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/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
new file mode 100644
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,
+};