1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bitops.h> 3 #include <linux/delay.h> 4 #include <linux/pci.h> 5 #include <asm/dma.h> 6 #include <linux/io.h> 7 #include <asm/processor-cyrix.h> 8 #include <asm/processor-flags.h> 9 #include <linux/timer.h> 10 #include <asm/pci-direct.h> 11 #include <asm/tsc.h> 12 #include <asm/cpufeature.h> 13 #include <linux/sched.h> 14 #include <linux/sched/clock.h> 15 16 #include "cpu.h" 17 18 /* 19 * Read NSC/Cyrix DEVID registers (DIR) to get more detailed info. about the CPU 20 */ 21 static void __do_cyrix_devid(unsigned char *dir0, unsigned char *dir1) 22 { 23 unsigned char ccr2, ccr3; 24 25 /* we test for DEVID by checking whether CCR3 is writable */ 26 ccr3 = getCx86(CX86_CCR3); 27 setCx86(CX86_CCR3, ccr3 ^ 0x80); 28 getCx86(0xc0); /* dummy to change bus */ 29 30 if (getCx86(CX86_CCR3) == ccr3) { /* no DEVID regs. */ 31 ccr2 = getCx86(CX86_CCR2); 32 setCx86(CX86_CCR2, ccr2 ^ 0x04); 33 getCx86(0xc0); /* dummy */ 34 35 if (getCx86(CX86_CCR2) == ccr2) /* old Cx486SLC/DLC */ 36 *dir0 = 0xfd; 37 else { /* Cx486S A step */ 38 setCx86(CX86_CCR2, ccr2); 39 *dir0 = 0xfe; 40 } 41 } else { 42 setCx86(CX86_CCR3, ccr3); /* restore CCR3 */ 43 44 /* read DIR0 and DIR1 CPU registers */ 45 *dir0 = getCx86(CX86_DIR0); 46 *dir1 = getCx86(CX86_DIR1); 47 } 48 } 49 50 static void do_cyrix_devid(unsigned char *dir0, unsigned char *dir1) 51 { 52 unsigned long flags; 53 54 local_irq_save(flags); 55 __do_cyrix_devid(dir0, dir1); 56 local_irq_restore(flags); 57 } 58 /* 59 * Cx86_dir0_msb is a HACK needed by check_cx686_cpuid/slop in bugs.h in 60 * order to identify the Cyrix CPU model after we're out of setup.c 61 * 62 * Actually since bugs.h doesn't even reference this perhaps someone should 63 * fix the documentation ??? 64 */ 65 static unsigned char Cx86_dir0_msb = 0; 66 67 static const char Cx86_model[][9] = { 68 "Cx486", "Cx486", "5x86 ", "6x86", "MediaGX ", "6x86MX ", 69 "M II ", "Unknown" 70 }; 71 static const char Cx486_name[][5] = { 72 "SLC", "DLC", "SLC2", "DLC2", "SRx", "DRx", 73 "SRx2", "DRx2" 74 }; 75 static const char Cx486S_name[][4] = { 76 "S", "S2", "Se", "S2e" 77 }; 78 static const char Cx486D_name[][4] = { 79 "DX", "DX2", "?", "?", "?", "DX4" 80 }; 81 static char Cx86_cb[] = "?.5x Core/Bus Clock"; 82 static const char cyrix_model_mult1[] = "12??43"; 83 static const char cyrix_model_mult2[] = "12233445"; 84 85 /* 86 * Reset the slow-loop (SLOP) bit on the 686(L) which is set by some old 87 * BIOSes for compatibility with DOS games. This makes the udelay loop 88 * work correctly, and improves performance. 89 * 90 * FIXME: our newer udelay uses the tsc. We don't need to frob with SLOP 91 */ 92 93 static void check_cx686_slop(struct cpuinfo_x86 *c) 94 { 95 unsigned long flags; 96 97 if (Cx86_dir0_msb == 3) { 98 unsigned char ccr3, ccr5; 99 100 local_irq_save(flags); 101 ccr3 = getCx86(CX86_CCR3); 102 setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */ 103 ccr5 = getCx86(CX86_CCR5); 104 if (ccr5 & 2) 105 setCx86(CX86_CCR5, ccr5 & 0xfd); /* reset SLOP */ 106 setCx86(CX86_CCR3, ccr3); /* disable MAPEN */ 107 local_irq_restore(flags); 108 109 if (ccr5 & 2) { /* possible wrong calibration done */ 110 pr_info("Recalibrating delay loop with SLOP bit reset\n"); 111 calibrate_delay(); 112 c->loops_per_jiffy = loops_per_jiffy; 113 } 114 } 115 } 116 117 118 static void set_cx86_reorder(void) 119 { 120 u8 ccr3; 121 122 pr_info("Enable Memory access reorder on Cyrix/NSC processor.