467 lines
12 KiB
C
467 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <linux/pci.h>
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#include <asm/dma.h>
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#include <linux/io.h>
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#include <asm/processor-cyrix.h>
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#include <asm/processor-flags.h>
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#include <linux/timer.h>
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#include <asm/pci-direct.h>
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#include <asm/tsc.h>
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#include <asm/cpufeature.h>
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#include <linux/sched.h>
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#include <linux/sched/clock.h>
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#include "cpu.h"
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/*
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* Read NSC/Cyrix DEVID registers (DIR) to get more detailed info. about the CPU
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*/
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static void __do_cyrix_devid(unsigned char *dir0, unsigned char *dir1)
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{
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unsigned char ccr2, ccr3;
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/* we test for DEVID by checking whether CCR3 is writable */
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ccr3 = getCx86(CX86_CCR3);
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setCx86(CX86_CCR3, ccr3 ^ 0x80);
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getCx86(0xc0); /* dummy to change bus */
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if (getCx86(CX86_CCR3) == ccr3) { /* no DEVID regs. */
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ccr2 = getCx86(CX86_CCR2);
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setCx86(CX86_CCR2, ccr2 ^ 0x04);
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getCx86(0xc0); /* dummy */
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if (getCx86(CX86_CCR2) == ccr2) /* old Cx486SLC/DLC */
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*dir0 = 0xfd;
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else { /* Cx486S A step */
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setCx86(CX86_CCR2, ccr2);
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*dir0 = 0xfe;
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}
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} else {
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setCx86(CX86_CCR3, ccr3); /* restore CCR3 */
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/* read DIR0 and DIR1 CPU registers */
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*dir0 = getCx86(CX86_DIR0);
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*dir1 = getCx86(CX86_DIR1);
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}
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}
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static void do_cyrix_devid(unsigned char *dir0, unsigned char *dir1)
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{
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unsigned long flags;
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local_irq_save(flags);
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__do_cyrix_devid(dir0, dir1);
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local_irq_restore(flags);
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}
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/*
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* Cx86_dir0_msb is a HACK needed by check_cx686_cpuid/slop in bugs.h in
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* order to identify the Cyrix CPU model after we're out of setup.c
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*
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* Actually since bugs.h doesn't even reference this perhaps someone should
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* fix the documentation ???
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*/
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static unsigned char Cx86_dir0_msb = 0;
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static const char Cx86_model[][9] = {
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"Cx486", "Cx486", "5x86 ", "6x86", "MediaGX ", "6x86MX ",
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"M II ", "Unknown"
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};
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static const char Cx486_name[][5] = {
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"SLC", "DLC", "SLC2", "DLC2", "SRx", "DRx",
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"SRx2", "DRx2"
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};
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static const char Cx486S_name[][4] = {
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"S", "S2", "Se", "S2e"
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};
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static const char Cx486D_name[][4] = {
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"DX", "DX2", "?", "?", "?", "DX4"
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};
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static char Cx86_cb[] = "?.5x Core/Bus Clock";
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static const char cyrix_model_mult1[] = "12??43";
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static const char cyrix_model_mult2[] = "12233445";
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/*
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* Reset the slow-loop (SLOP) bit on the 686(L) which is set by some old
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* BIOSes for compatibility with DOS games. This makes the udelay loop
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* work correctly, and improves performance.
