| /* |
| * 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/cpu_device_id.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 multiplier 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, }, |
| }; |
| MODULE_DEVICE_TABLE(pci, gx_chipset_tbl); |
| |
| static void gx_write_byte(int reg, int value) |
| { |
| pci_write_config_byte(gx_params->cs55x0, reg, value); |
| } |
| |
| /** |
| * gx_detect_chipset: |
| * |
| **/ |
| static struct pci_dev * __init gx_detect_chipset(void) |
| { |
| struct pci_dev *gx_pci = 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(struct cpufreq_policy *policy, unsigned int khz) |
| { |
| u8 suscfg, pmer1; |
| unsigned int new_khz; |
| unsigned long flags; |
| struct cpufreq_freqs freqs; |
| |
| 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_freq_transition_begin(policy, &freqs); |
| 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_freq_transition_end(policy, &freqs, 0); |
| |
| 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 frequency 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(policy, tmp_freq); |
| |
| return 0; |
| } |
| |
| static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy) |
| { |
| unsigned int maxfreq; |
| |
| 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; |
| |
| pr_debug("cpu max frequency is %d.\n", maxfreq); |
| |
| /* 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->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", |
| }; |
| |
| 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(*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); |
| |