serial: pxa: fine-tune clk useage

[linux/fpc-iii.git] / arch / arm / mach-pxa / cpufreq-pxa2xx.c

/*
 *  linux/arch/arm/mach-pxa/cpufreq-pxa2xx.c
 *
 *  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;
        freqs.cpu = policy->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(&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(&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);