drivers/cpufreq/pxa2xx-cpufreq.c - kernel/msm-4.9 - Gitiles

 /*
  *  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 void __init 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 void __init 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;
 		}
 	} else if (cpu_is_pxa27x()) {
 		*pxa_freqs = pxa27x_freqs;
 		*freq_table = pxa27x_freq_table;
 	} else {
 		BUG();
 	}
 }

 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;
 }

 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 idx)
 {
 	struct cpufreq_frequency_table *pxa_freqs_table;
 	pxa_freqs_t *pxa_freq_settings;
 	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);

 	new_freq_cpu = pxa_freq_settings[idx].khz;
 	new_freq_mem = pxa_freq_settings[idx].membus;

 	if (freq_debug)
 		pr_debug("Changing CPU frequency to %d Mhz, (SDRAM %d Mhz)\n",
 			 new_freq_cpu / 1000, (pxa_freq_settings[idx].div2) ?
 			 (new_freq_mem / 2000) : (new_freq_mem / 1000));

 	if (vcc_core && new_freq_cpu > policy->cur) {
 		ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 		if (ret)
 			return ret;
 	}

 	/* 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);

 	/*
 	 * 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 && new_freq_cpu < policy->cur)
 		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 */

 	/* 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].driver_data = 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].driver_data = 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].driver_data = i;
 	}
 	pxa27x_freq_table[i].driver_data = 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_table_validate_and_show(policy, pxa255_freq_table);
 	}
 	else if (cpu_is_pxa27x()) {
 		cpufreq_table_validate_and_show(policy, pxa27x_freq_table);
 	}

 	printk(KERN_INFO "PXA CPU frequency change support initialized\n");

 	return 0;
 }

 static struct cpufreq_driver pxa_cpufreq_driver = {
 	.flags	= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = 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);
	/*
	* 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 void __init 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 void __init 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;
	}
	} else if (cpu_is_pxa27x()) {
	*pxa_freqs = pxa27x_freqs;
	*freq_table = pxa27x_freq_table;
	} else {
	BUG();
	}
	}

	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;
	}

	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 idx)
	{
	struct cpufreq_frequency_table *pxa_freqs_table;
	pxa_freqs_t *pxa_freq_settings;
	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);

	new_freq_cpu = pxa_freq_settings[idx].khz;
	new_freq_mem = pxa_freq_settings[idx].membus;

	if (freq_debug)
	pr_debug("Changing CPU frequency to %d Mhz, (SDRAM %d Mhz)\n",
	new_freq_cpu / 1000, (pxa_freq_settings[idx].div2) ?
	(new_freq_mem / 2000) : (new_freq_mem / 1000));

	if (vcc_core && new_freq_cpu > policy->cur) {
	ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
	if (ret)
	return ret;
	}

	/* 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);

	/*
	* 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 && new_freq_cpu < policy->cur)
	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 */

	/* 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].driver_data = 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].driver_data = 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].driver_data = i;
	}
	pxa27x_freq_table[i].driver_data = 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_table_validate_and_show(policy, pxa255_freq_table);
	}
	else if (cpu_is_pxa27x()) {
	cpufreq_table_validate_and_show(policy, pxa27x_freq_table);
	}

	printk(KERN_INFO "PXA CPU frequency change support initialized\n");

	return 0;
	}

	static struct cpufreq_driver pxa_cpufreq_driver = {
	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = 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);