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*
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* FIXME: our newer udelay uses the tsc. We don't need to frob with SLOP
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*/
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static void check_cx686_slop(struct cpuinfo_x86 *c)
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{
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unsigned long flags;
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if (Cx86_dir0_msb == 3) {
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unsigned char ccr3, ccr5;
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local_irq_save(flags);
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ccr3 = getCx86(CX86_CCR3);
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setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */
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ccr5 = getCx86(CX86_CCR5);
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if (ccr5 & 2)
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setCx86(CX86_CCR5, ccr5 & 0xfd); /* reset SLOP */
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setCx86(CX86_CCR3, ccr3); /* disable MAPEN */
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local_irq_restore(flags);
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if (ccr5 & 2) { /* possible wrong calibration done */
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pr_info("Recalibrating delay loop with SLOP bit reset\n");
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calibrate_delay();
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c->loops_per_jiffy = loops_per_jiffy;
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}
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}
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}
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static void set_cx86_reorder(void)
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{
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u8 ccr3;
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pr_info("Enable Memory access reorder on Cyrix/NSC processor.\n");
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ccr3 = getCx86(CX86_CCR3);
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setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */
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/* Load/Store Serialize to mem access disable (=reorder it) */
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setCx86_old(CX86_PCR0, getCx86_old(CX86_PCR0) & ~0x80);
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/* set load/store serialize from 1GB to 4GB */
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ccr3 |= 0xe0;
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setCx86(CX86_CCR3, ccr3);
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}
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static void set_cx86_memwb(void)
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{
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pr_info("Enable Memory-Write-back mode on Cyrix/NSC processor.\n");
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/* CCR2 bit 2: unlock NW bit */
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setCx86_old(CX86_CCR2, getCx86_old(CX86_CCR2) & ~0x04);
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/* set 'Not Write-through' */
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write_cr0(read_cr0() | X86_CR0_NW);
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/* CCR2 bit 2: lock NW bit and set WT1 */
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setCx86_old(CX86_CCR2, getCx86_old(CX86_CCR2) | 0x14);
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}
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/*
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* Configure later MediaGX and/or Geode processor.
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*/
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static void geode_configure(void)
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{
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unsigned long flags;
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u8 ccr3;
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local_irq_save(flags);
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/* Suspend on halt power saving and enable #SUSP pin */
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setCx86_old(CX86_CCR2, getCx86_old(CX86_CCR2) | 0x88);
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ccr3 = getCx86(CX86_CCR3);
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setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */
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/* FPU fast, DTE cache, Mem bypass */
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setCx86_old(CX86_CCR4, getCx86_old(CX86_CCR4) | 0x38);
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setCx86(CX86_CCR3, ccr3); /* disable MAPEN */
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set_cx86_memwb();
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set_cx86_reorder();
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local_irq_restore(flags);
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}
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static void early_init_cyrix(struct cpuinfo_x86 *c)
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{
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unsigned char dir0, dir0_msn, dir1 = 0;
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__do_cyrix_devid(&dir0, &dir1);
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dir0_msn = dir0 >> 4; /* identifies CPU "family" */
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switch (dir0_msn) {
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case 3: /* 6x86/6x86L */
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/* Emulate MTRRs using Cyrix's ARRs. */
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set_cpu_cap(c, X86_FEATURE_CYRIX_ARR);
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break;
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case 5: /* 6x86MX/M II */
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/* Emulate MTRRs using Cyrix's ARRs. */
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set_cpu_cap(c, X86_FEATURE_CYRIX_ARR);
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break;
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}
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}
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static void init_cyrix(struct cpuinfo_x86 *c)
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{
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unsigned char dir0, dir0_msn, dir0_lsn, dir1 = 0;
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char *buf = c->x86_model_id;
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const char *p = NULL;
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/*
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* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
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* 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
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*/
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clear_cpu_cap(c, 0*32+31);
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/* Cyrix used bit 24 in extended (AMD) CPUID for Cyrix MMX extensions */
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if (test_cpu_cap(c, 1*32+24)) {
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clear_cpu_cap(c, 1*32+24);
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set_cpu_cap(c, X86_FEATURE_CXMMX);
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}
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do_cyrix_devid(&dir0, &dir1);
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check_cx686_slop(c);
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Cx86_dir0_msb = dir0_msn = dir0 >> 4; /* identifies CPU "family" */
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dir0_lsn = dir0 & 0xf; /* model or clock multiplier */
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/* common case step number/rev -- exceptions handled below */
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c->x86_model = (dir1 >> 4) + 1;
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c->x86_stepping = dir1 & 0xf;
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/* Now cook; the original recipe is by Channing Corn, from Cyrix.
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* We do the same thing for each generation: we work out
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* the model, multiplier and stepping. Black magic included,
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* to make the silicon step/rev numbers match the printed ones.
