[ARM] pxa: add preliminary CPUFREQ support for PXA3xx

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 259 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index 7ab8a2eddd11..d31c9979cfa3 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_PM)		+= pm.o sleep.o standby.o
 ifeq ($(CONFIG_CPU_FREQ),y)
 obj-$(CONFIG_PXA25x)            += cpufreq-pxa2xx.o
 obj-$(CONFIG_PXA27x)            += cpufreq-pxa2xx.o
+obj-$(CONFIG_PXA3xx)            += cpufreq-pxa3xx.o
 endif
 
 # Generic drivers that other drivers may depend upon
diff --git a/arch/arm/mach-pxa/cpufreq-pxa3xx.c b/arch/arm/mach-pxa/cpufreq-pxa3xx.c
new file mode 100644
index 000000000000..1ea0c9c0adaf
--- /dev/null
+++ b/arch/arm/mach-pxa/cpufreq-pxa3xx.c
@@ -0,0 +1,258 @@
+/*
+ * linux/arch/arm/mach-pxa/cpufreq-pxa3xx.c
+ *
+ * Copyright (C) 2008 Marvell International Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+
+#include <mach/hardware.h>
+#include <mach/pxa-regs.h>
+#include <mach/pxa3xx-regs.h>
+
+#include "generic.h"
+
+#define HSS_104M        (0)
+#define HSS_156M        (1)
+#define HSS_208M        (2)
+#define HSS_312M        (3)
+
+#define SMCFS_78M       (0)
+#define SMCFS_104M      (2)
+#define SMCFS_208M      (5)
+
+#define SFLFS_104M      (0)
+#define SFLFS_156M      (1)
+#define SFLFS_208M      (2)
+#define SFLFS_312M      (3)
+
+#define XSPCLK_156M     (0)
+#define XSPCLK_NONE     (3)
+
+#define DMCFS_26M       (0)
+#define DMCFS_260M      (3)
+
+struct pxa3xx_freq_info {
+        unsigned int cpufreq_mhz;
+        unsigned int core_xl : 5;
+        unsigned int core_xn : 3;
+        unsigned int hss : 2;
+        unsigned int dmcfs : 2;
+        unsigned int smcfs : 3;
+        unsigned int sflfs : 2;
+        unsigned int df_clkdiv : 3;
+
+        int     vcc_core;       /* in mV */
+        int     vcc_sram;       /* in mV */
+};
+
+#define OP(cpufreq, _xl, _xn, _hss, _dmc, _smc, _sfl, _dfi, vcore, vsram) \
+{                                                                       \
+        .cpufreq_mhz    = cpufreq,                                      \
+        .core_xl        = _xl,                                          \
+        .core_xn        = _xn,                                          \
+        .hss            = HSS_##_hss##M,                                \
+        .dmcfs          = DMCFS_##_dmc##M,                              \
+        .smcfs          = SMCFS_##_smc##M,                              \
+        .sflfs          = SFLFS_##_sfl##M,                              \
+        .df_clkdiv      = _dfi,                                         \
+        .vcc_core       = vcore,                                        \
+        .vcc_sram       = vsram,                                        \
+}
+
+static struct pxa3xx_freq_info pxa300_freqs[] = {
+        /*  CPU XL XN  HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
+        OP(104,  8, 1, 104, 260,  78, 104, 3, 1000, 1100), /* 104MHz */
+        OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
+        OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
+        OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
+};
+
+static struct pxa3xx_freq_info pxa320_freqs[] = {
+        /*  CPU XL XN  HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
+        OP(104,  8, 1, 104, 260,  78, 104, 3, 1000, 1100), /* 104MHz */
+        OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
+        OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
+        OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
+        OP(806, 31, 2, 208, 260, 208, 312, 3, 1400, 1400), /* 806MHz */
+};
+
+static unsigned int pxa3xx_freqs_num;
+static struct pxa3xx_freq_info *pxa3xx_freqs;
+static struct cpufreq_frequency_table *pxa3xx_freqs_table;
+
+static int setup_freqs_table(struct cpufreq_policy *policy,
+                             struct pxa3xx_freq_info *freqs, int num)
+{
+        struct cpufreq_frequency_table *table;
+        int i;
+
+        table = kzalloc((num + 1) * sizeof(*table), GFP_KERNEL);
+        if (table == NULL)
+                return -ENOMEM;
+
+        for (i = 0; i < num; i++) {
+                table[i].index = i;
+                table[i].frequency = freqs[i].cpufreq_mhz * 1000;
+        }
+        table[num].frequency = i;
+        table[num].frequency = CPUFREQ_TABLE_END;
+
+        pxa3xx_freqs = freqs;
+        pxa3xx_freqs_num = num;
