1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * SCMI performance domain support.
  4 *
  5 * Copyright (C) 2023 Linaro Ltd.
  6 */
  7
  8#include <linux/err.h>
  9#include <linux/device.h>
 10#include <linux/module.h>
 11#include <linux/pm_domain.h>
 12#include <linux/pm_opp.h>
 13#include <linux/scmi_protocol.h>
 14#include <linux/slab.h>
 15
 16struct scmi_perf_domain {
 17	struct generic_pm_domain genpd;
 18	const struct scmi_perf_proto_ops *perf_ops;
 19	const struct scmi_protocol_handle *ph;
 20	const struct scmi_perf_domain_info *info;
 21	u32 domain_id;
 22};
 23
 24#define to_scmi_pd(pd) container_of(pd, struct scmi_perf_domain, genpd)
 25
 26static int
 27scmi_pd_set_perf_state(struct generic_pm_domain *genpd, unsigned int state)
 28{
 29	struct scmi_perf_domain *pd = to_scmi_pd(genpd);
 30	int ret;
 31
 32	if (!pd->info->set_perf)
 33		return 0;
 34
 35	if (!state)
 36		return -EINVAL;
 37
 38	ret = pd->perf_ops->level_set(pd->ph, pd->domain_id, state, false);
 39	if (ret)
 40		dev_warn(&genpd->dev, "Failed with %d when trying to set %d perf level",
 41			 ret, state);
 42
 43	return ret;
 44}
 45
 46static int
 47scmi_pd_attach_dev(struct generic_pm_domain *genpd, struct device *dev)
 48{
 49	struct scmi_perf_domain *pd = to_scmi_pd(genpd);
 50	int ret;
 51
 52	/*
 53	 * Allow the device to be attached, but don't add the OPP table unless
 54	 * the performance level can be changed.
 55	 */
 56	if (!pd->info->set_perf)
 57		return 0;
 58
 59	ret = pd->perf_ops->device_opps_add(pd->ph, dev, pd->domain_id);
 60	if (ret)
 61		dev_warn(dev, "failed to add OPPs for the device\n");
 62
 63	return ret;
 64}
 65
 66static void
 67scmi_pd_detach_dev(struct generic_pm_domain *genpd, struct device *dev)
 68{
 69	struct scmi_perf_domain *pd = to_scmi_pd(genpd);
 70
 71	if (!pd->info->set_perf)
 72		return;
 73
 74	dev_pm_opp_remove_all_dynamic(dev);
 75}
 76
 77static int scmi_perf_domain_probe(struct scmi_device *sdev)
 78{
 79	struct device *dev = &sdev->dev;
 80	const struct scmi_handle *handle = sdev->handle;
 81	const struct scmi_perf_proto_ops *perf_ops;
 82	struct scmi_protocol_handle *ph;
 83	struct scmi_perf_domain *scmi_pd;
 84	struct genpd_onecell_data *scmi_pd_data;
 85	struct generic_pm_domain **domains;
 86	int num_domains, i, ret = 0;
 87
 88	if (!handle)
 89		return -ENODEV;
 90
 91	/* The OF node must specify us as a power-domain provider. */
 92	if (!of_find_property(dev->of_node, "#power-domain-cells", NULL))
 93		return 0;
 94
 95	perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
 96	if (IS_ERR(perf_ops))
 97		return PTR_ERR(perf_ops);
 98
 99	num_domains = perf_ops->num_domains_get(ph);
100	if (num_domains < 0) {
101		dev_warn(dev, "Failed with %d when getting num perf domains\n",
102			 num_domains);
103		return num_domains;
104	} else if (!num_domains) {
105		return 0;
106	}
107
108	scmi_pd = devm_kcalloc(dev, num_domains, sizeof(*scmi_pd), GFP_KERNEL);
109	if (!scmi_pd)
110		return -ENOMEM;
111
112	scmi_pd_data = devm_kzalloc(dev, sizeof(*scmi_pd_data), GFP_KERNEL);
113	if (!scmi_pd_data)
114		return -ENOMEM;
115
116	domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
117	if (!domains)
118		return -ENOMEM;
119
120	for (i = 0; i < num_domains; i++, scmi_pd++) {
121		scmi_pd->info = perf_ops->info_get(ph, i);
122
123		scmi_pd->domain_id = i;
124		scmi_pd->perf_ops = perf_ops;
125		scmi_pd->ph = ph;
126		scmi_pd->genpd.name = scmi_pd->info->name;
127		scmi_pd->genpd.flags = GENPD_FLAG_ALWAYS_ON |
128				       GENPD_FLAG_OPP_TABLE_FW |
129				       GENPD_FLAG_DEV_NAME_FW;
130		scmi_pd->genpd.set_performance_state = scmi_pd_set_perf_state;
131		scmi_pd->genpd.attach_dev = scmi_pd_attach_dev;
132		scmi_pd->genpd.detach_dev = scmi_pd_detach_dev;
133
134		ret = pm_genpd_init(&scmi_pd->genpd, NULL, false);
135		if (ret)
136			goto err;
137
138		domains[i] = &scmi_pd->genpd;
139	}
140
141	scmi_pd_data->domains = domains;
142	scmi_pd_data->num_domains = num_domains;
143
144	ret = of_genpd_add_provider_onecell(dev->of_node, scmi_pd_data);
145	if (ret)
146		goto err;
147
148	dev_set_drvdata(dev, scmi_pd_data);
149	dev_info(dev, "Initialized %d performance domains", num_domains);
150	return 0;
151err:
152	for (i--; i >= 0; i--)
153		pm_genpd_remove(domains[i]);
154	return ret;
155}
156
157static void scmi_perf_domain_remove(struct scmi_device *sdev)
158{
159	struct device *dev = &sdev->dev;
160	struct genpd_onecell_data *scmi_pd_data = dev_get_drvdata(dev);
161	int i;
162
163	if (!scmi_pd_data)
164		return;
165
166	of_genpd_del_provider(dev->of_node);
167
168	for (i = 0; i < scmi_pd_data->num_domains; i++)
169		pm_genpd_remove(scmi_pd_data->domains[i]);
170}
171
172static const struct scmi_device_id scmi_id_table[] = {
173	{ SCMI_PROTOCOL_PERF, "perf" },
174	{ },
175};
176MODULE_DEVICE_TABLE(scmi, scmi_id_table);
177
178static struct scmi_driver scmi_perf_domain_driver = {
179	.name		= "scmi-perf-domain",
180	.probe		= scmi_perf_domain_probe,
181	.remove		= scmi_perf_domain_remove,
182	.id_table	= scmi_id_table,
183};
184module_scmi_driver(scmi_perf_domain_driver);
185
186MODULE_AUTHOR("Ulf Hansson <ulf.hansson@linaro.org>");
187MODULE_DESCRIPTION("ARM SCMI perf domain driver");
188MODULE_LICENSE("GPL v2");