diff options
Diffstat (limited to 'kernel/drivers/cpufreq/cpufreq-nforce2.c')
| -rw-r--r-- | kernel/drivers/cpufreq/cpufreq-nforce2.c | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/kernel/drivers/cpufreq/cpufreq-nforce2.c b/kernel/drivers/cpufreq/cpufreq-nforce2.c new file mode 100644 index 000000000..a2258090b --- /dev/null +++ b/kernel/drivers/cpufreq/cpufreq-nforce2.c @@ -0,0 +1,445 @@ +/* + * (C) 2004-2006 Sebastian Witt <se.witt@gmx.net> + * + * Licensed under the terms of the GNU GPL License version 2. + * Based upon reverse engineered information + * + * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/init.h> +#include <linux/cpufreq.h> +#include <linux/pci.h> +#include <linux/delay.h> + +#define NFORCE2_XTAL 25 +#define NFORCE2_BOOTFSB 0x48 +#define NFORCE2_PLLENABLE 0xa8 +#define NFORCE2_PLLREG 0xa4 +#define NFORCE2_PLLADR 0xa0 +#define NFORCE2_PLL(mul, div) (0x100000 | (mul << 8) | div) + +#define NFORCE2_MIN_FSB 50 +#define NFORCE2_SAFE_DISTANCE 50 + +/* Delay in ms between FSB changes */ +/* #define NFORCE2_DELAY 10 */ + +/* + * nforce2_chipset: + * FSB is changed using the chipset + */ +static struct pci_dev *nforce2_dev; + +/* fid: + * multiplier * 10 + */ +static int fid; + +/* min_fsb, max_fsb: + * minimum and maximum FSB (= FSB at boot time) + */ +static int min_fsb; +static int max_fsb; + +MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>"); +MODULE_DESCRIPTION("nForce2 FSB changing cpufreq driver"); +MODULE_LICENSE("GPL"); + +module_param(fid, int, 0444); +module_param(min_fsb, int, 0444); + +MODULE_PARM_DESC(fid, "CPU multiplier to use (11.5 = 115)"); +MODULE_PARM_DESC(min_fsb, + "Minimum FSB to use, if not defined: current FSB - 50"); + +#define PFX "cpufreq-nforce2: " + +/** + * nforce2_calc_fsb - calculate FSB + * @pll: PLL value + * + * Calculates FSB from PLL value + */ +static int nforce2_calc_fsb(int pll) +{ + unsigned char mul, div; + + mul = (pll >> 8) & 0xff; + div = pll & 0xff; + + if (div > 0) + return NFORCE2_XTAL * mul / div; + + return 0; +} + +/** + * nforce2_calc_pll - calculate PLL value + * @fsb: FSB + * + * Calculate PLL value for given FSB + */ +static int nforce2_calc_pll(unsigned int fsb) +{ + unsigned char xmul, xdiv; + unsigned char mul = 0, div = 0; + int tried = 0; + + /* Try to calculate multiplier and divider up to 4 times */ + while (((mul == 0) || (div == 0)) && (tried <= 3)) { + for (xdiv = 2; xdiv <= 0x80; xdiv++) + for (xmul = 1; xmul <= 0xfe; xmul++) + if (nforce2_calc_fsb(NFORCE2_PLL(xmul, xdiv)) == + fsb + tried) { + mul = xmul; + div = xdiv; + } + tried++; + } + + if ((mul == 0) || (div == 0)) + return -1; + + return NFORCE2_PLL(mul, div); +} + +/** + * nforce2_write_pll - write PLL value to chipset + * @pll: PLL value + * + * Writes new FSB PLL value to chipset + */ +static void nforce2_write_pll(int pll) +{ + int temp; + + /* Set the pll addr. to 0x00 */ + pci_write_config_dword(nforce2_dev, NFORCE2_PLLADR, 0); + + /* Now write the value in all 64 registers */ + for (temp = 0; temp <= 0x3f; temp++) + pci_write_config_dword(nforce2_dev, NFORCE2_PLLREG, pll); + + return; +} + +/** + * nforce2_fsb_read - Read FSB + * + * Read FSB from chipset + * If bootfsb != 0, return FSB at boot-time + */ +static unsigned int nforce2_fsb_read(int bootfsb) +{ + struct pci_dev *nforce2_sub5; + u32 fsb, temp = 0; + + /* Get chipset boot FSB from subdevice 5 (FSB at boot-time) */ + nforce2_sub5 = pci_get_subsys(PCI_VENDOR_ID_NVIDIA, 0x01EF, + PCI_ANY_ID, PCI_ANY_ID, NULL); + if (!nforce2_sub5) + return 0; + + pci_read_config_dword(nforce2_sub5, NFORCE2_BOOTFSB, &fsb); + fsb /= 1000000; + + /* Check if PLL register is already set */ + pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp); + + if (bootfsb || !temp) + return fsb; + + /* Use PLL register FSB value */ + pci_read_config_dword(nforce2_dev, NFORCE2_PLLREG, &temp); + fsb = nforce2_calc_fsb(temp); + + return fsb; +} + +/** + * nforce2_set_fsb - set new FSB + * @fsb: New FSB + * + * Sets new FSB + */ +static int nforce2_set_fsb(unsigned int fsb) +{ + u32 temp = 0; + unsigned int tfsb; + int diff; + int pll = 0; + + if ((fsb > max_fsb) || (fsb < NFORCE2_MIN_FSB)) { + printk(KERN_ERR PFX "FSB %d is out of range!\n", fsb); + return -EINVAL; + } + + tfsb = nforce2_fsb_read(0); + if (!tfsb) { + printk(KERN_ERR PFX "Error while reading the FSB\n"); + return -EINVAL; + } + + /* First write? Then set actual value */ + pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp); + if (!temp) { + pll = nforce2_calc_pll(tfsb); + + if (pll < 0) + return -EINVAL; + + nforce2_write_pll(pll); + } + + /* Enable write access */ + temp = 0x01; + pci_write_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8)temp); + + diff = tfsb - fsb; + + if (!diff) + return 0; + + while ((tfsb != fsb) && (tfsb <= max_fsb) && (tfsb >= min_fsb)) { + if (diff < 0) + tfsb++; + else + tfsb--; + + /* Calculate the PLL reg. value */ + pll = nforce2_calc_pll(tfsb); + if (pll == -1) + return -EINVAL; + + nforce2_write_pll(pll); +#ifdef NFORCE2_DELAY + mdelay(NFORCE2_DELAY); +#endif + } + + temp = 0x40; + pci_write_config_byte(nforce2_dev, NFORCE2_PLLADR, (u8)temp); + + return 0; +} + +/** + * nforce2_get - get the CPU frequency + * @cpu: CPU number + * + * Returns the CPU frequency + */ +static unsigned int nforce2_get(unsigned int cpu) +{ + if (cpu) + return 0; + return nforce2_fsb_read(0) * fid * 100; +} + +/** + * nforce2_target - set a new CPUFreq policy + * @policy: new policy + * @target_freq: the target frequency + * @relation: how that frequency relates to achieved frequency + * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H) + * + * Sets a new CPUFreq policy. + */ +static int nforce2_target(struct cpufreq_policy *policy, + unsigned int target_freq, unsigned int relation) +{ +/* unsigned long flags; */ + struct cpufreq_freqs freqs; + unsigned int target_fsb; + + if ((target_freq > policy->max) || (target_freq < policy->min)) + return -EINVAL; + + target_fsb = target_freq / (fid * 100); + + freqs.old = nforce2_get(policy->cpu); + freqs.new = target_fsb * fid * 100; + + if (freqs.old == freqs.new) + return 0; + + pr_debug("Old CPU frequency %d kHz, new %d kHz\n", + freqs.old, freqs.new); + + cpufreq_freq_transition_begin(policy, &freqs); + + /* Disable IRQs */ + /* local_irq_save(flags); */ + + if (nforce2_set_fsb(target_fsb) < 0) + printk(KERN_ERR PFX "Changing FSB to %d failed\n", + target_fsb); + else + pr_debug("Changed FSB successfully to %d\n", + target_fsb); + + /* Enable IRQs */ + /* local_irq_restore(flags); */ + + cpufreq_freq_transition_end(policy, &freqs, 0); + + return 