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