diff options
Diffstat (limited to 'arch/x86/kernel/cpu/cyrix.c')
-rw-r--r-- | arch/x86/kernel/cpu/cyrix.c | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c new file mode 100644 index 0000000000..9651275aec --- /dev/null +++ b/arch/x86/kernel/cpu/cyrix.c @@ -0,0 +1,467 @@ +// 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); |