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*/
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switch (dir0_msn) {
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unsigned char tmp;
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case 0: /* Cx486SLC/DLC/SRx/DRx */
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p = Cx486_name[dir0_lsn & 7];
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break;
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case 1: /* Cx486S/DX/DX2/DX4 */
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p = (dir0_lsn & 8) ? Cx486D_name[dir0_lsn & 5]
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: Cx486S_name[dir0_lsn & 3];
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break;
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case 2: /* 5x86 */
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Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5];
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p = Cx86_cb+2;
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break;
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case 3: /* 6x86/6x86L */
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Cx86_cb[1] = ' ';
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Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5];
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if (dir1 > 0x21) { /* 686L */
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Cx86_cb[0] = 'L';
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p = Cx86_cb;
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(c->x86_model)++;
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} else /* 686 */
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p = Cx86_cb+1;
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/* Emulate MTRRs using Cyrix's ARRs. */
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set_cpu_cap(c, X86_FEATURE_CYRIX_ARR);
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/* 6x86's contain this bug */
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set_cpu_bug(c, X86_BUG_COMA);
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break;
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case 4: /* MediaGX/GXm or Geode GXM/GXLV/GX1 */
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case 11: /* GX1 with inverted Device ID */
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#ifdef CONFIG_PCI
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{
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u32 vendor, device;
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/*
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* It isn't really a PCI quirk directly, but the cure is the
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* same. The MediaGX has deep magic SMM stuff that handles the
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* SB emulation. It throws away the fifo on disable_dma() which
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* is wrong and ruins the audio.
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*
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* Bug2: VSA1 has a wrap bug so that using maximum sized DMA
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* causes bad things. According to NatSemi VSA2 has another
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* bug to do with 'hlt'. I've not seen any boards using VSA2
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* and X doesn't seem to support it either so who cares 8).
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* VSA1 we work around however.
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*/
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pr_info("Working around Cyrix MediaGX virtual DMA bugs.\n");
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isa_dma_bridge_buggy = 2;
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/* We do this before the PCI layer is running. However we
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are safe here as we know the bridge must be a Cyrix
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companion and must be present */
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vendor = read_pci_config_16(0, 0, 0x12, PCI_VENDOR_ID);
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device = read_pci_config_16(0, 0, 0x12, PCI_DEVICE_ID);
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/*
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* The 5510/5520 companion chips have a funky PIT.
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*/
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if (vendor == PCI_VENDOR_ID_CYRIX &&
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(device == PCI_DEVICE_ID_CYRIX_5510 ||
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device == PCI_DEVICE_ID_CYRIX_5520))
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mark_tsc_unstable("cyrix 5510/5520 detected");
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}
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#endif
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c->x86_cache_size = 16; /* Yep 16K integrated cache thats it */
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/* GXm supports extended cpuid levels 'ala' AMD */
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if (c->cpuid_level == 2) {
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/* Enable cxMMX extensions (GX1 Datasheet 54) */
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setCx86_old(CX86_CCR7, getCx86_old(CX86_CCR7) | 1);
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/*
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* GXm : 0x30 ... 0x5f GXm datasheet 51
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* GXlv: 0x6x GXlv datasheet 54
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* ? : 0x7x
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* GX1 : 0x8x GX1 datasheet 56
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*/
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if ((0x30 <= dir1 && dir1 <= 0x6f) ||
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(0x80 <= dir1 && dir1 <= 0x8f))
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geode_configure();
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return;
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} else { /* MediaGX */
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Cx86_cb[2] = (dir0_lsn & 1) ? '3' : '4';
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p = Cx86_cb+2;
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c->x86_model = (dir1 & 0x20) ? 1 : 2;
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}
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break;
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case 5: /* 6x86MX/M II */
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if (dir1 > 7) {
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dir0_msn++; /* M II */
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/* Enable MMX extensions (App note 108) */
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setCx86_old(CX86_CCR7, getCx86_old(CX86_CCR7)|1);
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} else {
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/* A 6x86MX - it has the bug. */
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set_cpu_bug(c, X86_BUG_COMA);
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}
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tmp = (!(dir0_lsn & 7) || dir0_lsn & 1) ? 2 : 0;
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Cx86_cb[tmp] = cyrix_model_mult2[dir0_lsn & 7];
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p = Cx86_cb+tmp;
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if (((dir1 & 0x0f) > 4) || ((dir1 & 0xf0) == 0x20))
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(c->x86_model)++;
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/* Emulate MTRRs using Cyrix's ARRs. */
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set_cpu_cap(c, X86_FEATURE_CYRIX_ARR);
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break;
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case 0xf: /* Cyrix 486 without DEVID registers */
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switch (dir0_lsn) {
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case 0xd: /* either a 486SLC or DLC w/o DEVID */
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dir0_msn = 0;
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p = Cx486_name[!!boot_cpu_has(X86_FEATURE_FPU)];
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break;
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case 0xe: /* a 486S A step */
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dir0_msn = 0;
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p = Cx486S_name[0];
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break;
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}
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break;
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default: /* unknown (shouldn't happen, we know everyone ;-) */
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dir0_msn = 7;
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break;
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}
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strcpy(buf, Cx86_model[dir0_msn & 7]);
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if (p)
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strcat(buf, p);
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return;
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}
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/*
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* Handle National Semiconductor branded processors
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*/
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static void init_nsc(struct cpuinfo_x86 *c)
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{
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/*
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* There may be GX1 processors in the wild that are branded
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* NSC and not Cyrix.
