1 files changed, 514 insertions, 0 deletions

diff --git a/drivers/cpufreq/gx-suspmod.c b/drivers/cpufreq/gx-suspmod.c
new file mode 100644
index 000000000000..ffe1f2c92ed3
--- /dev/null
+++ b/drivers/cpufreq/gx-suspmod.c
@@ -0,0 +1,514 @@
+/*
+ *      Cyrix MediaGX and NatSemi Geode Suspend Modulation
+ *      (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
+ *      (C) 2002 Hiroshi Miura   <miura@da-cha.org>
+ *      All Rights Reserved
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      version 2 as published by the Free Software Foundation
+ *
+ *      The author(s) of this software shall not be held liable for damages
+ *      of any nature resulting due to the use of this software. This
+ *      software is provided AS-IS with no warranties.
+ *
+ * Theoretical note:
+ *
+ *      (see Geode(tm) CS5530 manual (rev.4.1) page.56)
+ *
+ *      CPU frequency control on NatSemi Geode GX1/GXLV processor and CS55x0
+ *      are based on Suspend Modulation.
+ *
+ *      Suspend Modulation works by asserting and de-asserting the SUSP# pin
+ *      to CPU(GX1/GXLV) for configurable durations. When asserting SUSP#
+ *      the CPU enters an idle state. GX1 stops its core clock when SUSP# is
+ *      asserted then power consumption is reduced.
+ *
+ *      Suspend Modulation's OFF/ON duration are configurable
+ *      with 'Suspend Modulation OFF Count Register'
+ *      and 'Suspend Modulation ON Count Register'.
+ *      These registers are 8bit counters that represent the number of
+ *      32us intervals which the SUSP# pin is asserted(ON)/de-asserted(OFF)
+ *      to the processor.
+ *
+ *      These counters define a ratio which is the effective frequency
+ *      of operation of the system.
+ *
+ *                             OFF Count
+ *      F_eff = Fgx * ----------------------
+ *                      OFF Count + ON Count
+ *
+ *      0 <= On Count, Off Count <= 255
+ *
+ *      From these limits, we can get register values
+ *
+ *      off_duration + on_duration <= MAX_DURATION
+ *      on_duration = off_duration * (stock_freq - freq) / freq
+ *
+ *      off_duration  =  (freq * DURATION) / stock_freq
+ *      on_duration = DURATION - off_duration
+ *
+ *
+ *---------------------------------------------------------------------------
+ *
+ * ChangeLog:
+ *      Dec. 12, 2003   Hiroshi Miura <miura@da-cha.org>
+ *              - fix on/off register mistake
+ *              - fix cpu_khz calc when it stops cpu modulation.
+ *
+ *      Dec. 11, 2002   Hiroshi Miura <miura@da-cha.org>
+ *              - rewrite for Cyrix MediaGX Cx5510/5520 and
+ *                NatSemi Geode Cs5530(A).
+ *
+ *      Jul. ??, 2002  Zwane Mwaikambo <zwane@commfireservices.com>
+ *              - cs5530_mod patch for 2.4.19-rc1.
+ *
+ *---------------------------------------------------------------------------
+ *
+ * Todo
+ *      Test on machines with 5510, 5530, 5530A
+ */
+
+/************************************************************************
+ *                      Suspend Modulation - Definitions                *
+ ************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/cpufreq.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include <asm/processor-cyrix.h>
+
+/* PCI config registers, all at F0 */
+#define PCI_PMER1       0x80    /* power management enable register 1 */
+#define PCI_PMER2       0x81    /* power management enable register 2 */
+#define PCI_PMER3       0x82    /* power management enable register 3 */
+#define PCI_IRQTC       0x8c    /* irq speedup timer counter register:typical 2 to 4ms */
+#define PCI_VIDTC       0x8d    /* video speedup timer counter register: typical 50 to 100ms */
+#define PCI_MODOFF      0x94    /* suspend modulation OFF counter register, 1 = 32us */
+#define PCI_MODON       0x95    /* suspend modulation ON counter register */
+#define PCI_SUSCFG      0x96    /* suspend configuration register */
+
+/* PMER1 bits */
+#define GPM             (1<<0)  /* global power management */
