cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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scpi_pm_domain.c (3879B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * SCPI Generic power domain support.
      4 *
      5 * Copyright (C) 2016 ARM Ltd.
      6 */
      7
      8#include <linux/err.h>
      9#include <linux/io.h>
     10#include <linux/module.h>
     11#include <linux/of_platform.h>
     12#include <linux/pm_domain.h>
     13#include <linux/scpi_protocol.h>
     14
     15struct scpi_pm_domain {
     16	struct generic_pm_domain genpd;
     17	struct scpi_ops *ops;
     18	u32 domain;
     19};
     20
     21/*
     22 * These device power state values are not well-defined in the specification.
     23 * In case, different implementations use different values, we can make these
     24 * specific to compatibles rather than getting these values from device tree.
     25 */
     26enum scpi_power_domain_state {
     27	SCPI_PD_STATE_ON = 0,
     28	SCPI_PD_STATE_OFF = 3,
     29};
     30
     31#define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd)
     32
     33static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on)
     34{
     35	int ret;
     36	enum scpi_power_domain_state state;
     37
     38	if (power_on)
     39		state = SCPI_PD_STATE_ON;
     40	else
     41		state = SCPI_PD_STATE_OFF;
     42
     43	ret = pd->ops->device_set_power_state(pd->domain, state);
     44	if (ret)
     45		return ret;
     46
     47	return !(state == pd->ops->device_get_power_state(pd->domain));
     48}
     49
     50static int scpi_pd_power_on(struct generic_pm_domain *domain)
     51{
     52	struct scpi_pm_domain *pd = to_scpi_pd(domain);
     53
     54	return scpi_pd_power(pd, true);
     55}
     56
     57static int scpi_pd_power_off(struct generic_pm_domain *domain)
     58{
     59	struct scpi_pm_domain *pd = to_scpi_pd(domain);
     60
     61	return scpi_pd_power(pd, false);
     62}
     63
     64static int scpi_pm_domain_probe(struct platform_device *pdev)
     65{
     66	struct device *dev = &pdev->dev;
     67	struct device_node *np = dev->of_node;
     68	struct scpi_pm_domain *scpi_pd;
     69	struct genpd_onecell_data *scpi_pd_data;
     70	struct generic_pm_domain **domains;
     71	struct scpi_ops *scpi_ops;
     72	int ret, num_domains, i;
     73
     74	scpi_ops = get_scpi_ops();
     75	if (!scpi_ops)
     76		return -EPROBE_DEFER;
     77
     78	if (!np) {
     79		dev_err(dev, "device tree node not found\n");
     80		return -ENODEV;
     81	}
     82
     83	if (!scpi_ops->device_set_power_state ||
     84	    !scpi_ops->device_get_power_state) {
     85		dev_err(dev, "power domains not supported in the firmware\n");
     86		return -ENODEV;
     87	}
     88
     89	ret = of_property_read_u32(np, "num-domains", &num_domains);
     90	if (ret) {
     91		dev_err(dev, "number of domains not found\n");
     92		return -EINVAL;
     93	}
     94
     95	scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL);
     96	if (!scpi_pd)
     97		return -ENOMEM;
     98
     99	scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL);
    100	if (!scpi_pd_data)
    101		return -ENOMEM;
    102
    103	domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
    104	if (!domains)
    105		return -ENOMEM;
    106
    107	for (i = 0; i < num_domains; i++, scpi_pd++) {
    108		domains[i] = &scpi_pd->genpd;
    109
    110		scpi_pd->domain = i;
    111		scpi_pd->ops = scpi_ops;
    112		scpi_pd->genpd.name = devm_kasprintf(dev, GFP_KERNEL,
    113						     "%pOFn.%d", np, i);
    114		if (!scpi_pd->genpd.name) {
    115			dev_err(dev, "Failed to allocate genpd name:%pOFn.%d\n",
    116				np, i);
    117			continue;
    118		}
    119		scpi_pd->genpd.power_off = scpi_pd_power_off;
    120		scpi_pd->genpd.power_on = scpi_pd_power_on;
    121
    122		/*
    123		 * Treat all power domains as off at boot.
    124		 *
    125		 * The SCP firmware itself may have switched on some domains,
    126		 * but for reference counting purpose, keep it this way.
    127		 */
    128		pm_genpd_init(&scpi_pd->genpd, NULL, true);
    129	}
    130
    131	scpi_pd_data->domains = domains;
    132	scpi_pd_data->num_domains = num_domains;
    133
    134	of_genpd_add_provider_onecell(np, scpi_pd_data);
    135
    136	return 0;
    137}
    138
    139static const struct of_device_id scpi_power_domain_ids[] = {
    140	{ .compatible = "arm,scpi-power-domains", },
    141	{ /* sentinel */ }
    142};
    143MODULE_DEVICE_TABLE(of, scpi_power_domain_ids);
    144
    145static struct platform_driver scpi_power_domain_driver = {
    146	.driver	= {
    147		.name = "scpi_power_domain",
    148		.of_match_table = scpi_power_domain_ids,
    149	},
    150	.probe = scpi_pm_domain_probe,
    151};
    152module_platform_driver(scpi_power_domain_driver);
    153
    154MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
    155MODULE_DESCRIPTION("ARM SCPI power domain driver");
    156MODULE_LICENSE("GPL v2");