![Viresh Kumar](/assets/img/avatar_default.png)
Sometimes boot loaders set CPU frequency to a value outside of frequency table present with cpufreq core. In such cases CPU might be unstable if it has to run on that frequency for long duration of time and so its better to set it to a frequency which is specified in frequency table. On some systems we can't really say what frequency we're running at the moment and so for these we shouldn't check if we are running at a frequency present in frequency table. And so we really can't force this for all the cpufreq drivers. Hence we are created another flag here: CPUFREQ_NEED_INITIAL_FREQ_CHECK that will be marked by platforms which want to go for this check at boot time. Initially this is done for all ARM platforms but others may follow if required. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
230 lines
5.7 KiB
C
230 lines
5.7 KiB
C
/*
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* Copyright (C) 2008 Marvell International Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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/sched.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <mach/generic.h>
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#include <mach/pxa3xx-regs.h>
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#define HSS_104M (0)
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#define HSS_156M (1)
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#define HSS_208M (2)
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#define HSS_312M (3)
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#define SMCFS_78M (0)
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#define SMCFS_104M (2)
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#define SMCFS_208M (5)
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#define SFLFS_104M (0)
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#define SFLFS_156M (1)
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#define SFLFS_208M (2)
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#define SFLFS_312M (3)
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#define XSPCLK_156M (0)
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#define XSPCLK_NONE (3)
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#define DMCFS_26M (0)
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#define DMCFS_260M (3)
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struct pxa3xx_freq_info {
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unsigned int cpufreq_mhz;
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unsigned int core_xl : 5;
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unsigned int core_xn : 3;
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unsigned int hss : 2;
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unsigned int dmcfs : 2;
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unsigned int smcfs : 3;
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unsigned int sflfs : 2;
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unsigned int df_clkdiv : 3;
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int vcc_core; /* in mV */
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int vcc_sram; /* in mV */
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};
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#define OP(cpufreq, _xl, _xn, _hss, _dmc, _smc, _sfl, _dfi, vcore, vsram) \
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{ \
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.cpufreq_mhz = cpufreq, \
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.core_xl = _xl, \
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.core_xn = _xn, \
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.hss = HSS_##_hss##M, \
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.dmcfs = DMCFS_##_dmc##M, \
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.smcfs = SMCFS_##_smc##M, \
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.sflfs = SFLFS_##_sfl##M, \
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.df_clkdiv = _dfi, \
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.vcc_core = vcore, \
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.vcc_sram = vsram, \
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}
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static struct pxa3xx_freq_info pxa300_freqs[] = {
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/* CPU XL XN HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
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OP(104, 8, 1, 104, 260, 78, 104, 3, 1000, 1100), /* 104MHz */
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OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
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OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
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OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
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};
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static struct pxa3xx_freq_info pxa320_freqs[] = {
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/* CPU XL XN HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
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OP(104, 8, 1, 104, 260, 78, 104, 3, 1000, 1100), /* 104MHz */
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OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
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OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
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OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
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OP(806, 31, 2, 208, 260, 208, 312, 3, 1400, 1400), /* 806MHz */
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};
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static unsigned int pxa3xx_freqs_num;
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static struct pxa3xx_freq_info *pxa3xx_freqs;
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static struct cpufreq_frequency_table *pxa3xx_freqs_table;
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static int setup_freqs_table(struct cpufreq_policy *policy,
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struct pxa3xx_freq_info *freqs, int num)
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{
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struct cpufreq_frequency_table *table;
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int i;
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table = kzalloc((num + 1) * sizeof(*table), GFP_KERNEL);
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if (table == NULL)
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return -ENOMEM;
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for (i = 0; i < num; i++) {
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table[i].driver_data = i;
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table[i].frequency = freqs[i].cpufreq_mhz * 1000;
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}
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table[num].driver_data = i;
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table[num].frequency = CPUFREQ_TABLE_END;
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pxa3xx_freqs = freqs;
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pxa3xx_freqs_num = num;