+#define GIT             (1<<1)  /* globally enable PM device idle timers */
+#define GTR             (1<<2)  /* globally enable IO traps */
+#define IRQ_SPDUP       (1<<3)  /* disable clock throttle during interrupt handling */
+#define VID_SPDUP       (1<<4)  /* disable clock throttle during vga video handling */
+
+/* SUSCFG bits */
+#define SUSMOD          (1<<0)  /* enable/disable suspend modulation */
+/* the below is supported only with cs5530 (after rev.1.2)/cs5530A */
+#define SMISPDUP        (1<<1)  /* select how SMI re-enable suspend modulation: */
+                                /* IRQTC timer or read SMI speedup disable reg.(F1BAR[08-09h]) */
+#define SUSCFG          (1<<2)  /* enable powering down a GXLV processor. "Special 3Volt Suspend" mode */
+/* the below is supported only with cs5530A */
+#define PWRSVE_ISA      (1<<3)  /* stop ISA clock  */
+#define PWRSVE          (1<<4)  /* active idle */
+
+struct gxfreq_params {
+        u8 on_duration;
+        u8 off_duration;
+        u8 pci_suscfg;
+        u8 pci_pmer1;
+        u8 pci_pmer2;
+        struct pci_dev *cs55x0;
+};
+
+static struct gxfreq_params *gx_params;
+static int stock_freq;
+
+/* PCI bus clock - defaults to 30.000 if cpu_khz is not available */
+static int pci_busclk;
+module_param(pci_busclk, int, 0444);
+
+/* maximum duration for which the cpu may be suspended
+ * (32us * MAX_DURATION). If no parameter is given, this defaults
+ * to 255.
+ * Note that this leads to a maximum of 8 ms(!) where the CPU clock
+ * is suspended -- processing power is just 0.39% of what it used to be,
+ * though. 781.25 kHz(!) for a 200 MHz processor -- wow. */
+static int max_duration = 255;
+module_param(max_duration, int, 0444);
+
+/* For the default policy, we want at least some processing power
+ * - let's say 5%. (min = maxfreq / POLICY_MIN_DIV)
+ */
+#define POLICY_MIN_DIV 20
+
+
+/**
+ * we can detect a core multipiler from dir0_lsb
+ * from GX1 datasheet p.56,
+ *      MULT[3:0]:
+ *      0000 = SYSCLK multiplied by 4 (test only)
+ *      0001 = SYSCLK multiplied by 10
+ *      0010 = SYSCLK multiplied by 4
+ *      0011 = SYSCLK multiplied by 6
+ *      0100 = SYSCLK multiplied by 9
+ *      0101 = SYSCLK multiplied by 5
+ *      0110 = SYSCLK multiplied by 7
+ *      0111 = SYSCLK multiplied by 8
+ *              of 33.3MHz
+ **/
+static int gx_freq_mult[16] = {
+                4, 10, 4, 6, 9, 5, 7, 8,
+                0, 0, 0, 0, 0, 0, 0, 0
+};
+
+
+/****************************************************************
+ *      Low Level chipset interface                             *
+ ****************************************************************/
+static struct pci_device_id gx_chipset_tbl[] __initdata = {
+        { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY), },
+        { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5520), },
+        { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5510), },
+        { 0, },
+};
+
+static void gx_write_byte(int reg, int value)
+{
+        pci_write_config_byte(gx_params->cs55x0, reg, value);
+}
+
+/**
+ * gx_detect_chipset:
+ *
+ **/
+static __init struct pci_dev *gx_detect_chipset(void)
+{
+        struct pci_dev *gx_pci = NULL;
+
+        /* check if CPU is a MediaGX or a Geode. */
+        if ((boot_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
+            (boot_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
+                pr_debug("error: no MediaGX/Geode processor found!\n");
+                return NULL;
+        }
+
+        /* detect which companion chip is used */
+        for_each_pci_dev(gx_pci) {
+                if ((pci_match_id(gx_chipset_tbl, gx_pci)) != NULL)
+                        return gx_pci;
+        }
+
+        pr_debug("error: no supported chipset found!\n");
+        return NULL;
+}
+
+/**
+ * gx_get_cpuspeed:
+ *
+ * Finds out at which efficient frequency the Cyrix MediaGX/NatSemi
+ * Geode CPU runs.