\n"); 123 ccr3 = getCx86(CX86_CCR3); 124 setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */ 125 126 /* Load/Store Serialize to mem access disable (=reorder it) */ 127 setCx86(CX86_PCR0, getCx86(CX86_PCR0) & ~0x80); 128 /* set load/store serialize from 1GB to 4GB */ 129 ccr3 |= 0xe0; 130 setCx86(CX86_CCR3, ccr3); 131 } 132 133 static void set_cx86_memwb(void) 134 { 135 pr_info("Enable Memory-Write-back mode on Cyrix/NSC processor.\n"); 136 137 /* CCR2 bit 2: unlock NW bit */ 138 setCx86(CX86_CCR2, getCx86(CX86_CCR2) & ~0x04); 139 /* set 'Not Write-through' */ 140 write_cr0(read_cr0() | X86_CR0_NW); 141 /* CCR2 bit 2: lock NW bit and set WT1 */ 142 setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x14); 143 } 144 145 /* 146 * Configure later MediaGX and/or Geode processor. 147 */ 148 149 static void geode_configure(void) 150 { 151 unsigned long flags; 152 u8 ccr3; 153 local_irq_save(flags); 154 155 /* Suspend on halt power saving and enable #SUSP pin */ 156 setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88); 157 158 ccr3 = getCx86(CX86_CCR3); 159 setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */ 160 161 162 /* FPU fast, DTE cache, Mem bypass */ 163 setCx86(CX86_CCR4, getCx86(CX86_CCR4) | 0x38); 164 setCx86(CX86_CCR3, ccr3); /* disable MAPEN */ 165 166 set_cx86_memwb(); 167 set_cx86_reorder(); 168 169 local_irq_restore(flags); 170 } 171 172 static void early_init_cyrix(struct cpuinfo_x86 *c) 173 { 174 unsigned char dir0, dir0_msn, dir1 = 0; 175 176 __do_cyrix_devid(&dir0, &dir1); 177 dir0_msn = dir0 >> 4; /* identifies CPU "family" */ 178 179 switch (dir0_msn) { 180 case 3: /* 6x86/6x86L */ 181 /* Emulate MTRRs using Cyrix's ARRs. */ 182 set_cpu_cap(c, X86_FEATURE_CYRIX_ARR); 183 break; 184 case 5: /* 6x86MX/M II */ 185 /* Emulate MTRRs using Cyrix's ARRs. */ 186 set_cpu_cap(c, X86_FEATURE_CYRIX_ARR); 187 break; 188 } 189 } 190 191 static void init_cyrix(struct cpuinfo_x86 *c) 192 { 193 unsigned char dir0, dir0_msn, dir0_lsn, dir1 = 0; 194 char *buf = c->x86_model_id; 195 const char *p = NULL; 196 197 /* 198 * Bit 31 in normal CPUID used for nonstandard 3DNow ID; 199 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway 200 */ 201 clear_cpu_cap(c, 0*32+31); 202 203 /* Cyrix used bit 24 in extended (AMD) CPUID for Cyrix MMX extensions */ 204 if (test_cpu_cap(c, 1*32+24)) { 205 clear_cpu_cap(c, 1*32+24); 206 set_cpu_cap(c, X86_FEATURE_CXMMX); 207 } 208 209 do_cyrix_devid(&dir0, &dir1); 210 211 check_cx686_slop(c); 212 213 Cx86_dir0_msb = dir0_msn = dir0 >> 4; /* identifies CPU "family" */ 214 dir0_lsn = dir0 & 0xf; /* model or clock multiplier */ 215 216 /* common case step number/rev -- exceptions handled below */ 217 c->x86_model = (dir1 >> 4) + 1; 218 c->x86_stepping = dir1 & 0xf; 219 220 /* Now cook; the original recipe is by Channing Corn, from Cyrix. 