cpufreq: pxa2xx: move cpufreq driver to drivers/cpufreq

This patch moves cpufreq driver of ARM based pxa2xx platform to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 491 insertions, 0 deletions

diff --git a/drivers/cpufreq/pxa2xx-cpufreq.c b/drivers/cpufreq/pxa2xx-cpufreq.c
new file mode 100644
index 000000000000..fe4c55b38ec3
--- /dev/null
+++ b/drivers/cpufreq/pxa2xx-cpufreq.c
@@ -0,0 +1,491 @@
+/*
+ *  Copyright (C) 2002,2003 Intrinsyc Software
+ *
+ * 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 of the License, 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * History:
+ *   31-Jul-2002 : Initial version [FB]
+ *   29-Jan-2003 : added PXA255 support [FB]
+ *   20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
+ *
+ * Note:
+ *   This driver may change the memory bus clock rate, but will not do any
+ *   platform specific access timing changes... for example if you have flash
+ *   memory connected to CS0, you will need to register a platform specific
+ *   notifier which will adjust the memory access strobes to maintain a
+ *   minimum strobe width.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/regulator/consumer.h>
+#include <linux/io.h>
+
+#include <mach/pxa2xx-regs.h>
+#include <mach/smemc.h>
+
+#ifdef DEBUG
+static unsigned int freq_debug;
+module_param(freq_debug, uint, 0);
+MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
+#else
+#define freq_debug  0
+#endif
+
+static struct regulator *vcc_core;
+
+static unsigned int pxa27x_maxfreq;
+module_param(pxa27x_maxfreq, uint, 0);
+MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
+                 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
+
+typedef struct {
+        unsigned int khz;
+        unsigned int membus;
+        unsigned int cccr;
+        unsigned int div2;
+        unsigned int cclkcfg;
+        int vmin;
+        int vmax;
+} pxa_freqs_t;
+
+/* Define the refresh period in mSec for the SDRAM and the number of rows */
+#define SDRAM_TREF      64      /* standard 64ms SDRAM */
+static unsigned int sdram_rows;
+
+#define CCLKCFG_TURBO           0x1
+#define CCLKCFG_FCS             0x2
+#define CCLKCFG_HALFTURBO       0x4
+#define CCLKCFG_FASTBUS         0x8
+#define MDREFR_DB2_MASK         (MDREFR_K2DB2 | MDREFR_K1DB2)
+#define MDREFR_DRI_MASK         0xFFF
+
+#define MDCNFG_DRAC2(mdcnfg) (((mdcnfg) >> 21) & 0x3)
+#define MDCNFG_DRAC0(mdcnfg) (((mdcnfg) >> 5) & 0x3)
+
+/*
+ * PXA255 definitions
+ */
+/* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */
+#define CCLKCFG                 CCLKCFG_TURBO | CCLKCFG_FCS
+
+static pxa_freqs_t pxa255_run_freqs[] =
+{
+        /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG                run  turbo PXbus SDRAM */
+        { 99500,  99500, 0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
+        {132700, 132700, 0x123, 1,  CCLKCFG, -1, -1},   /* 133,  133,   66,   66  */
+        {199100,  99500, 0x141, 0,  CCLKCFG, -1, -1},   /* 199,  199,   99,   99  */
+        {265400, 132700, 0x143, 1,  CCLKCFG, -1, -1},   /* 265,  265,  133,   66  */
+        {331800, 165900, 0x145, 1,  CCLKCFG, -1, -1},   /* 331,  331,  166,   83  */
+        {398100,  99500, 0x161, 0,  CCLKCFG, -1, -1},   /* 398,  398,  196,   99  */
+};
+
+/* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
+static pxa_freqs_t pxa255_turbo_freqs[] =
+{
+        /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG        run  turbo PXbus SDRAM */
+        { 99500, 99500,  0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
+        {199100, 99500,  0x221, 0,  CCLKCFG, -1, -1},   /*  99,  199,   50,   99  */
+        {298500, 99500,  0x321, 0,  CCLKCFG, -1, -1},   /*  99,  287,   50,   99  */
+        {298600, 99500,  0x1c1, 0,  CCLKCFG, -1, -1},   /* 199,  287,   99,   99  */
+        {398100, 99500,  0x241, 0,  CCLKCFG, -1, -1},   /* 199,  398,   99,   99  */
+};
+
+#define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
+#define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
+
+static struct cpufreq_frequency_table
+        pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
+static struct cpufreq_frequency_table
+        pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
+
+static unsigned int pxa255_turbo_table;
+module_param(pxa255_turbo_table, uint, 0);
+MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
+
+/*
+ * PXA270 definitions
+ *
+ * For the PXA27x:
+ * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
+ *
+ * A = 0 => memory controller clock from table 3-7,
+ * A = 1 => memory controller clock = system bus clock
+ * Run mode frequency   = 13 MHz * L
+ * Turbo mode frequency = 13 MHz * L * N
+ * System bus frequency = 13 MHz * L / (B + 1)
+ *
+ * In CCCR:
+ * A = 1
+ * L = 16         oscillator to run mode ratio
+ * 2N = 6         2 * (turbo mode to run mode ratio)
+ *
+ * In CCLKCFG:
+ * B = 1          Fast bus mode
+ * HT = 0         Half-Turbo mode
+ * T = 1          Turbo mode
+ *
+ * For now, just support some of the combinations in table 3-7 of
+ * PXA27x Processor Family Developer's Manual to simplify frequency
+ * change sequences.
