diff options
Diffstat (limited to 'drivers/cpufreq/pasemi-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/pasemi-cpufreq.c | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/drivers/cpufreq/pasemi-cpufreq.c b/drivers/cpufreq/pasemi-cpufreq.c new file mode 100644 index 00000000000..35dd4d7ffee --- /dev/null +++ b/drivers/cpufreq/pasemi-cpufreq.c @@ -0,0 +1,291 @@ +/* + * Copyright (C) 2007 PA Semi, Inc + * + * Authors: Egor Martovetsky <egor@pasemi.com> + * Olof Johansson <olof@lixom.net> + * + * Maintained by: Olof Johansson <olof@lixom.net> + * + * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c: + * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <linux/cpufreq.h> +#include <linux/timer.h> +#include <linux/module.h> +#include <linux/of_address.h> + +#include <asm/hw_irq.h> +#include <asm/io.h> +#include <asm/prom.h> +#include <asm/time.h> +#include <asm/smp.h> + +#define SDCASR_REG 0x0100 +#define SDCASR_REG_STRIDE 0x1000 +#define SDCPWR_CFGA0_REG 0x0100 +#define SDCPWR_PWST0_REG 0x0000 +#define SDCPWR_GIZTIME_REG 0x0440 + +/* SDCPWR_GIZTIME_REG fields */ +#define SDCPWR_GIZTIME_GR 0x80000000 +#define SDCPWR_GIZTIME_LONGLOCK 0x000000ff + +/* Offset of ASR registers from SDC base */ +#define SDCASR_OFFSET 0x120000 + +static void __iomem *sdcpwr_mapbase; +static void __iomem *sdcasr_mapbase; + +/* Current astate, is used when waking up from power savings on + * one core, in case the other core has switched states during + * the idle time. + */ +static int current_astate; + +/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */ +static struct cpufreq_frequency_table pas_freqs[] = { + {0, 0, 0}, + {0, 1, 0}, + {0, 2, 0}, + {0, 3, 0}, + {0, 4, 0}, + {0, 0, CPUFREQ_TABLE_END}, +}; + +/* + * hardware specific functions + */ + +static int get_astate_freq(int astate) +{ + u32 ret; + ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10)); + + return ret & 0x3f; +} + +static int get_cur_astate(int cpu) +{ + u32 ret; + + ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG); + ret = (ret >> (cpu * 4)) & 0x7; + + return ret; +} + +static int get_gizmo_latency(void) +{ + u32 giztime, ret; + + giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG); + + /* just provide the upper bound */ + if (giztime & SDCPWR_GIZTIME_GR) + ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000; + else + ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000; + + return ret; +} + +static void set_astate(int cpu, unsigned int astate) +{ + unsigned long flags; + + /* Return if called before init has run */ + if (unlikely(!sdcasr_mapbase)) + return; + + local_irq_save(flags); + + out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate); + + local_irq_restore(flags); +} + +int check_astate(void) +{ + return get_cur_astate(hard_smp_processor_id()); +} + +void restore_astate(int cpu) +{ + set_astate(cpu, current_astate); +} + +/* + * cpufreq functions + */ + +static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + struct cpufreq_frequency_table *pos; + const u32 *max_freqp; + u32 max_freq; + int cur_astate; + struct resource res; + struct device_node *cpu, *dn; + int err = -ENODEV; + + cpu = of_get_cpu_node(policy->cpu, NULL); + + if (!cpu) + goto out; + + dn = of_find_compatible_node(NULL, NULL, "1682m-sdc"); + if (!dn) + dn = of_find_compatible_node(NULL, NULL, + "pasemi,pwrficient-sdc"); + if (!dn) + goto out; + err = of_address_to_resource(dn, 0, &res); + of_node_put(dn); + if (err) + goto out; + sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000); + if (!sdcasr_mapbase) { + err = -EINVAL; + goto out; + } + + dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo"); + if (!dn) + dn = of_find_compatible_node(NULL, NULL, + "pasemi,pwrficient-gizmo"); + if (!dn) { + err = -ENODEV; + goto out_unmap_sdcasr; + } + err = of_address_to_resource(dn, 0, &res); + of_node_put(dn); + if (err) + goto out_unmap_sdcasr; + sdcpwr_mapbase = ioremap(res.start, 0x1000); + if (!sdcpwr_mapbase) { + err = -EINVAL; + goto out_unmap_sdcasr; + } + + pr_debug("init cpufreq on CPU %d\n", policy->cpu); + + max_freqp = of_get_property(cpu, "clock-frequency", NULL); + if (!max_freqp) { + err = -EINVAL; + goto out_unmap_sdcpwr; + } + + /* we need the freq in kHz */ + max_freq = *max_freqp / 1000; + + pr_debug("max clock-frequency is at %u kHz\n", max_freq); + pr_debug("initializing frequency table\n"); + + /* initialize frequency table */ + cpufreq_for_each_entry(pos, pas_freqs) { + pos->frequency = get_astate_freq(pos->driver_data) * 100000; + pr_debug("%d: %d\n", (int)(pos - pas_freqs), pos->frequency); + } + + cur_astate = get_cur_astate(policy->cpu); + pr_debug("current astate is at %d\n",cur_astate); + + policy->cur = pas_freqs[cur_astate].frequency; + ppc_proc_freq = policy->cur * 1000ul; + + return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency()); + +out_unmap_sdcpwr: + iounmap(sdcpwr_mapbase); + +out_unmap_sdcasr: + iounmap(sdcasr_mapbase); +out: + return err; +} + +static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy) +{ + /* + * We don't support CPU hotplug. Don't unmap after the system + * has already made it to a running state. + */ + if (system_state != SYSTEM_BOOTING) + return 0; + + if (sdcasr_mapbase) + iounmap(sdcasr_mapbase); + if (sdcpwr_mapbase) + iounmap(sdcpwr_mapbase); + + return 0; +} + +static int pas_cpufreq_target(struct cpufreq_policy *policy, + unsigned int pas_astate_new) +{ + int i; + + pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n", + policy->cpu, + pas_freqs[pas_astate_new].frequency, + pas_freqs[pas_astate_new].driver_data); + + current_astate = pas_astate_new; + + for_each_online_cpu(i) + set_astate(i, pas_astate_new); + + ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul; + return 0; +} + +static struct cpufreq_driver pas_cpufreq_driver = { + .name = "pas-cpufreq", + .flags = CPUFREQ_CONST_LOOPS, + .init = pas_cpufreq_cpu_init, + .exit = pas_cpufreq_cpu_exit, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = pas_cpufreq_target, + .attr = cpufreq_generic_attr, +}; + +/* + * module init and destoy + */ + +static int __init pas_cpufreq_init(void) +{ + if (!of_machine_is_compatible("PA6T-1682M") && + !of_machine_is_compatible("pasemi,pwrficient")) + return -ENODEV; + + return cpufreq_register_driver(&pas_cpufreq_driver); +} + +static void __exit pas_cpufreq_exit(void) +{ + cpufreq_unregister_driver(&pas_cpufreq_driver); +} + +module_init(pas_cpufreq_init); +module_exit(pas_cpufreq_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>"); |