+        pxa3xx_freqs_table = table;
+
+        return cpufreq_frequency_table_cpuinfo(policy, table);
+}
+
+static void __update_core_freq(struct pxa3xx_freq_info *info)
+{
+        uint32_t mask = ACCR_XN_MASK | ACCR_XL_MASK;
+        uint32_t accr = ACCR;
+        uint32_t xclkcfg;
+
+        accr &= ~(ACCR_XN_MASK | ACCR_XL_MASK | ACCR_XSPCLK_MASK);
+        accr |= ACCR_XN(info->core_xn) | ACCR_XL(info->core_xl);
+
+        /* No clock until core PLL is re-locked */
+        accr |= ACCR_XSPCLK(XSPCLK_NONE);
+
+        xclkcfg = (info->core_xn == 2) ? 0x3 : 0x2;     /* turbo bit */
+
+        ACCR = accr;
+        __asm__("mcr p14, 0, %0, c6, c0, 0\n" : : "r"(xclkcfg));
+
+        while ((ACSR & mask) != (accr & mask))
+                cpu_relax();
+}
+
+static void __update_bus_freq(struct pxa3xx_freq_info *info)
+{
+        uint32_t mask;
+        uint32_t accr = ACCR;
+
+        mask = ACCR_SMCFS_MASK | ACCR_SFLFS_MASK | ACCR_HSS_MASK |
+                ACCR_DMCFS_MASK;
+
+        accr &= ~mask;
+        accr |= ACCR_SMCFS(info->smcfs) | ACCR_SFLFS(info->sflfs) |
+                ACCR_HSS(info->hss) | ACCR_DMCFS(info->dmcfs);
+
+        ACCR = accr;
+
+        while ((ACSR & mask) != (accr & mask))
+                cpu_relax();
+}
+
+static int pxa3xx_cpufreq_verify(struct cpufreq_policy *policy)
+{
+        return cpufreq_frequency_table_verify(policy, pxa3xx_freqs_table);
+}
+
+static unsigned int pxa3xx_cpufreq_get(unsigned int cpu)
+{
+        return get_clk_frequency_khz(0);
+}
+
+static int pxa3xx_cpufreq_set(struct cpufreq_policy *policy,
+                              unsigned int target_freq,
+                              unsigned int relation)
+{
+        struct pxa3xx_freq_info *next;
+        struct cpufreq_freqs freqs;
+        unsigned long flags;
+        int idx;
+
+        if (policy->cpu != 0)
+                return -EINVAL;
+
+        /* Lookup the next frequency */
+        if (cpufreq_frequency_table_target(policy, pxa3xx_freqs_table,
+                                target_freq, relation, &idx))
+                return -EINVAL;
+
+        next = &pxa3xx_freqs[idx];
+
+        freqs.old = policy->cur;
+        freqs.new = next->cpufreq_mhz * 1000;
+        freqs.cpu = policy->cpu;
+
+        pr_debug("CPU frequency from %d MHz to %d MHz%s\n",
+                        freqs.old / 1000, freqs.new / 1000,
+                        (freqs.old == freqs.new) ? " (skipped)" : "");
+
+        if (freqs.old == target_freq)
+                return 0;
+
+        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+        local_irq_save(flags);
+        __update_core_freq(next);
+        __update_bus_freq(next);
+        local_irq_restore(flags);
+
+        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+        return 0;
+}
+
+static __init int pxa3xx_cpufreq_init(struct cpufreq_policy *policy)
+{
+        int ret = -EINVAL;
+
+        /* set default policy and cpuinfo */
+        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+        policy->cpuinfo.min_freq = 104000;
+        policy->cpuinfo.max_freq = (cpu_is_pxa320()) ? 806000 : 624000;
+        policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
+        policy->cur = policy->min = policy->max = get_clk_frequency_khz(0);
+
+        if (cpu_is_pxa300() || cpu_is_pxa310())
+                ret = setup_freqs_table(policy, ARRAY_AND_SIZE(pxa300_freqs));
+
+        if (cpu_is_pxa320())
+                ret = setup_freqs_table(policy, ARRAY_AND_SIZE(pxa320_freqs));
+
+        if (ret) {
+                pr_err("failed to setup frequency table\n");
+                return ret;
+        }
+
+        pr_info("CPUFREQ support for PXA3xx initialized\n");
+        return 0;
+}
+
+static struct cpufreq_driver pxa3xx_cpufreq_driver = {
+        .verify         = pxa3xx_cpufreq_verify,
+        .target         = pxa3xx_cpufreq_set,
+        .init           = pxa3xx_cpufreq_init,
+        .get            = pxa3xx_cpufreq_get,
+        .name           = "pxa3xx-cpufreq",
+};
+
+static int __init cpufreq_init(void)
+{
+        if (cpu_is_pxa3xx())
+                return cpufreq_register_driver(&pxa3xx_cpufreq_driver);
+
+        return 0;
+}
+module_init(cpufreq_init);
+
+static void __exit cpufreq_exit(void)
+{
+        cpufreq_unregister_driver(&pxa3xx_cpufreq_driver);
+}
+module_exit(cpufreq_exit);
+
+MODULE_DESCRIPTION("CPU frequency scaling driver for PXA3xx");
+MODULE_LICENSE("GPL");