/* * Copyright (C) 2010 Google, Inc. * * Author: * Colin Cross * Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that 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. * */ #include #include #include #include #include #include #include static struct cpufreq_frequency_table freq_table[] = { { .frequency = 216000 }, { .frequency = 312000 }, { .frequency = 456000 }, { .frequency = 608000 }, { .frequency = 760000 }, { .frequency = 816000 }, { .frequency = 912000 }, { .frequency = 1000000 }, { .frequency = CPUFREQ_TABLE_END }, }; struct tegra20_cpufreq { struct device *dev; struct cpufreq_driver driver; struct clk *cpu_clk; struct clk *pll_x_clk; struct clk *pll_p_clk; bool pll_x_prepared; }; static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy, unsigned int index) { struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data(); unsigned int ifreq = clk_get_rate(cpufreq->pll_p_clk) / 1000; /* * Don't switch to intermediate freq if: * - we are already at it, i.e. policy->cur == ifreq * - index corresponds to ifreq */ if (freq_table[index].frequency == ifreq || policy->cur == ifreq) return 0; return ifreq; } static int tegra_target_intermediate(struct cpufreq_policy *policy, unsigned int index) { struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data(); int ret; /* * Take an extra reference to the main pll so it doesn't turn * off when we move the cpu off of it as enabling it again while we * switch to it from tegra_target() would take additional time. * * When target-freq is equal to intermediate freq we don't need to * switch to an intermediate freq and so this routine isn't called. * Also, we wouldn't be using pll_x anymore and must not take extra * reference to it, as it can be disabled now to save some power. */ clk_prepare_enable(cpufreq->pll_x_clk); ret = clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_p_clk); if (ret) clk_disable_unprepare(cpufreq->pll_x_clk); else cpufreq->pll_x_prepared = true; return ret; } static int tegra_target(struct cpufreq_policy *policy, unsigned int index) { struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data(); unsigned long rate = freq_table[index].frequency; unsigned int ifreq = clk_get_rate(cpufreq->pll_p_clk) / 1000; int ret; /* * target freq == pll_p, don't need to take extra reference to pll_x_clk * as it isn't used anymore. */ if (rate == ifreq) return clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_p_clk); ret = clk_set_rate(cpufreq->pll_x_clk, rate * 1000); /* Restore to earlier frequency on error, i.e. pll_x */ if (ret) dev_err(cpufreq->dev, "Failed to change pll_x to %lu\n", rate); ret = clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_x_clk); /* This shouldn't fail while changing or restoring */ WARN_ON(ret); /* * Drop count to pll_x clock only if we switched to intermediate freq * earlier while transitioning to a target frequency. */ if (cpufreq->pll_x_prepared) { clk_disable_unprepare(cpufreq->pll_x_clk); cpufreq->pll_x_prepared = false; } return ret; } static int tegra_cpu_init(struct cpufreq_policy *policy) { struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data(); int ret; clk_prepare_enable(cpufreq->cpu_clk); /* FIXME: what's the actual transition time? */ ret = cpufreq_generic_init(policy, freq_table, 300 * 1000); if (ret) { clk_disable_unprepare(cpufreq->cpu_clk); return ret; } policy->clk = cpufreq->cpu_clk; policy->suspend_freq = freq_table[0].frequency; return 0; } static int tegra_cpu_exit(struct cpufreq_policy *policy) { struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data(); clk_disable_unprepare(cpufreq->cpu_clk); return 0; } static int tegra20_cpufreq_probe(struct platform_device *pdev) { struct tegra20_cpufreq *cpufreq; int err; cpufreq = devm_kzalloc(&pdev->dev, sizeof(*cpufreq), GFP_KERNEL); if (!cpufreq) return -ENOMEM; cpufreq->cpu_clk = clk_get_sys(NULL, "cclk"); if (IS_ERR(cpufreq->cpu_clk)) return PTR_ERR(cpufreq->cpu_clk); cpufreq->pll_x_clk = clk_get_sys(NULL, "pll_x"); if (IS_ERR(cpufreq->pll_x_clk)) { err = PTR_ERR(cpufreq->pll_x_clk); goto put_cpu; } cpufreq->pll_p_clk = clk_get_sys(NULL, "pll_p"); if (IS_ERR(cpufreq->pll_p_clk)) { err = PTR_ERR(cpufreq->pll_p_clk); goto put_pll_x; } cpufreq->dev = &pdev->dev; cpufreq->driver.get = cpufreq_generic_get; cpufreq->driver.attr = cpufreq_generic_attr; cpufreq->driver.init = tegra_cpu_init; cpufreq->driver.exit = tegra_cpu_exit; cpufreq->driver.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK; cpufreq->driver.verify = cpufreq_generic_frequency_table_verify; cpufreq->driver.suspend = cpufreq_generic_suspend; cpufreq->driver.driver_data = cpufreq; cpufreq->driver.target_index = tegra_target; cpufreq->driver.get_intermediate = tegra_get_intermediate; cpufreq->driver.target_intermediate = tegra_target_intermediate; snprintf(cpufreq->driver.name, CPUFREQ_NAME_LEN, "tegra"); err = cpufreq_register_driver(&cpufreq->driver); if (err) goto put_pll_p; platform_set_drvdata(pdev, cpufreq); return 0; put_pll_p: clk_put(cpufreq->pll_p_clk); put_pll_x: clk_put(cpufreq->pll_x_clk); put_cpu: clk_put(cpufreq->cpu_clk); return err; } static int tegra20_cpufreq_remove(struct platform_device *pdev) { struct tegra20_cpufreq *cpufreq = platform_get_drvdata(pdev); cpufreq_unregister_driver(&cpufreq->driver); clk_put(cpufreq->pll_p_clk); clk_put(cpufreq->pll_x_clk); clk_put(cpufreq->cpu_clk); return 0; } static struct platform_driver tegra20_cpufreq_driver = { .probe = tegra20_cpufreq_probe, .remove = tegra20_cpufreq_remove, .driver = { .name = "tegra20-cpufreq", }, }; module_platform_driver(tegra20_cpufreq_driver); MODULE_ALIAS("platform:tegra20-cpufreq"); MODULE_AUTHOR("Colin Cross "); MODULE_DESCRIPTION("NVIDIA Tegra20 cpufreq driver"); MODULE_LICENSE("GPL");