// SPDX-License-Identifier: GPL-2.0 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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);