0; +} + +/** + * nforce2_verify - verifies a new CPUFreq policy + * @policy: new policy + */ +static int nforce2_verify(struct cpufreq_policy *policy) +{ + unsigned int fsb_pol_max; + + fsb_pol_max = policy->max / (fid * 100); + + if (policy->min < (fsb_pol_max * fid * 100)) + policy->max = (fsb_pol_max + 1) * fid * 100; + + cpufreq_verify_within_cpu_limits(policy); + return 0; +} + +static int nforce2_cpu_init(struct cpufreq_policy *policy) +{ + unsigned int fsb; + unsigned int rfid; + + /* capability check */ + if (policy->cpu != 0) + return -ENODEV; + + /* Get current FSB */ + fsb = nforce2_fsb_read(0); + + if (!fsb) + return -EIO; + + /* FIX: Get FID from CPU */ + if (!fid) { + if (!cpu_khz) { + printk(KERN_WARNING PFX + "cpu_khz not set, can't calculate multiplier!\n"); + return -ENODEV; + } + + fid = cpu_khz / (fsb * 100); + rfid = fid % 5; + + if (rfid) { + if (rfid > 2) + fid += 5 - rfid; + else + fid -= rfid; + } + } + + printk(KERN_INFO PFX "FSB currently at %i MHz, FID %d.%d\n", fsb, + fid / 10, fid % 10); + + /* Set maximum FSB to FSB at boot time */ + max_fsb = nforce2_fsb_read(1); + + if (!max_fsb) + return -EIO; + + if (!min_fsb) + min_fsb = max_fsb - NFORCE2_SAFE_DISTANCE; + + if (min_fsb < NFORCE2_MIN_FSB) + min_fsb = NFORCE2_MIN_FSB; + + /* cpuinfo and default policy values */ + policy->min = policy->cpuinfo.min_freq = min_fsb * fid * 100; + policy->max = policy->cpuinfo.max_freq = max_fsb * fid * 100; + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + + return 0; +} + +static int nforce2_cpu_exit(struct cpufreq_policy *policy) +{ + return 0; +} + +static struct cpufreq_driver nforce2_driver = { + .name = "nforce2", + .verify = nforce2_verify, + .target = nforce2_target, + .get = nforce2_get, + .init = nforce2_cpu_init, + .exit = nforce2_cpu_exit, +}; + +#ifdef MODULE +static const struct pci_device_id nforce2_ids[] = { + { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE2 }, + {} +}; +MODULE_DEVICE_TABLE(pci, nforce2_ids); +#endif + +/** + * nforce2_detect_chipset - detect the Southbridge which contains FSB PLL logic + * + * Detects nForce2 A2 and C1 stepping + * + */ +static int nforce2_detect_chipset(void) +{ + nforce2_dev = pci_get_subsys(PCI_VENDOR_ID_NVIDIA, + PCI_DEVICE_ID_NVIDIA_NFORCE2, + PCI_ANY_ID, PCI_ANY_ID, NULL); + + if (nforce2_dev == NULL) + return -ENODEV; + + printk(KERN_INFO PFX "Detected nForce2 chipset revision %X\n", + nforce2_dev->revision); + printk(KERN_INFO PFX + "FSB changing is maybe unstable and can lead to " + "crashes and data loss.\n"); + + return 0; +} + +/** + * nforce2_init - initializes the nForce2 CPUFreq driver + * + * Initializes the nForce2 FSB support. Returns -ENODEV on unsupported + * devices, -EINVAL on problems during initiatization, and zero on + * success. + */ +static int __init nforce2_init(void) +{ + /* TODO: do we need to detect the processor? */ + + /* detect chipset */ + if (nforce2_detect_chipset()) { + printk(KERN_INFO PFX "No nForce2 chipset.\n"); + return -ENODEV; + } + + return cpufreq_register_driver(&nforce2_driver); +} + +/** + * nforce2_exit - unregisters cpufreq module + * + * Unregisters nForce2 FSB change support. + */ +static void __exit nforce2_exit(void) +{ + cpufreq_unregister_driver(&nforce2_driver); +} + +module_init(nforce2_init); +module_exit(nforce2_exit); + |