+ */
+#define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
+#define CCLKCFG2(B, HT, T) \
+  (CCLKCFG_FCS | \
+   ((B)  ? CCLKCFG_FASTBUS : 0) | \
+   ((HT) ? CCLKCFG_HALFTURBO : 0) | \
+   ((T)  ? CCLKCFG_TURBO : 0))
+
+static pxa_freqs_t pxa27x_freqs[] = {
+        {104000, 104000, PXA27x_CCCR(1,  8, 2), 0, CCLKCFG2(1, 0, 1),  900000, 1705000 },
+        {156000, 104000, PXA27x_CCCR(1,  8, 3), 0, CCLKCFG2(1, 0, 1), 1000000, 1705000 },
+        {208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1), 1180000, 1705000 },
+        {312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1), 1250000, 1705000 },
+        {416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1), 1350000, 1705000 },
+        {520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1), 1450000, 1705000 },
+        {624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1), 1550000, 1705000 }
+};
+
+#define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
+static struct cpufreq_frequency_table
+        pxa27x_freq_table[NUM_PXA27x_FREQS+1];
+
+extern unsigned get_clk_frequency_khz(int info);
+
+#ifdef CONFIG_REGULATOR
+
+static int pxa_cpufreq_change_voltage(pxa_freqs_t *pxa_freq)
+{
+        int ret = 0;
+        int vmin, vmax;
+
+        if (!cpu_is_pxa27x())
+                return 0;
+
+        vmin = pxa_freq->vmin;
+        vmax = pxa_freq->vmax;
+        if ((vmin == -1) || (vmax == -1))
+                return 0;
+
+        ret = regulator_set_voltage(vcc_core, vmin, vmax);
+        if (ret)
+                pr_err("cpufreq: Failed to set vcc_core in [%dmV..%dmV]\n",
+                       vmin, vmax);
+        return ret;
+}
+
+static __init void pxa_cpufreq_init_voltages(void)
+{
+        vcc_core = regulator_get(NULL, "vcc_core");
+        if (IS_ERR(vcc_core)) {
+                pr_info("cpufreq: Didn't find vcc_core regulator\n");
+                vcc_core = NULL;
+        } else {
+                pr_info("cpufreq: Found vcc_core regulator\n");
+        }
+}
+#else
+static int pxa_cpufreq_change_voltage(pxa_freqs_t *pxa_freq)
+{
+        return 0;
+}
+
+static __init void pxa_cpufreq_init_voltages(void) { }
+#endif
+
+static void find_freq_tables(struct cpufreq_frequency_table **freq_table,
+                             pxa_freqs_t **pxa_freqs)
+{
+        if (cpu_is_pxa25x()) {
+                if (!pxa255_turbo_table) {
+                        *pxa_freqs = pxa255_run_freqs;
+                        *freq_table = pxa255_run_freq_table;
+                } else {
+                        *pxa_freqs = pxa255_turbo_freqs;
+                        *freq_table = pxa255_turbo_freq_table;
+                }
+        }
+        if (cpu_is_pxa27x()) {
+                *pxa_freqs = pxa27x_freqs;
+                *freq_table = pxa27x_freq_table;
+        }
+}
+
+static void pxa27x_guess_max_freq(void)
+{
+        if (!pxa27x_maxfreq) {
+                pxa27x_maxfreq = 416000;
+                printk(KERN_INFO "PXA CPU 27x max frequency not defined "
+                       "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
+                       pxa27x_maxfreq);
+        } else {
+                pxa27x_maxfreq *= 1000;
+        }
+}
+
+static void init_sdram_rows(void)
+{
+        uint32_t mdcnfg = __raw_readl(MDCNFG);
+        unsigned int drac2 = 0, drac0 = 0;
+
+        if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3))
+                drac2 = MDCNFG_DRAC2(mdcnfg);
+
+        if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1))
+                drac0 = MDCNFG_DRAC0(mdcnfg);
+
+        sdram_rows = 1 << (11 + max(drac0, drac2));
+}
+
+static u32 mdrefr_dri(unsigned int freq)
+{
+        u32 interval = freq * SDRAM_TREF / sdram_rows;
+
+        return (interval - (cpu_is_pxa27x() ? 31 : 0)) / 32;
+}
+
+/* find a valid frequency point */
+static int pxa_verify_policy(struct cpufreq_policy *policy)
+{
+        struct cpufreq_frequency_table *pxa_freqs_table;
+        pxa_freqs_t *pxa_freqs;
+        int ret;
+
+        find_freq_tables(&pxa_freqs_table, &pxa_freqs);
+        ret = cpufreq_frequency_table_verify(policy, pxa_freqs_table);
+
+        if (freq_debug)
+                pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n",
+                         policy->min, policy->max);
