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);