diff options
Diffstat (limited to 'drivers/firmware/scpi_pm_domain.c')
| -rw-r--r-- | drivers/firmware/scpi_pm_domain.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/firmware/scpi_pm_domain.c b/drivers/firmware/scpi_pm_domain.c new file mode 100644 index 000000000000..f395dec27113 --- /dev/null +++ b/drivers/firmware/scpi_pm_domain.c @@ -0,0 +1,163 @@ +/* + * SCPI Generic power domain support. + * + * Copyright (C) 2016 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along + * with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/err.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/pm_domain.h> +#include <linux/scpi_protocol.h> + +struct scpi_pm_domain { + struct generic_pm_domain genpd; + struct scpi_ops *ops; + u32 domain; + char name[30]; +}; + +/* + * These device power state values are not well-defined in the specification. + * In case, different implementations use different values, we can make these + * specific to compatibles rather than getting these values from device tree. + */ +enum scpi_power_domain_state { + SCPI_PD_STATE_ON = 0, + SCPI_PD_STATE_OFF = 3, +}; + +#define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd) + +static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on) +{ + int ret; + enum scpi_power_domain_state state; + + if (power_on) + state = SCPI_PD_STATE_ON; + else + state = SCPI_PD_STATE_OFF; + + ret = pd->ops->device_set_power_state(pd->domain, state); + if (ret) + return ret; + + return !(state == pd->ops->device_get_power_state(pd->domain)); +} + +static int scpi_pd_power_on(struct generic_pm_domain *domain) +{ + struct scpi_pm_domain *pd = to_scpi_pd(domain); + + return scpi_pd_power(pd, true); +} + +static int scpi_pd_power_off(struct generic_pm_domain *domain) +{ + struct scpi_pm_domain *pd = to_scpi_pd(domain); + + return scpi_pd_power(pd, false); +} + +static int scpi_pm_domain_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct scpi_pm_domain *scpi_pd; + struct genpd_onecell_data *scpi_pd_data; + struct generic_pm_domain **domains; + struct scpi_ops *scpi_ops; + int ret, num_domains, i; + + scpi_ops = get_scpi_ops(); + if (!scpi_ops) + return -EPROBE_DEFER; + + if (!np) { + dev_err(dev, "device tree node not found\n"); + return -ENODEV; + } + + if (!scpi_ops->device_set_power_state || + !scpi_ops->device_get_power_state) { + dev_err(dev, "power domains not supported in the firmware\n"); + return -ENODEV; + } + + ret = of_property_read_u32(np, "num-domains", &num_domains); + if (ret) { + dev_err(dev, "number of domains not found\n"); + return -EINVAL; + } + + scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL); + if (!scpi_pd) + return -ENOMEM; + + scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL); + if (!scpi_pd_data) + return -ENOMEM; + + domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL); + if (!domains) + return -ENOMEM; + + for (i = 0; i < num_domains; i++, scpi_pd++) { + domains[i] = &scpi_pd->genpd; + + scpi_pd->domain = i; + scpi_pd->ops = scpi_ops; + sprintf(scpi_pd->name, "%s.%d", np->name, i); + scpi_pd->genpd.name = scpi_pd->name; + scpi_pd->genpd.power_off = scpi_pd_power_off; + scpi_pd->genpd.power_on = scpi_pd_power_on; + + /* + * Treat all power domains as off at boot. + * + * The SCP firmware itself may have switched on some domains, + * but for reference counting purpose, keep it this way. + */ + pm_genpd_init(&scpi_pd->genpd, NULL, true); + } + + scpi_pd_data->domains = domains; + scpi_pd_data->num_domains = num_domains; + + of_genpd_add_provider_onecell(np, scpi_pd_data); + + return 0; +} + +static const struct of_device_id scpi_power_domain_ids[] = { + { .compatible = "arm,scpi-power-domains", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, scpi_power_domain_ids); + +static struct platform_driver scpi_power_domain_driver = { + .driver = { + .name = "scpi_power_domain", + .of_match_table = scpi_power_domain_ids, + }, + .probe = scpi_pm_domain_probe, +}; +module_platform_driver(scpi_power_domain_driver); + +MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); +MODULE_DESCRIPTION("ARM SCPI power domain driver"); +MODULE_LICENSE("GPL v2"); |