+
+        return ret;
+}
+
+static unsigned int pxa_cpufreq_get(unsigned int cpu)
+{
+        return get_clk_frequency_khz(0);
+}
+
+static int pxa_set_target(struct cpufreq_policy *policy,
+                          unsigned int target_freq,
+                          unsigned int relation)
+{
+        struct cpufreq_frequency_table *pxa_freqs_table;
+        pxa_freqs_t *pxa_freq_settings;
+        struct cpufreq_freqs freqs;
+        unsigned int idx;
+        unsigned long flags;
+        unsigned int new_freq_cpu, new_freq_mem;
+        unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg;
+        int ret = 0;
+
+        /* Get the current policy */
+        find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
+
+        /* Lookup the next frequency */
+        if (cpufreq_frequency_table_target(policy, pxa_freqs_table,
+                                           target_freq, relation, &idx)) {
+                return -EINVAL;
+        }
+
+        new_freq_cpu = pxa_freq_settings[idx].khz;
+        new_freq_mem = pxa_freq_settings[idx].membus;
+        freqs.old = policy->cur;
+        freqs.new = new_freq_cpu;
+
+        if (freq_debug)
+                pr_debug("Changing CPU frequency to %d Mhz, (SDRAM %d Mhz)\n",
+                         freqs.new / 1000, (pxa_freq_settings[idx].div2) ?
+                         (new_freq_mem / 2000) : (new_freq_mem / 1000));
+
+        if (vcc_core && freqs.new > freqs.old)
+                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
+        if (ret)
+                return ret;
+        /*
+         * Tell everyone what we're about to do...
+         * you should add a notify client with any platform specific
+         * Vcc changing capability
+         */
+        cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+        /* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
+         * we need to preset the smaller DRI before the change.  If we're
+         * speeding up we need to set the larger DRI value after the change.
+         */
+        preset_mdrefr = postset_mdrefr = __raw_readl(MDREFR);
+        if ((preset_mdrefr & MDREFR_DRI_MASK) > mdrefr_dri(new_freq_mem)) {
+                preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
+                preset_mdrefr |= mdrefr_dri(new_freq_mem);
+        }
+        postset_mdrefr =
+                (postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem);
+
+        /* If we're dividing the memory clock by two for the SDRAM clock, this
+         * must be set prior to the change.  Clearing the divide must be done
+         * after the change.
+         */
+        if (pxa_freq_settings[idx].div2) {
+                preset_mdrefr  |= MDREFR_DB2_MASK;
+                postset_mdrefr |= MDREFR_DB2_MASK;
+        } else {
+                postset_mdrefr &= ~MDREFR_DB2_MASK;
+        }
+
+        local_irq_save(flags);
+
+        /* Set new the CCCR and prepare CCLKCFG */
+        CCCR = pxa_freq_settings[idx].cccr;
+        cclkcfg = pxa_freq_settings[idx].cclkcfg;
+
+        asm volatile("                                                  \n\
+                ldr     r4, [%1]                /* load MDREFR */       \n\
+                b       2f                                              \n\
+                .align  5                                               \n\
+1:                                                                      \n\
+                str     %3, [%1]                /* preset the MDREFR */ \n\
+                mcr     p14, 0, %2, c6, c0, 0   /* set CCLKCFG[FCS] */  \n\
+                str     %4, [%1]                /* postset the MDREFR */ \n\
+                                                                        \n\
+                b       3f                                              \n\
+2:              b       1b                                              \n\
+3:              nop                                                     \n\
+          "
+                     : "=&r" (unused)
+                     : "r" (MDREFR), "r" (cclkcfg),
+                       "r" (preset_mdrefr), "r" (postset_mdrefr)
+                     : "r4", "r5");
+        local_irq_restore(flags);
+
+        /*
+         * Tell everyone what we've just done...