221 * We do the same thing for each generation: we work out 222 * the model, multiplier and stepping. Black magic included, 223 * to make the silicon step/rev numbers match the printed ones. 224 */ 225 226 switch (dir0_msn) { 227 unsigned char tmp; 228 229 case 0: /* Cx486SLC/DLC/SRx/DRx */ 230 p = Cx486_name[dir0_lsn & 7]; 231 break; 232 233 case 1: /* Cx486S/DX/DX2/DX4 */ 234 p = (dir0_lsn & 8) ? Cx486D_name[dir0_lsn & 5] 235 : Cx486S_name[dir0_lsn & 3]; 236 break; 237 238 case 2: /* 5x86 */ 239 Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5]; 240 p = Cx86_cb+2; 241 break; 242 243 case 3: /* 6x86/6x86L */ 244 Cx86_cb[1] = ' '; 245 Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5]; 246 if (dir1 > 0x21) { /* 686L */ 247 Cx86_cb[0] = 'L'; 248 p = Cx86_cb; 249 (c->x86_model)++; 250 } else /* 686 */ 251 p = Cx86_cb+1; 252 /* Emulate MTRRs using Cyrix's ARRs. */ 253 set_cpu_cap(c, X86_FEATURE_CYRIX_ARR); 254 /* 6x86's contain this bug */ 255 set_cpu_bug(c, X86_BUG_COMA); 256 break; 257 258 case 4: /* MediaGX/GXm or Geode GXM/GXLV/GX1 */ 259 case 11: /* GX1 with inverted Device ID */ 260 #ifdef CONFIG_PCI 261 { 262 u32 vendor, device; 263 /* 264 * It isn't really a PCI quirk directly, but the cure is the 265 * same. The MediaGX has deep magic SMM stuff that handles the 266 * SB emulation. It throws away the fifo on disable_dma() which 267 * is wrong and ruins the audio. 268 * 269 * Bug2: VSA1 has a wrap bug so that using maximum sized DMA 270 * causes bad things. According to NatSemi VSA2 has another 271 * bug to do with 'hlt'. I've not seen any boards using VSA2 272 * and X doesn't seem to support it either so who cares 8). 273 * VSA1 we work around however. 274 */ 275 276 pr_info("Working around Cyrix MediaGX virtual DMA bugs.\n"); 277 isa_dma_bridge_buggy = 2; 278 279 /* We do this before the PCI layer is running. However we 280 are safe here as we know the bridge must be a Cyrix 281 companion and must be present */ 282 vendor = read_pci_config_16(0, 0, 0x12, PCI_VENDOR_ID); 283 device = read_pci_config_16(0, 0, 0x12, PCI_DEVICE_ID); 284 285 /* 286 * The 5510/5520 companion chips have a funky PIT. 287 */ 288 if (vendor == PCI_VENDOR_ID_CYRIX && 289 (device == PCI_DEVICE_ID_CYRIX_5510 || 290 device == PCI_DEVICE_ID_CYRIX_5520)) 291 mark_tsc_unstable("cyrix 5510/5520 detected"); 292 } 293 #endif 294 c->x86_cache_size = 16; /* Yep 16K integrated cache thats it */ 295 296 /* GXm supports extended cpuid levels 'ala' AMD */ 297 if (c->cpuid_level == 2) { 298 /* Enable cxMMX extensions (GX1 Datasheet 54) */ 299 setCx86(CX86_CCR7, getCx86(CX86_CCR7) | 1); 300 301 /* 302 * GXm : 0x30 ... 0x5f GXm datasheet 51 303 * GXlv: 0x6x GXlv datasheet 54 304 * ? : 0x7x 305 * GX1 : 0x8x GX1 datasheet 56 306 */ 307 if ((0x30 <= dir1 && dir1 <= 0x6f) || 308 (0x80 <= dir1 && dir1 <= 0x8f)) 309 geode_configure(); 310 return; 311 } else { /* MediaGX */ 312 Cx86_cb[2] = (dir0_lsn & 1) ? '3' : '4'; 313 p = Cx86_cb+2; 314 c->x86_model = (dir1 & 0x20) ? 1 : 2; 315 } 316 break; 317 318 case 5: /* 6x86MX/M II */ 319 if (dir1 > 7) { 320 dir0_msn++; /* M II */ 321 /* Enable MMX extensions (App note 108) */ 322 setCx86(CX86_CCR7, getCx86(CX86_CCR7)|1); 323 } else { 324 /* A 6x86MX - it has the bug. */ 325 set_cpu_bug(c, X86_BUG_COMA); 326 } 327 tmp = (!(dir0_lsn & 7) || dir0_lsn & 1) ? 