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*
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* This function only handles the GX processor, and kicks every
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* thing else to the Cyrix init function above - that should
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* cover any processors that might have been branded differently
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* after NSC acquired Cyrix.
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*
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* If this breaks your GX1 horribly, please e-mail
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* info-linux@ldcmail.amd.com to tell us.
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*/
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/* Handle the GX (Formally known as the GX2) */
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if (c->x86 == 5 && c->x86_model == 5)
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cpu_detect_cache_sizes(c);
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else
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init_cyrix(c);
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}
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/*
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* Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
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* by the fact that they preserve the flags across the division of 5/2.
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* PII and PPro exhibit this behavior too, but they have cpuid available.
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*/
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/*
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* Perform the Cyrix 5/2 test. A Cyrix won't change
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* the flags, while other 486 chips will.
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*/
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static inline int test_cyrix_52div(void)
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{
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unsigned int test;
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__asm__ __volatile__(
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"sahf\n\t" /* clear flags (%eax = 0x0005) */
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"div %b2\n\t" /* divide 5 by 2 */
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"lahf" /* store flags into %ah */
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: "=a" (test)
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: "0" (5), "q" (2)
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: "cc");
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/* AH is 0x02 on Cyrix after the divide.. */
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return (unsigned char) (test >> 8) == 0x02;
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}
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static void cyrix_identify(struct cpuinfo_x86 *c)
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{
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/* Detect Cyrix with disabled CPUID */
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if (c->x86 == 4 && test_cyrix_52div()) {
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unsigned char dir0, dir1;
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strcpy(c->x86_vendor_id, "CyrixInstead");
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c->x86_vendor = X86_VENDOR_CYRIX;
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/* Actually enable cpuid on the older cyrix */
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/* Retrieve CPU revisions */
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do_cyrix_devid(&dir0, &dir1);
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dir0 >>= 4;
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/* Check it is an affected model */
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if (dir0 == 5 || dir0 == 3) {
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unsigned char ccr3;
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unsigned long flags;
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pr_info("Enabling CPUID on Cyrix processor.\n");
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local_irq_save(flags);
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ccr3 = getCx86(CX86_CCR3);
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/* enable MAPEN */
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setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);
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/* enable cpuid */
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setCx86_old(CX86_CCR4, getCx86_old(CX86_CCR4) | 0x80);
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/* disable MAPEN */
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setCx86(CX86_CCR3, ccr3);
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local_irq_restore(flags);
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}
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}
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}
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static const struct cpu_dev cyrix_cpu_dev = {
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.c_vendor = "Cyrix",
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.c_ident = { "CyrixInstead" },
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.c_early_init = early_init_cyrix,
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.c_init = init_cyrix,
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.c_identify = cyrix_identify,
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.c_x86_vendor = X86_VENDOR_CYRIX,
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};
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cpu_dev_register(cyrix_cpu_dev);
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static const struct cpu_dev nsc_cpu_dev = {
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.c_vendor = "NSC",
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.c_ident = { "Geode by NSC" },
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.c_init = init_nsc,
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.c_x86_vendor = X86_VENDOR_NSC,
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};
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cpu_dev_register(nsc_cpu_dev);
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