+         * you should add a notify client with any platform specific
+         * SDRAM refresh timer adjustments
+         */
+        cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+
+        /*
+         * Even if voltage setting fails, we don't report it, as the frequency
+         * change succeeded. The voltage reduction is not a critical failure,
+         * only power savings will suffer from this.
+         *
+         * Note: if the voltage change fails, and a return value is returned, a
+         * bug is triggered (seems a deadlock). Should anybody find out where,
+         * the "return 0" should become a "return ret".
+         */
+        if (vcc_core && freqs.new < freqs.old)
+                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
+
+        return 0;
+}
+
+static int pxa_cpufreq_init(struct cpufreq_policy *policy)
+{
+        int i;
+        unsigned int freq;
+        struct cpufreq_frequency_table *pxa255_freq_table;
+        pxa_freqs_t *pxa255_freqs;
+
+        /* try to guess pxa27x cpu */
+        if (cpu_is_pxa27x())
+                pxa27x_guess_max_freq();
+
+        pxa_cpufreq_init_voltages();
+
+        init_sdram_rows();
+
+        /* set default policy and cpuinfo */
+        policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
+        policy->cur = get_clk_frequency_khz(0);    /* current freq */
+        policy->min = policy->max = policy->cur;
+
+        /* Generate pxa25x the run cpufreq_frequency_table struct */
+        for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
+                pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
+                pxa255_run_freq_table[i].index = i;
+        }
+        pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+        /* Generate pxa25x the turbo cpufreq_frequency_table struct */
+        for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
+                pxa255_turbo_freq_table[i].frequency =
+                        pxa255_turbo_freqs[i].khz;
+                pxa255_turbo_freq_table[i].index = i;
+        }
+        pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+        pxa255_turbo_table = !!pxa255_turbo_table;
+
+        /* Generate the pxa27x cpufreq_frequency_table struct */
+        for (i = 0; i < NUM_PXA27x_FREQS; i++) {
+                freq = pxa27x_freqs[i].khz;
+                if (freq > pxa27x_maxfreq)
+                        break;
+                pxa27x_freq_table[i].frequency = freq;
+                pxa27x_freq_table[i].index = i;
+        }
+        pxa27x_freq_table[i].index = i;
+        pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+        /*
+         * Set the policy's minimum and maximum frequencies from the tables
+         * just constructed.  This sets cpuinfo.mxx_freq, min and max.
+         */
+        if (cpu_is_pxa25x()) {
+                find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
+                pr_info("PXA255 cpufreq using %s frequency table\n",
+                        pxa255_turbo_table ? "turbo" : "run");
+                cpufreq_frequency_table_cpuinfo(policy, pxa255_freq_table);
+        }
+        else if (cpu_is_pxa27x())
+                cpufreq_frequency_table_cpuinfo(policy, pxa27x_freq_table);
+
+        printk(KERN_INFO "PXA CPU frequency change support initialized\n");
+
+        return 0;
+}
+
+static struct cpufreq_driver pxa_cpufreq_driver = {
+        .verify = pxa_verify_policy,
+        .target = pxa_set_target,
+        .init   = pxa_cpufreq_init,
+        .get    = pxa_cpufreq_get,
+        .name   = "PXA2xx",
+};
+
+static int __init pxa_cpu_init(void)
+{
+        int ret = -ENODEV;
+        if (cpu_is_pxa25x() || cpu_is_pxa27x())
+                ret = cpufreq_register_driver(&pxa_cpufreq_driver);
+        return ret;
+}
+
+static void __exit pxa_cpu_exit(void)
+{
+        cpufreq_unregister_driver(&pxa_cpufreq_driver);
+}
+
+
+MODULE_AUTHOR("Intrinsyc Software Inc.");
+MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
+MODULE_LICENSE("GPL");
+module_init(pxa_cpu_init);
+module_exit(pxa_cpu_exit);