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