9c0ebcf78f
Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
153 lines
3.3 KiB
C
153 lines
3.3 KiB
C
/*
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* sc520_freq.c: cpufreq driver for the AMD Elan sc520
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*
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* Copyright (C) 2005 Sean Young <sean@mess.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Based on elanfreq.c
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*
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* 2005-03-30: - initial revision
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/cpufreq.h>
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#include <linux/timex.h>
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#include <linux/io.h>
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#include <asm/cpu_device_id.h>
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#include <asm/msr.h>
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#define MMCR_BASE 0xfffef000 /* The default base address */
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#define OFFS_CPUCTL 0x2 /* CPU Control Register */
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static __u8 __iomem *cpuctl;
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#define PFX "sc520_freq: "
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static struct cpufreq_frequency_table sc520_freq_table[] = {
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{0x01, 100000},
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{0x02, 133000},
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{0, CPUFREQ_TABLE_END},
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};
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static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)
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{
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u8 clockspeed_reg = *cpuctl;
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switch (clockspeed_reg & 0x03) {
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default:
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printk(KERN_ERR PFX "error: cpuctl register has unexpected "
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"value %02x\n", clockspeed_reg);
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case 0x01:
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return 100000;
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case 0x02:
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return 133000;
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}
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}
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static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state)
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{
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struct cpufreq_freqs freqs;
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u8 clockspeed_reg;
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freqs.old = sc520_freq_get_cpu_frequency(0);
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freqs.new = sc520_freq_table[state].frequency;
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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pr_debug("attempting to set frequency to %i kHz\n",
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sc520_freq_table[state].frequency);
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local_irq_disable();
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clockspeed_reg = *cpuctl & ~0x03;
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*cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data;
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local_irq_enable();
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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return 0;
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}
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/*
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* Module init and exit code
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*/
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static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
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{
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struct cpuinfo_x86 *c = &cpu_data(0);
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/* capability check */
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if (c->x86_vendor != X86_VENDOR_AMD ||
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c->x86 != 4 || c->x86_model != 9)
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return -ENODEV;
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/* cpuinfo and default policy values */
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policy->cpuinfo.transition_latency = 1000000; /* 1ms */
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return cpufreq_table_validate_and_show(policy, sc520_freq_table);
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}
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static struct cpufreq_driver sc520_freq_driver = {
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.get = sc520_freq_get_cpu_frequency,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = sc520_freq_target,
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.init = sc520_freq_cpu_init,
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.exit = cpufreq_generic_exit,
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.name = "sc520_freq",
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.attr = cpufreq_generic_attr,
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};
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static const struct x86_cpu_id sc520_ids[] = {
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{ X86_VENDOR_AMD, 4, 9 },
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, sc520_ids);
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static int __init sc520_freq_init(void)
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{
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int err;
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if (!x86_match_cpu(sc520_ids))
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return -ENODEV;
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cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
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if (!cpuctl) {
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printk(KERN_ERR "sc520_freq: error: failed to remap memory\n");
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return -ENOMEM;
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}
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err = cpufreq_register_driver(&sc520_freq_driver);
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if (err)
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iounmap(cpuctl);
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return err;
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}
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static void __exit sc520_freq_exit(void)
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{
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cpufreq_unregister_driver(&sc520_freq_driver);
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iounmap(cpuctl);
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}
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Sean Young <sean@mess.org>");
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MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU");
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module_init(sc520_freq_init);
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module_exit(sc520_freq_exit);
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