313 lines
7.1 KiB
C
313 lines
7.1 KiB
C
/*
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* Copyright (C) 2007 PA Semi, Inc
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*
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* Authors: Egor Martovetsky <egor@pasemi.com>
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* Olof Johansson <olof@lixom.net>
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*
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* Maintained by: Olof Johansson <olof@lixom.net>
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*
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* Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
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* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
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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, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/cpufreq.h>
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#include <linux/timer.h>
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#include <asm/hw_irq.h>
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#include <asm/io.h>
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#include <asm/prom.h>
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#include <asm/time.h>
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#define SDCASR_REG 0x0100
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#define SDCASR_REG_STRIDE 0x1000
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#define SDCPWR_CFGA0_REG 0x0100
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#define SDCPWR_PWST0_REG 0x0000
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#define SDCPWR_GIZTIME_REG 0x0440
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/* SDCPWR_GIZTIME_REG fields */
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#define SDCPWR_GIZTIME_GR 0x80000000
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#define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
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/* Offset of ASR registers from SDC base */
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#define SDCASR_OFFSET 0x120000
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static void __iomem *sdcpwr_mapbase;
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static void __iomem *sdcasr_mapbase;
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static DEFINE_MUTEX(pas_switch_mutex);
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/* Current astate, is used when waking up from power savings on
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* one core, in case the other core has switched states during
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* the idle time.
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*/
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static int current_astate;
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/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
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static struct cpufreq_frequency_table pas_freqs[] = {
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{0, 0},
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{1, 0},
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{2, 0},
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{3, 0},
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{4, 0},
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{0, CPUFREQ_TABLE_END},
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};
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static struct freq_attr *pas_cpu_freqs_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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/*
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* hardware specific functions
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*/
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static int get_astate_freq(int astate)
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{
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u32 ret;
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ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
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return ret & 0x3f;
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}
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static int get_cur_astate(int cpu)
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{
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u32 ret;
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ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
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ret = (ret >> (cpu * 4)) & 0x7;
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return ret;
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}
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static int get_gizmo_latency(void)
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{
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u32 giztime, ret;
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giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
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/* just provide the upper bound */
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if (giztime & SDCPWR_GIZTIME_GR)
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ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
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else
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ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
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return ret;
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}
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static void set_astate(int cpu, unsigned int astate)
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{
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u64 flags;
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/* Return if called before init has run */
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if (unlikely(!sdcasr_mapbase))
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return;
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local_irq_save(flags);
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out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
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local_irq_restore(flags);
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}
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void restore_astate(int cpu)
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{
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set_astate(cpu, current_astate);
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}
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/*
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* cpufreq functions
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*/
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static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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const u32 *max_freqp;
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u32 max_freq;
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int i, cur_astate;
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struct resource res;
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struct device_node *cpu, *dn;
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int err = -ENODEV;
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cpu = of_get_cpu_node(policy->cpu, NULL);
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if (!cpu)
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goto out;
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dn = of_find_compatible_node(NULL, "sdc", "1682m-sdc");
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if (!dn)
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goto out;
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err = of_address_to_resource(dn, 0, &res);
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of_node_put(dn);
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if (err)
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goto out;
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sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
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if (!sdcasr_mapbase) {
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err = -EINVAL;
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goto out;
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}
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dn = of_find_compatible_node(NULL, "gizmo", "1682m-gizmo");
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if (!dn) {
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err = -ENODEV;
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goto out_unmap_sdcasr;
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}
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err = of_address_to_resource(dn, 0, &res);
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of_node_put(dn);
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if (err)
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goto out_unmap_sdcasr;
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sdcpwr_mapbase = ioremap(res.start, 0x1000);
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if (!sdcpwr_mapbase) {
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err = -EINVAL;
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goto out_unmap_sdcasr;
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}
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pr_debug("init cpufreq on CPU %d\n", policy->cpu);
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max_freqp = of_get_property(cpu, "clock-frequency", NULL);
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if (!max_freqp) {
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err = -EINVAL;
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goto out_unmap_sdcpwr;
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}
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/* we need the freq in kHz */
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max_freq = *max_freqp / 1000;
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pr_debug("max clock-frequency is at %u kHz\n", max_freq);
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pr_debug("initializing frequency table\n");
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/* initialize frequency table */
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for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
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pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
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pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
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}
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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policy->cpuinfo.transition_latency = get_gizmo_latency();
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cur_astate = get_cur_astate(policy->cpu);
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pr_debug("current astate is at %d\n",cur_astate);
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policy->cur = pas_freqs[cur_astate].frequency;
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policy->cpus = cpu_online_map;
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ppc_proc_freq = policy->cur * 1000ul;
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cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
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/* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
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* are set correctly
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*/
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return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
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out_unmap_sdcpwr:
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iounmap(sdcpwr_mapbase);
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out_unmap_sdcasr:
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iounmap(sdcasr_mapbase);
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out:
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return err;
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}
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static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
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{
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if (sdcasr_mapbase)
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iounmap(sdcasr_mapbase);
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if (sdcpwr_mapbase)
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iounmap(sdcpwr_mapbase);
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cpufreq_frequency_table_put_attr(policy->cpu);
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return 0;
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}
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static int pas_cpufreq_verify(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, pas_freqs);
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}
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static int pas_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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int pas_astate_new;
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int i;
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cpufreq_frequency_table_target(policy,
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pas_freqs,
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target_freq,
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relation,
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&pas_astate_new);
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freqs.old = policy->cur;
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freqs.new = pas_freqs[pas_astate_new].frequency;
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freqs.cpu = policy->cpu;
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mutex_lock(&pas_switch_mutex);
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
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policy->cpu,
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pas_freqs[pas_astate_new].frequency,
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pas_freqs[pas_astate_new].index);
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current_astate = pas_astate_new;
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for_each_online_cpu(i)
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set_astate(i, pas_astate_new);
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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mutex_unlock(&pas_switch_mutex);
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ppc_proc_freq = freqs.new * 1000ul;
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return 0;
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}
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static struct cpufreq_driver pas_cpufreq_driver = {
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.name = "pas-cpufreq",
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.owner = THIS_MODULE,
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.flags = CPUFREQ_CONST_LOOPS,
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.init = pas_cpufreq_cpu_init,
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.exit = pas_cpufreq_cpu_exit,
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.verify = pas_cpufreq_verify,
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.target = pas_cpufreq_target,
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.attr = pas_cpu_freqs_attr,
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};
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/*
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* module init and destoy
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*/
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static int __init pas_cpufreq_init(void)
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{
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if (!machine_is_compatible("PA6T-1682M"))
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return -ENODEV;
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return cpufreq_register_driver(&pas_cpufreq_driver);
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}
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static void __exit pas_cpufreq_exit(void)
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{
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cpufreq_unregister_driver(&pas_cpufreq_driver);
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}
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module_init(pas_cpufreq_init);
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module_exit(pas_cpufreq_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
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