+++ /dev/null
-/*
- * Copyright (C) 2010 Google, Inc.
- *
- * Author:
- * Colin Cross <ccross@google.com>
- * 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 <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/types.h>
-#include <linux/sched.h>
-#include <linux/cpufreq.h>
-#include <linux/delay.h>
-#include <linux/init.h>
-#include <linux/err.h>
-#include <linux/clk.h>
-#include <linux/io.h>
-
-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 },
-};
-
-#define NUM_CPUS 2
-
-static struct clk *cpu_clk;
-static struct clk *pll_x_clk;
-static struct clk *pll_p_clk;
-static struct clk *emc_clk;
-static bool pll_x_prepared;
-
-static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy,
- unsigned int index)
-{
- unsigned int ifreq = clk_get_rate(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)
-{
- 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(pll_x_clk);
-
- ret = clk_set_parent(cpu_clk, pll_p_clk);
- if (ret)
- clk_disable_unprepare(pll_x_clk);
- else
- pll_x_prepared = true;
-
- return ret;
-}
-
-static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
-{
- unsigned long rate = freq_table[index].frequency;
- unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
- int ret = 0;
-
- /*
- * Vote on memory bus frequency based on cpu frequency
- * This sets the minimum frequency, display or avp may request higher
- */
- if (rate >= 816000)
- clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
- else if (rate >= 456000)
- clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
- else
- clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
-
- /*
- * 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(cpu_clk, pll_p_clk);
-
- ret = clk_set_rate(pll_x_clk, rate * 1000);
- /* Restore to earlier frequency on error, i.e. pll_x */
- if (ret)
- pr_err("Failed to change pll_x to %lu\n", rate);
-
- ret = clk_set_parent(cpu_clk, 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 (pll_x_prepared) {
- clk_disable_unprepare(pll_x_clk);
- pll_x_prepared = false;
- }
-
- return ret;
-}
-
-static int tegra_cpu_init(struct cpufreq_policy *policy)
-{
- int ret;
-
- if (policy->cpu >= NUM_CPUS)
- return -EINVAL;
-
- clk_prepare_enable(emc_clk);
- clk_prepare_enable(cpu_clk);
-
- /* FIXME: what's the actual transition time? */
- ret = cpufreq_generic_init(policy, freq_table, 300 * 1000);
- if (ret) {
- clk_disable_unprepare(cpu_clk);
- clk_disable_unprepare(emc_clk);
- return ret;
- }
-
- policy->clk = cpu_clk;
- policy->suspend_freq = freq_table[0].frequency;
- return 0;
-}
-
-static int tegra_cpu_exit(struct cpufreq_policy *policy)
-{
- clk_disable_unprepare(cpu_clk);
- clk_disable_unprepare(emc_clk);
- return 0;
-}
-
-static struct cpufreq_driver tegra_cpufreq_driver = {
- .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
- .verify = cpufreq_generic_frequency_table_verify,
- .get_intermediate = tegra_get_intermediate,
- .target_intermediate = tegra_target_intermediate,
- .target_index = tegra_target,
- .get = cpufreq_generic_get,
- .init = tegra_cpu_init,
- .exit = tegra_cpu_exit,
- .name = "tegra",
- .attr = cpufreq_generic_attr,
-#ifdef CONFIG_PM
- .suspend = cpufreq_generic_suspend,
-#endif
-};
-
-static int __init tegra_cpufreq_init(void)
-{
- cpu_clk = clk_get_sys(NULL, "cclk");
- if (IS_ERR(cpu_clk))
- return PTR_ERR(cpu_clk);
-
- pll_x_clk = clk_get_sys(NULL, "pll_x");
- if (IS_ERR(pll_x_clk))
- return PTR_ERR(pll_x_clk);
-
- pll_p_clk = clk_get_sys(NULL, "pll_p");
- if (IS_ERR(pll_p_clk))
- return PTR_ERR(pll_p_clk);
-
- emc_clk = clk_get_sys("cpu", "emc");
- if (IS_ERR(emc_clk)) {
- clk_put(cpu_clk);
- return PTR_ERR(emc_clk);
- }
-
- return cpufreq_register_driver(&tegra_cpufreq_driver);
-}
-
-static void __exit tegra_cpufreq_exit(void)
-{
- cpufreq_unregister_driver(&tegra_cpufreq_driver);
- clk_put(emc_clk);
- clk_put(cpu_clk);
-}
-
-
-MODULE_AUTHOR("Colin Cross <ccross@android.com>");
-MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
-MODULE_LICENSE("GPL");
-module_init(tegra_cpufreq_init);
-module_exit(tegra_cpufreq_exit);
Code Review / kvmfornfv.git / blobdiff