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pxa3xx_freqs_table = table;
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return cpufreq_table_validate_and_show(policy, table);
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}
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static void __update_core_freq(struct pxa3xx_freq_info *info)
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{
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uint32_t mask = ACCR_XN_MASK | ACCR_XL_MASK;
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uint32_t accr = ACCR;
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uint32_t xclkcfg;
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accr &= ~(ACCR_XN_MASK | ACCR_XL_MASK | ACCR_XSPCLK_MASK);
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accr |= ACCR_XN(info->core_xn) | ACCR_XL(info->core_xl);
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/* No clock until core PLL is re-locked */
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accr |= ACCR_XSPCLK(XSPCLK_NONE);
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xclkcfg = (info->core_xn == 2) ? 0x3 : 0x2; /* turbo bit */
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ACCR = accr;
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__asm__("mcr p14, 0, %0, c6, c0, 0\n" : : "r"(xclkcfg));
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while ((ACSR & mask) != (accr & mask))
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cpu_relax();
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}
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static void __update_bus_freq(struct pxa3xx_freq_info *info)
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{
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uint32_t mask;
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uint32_t accr = ACCR;
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mask = ACCR_SMCFS_MASK | ACCR_SFLFS_MASK | ACCR_HSS_MASK |
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ACCR_DMCFS_MASK;
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accr &= ~mask;
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accr |= ACCR_SMCFS(info->smcfs) | ACCR_SFLFS(info->sflfs) |
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ACCR_HSS(info->hss) | ACCR_DMCFS(info->dmcfs);
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ACCR = accr;
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while ((ACSR & mask) != (accr & mask))
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cpu_relax();
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}
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static unsigned int pxa3xx_cpufreq_get(unsigned int cpu)
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{
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return pxa3xx_get_clk_frequency_khz(0);
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}
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static int pxa3xx_cpufreq_set(struct cpufreq_policy *policy, unsigned int index)
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{
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struct pxa3xx_freq_info *next;
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unsigned long flags;
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if (policy->cpu != 0)
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return -EINVAL;
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next = &pxa3xx_freqs[index];
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local_irq_save(flags);
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__update_core_freq(next);
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__update_bus_freq(next);
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local_irq_restore(flags);
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return 0;
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}
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static int pxa3xx_cpufreq_init(struct cpufreq_policy *policy)
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{
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int ret = -EINVAL;
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/* set default policy and cpuinfo */
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policy->min = policy->cpuinfo.min_freq = 104000;
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policy->max = policy->cpuinfo.max_freq =
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(cpu_is_pxa320()) ? 806000 : 624000;
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policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
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if (cpu_is_pxa300() || cpu_is_pxa310())
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ret = setup_freqs_table(policy, pxa300_freqs,
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ARRAY_SIZE(pxa300_freqs));
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if (cpu_is_pxa320())
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ret = setup_freqs_table(policy, pxa320_freqs,
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ARRAY_SIZE(pxa320_freqs));
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if (ret) {
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pr_err("failed to setup frequency table\n");
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return ret;
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}
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pr_info("CPUFREQ support for PXA3xx initialized\n");
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return 0;
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}
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static struct cpufreq_driver pxa3xx_cpufreq_driver = {
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.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = pxa3xx_cpufreq_set,
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.init = pxa3xx_cpufreq_init,
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.exit = cpufreq_generic_exit,
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.get = pxa3xx_cpufreq_get,
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.name = "pxa3xx-cpufreq",
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};
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static int __init cpufreq_init(void)
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{
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if (cpu_is_pxa3xx())
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return cpufreq_register_driver(&pxa3xx_cpufreq_driver);
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return 0;
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}
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module_init(cpufreq_init);
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static void __exit cpufreq_exit(void)
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{
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cpufreq_unregister_driver(&pxa3xx_cpufreq_driver);
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}
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module_exit(cpufreq_exit);
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MODULE_DESCRIPTION("CPU frequency scaling driver for PXA3xx");
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MODULE_LICENSE("GPL");
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