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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - arch/x86/kernel/cpu/cyrix.c
1 #include <linux/bitops.h>
2 #include <linux/delay.h>
6 #include <asm/processor-cyrix.h>
7 #include <asm/processor-flags.h>
8 #include <linux/timer.h>
9 #include <asm/pci-direct.h>
11 #include <asm/cpufeature.h>
12 #include <linux/sched.h>
13 #include <linux/sched/clock.h>
18 * Read NSC/Cyrix DEVID registers (DIR) to get more detailed info. about the CPU
20 static void __do_cyrix_devid(unsigned char *dir0
, unsigned char *dir1
)
22 unsigned char ccr2
, ccr3
;
24 /* we test for DEVID by checking whether CCR3 is writable */
25 ccr3
= getCx86(CX86_CCR3
);
26 setCx86(CX86_CCR3
, ccr3
^ 0x80);
27 getCx86(0xc0); /* dummy to change bus */
29 if (getCx86(CX86_CCR3
) == ccr3
) { /* no DEVID regs. */
30 ccr2
= getCx86(CX86_CCR2
);
31 setCx86(CX86_CCR2
, ccr2
^ 0x04);
32 getCx86(0xc0); /* dummy */
34 if (getCx86(CX86_CCR2
) == ccr2
) /* old Cx486SLC/DLC */
36 else { /* Cx486S A step */
37 setCx86(CX86_CCR2
, ccr2
);
41 setCx86(CX86_CCR3
, ccr3
); /* restore CCR3 */
43 /* read DIR0 and DIR1 CPU registers */
44 *dir0
= getCx86(CX86_DIR0
);
45 *dir1
= getCx86(CX86_DIR1
);
49 static void do_cyrix_devid(unsigned char *dir0
, unsigned char *dir1
)
53 local_irq_save(flags
);
54 __do_cyrix_devid(dir0
, dir1
);
55 local_irq_restore(flags
);
58 * Cx86_dir0_msb is a HACK needed by check_cx686_cpuid/slop in bugs.h in
59 * order to identify the Cyrix CPU model after we're out of setup.c
61 * Actually since bugs.h doesn't even reference this perhaps someone should
62 * fix the documentation ???
64 static unsigned char Cx86_dir0_msb
= 0;
66 static const char Cx86_model
[][9] = {
67 "Cx486", "Cx486", "5x86 ", "6x86", "MediaGX ", "6x86MX ",
70 static const char Cx486_name
[][5] = {
71 "SLC", "DLC", "SLC2", "DLC2", "SRx", "DRx",
74 static const char Cx486S_name
[][4] = {
75 "S", "S2", "Se", "S2e"
77 static const char Cx486D_name
[][4] = {
78 "DX", "DX2", "?", "?", "?", "DX4"
80 static char Cx86_cb
[] = "?.5x Core/Bus Clock";
81 static const char cyrix_model_mult1
[] = "12??43";
82 static const char cyrix_model_mult2
[] = "12233445";
85 * Reset the slow-loop (SLOP) bit on the 686(L) which is set by some old
86 * BIOSes for compatibility with DOS games. This makes the udelay loop
87 * work correctly, and improves performance.