2 : 0; 328 Cx86_cb[tmp] = cyrix_model_mult2[dir0_lsn & 7]; 329 p = Cx86_cb+tmp; 330 if (((dir1 & 0x0f) > 4) || ((dir1 & 0xf0) == 0x20)) 331 (c->x86_model)++; 332 /* Emulate MTRRs using Cyrix's ARRs. */ 333 set_cpu_cap(c, X86_FEATURE_CYRIX_ARR); 334 break; 335 336 case 0xf: /* Cyrix 486 without DEVID registers */ 337 switch (dir0_lsn) { 338 case 0xd: /* either a 486SLC or DLC w/o DEVID */ 339 dir0_msn = 0; 340 p = Cx486_name[!!boot_cpu_has(X86_FEATURE_FPU)]; 341 break; 342 343 case 0xe: /* a 486S A step */ 344 dir0_msn = 0; 345 p = Cx486S_name[0]; 346 break; 347 } 348 break; 349 350 default: /* unknown (shouldn't happen, we know everyone ;-) */ 351 dir0_msn = 7; 352 break; 353 } 354 strcpy(buf, Cx86_model[dir0_msn & 7]); 355 if (p) 356 strcat(buf, p); 357 return; 358 } 359 360 /* 361 * Handle National Semiconductor branded processors 362 */ 363 static void init_nsc(struct cpuinfo_x86 *c) 364 { 365 /* 366 * There may be GX1 processors in the wild that are branded 367 * NSC and not Cyrix. 368 * 369 * This function only handles the GX processor, and kicks every 370 * thing else to the Cyrix init function above - that should 371 * cover any processors that might have been branded differently 372 * after NSC acquired Cyrix. 373 * 374 * If this breaks your GX1 horribly, please e-mail 375 * info-linux@ldcmail.amd.com to tell us. 376 */ 377 378 /* Handle the GX (Formally known as the GX2) */ 379 380 if (c->x86 == 5 && c->x86_model == 5) 381 cpu_detect_cache_sizes(c); 382 else 383 init_cyrix(c); 384 } 385 386 /* 387 * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected 388 * by the fact that they preserve the flags across the division of 5/2. 389 * PII and PPro exhibit this behavior too, but they have cpuid available. 390 */ 391 392 /* 393 * Perform the Cyrix 5/2 test. A Cyrix won't change 394 * the flags, while other 486 chips will. 395 */ 396 static inline int test_cyrix_52div(void) 397 { 398 unsigned int test; 399 400 __asm__ __volatile__( 401 "sahf\n\t" /* clear flags (%eax = 0x0005) */ 402 "div %b2\n\t" /* divide 5 by 2 */ 403 "lahf" /* store flags into %ah */ 404 : "=a" (test) 405 : "0" (5), "q" (2) 406 : "cc"); 407 408 /* AH is 0x02 on Cyrix after the divide.. */ 409 return (unsigned char) (test >> 8) == 0x02; 410 } 411 412 static void cyrix_identify(struct cpuinfo_x86 *c) 413 { 414 /* Detect Cyrix with disabled CPUID */ 415 if (c->x86 == 4 && test_cyrix_52div()) { 416 unsigned char dir0, dir1; 417 418 strcpy(c->x86_vendor_id, "CyrixInstead"); 419 c->x86_vendor = X86_VENDOR_CYRIX; 420 421 /* Actually enable cpuid on the older cyrix */ 422 423 /* Retrieve CPU revisions */ 424 425 do_cyrix_devid(&dir0, &dir1); 426 427 dir0 >>= 4; 428 429 /* Check it is an affected model */ 430 431 if (dir0 == 5 || dir0 == 3) { 432 unsigned char ccr3; 433 unsigned long flags; 434 pr_info("Enabling CPUID on Cyrix processor.\n"); 435 local_irq_save(flags); 436 ccr3 = getCx86(CX86_CCR3); 437 /* enable MAPEN */ 438 setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); 439 /* enable cpuid */ 440 setCx86(CX86_CCR4, getCx86(CX86_CCR4) | 0x80); 441 /* disable MAPEN */ 442 setCx86(CX86_CCR3, ccr3); 443 local_irq_restore(flags); 444 } 445 } 446 } 447 448 static const struct cpu_dev cyrix_cpu_dev = { 449 .c_vendor = "Cyrix", 450 .c_ident = { "CyrixInstead" }, 451 .c_early_init = early_init_cyrix, 452 .c_init = init_cyrix, 453 .c_identify = cyrix_identify, 454 .c_x86_vendor = X86_VENDOR_CYRIX, 455 }; 456 457 cpu_dev_register(cyrix_cpu_dev); 458 459 static const struct cpu_dev nsc_cpu_dev = { 460 .c_vendor = "NSC", 461 .c_ident = { "Geode by NSC" }, 462 .c_init = init_nsc, 463 .c_x86_vendor = X86_VENDOR_NSC, 464 }; 465 466 cpu_dev_register(nsc_cpu_dev); 467