linux/drivers/firmware/arm_scmi/reset.c

// 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 {
	u32 version;
	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->reset_state = 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);
	}

	pinfo->version = version;
	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);