89 * FIXME: our newer udelay uses the tsc. We don't need to frob with SLOP
92 static void check_cx686_slop(struct cpuinfo_x86
*c
)
96 if (Cx86_dir0_msb
== 3) {
97 unsigned char ccr3
, ccr5
;
99 local_irq_save(flags
);
100 ccr3
= getCx86(CX86_CCR3
);
101 setCx86(CX86_CCR3
, (ccr3
& 0x0f) | 0x10); /* enable MAPEN */
102 ccr5
= getCx86(CX86_CCR5
);
104 setCx86(CX86_CCR5
, ccr5
& 0xfd); /* reset SLOP */
105 setCx86(CX86_CCR3
, ccr3
); /* disable MAPEN */
106 local_irq_restore(flags
);
108 if (ccr5
& 2) { /* possible wrong calibration done */
109 pr_info("Recalibrating delay loop with SLOP bit reset\n");
111 c
->loops_per_jiffy
= loops_per_jiffy
;
117 static void set_cx86_reorder(void)
121 pr_info("Enable Memory access reorder on Cyrix/NSC processor.\n");
122 ccr3
= getCx86(CX86_CCR3
);
123 setCx86(CX86_CCR3
, (ccr3
& 0x0f) | 0x10); /* enable MAPEN */
125 /* Load/Store Serialize to mem access disable (=reorder it) */
126 setCx86_old(CX86_PCR0
, getCx86_old(CX86_PCR0
) & ~0x80);
127 /* set load/store serialize from 1GB to 4GB */
129 setCx86(CX86_CCR3
, ccr3
);
132 static void set_cx86_memwb(void)
134 pr_info("Enable Memory-Write-back mode on Cyrix/NSC processor.\n");
136 /* CCR2 bit 2: unlock NW bit */
137 setCx86_old(CX86_CCR2
, getCx86_old(CX86_CCR2
) & ~0x04);
138 /* set 'Not Write-through' */
139 write_cr0(read_cr0() | X86_CR0_NW
);
140 /* CCR2 bit 2: lock NW bit and set WT1 */
141 setCx86_old(CX86_CCR2
, getCx86_old(CX86_CCR2
) | 0x14);
145 * Configure later MediaGX and/or Geode processor.
148 static void geode_configure(void)
152 local_irq_save(flags
);
154 /* Suspend on halt power saving and enable #SUSP pin */
155 setCx86_old(CX86_CCR2
, getCx86_old(CX86_CCR2
) | 0x88);
157 ccr3
= getCx86(CX86_CCR3
);
158 setCx86(CX86_CCR3
, (ccr3
& 0x0f) | 0x10); /* enable MAPEN */
161 /* FPU fast, DTE cache, Mem bypass */
162 setCx86_old(CX86_CCR4
, getCx86_old(CX86_CCR4
) | 0x38);
163 setCx86(CX86_CCR3
, ccr3
); /* disable MAPEN */
168 local_irq_restore(flags
);
171 static void early_init_cyrix(struct cpuinfo_x86
*c
)
173 unsigned char dir0
, dir0_msn
, dir1
= 0;
175 __do_cyrix_devid(&dir0
, &dir1
);
176 dir0_msn
= dir0
>> 4; /* identifies CPU "family" */
179 case 3: /* 6x86/6x86L */
180 /* Emulate MTRRs using Cyrix's ARRs. */
181 set_cpu_cap(c
, X86_FEATURE_CYRIX_ARR
);
183 case 5: /* 6x86MX/M II */
184 /* Emulate MTRRs using Cyrix's ARRs. */
185 set_cpu_cap(c
, X86_FEATURE_CYRIX_ARR
);
190 static void init_cyrix(struct cpuinfo_x86
*c
)
192 unsigned char dir0
, dir0_msn
, dir0_lsn
, dir1
= 0;
193 char *buf
= c
->x86_model_id
;
194 const char *p
= NULL
;
197 * Bit 31 in normal CPUID used for nonstandard 3DNow ID;
198 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
200 clear_cpu_cap(c
, 0*32+31);
202 /* Cyrix used bit 24 in extended (AMD) CPUID for Cyrix MMX extensions */
203 if (test_cpu_cap(c
, 1*32+24)) {
204 clear_cpu_cap(c
, 1*32+24);
205 set_cpu_cap(c
, X86_FEATURE_CXMMX
);
208 do_cyrix_devid(&dir0
, &dir1
);
212 Cx86_dir0_msb
= dir0_msn
= dir0
>> 4; /* identifies CPU "family" */
213 dir0_lsn
= dir0
& 0xf; /* model or clock multiplier */
215 /* common case step number/rev -- exceptions handled below */
216 c
->x86_model
= (dir1
>> 4) + 1;
217 c
->x86_mask
= dir1
& 0xf;
219 /* Now cook; the original recipe is by Channing Corn, from Cyrix.
