157 lines
3.8 KiB
C
157 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* SCPI Generic power domain support.
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*
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* Copyright (C) 2016 ARM Ltd.
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*/
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/pm_domain.h>
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#include <linux/scpi_protocol.h>
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struct scpi_pm_domain {
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struct generic_pm_domain genpd;
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struct scpi_ops *ops;
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u32 domain;
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};
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/*
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* These device power state values are not well-defined in the specification.
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* In case, different implementations use different values, we can make these
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* specific to compatibles rather than getting these values from device tree.
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*/
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enum scpi_power_domain_state {
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SCPI_PD_STATE_ON = 0,
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SCPI_PD_STATE_OFF = 3,
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};
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#define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd)
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static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on)
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{
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int ret;
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enum scpi_power_domain_state state;
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if (power_on)
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state = SCPI_PD_STATE_ON;
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else
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state = SCPI_PD_STATE_OFF;
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ret = pd->ops->device_set_power_state(pd->domain, state);
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if (ret)
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return ret;
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return !(state == pd->ops->device_get_power_state(pd->domain));
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}
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static int scpi_pd_power_on(struct generic_pm_domain *domain)
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{
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struct scpi_pm_domain *pd = to_scpi_pd(domain);
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return scpi_pd_power(pd, true);
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}
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static int scpi_pd_power_off(struct generic_pm_domain *domain)
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{
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struct scpi_pm_domain *pd = to_scpi_pd(domain);
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return scpi_pd_power(pd, false);
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}
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static int scpi_pm_domain_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct scpi_pm_domain *scpi_pd;
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struct genpd_onecell_data *scpi_pd_data;
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struct generic_pm_domain **domains;
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struct scpi_ops *scpi_ops;
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int ret, num_domains, i;
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scpi_ops = get_scpi_ops();
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if (!scpi_ops)
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return -EPROBE_DEFER;
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if (!np) {
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dev_err(dev, "device tree node not found\n");
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return -ENODEV;
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}
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if (!scpi_ops->device_set_power_state ||
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!scpi_ops->device_get_power_state) {
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dev_err(dev, "power domains not supported in the firmware\n");
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return -ENODEV;
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}
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ret = of_property_read_u32(np, "num-domains", &num_domains);
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if (ret) {
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dev_err(dev, "number of domains not found\n");
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return -EINVAL;
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}
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scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL);
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if (!scpi_pd)
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return -ENOMEM;
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scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL);
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if (!scpi_pd_data)
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return -ENOMEM;
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domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
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if (!domains)
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return -ENOMEM;
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for (i = 0; i < num_domains; i++, scpi_pd++) {
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domains[i] = &scpi_pd->genpd;
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scpi_pd->domain = i;
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scpi_pd->ops = scpi_ops;
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scpi_pd->genpd.name = devm_kasprintf(dev, GFP_KERNEL,
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"%pOFn.%d", np, i);
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if (!scpi_pd->genpd.name) {
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dev_err(dev, "Failed to allocate genpd name:%pOFn.%d\n",
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np, i);
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continue;
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}
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scpi_pd->genpd.power_off = scpi_pd_power_off;
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scpi_pd->genpd.power_on = scpi_pd_power_on;
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/*
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* Treat all power domains as off at boot.
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*
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* The SCP firmware itself may have switched on some domains,
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* but for reference counting purpose, keep it this way.
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*/
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pm_genpd_init(&scpi_pd->genpd, NULL, true);
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}
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scpi_pd_data->domains = domains;
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scpi_pd_data->num_domains = num_domains;
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of_genpd_add_provider_onecell(np, scpi_pd_data);
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return 0;
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}
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static const struct of_device_id scpi_power_domain_ids[] = {
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{ .compatible = "arm,scpi-power-domains", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, scpi_power_domain_ids);
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static struct platform_driver scpi_power_domain_driver = {
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.driver = {
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.name = "scpi_power_domain",
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.of_match_table = scpi_power_domain_ids,
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},
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.probe = scpi_pm_domain_probe,
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};
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module_platform_driver(scpi_power_domain_driver);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCPI power domain driver");
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MODULE_LICENSE("GPL v2");
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