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authorSudeep Holla <sudeep.holla@arm.com>2019-07-08 09:41:06 +0100
committerSudeep Holla <sudeep.holla@arm.com>2019-08-12 12:23:02 +0100
commit95a15d80aa0de938299acfcbc6aa6f2b16f5d7e5 (patch)
tree339d10ad126f4c55a8a284443474134f11db7e8d /drivers/firmware/arm_scmi
parentae39913ce4095682d1a6e5734a5558062a59d29f (diff)
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firmware: arm_scmi: Add RESET protocol in SCMI v2.0
SCMIv2.0 adds a new Reset Management Protocol to manage various reset states a given device or domain can enter. Device(s) that can be collectively reset through a common reset signal constitute a reset domain for the firmware. A reset domain can be reset autonomously or explicitly through assertion and de-assertion of the signal. When autonomous reset is chosen, the firmware is responsible for taking the necessary steps to reset the domain and to subsequently bring it out of reset. When explicit reset is chosen, the caller has to specifically assert and then de-assert the reset signal by issuing two separate RESET commands. Add the basic SCMI reset infrastructure that can be used by Linux reset controller driver. Reviewed-by: Peng Fan <peng.fan@nxp.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/firmware/arm_scmi')
-rw-r--r--drivers/firmware/arm_scmi/Makefile2
-rw-r--r--drivers/firmware/arm_scmi/reset.c231
2 files changed, 232 insertions, 1 deletions
diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index c47d28d556b6..5f298f00a82e 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -2,5 +2,5 @@
obj-y = scmi-bus.o scmi-driver.o scmi-protocols.o
scmi-bus-y = bus.o
scmi-driver-y = driver.o
-scmi-protocols-y = base.o clock.o perf.o power.o sensors.o
+scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o
obj-$(CONFIG_ARM_SCMI_POWER_DOMAIN) += scmi_pm_domain.o
diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c
new file mode 100644
index 000000000000..64cc81915581
--- /dev/null
+++ b/drivers/firmware/arm_scmi/reset.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Reset Protocol
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include "common.h"
+
+enum scmi_reset_protocol_cmd {
+ RESET_DOMAIN_ATTRIBUTES = 0x3,
+ RESET = 0x4,
+ RESET_NOTIFY = 0x5,
+};
+
+enum scmi_reset_protocol_notify {
+ RESET_ISSUED = 0x0,
+};
+
+#define NUM_RESET_DOMAIN_MASK 0xffff
+#define RESET_NOTIFY_ENABLE BIT(0)
+
+struct scmi_msg_resp_reset_domain_attributes {
+ __le32 attributes;
+#define SUPPORTS_ASYNC_RESET(x) ((x) & BIT(31))
+#define SUPPORTS_NOTIFY_RESET(x) ((x) & BIT(30))
+ __le32 latency;
+ u8 name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_msg_reset_domain_reset {
+ __le32 domain_id;
+ __le32 flags;
+#define AUTONOMOUS_RESET BIT(0)
+#define EXPLICIT_RESET_ASSERT BIT(1)
+#define ASYNCHRONOUS_RESET BIT(2)
+ __le32 reset_state;
+#define ARCH_RESET_TYPE BIT(31)
+#define COLD_RESET_STATE BIT(0)
+#define ARCH_COLD_RESET (ARCH_RESET_TYPE | COLD_RESET_STATE)
+};
+
+struct reset_dom_info {
+ bool async_reset;
+ bool reset_notify;
+ u32 latency_us;
+ char name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_reset_info {
+ int num_domains;
+ struct reset_dom_info *dom_info;
+};
+
+static int scmi_reset_attributes_get(const struct scmi_handle *handle,
+ struct scmi_reset_info *pi)
+{
+ int ret;
+ struct scmi_xfer *t;
+ u32 attr;
+
+ ret = scmi_xfer_get_init(handle, PROTOCOL_ATTRIBUTES,
+ SCMI_PROTOCOL_RESET, 0, sizeof(attr), &t);
+ if (ret)
+ return ret;
+
+ ret = scmi_do_xfer(handle, t);
+ if (!ret) {
+ attr = get_unaligned_le32(t->rx.buf);
+ pi->num_domains = attr & NUM_RESET_DOMAIN_MASK;
+ }
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int
+scmi_reset_domain_attributes_get(const struct scmi_handle *handle, u32 domain,
+ struct reset_dom_info *dom_info)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct scmi_msg_resp_reset_domain_attributes *attr;