+ */
+static unsigned int gx_get_cpuspeed(unsigned int cpu)
+{
+        if ((gx_params->pci_suscfg & SUSMOD) == 0)
+                return stock_freq;
+
+        return (stock_freq * gx_params->off_duration)
+                / (gx_params->on_duration + gx_params->off_duration);
+}
+
+/**
+ *      gx_validate_speed:
+ *      determine current cpu speed
+ *
+ **/
+
+static unsigned int gx_validate_speed(unsigned int khz, u8 *on_duration,
+                u8 *off_duration)
+{
+        unsigned int i;
+        u8 tmp_on, tmp_off;
+        int old_tmp_freq = stock_freq;
+        int tmp_freq;
+
+        *off_duration = 1;
+        *on_duration = 0;
+
+        for (i = max_duration; i > 0; i--) {
+                tmp_off = ((khz * i) / stock_freq) & 0xff;
+                tmp_on = i - tmp_off;
+                tmp_freq = (stock_freq * tmp_off) / i;
+                /* if this relation is closer to khz, use this. If it's equal,
+                 * prefer it, too - lower latency */
+                if (abs(tmp_freq - khz) <= abs(old_tmp_freq - khz)) {
+                        *on_duration = tmp_on;
+                        *off_duration = tmp_off;
+                        old_tmp_freq = tmp_freq;
+                }
+        }
+
+        return old_tmp_freq;
+}
+
+
+/**
+ * gx_set_cpuspeed:
+ * set cpu speed in khz.
+ **/
+
+static void gx_set_cpuspeed(unsigned int khz)
+{
+        u8 suscfg, pmer1;
+        unsigned int new_khz;
+        unsigned long flags;
+        struct cpufreq_freqs freqs;
+
+        freqs.cpu = 0;
+        freqs.old = gx_get_cpuspeed(0);
+
+        new_khz = gx_validate_speed(khz, &gx_params->on_duration,
+                        &gx_params->off_duration);
+
+        freqs.new = new_khz;
+
+        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+        local_irq_save(flags);
+
+
+
+        if (new_khz != stock_freq) {
+                /* if new khz == 100% of CPU speed, it is special case */
+                switch (gx_params->cs55x0->device) {
+                case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
+                        pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
+                        /* FIXME: need to test other values -- Zwane,Miura */
+                        /* typical 2 to 4ms */
+                        gx_write_byte(PCI_IRQTC, 4);
+                        /* typical 50 to 100ms */
+                        gx_write_byte(PCI_VIDTC, 100);
+                        gx_write_byte(PCI_PMER1, pmer1);
+
+                        if (gx_params->cs55x0->revision < 0x10) {
+                                /* CS5530(rev 1.2, 1.3) */
+                                suscfg = gx_params->pci_suscfg|SUSMOD;
+                        } else {
+                                /* CS5530A,B.. */
+                                suscfg = gx_params->pci_suscfg|SUSMOD|PWRSVE;
+                        }
+                        break;
+                case PCI_DEVICE_ID_CYRIX_5520:
+                case PCI_DEVICE_ID_CYRIX_5510:
+                        suscfg = gx_params->pci_suscfg | SUSMOD;
+                        break;
+                default:
+                        local_irq_restore(flags);
+                        pr_debug("fatal: try to set unknown chipset.\n");
+                        return;
+                }
+        } else {
+                suscfg = gx_params->pci_suscfg & ~(SUSMOD);
+                gx_params->off_duration = 0;
+                gx_params->on_duration = 0;
+                pr_debug("suspend modulation disabled: cpu runs 100%% speed.\n");
+        }
+
+        gx_write_byte(PCI_MODOFF, gx_params->off_duration);
+        gx_write_byte(PCI_MODON, gx_params->on_duration);
+
+        gx_write_byte(PCI_SUSCFG, suscfg);
+        pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);
+
+        local_irq_restore(flags);
+
+        gx_params->pci_suscfg = suscfg;
+
+        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+        pr_debug("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
+                gx_params->on_duration * 32, gx_params->off_duration * 32);
+        pr_debug("suspend modulation w/ clock speed: %d kHz.\n", freqs.new);
+}
+
+/****************************************************************
+ *             High level functions                             *
+ ****************************************************************/
+
+/*
+ *      cpufreq_gx_verify: test if frequency range is valid
+ *
+ *      This function checks if a given frequency range in kHz is valid
+ *      for the hardware supported by the driver.
+ */
+
+static int cpufreq_gx_verify(struct cpufreq_policy *policy)
+{
+        unsigned int tmp_freq = 0;
+        u8 tmp1, tmp2;
+
+        if (!stock_freq || !policy)
+                return -EINVAL;
+
+        policy->cpu = 0;
+        cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
+                        stock_freq);
+
+        /* it needs to be assured that at least one supported frequency is
+         * within policy->min and policy->max. If it is not, policy->max
+         * needs to be increased until one freuqency is supported.
