/* * Cyrix MediaGX and NatSemi Geode Suspend Modulation * (C) 2002 Zwane Mwaikambo * (C) 2002 Hiroshi Miura * 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 * - fix on/off register mistake * - fix cpu_khz calc when it stops cpu modulation. * * Dec. 11, 2002 Hiroshi Miura * - rewrite for Cyrix MediaGX Cx5510/5520 and * NatSemi Geode Cs5530(A). * * Jul. ??, 2002 Zwane Mwaikambo * - cs5530_mod patch for 2.4.19-rc1. * *--------------------------------------------------------------------------- * * Todo * Test on machines with 5510, 5530, 5530A */ /************************************************************************ * Suspend Modulation - Definitions * ************************************************************************/ #include #include #include #include #include #include #include #include #include #include /* 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, }, }; 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 __init struct pci_dev *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(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 "); MODULE_DESCRIPTION("Cpufreq driver for Cyrix MediaGX and NatSemi Geode"); MODULE_LICENSE("GPL"); module_init(cpufreq_gx_init); module_exit(cpufreq_gx_exit);