+
+ ret = scmi_xfer_get_init(handle, RESET_DOMAIN_ATTRIBUTES,
+ SCMI_PROTOCOL_RESET, sizeof(domain),
+ sizeof(*attr), &t);
+ if (ret)
+ return ret;
+
+ put_unaligned_le32(domain, t->tx.buf);
+ attr = t->rx.buf;
+
+ ret = scmi_do_xfer(handle, t);
+ if (!ret) {
+ u32 attributes = le32_to_cpu(attr->attributes);
+
+ dom_info->async_reset = SUPPORTS_ASYNC_RESET(attributes);
+ dom_info->reset_notify = SUPPORTS_NOTIFY_RESET(attributes);
+ dom_info->latency_us = le32_to_cpu(attr->latency);
+ if (dom_info->latency_us == U32_MAX)
+ dom_info->latency_us = 0;
+ strlcpy(dom_info->name, attr->name, SCMI_MAX_STR_SIZE);
+ }
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int scmi_reset_num_domains_get(const struct scmi_handle *handle)
+{
+ struct scmi_reset_info *pi = handle->reset_priv;
+
+ return pi->num_domains;
+}
+
+static char *scmi_reset_name_get(const struct scmi_handle *handle, u32 domain)
+{
+ struct scmi_reset_info *pi = handle->reset_priv;
+ struct reset_dom_info *dom = pi->dom_info + domain;
+
+ return dom->name;
+}
+
+static int scmi_reset_latency_get(const struct scmi_handle *handle, u32 domain)
+{
+ struct scmi_reset_info *pi = handle->reset_priv;
+ struct reset_dom_info *dom = pi->dom_info + domain;
+
+ return dom->latency_us;
+}
+
+static int scmi_domain_reset(const struct scmi_handle *handle, u32 domain,
+ u32 flags, u32 state)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct scmi_msg_reset_domain_reset *dom;
+ struct scmi_reset_info *pi = handle->reset_priv;
+ struct reset_dom_info *rdom = pi->dom_info + domain;
+
+ if (rdom->async_reset)
+ flags |= ASYNCHRONOUS_RESET;
+
+ ret = scmi_xfer_get_init(handle, RESET, SCMI_PROTOCOL_RESET,
+ sizeof(*dom), 0, &t);
+ if (ret)
+ return ret;
+
+ dom = t->tx.buf;
+ dom->domain_id = cpu_to_le32(domain);
+ dom->flags = cpu_to_le32(flags);
+ dom->domain_id = cpu_to_le32(state);
+
+ if (rdom->async_reset)
+ ret = scmi_do_xfer_with_response(handle, t);
+ else
+ ret = scmi_do_xfer(handle, t);
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int scmi_reset_domain_reset(const struct scmi_handle *handle, u32 domain)
+{
+ return scmi_domain_reset(handle, domain, AUTONOMOUS_RESET,
+ ARCH_COLD_RESET);
+}
+
+static int
+scmi_reset_domain_assert(const struct scmi_handle *handle, u32 domain)
+{
+ return scmi_domain_reset(handle, domain, EXPLICIT_RESET_ASSERT,
+ ARCH_COLD_RESET);
+}
+
+static int
+scmi_reset_domain_deassert(const struct scmi_handle *handle, u32 domain)
+{
+ return scmi_domain_reset(handle, domain, 0, ARCH_COLD_RESET);
+}
+
+static struct scmi_reset_ops reset_ops = {
+ .num_domains_get = scmi_reset_num_domains_get,
+ .name_get = scmi_reset_name_get,
+ .latency_get = scmi_reset_latency_get,
+ .reset = scmi_reset_domain_reset,
+ .assert = scmi_reset_domain_assert,
+ .deassert = scmi_reset_domain_deassert,
+};
+
+static int scmi_reset_protocol_init(struct scmi_handle *handle)
+{
+ int domain;
+ u32 version;
+ struct scmi_reset_info *pinfo;
+
+ scmi_version_get(handle, SCMI_PROTOCOL_RESET, &version);
+
+ dev_dbg(handle->dev, "Reset Version %d.%d\n",
+ PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+ pinfo = devm_kzalloc(handle->dev, sizeof(*pinfo), GFP_KERNEL);
+ if (!pinfo)
+ return -ENOMEM;
+
+ scmi_reset_attributes_get(handle, pinfo);
+
+ pinfo->dom_info = devm_kcalloc(handle->dev, pinfo->num_domains,
+ sizeof(*pinfo->dom_info), GFP_KERNEL);
+ if (!pinfo->dom_info)
+ return -ENOMEM;
+
+ for (domain = 0; domain < pinfo->num_domains; domain++) {
+ struct reset_dom_info *dom = pinfo->dom_info + domain;
+
+ scmi_reset_domain_attributes_get(handle, domain, dom);
+ }
+
+ handle->reset_ops = &reset_ops;
+ handle->reset_priv = pinfo;
+
+ return 0;
+}
+
+static int __init scmi_reset_init(void)
+{
+ return scmi_protocol_register(SCMI_PROTOCOL_RESET,
+ &scmi_reset_protocol_init);
+}
+subsys_initcall(scmi_reset_init);