[POWERPC] pasemi: Cpufreq driver
Cpufreq driver for PA Semi PWRficient processors.
Signed-off-by: Egor Martovetsky <egor@pasemi.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/pasemi/cpufreq.c b/arch/powerpc/platforms/pasemi/cpufreq.c
new file mode 100644
index 0000000..4dd5c51
--- /dev/null
+++ b/arch/powerpc/platforms/pasemi/cpufreq.c
@@ -0,0 +1,307 @@
+/*
+ * 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 <asm/hw_irq.h>
+#include <asm/io.h>
+#include <asm/prom.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;
+
+static DEFINE_MUTEX(pas_switch_mutex);
+
+/* 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},
+ {1, 0},
+ {2, 0},
+ {3, 0},
+ {4, 0},
+ {0, CPUFREQ_TABLE_END},
+};
+
+static struct freq_attr *pas_cpu_freqs_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+/*
+ * 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)
+{
+ u64 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);
+}
+
+void restore_astate(int cpu)
+{
+ set_astate(cpu, current_astate);
+}
+
+/*
+ * cpufreq functions
+ */
+
+static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ u32 *max_freq;
+ int i, 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, "sdc", "1682m-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, "gizmo", "1682m-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_freq = (u32*) get_property(cpu, "clock-frequency", NULL);
+ if (!max_freq) {
+ err = -EINVAL;
+ goto out_unmap_sdcpwr;
+ }
+
+ /* we need the freq in kHz */
+ *max_freq /= 1000;
+
+ pr_debug("max clock-frequency is at %u kHz\n", *max_freq);
+ pr_debug("initializing frequency table\n");
+
+ /* initialize frequency table */
+ for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
+ pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
+ pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
+ }
+
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+ policy->cpuinfo.transition_latency = get_gizmo_latency();
+
+ cur_astate = get_cur_astate(policy->cpu);
+ pr_debug("current astate is at %d\n",cur_astate);
+
+ policy->cur = pas_freqs[cur_astate].frequency;
+ policy->cpus = cpu_online_map;
+
+ cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
+
+ /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
+ * are set correctly
+ */
+ return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
+
+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)
+{
+ if (sdcasr_mapbase)
+ iounmap(sdcasr_mapbase);
+ if (sdcpwr_mapbase)
+ iounmap(sdcpwr_mapbase);
+
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ return 0;
+}
+
+static int pas_cpufreq_verify(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, pas_freqs);
+}
+
+static int pas_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct cpufreq_freqs freqs;
+ int pas_astate_new;
+ int i;
+
+ cpufreq_frequency_table_target(policy,
+ pas_freqs,
+ target_freq,
+ relation,
+ &pas_astate_new);
+
+ freqs.old = policy->cur;
+ freqs.new = pas_freqs[pas_astate_new].frequency;
+ freqs.cpu = policy->cpu;
+
+ mutex_lock(&pas_switch_mutex);
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+ 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].index);
+
+ current_astate = pas_astate_new;
+
+ for_each_online_cpu(i)
+ set_astate(i, pas_astate_new);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ mutex_unlock(&pas_switch_mutex);
+
+ return 0;
+}
+
+static struct cpufreq_driver pas_cpufreq_driver = {
+ .name = "pas-cpufreq",
+ .owner = THIS_MODULE,
+ .flags = CPUFREQ_CONST_LOOPS,
+ .init = pas_cpufreq_cpu_init,
+ .exit = pas_cpufreq_cpu_exit,
+ .verify = pas_cpufreq_verify,
+ .target = pas_cpufreq_target,
+ .attr = pas_cpu_freqs_attr,
+};
+
+/*
+ * module init and destoy
+ */
+
+static int __init pas_cpufreq_init(void)
+{
+ if (!machine_is_compatible("PA6T-1682M"))
+ 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>");