+         * policy->min may not be decreased, though. This way we guarantee a
+         * specific processing capacity.
+         */
+        tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
+        if (tmp_freq < policy->min)
+                tmp_freq += stock_freq / max_duration;
+        policy->min = tmp_freq;
+        if (policy->min > policy->max)
+                policy->max = tmp_freq;
+        tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
+        if (tmp_freq > policy->max)
+                tmp_freq -= stock_freq / max_duration;
+        policy->max = tmp_freq;
+        if (policy->max < policy->min)
+                policy->max = policy->min;
+        cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
+                        stock_freq);
+
+        return 0;
+}
+
+/*
+ *      cpufreq_gx_target:
+ *
+ */
+static int cpufreq_gx_target(struct cpufreq_policy *policy,
+                             unsigned int target_freq,
+                             unsigned int relation)
+{
+        u8 tmp1, tmp2;
+        unsigned int tmp_freq;
+
+        if (!stock_freq || !policy)
+                return -EINVAL;
+
+        policy->cpu = 0;
+
+        tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
+        while (tmp_freq < policy->min) {
+                tmp_freq += stock_freq / max_duration;
+                tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
+        }
+        while (tmp_freq > policy->max) {
+                tmp_freq -= stock_freq / max_duration;
+                tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
+        }
+
+        gx_set_cpuspeed(tmp_freq);
+
+        return 0;
+}
+
+static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
+{
+        unsigned int maxfreq, curfreq;
+
+        if (!policy || policy->cpu != 0)
+                return -ENODEV;
+
+        /* determine maximum frequency */
+        if (pci_busclk)
+                maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
+        else if (cpu_khz)
+                maxfreq = cpu_khz;
+        else
+                maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
+
+        stock_freq = maxfreq;
+        curfreq = gx_get_cpuspeed(0);
+
+        pr_debug("cpu max frequency is %d.\n", maxfreq);
+        pr_debug("cpu current frequency is %dkHz.\n", curfreq);
+
+        /* setup basic struct for cpufreq API */
+        policy->cpu = 0;
+
+        if (max_duration < POLICY_MIN_DIV)
+                policy->min = maxfreq / max_duration;
+        else
+                policy->min = maxfreq / POLICY_MIN_DIV;
+        policy->max = maxfreq;
+        policy->cur = curfreq;
+        policy->cpuinfo.min_freq = maxfreq / max_duration;
+        policy->cpuinfo.max_freq = maxfreq;
+        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+
+        return 0;
+}
+
+/*
+ * cpufreq_gx_init:
+ *   MediaGX/Geode GX initialize cpufreq driver
+ */
+static struct cpufreq_driver gx_suspmod_driver = {
+        .get            = gx_get_cpuspeed,
+        .verify         = cpufreq_gx_verify,
+        .target         = cpufreq_gx_target,
+        .init           = cpufreq_gx_cpu_init,
+        .name           = "gx-suspmod",
+        .owner          = THIS_MODULE,
+};
+
+static int __init cpufreq_gx_init(void)
+{
+        int ret;
+        struct gxfreq_params *params;
+        struct pci_dev *gx_pci;
+
+        /* Test if we have the right hardware */
+        gx_pci = gx_detect_chipset();
+        if (gx_pci == NULL)
+                return -ENODEV;
+
+        /* check whether module parameters are sane */
+        if (max_duration > 0xff)
+                max_duration = 0xff;
+
+        pr_debug("geode suspend modulation available.\n");
+
+        params = kzalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
+        if (params == NULL)
+                return -ENOMEM;
+
+        params->cs55x0 = gx_pci;
+        gx_params = params;
+
+        /* keep cs55x0 configurations */
+        pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
+        pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
+        pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
+        pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
+        pci_read_config_byte(params->cs55x0, PCI_MODOFF,
+                        &(params->off_duration));
+
+        ret = cpufreq_register_driver(&gx_suspmod_driver);
+        if (ret) {
+                kfree(params);
+                return ret;                   /* register error! */
+        }
+
+        return 0;
+}
+
+static void __exit cpufreq_gx_exit(void)
+{
+        cpufreq_unregister_driver(&gx_suspmod_driver);
+        pci_dev_put(gx_params->cs55x0);
+        kfree(gx_params);
+}
+
+MODULE_AUTHOR("Hiroshi Miura <miura@da-cha.org>");
+MODULE_DESCRIPTION("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
+MODULE_LICENSE("GPL");
+
+module_init(cpufreq_gx_init);
+module_exit(cpufreq_gx_exit);
+