reset controller driver for SCMI agents

This change introduces a reset controller driver for SCMI agent devices.
When SCMI agent and SCMI reset domain drivers are enabled, SCMI agent
binds a reset controller device for each SCMI reset domain protocol
devices enabled in the FDT.

SCMI reset driver is embedded upon CONFIG_RESET_SCMI=y. If enabled,
CONFIG_SCMI_AGENT is also enabled.

SCMI Reset Domain protocol is defined in the SCMI specification [1].

Links: [1] https://developer.arm.com/architectures/system-architectures/software-standards/scmi
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
index 1f36f23..77160b1 100644 (file)
--- a/drivers/firmware/scmi/scmi_agent-uclass.c
+++ b/drivers/firmware/scmi/scmi_agent-uclass.c
@@ -74,6 +74,10 @@ static int scmi_bind_protocols(struct udevice *dev)
                        if (IS_ENABLED(CONFIG_CLK_SCMI))
                                drv = DM_GET_DRIVER(scmi_clock);
                        break;
+               case SCMI_PROTOCOL_ID_RESET_DOMAIN:
+                       if (IS_ENABLED(CONFIG_RESET_SCMI))
+                               drv = DM_GET_DRIVER(scmi_reset_domain);
+                       break;
                default:
                        break;
                }

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 3fdfe4a..b60e11f 100644 (file)
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -181,4 +181,12 @@ config RESET_RASPBERRYPI
          relevant. This driver provides a reset controller capable of
          interfacing with RPi4's co-processor and model these firmware
          initialization routines as reset lines.
+
+config RESET_SCMI
+       bool "Enable SCMI reset domain driver"
+       select SCMI_FIRMWARE
+       help
+         Enable this option if you want to support reset controller
+         devices exposed by a SCMI agent based on SCMI reset domain
+         protocol communication with a SCMI server.
 endmenu

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 5176da5..10a7973 100644 (file)
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -27,3 +27,4 @@ obj-$(CONFIG_RESET_IPQ419) += reset-ipq4019.o
 obj-$(CONFIG_RESET_SIFIVE) += reset-sifive.o
 obj-$(CONFIG_RESET_SYSCON) += reset-syscon.o
 obj-$(CONFIG_RESET_RASPBERRYPI) += reset-raspberrypi.o
+obj-$(CONFIG_RESET_SCMI) += reset-scmi.o

diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
new file mode 100644 (file)
index 0000000..1bff807
--- /dev/null
+++ b/drivers/reset/reset-scmi.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019-2020 Linaro Limited
+ */
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <reset-uclass.h>
+#include <scmi_agent.h>
+#include <scmi_protocols.h>
+#include <asm/types.h>
+
+static int scmi_reset_set_level(struct reset_ctl *rst, bool assert_not_deassert)
+{
+       struct scmi_rd_reset_in in = {
+               .domain_id = rst->id,
+               .flags = assert_not_deassert ? SCMI_RD_RESET_FLAG_ASSERT : 0,
+               .reset_state = 0,
+       };
+       struct scmi_rd_reset_out out;
+       struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_RESET_DOMAIN,
+                                         SCMI_RESET_DOMAIN_RESET,
+                                         in, out);
+       int ret;
+
+       ret = devm_scmi_process_msg(rst->dev->parent, &msg);
+       if (ret)
+               return ret;
+
+       return scmi_to_linux_errno(out.status);
+}
+
+static int scmi_reset_assert(struct reset_ctl *rst)
+{
+       return scmi_reset_set_level(rst, true);
+}
+
+static int scmi_reset_deassert(struct reset_ctl *rst)
+{
+       return scmi_reset_set_level(rst, false);
+}
+
+static int scmi_reset_request(struct reset_ctl *rst)
+{
+       struct scmi_rd_attr_in in = {
+               .domain_id = rst->id,
+       };
+       struct scmi_rd_attr_out out;
+       struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_RESET_DOMAIN,
+                                         SCMI_RESET_DOMAIN_ATTRIBUTES,
+                                         in, out);
+       int ret;
+
+       /*
+        * We don't really care about the attribute, just check
+        * the reset domain exists.
+        */
+       ret = devm_scmi_process_msg(rst->dev->parent, &msg);
+       if (ret)
+               return ret;
+
+       return scmi_to_linux_errno(out.status);
+}
+
+static int scmi_reset_rfree(struct reset_ctl *rst)
+{
+       return 0;
+}
+
+static const struct reset_ops scmi_reset_domain_ops = {
+       .request        = scmi_reset_request,
+       .rfree          = scmi_reset_rfree,
+       .rst_assert     = scmi_reset_assert,
+       .rst_deassert   = scmi_reset_deassert,
+};
+
+U_BOOT_DRIVER(scmi_reset_domain) = {
+       .name = "scmi_reset_domain",
+       .id = UCLASS_RESET,
+       .ops = &scmi_reset_domain_ops,
+};

diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
index 4778bcf..ccab97c 100644 (file)
--- a/include/scmi_protocols.h
+++ b/include/scmi_protocols.h
@@ -116,4 +116,64 @@ struct scmi_clk_rate_set_out {
        s32 status;
 };
 
+/*
+ * SCMI Reset Domain Protocol
+ */
+
+enum scmi_reset_domain_message_id {
+       SCMI_RESET_DOMAIN_ATTRIBUTES = 0x3,
+       SCMI_RESET_DOMAIN_RESET = 0x4,
+};
+
+#define SCMI_RD_NAME_LEN               16
+
+#define SCMI_RD_ATTRIBUTES_FLAG_ASYNC  BIT(31)
+#define SCMI_RD_ATTRIBUTES_FLAG_NOTIF  BIT(30)
+
+#define SCMI_RD_RESET_FLAG_ASYNC       BIT(2)
+#define SCMI_RD_RESET_FLAG_ASSERT      BIT(1)
+#define SCMI_RD_RESET_FLAG_CYCLE       BIT(0)
+
+/**
+ * struct scmi_rd_attr_in - Payload for RESET_DOMAIN_ATTRIBUTES message
+ * @domain_id: SCMI reset domain ID
+ */
+struct scmi_rd_attr_in {
+       u32 domain_id;
+};
+
+/**
+ * struct scmi_rd_attr_out - Payload for RESET_DOMAIN_ATTRIBUTES response
+ * @status:    SCMI command status
+ * @attributes:        Retrieved attributes of the reset domain
+ * @latency:   Reset cycle max lantency
+ * @name:      Reset domain name
+ */
+struct scmi_rd_attr_out {
+       s32 status;
+       u32 attributes;
+       u32 latency;
+       char name[SCMI_RD_NAME_LEN];
+};
+
+/**
+ * struct scmi_rd_reset_in - Message payload for RESET command
+ * @domain_id:         SCMI reset domain ID
+ * @flags:             Flags for the reset request
+ * @reset_state:       Reset target state
+ */
+struct scmi_rd_reset_in {
+       u32 domain_id;
+       u32 flags;
+       u32 reset_state;
+};
+
+/**
+ * struct scmi_rd_reset_out - Response payload for RESET command
+ * @status:    SCMI command status
+ */
+struct scmi_rd_reset_out {
+       s32 status;
+};
+
 #endif /* _SCMI_PROTOCOLS_H */