220 * We do the same thing for each generation: we work out
221 * the model, multiplier and stepping. Black magic included,
222 * to make the silicon step/rev numbers match the printed ones.
228 case 0: /* Cx486SLC/DLC/SRx/DRx */
229 p
= Cx486_name
[dir0_lsn
& 7];
232 case 1: /* Cx486S/DX/DX2/DX4 */
233 p
= (dir0_lsn
& 8) ? Cx486D_name
[dir0_lsn
& 5]
234 : Cx486S_name
[dir0_lsn
& 3];
238 Cx86_cb
[2] = cyrix_model_mult1
[dir0_lsn
& 5];
242 case 3: /* 6x86/6x86L */
244 Cx86_cb
[2] = cyrix_model_mult1
[dir0_lsn
& 5];
245 if (dir1
> 0x21) { /* 686L */
251 /* Emulate MTRRs using Cyrix's ARRs. */
252 set_cpu_cap(c
, X86_FEATURE_CYRIX_ARR
);
253 /* 6x86's contain this bug */
254 set_cpu_bug(c
, X86_BUG_COMA
);
257 case 4: /* MediaGX/GXm or Geode GXM/GXLV/GX1 */
258 case 11: /* GX1 with inverted Device ID */
263 * It isn't really a PCI quirk directly, but the cure is the
264 * same. The MediaGX has deep magic SMM stuff that handles the
265 * SB emulation. It throws away the fifo on disable_dma() which
266 * is wrong and ruins the audio.
268 * Bug2: VSA1 has a wrap bug so that using maximum sized DMA
269 * causes bad things. According to NatSemi VSA2 has another
270 * bug to do with 'hlt'. I've not seen any boards using VSA2
271 * and X doesn't seem to support it either so who cares 8).
272 * VSA1 we work around however.
275 pr_info("Working around Cyrix MediaGX virtual DMA bugs.\n");
276 isa_dma_bridge_buggy
= 2;
278 /* We do this before the PCI layer is running. However we
279 are safe here as we know the bridge must be a Cyrix
280 companion and must be present */
281 vendor
= read_pci_config_16(0, 0, 0x12, PCI_VENDOR_ID
);
282 device
= read_pci_config_16(0, 0, 0x12, PCI_DEVICE_ID
);
285 * The 5510/5520 companion chips have a funky PIT.
287 if (vendor
== PCI_VENDOR_ID_CYRIX
&&
288 (device
== PCI_DEVICE_ID_CYRIX_5510
||
289 device
== PCI_DEVICE_ID_CYRIX_5520
))
290 mark_tsc_unstable("cyrix 5510/5520 detected");
293 c
->x86_cache_size
= 16; /* Yep 16K integrated cache thats it */
295 /* GXm supports extended cpuid levels 'ala' AMD */
296 if (c
->cpuid_level
== 2) {
297 /* Enable cxMMX extensions (GX1 Datasheet 54) */
298 setCx86_old(CX86_CCR7
, getCx86_old(CX86_CCR7
) | 1);
301 * GXm : 0x30 ... 0x5f GXm datasheet 51
302 * GXlv: 0x6x GXlv datasheet 54
304 * GX1 : 0x8x GX1 datasheet 56
306 if ((0x30 <= dir1
&& dir1
<= 0x6f) ||
307 (0x80 <= dir1
&& dir1
<= 0x8f))
310 } else { /* MediaGX */
311 Cx86_cb
[2] = (dir0_lsn
& 1) ? '3' : '4';
313 c
->x86_model
= (dir1
& 0x20) ? 1 : 2;
317 case 5: /* 6x86MX/M II */
319 dir0_msn
++; /* M II */
320 /* Enable MMX extensions (App note 108) */
321 setCx86_old(CX86_CCR7
, getCx86_old(CX86_CCR7
)|1);
323 /* A 6x86MX - it has the bug. */
324 set_cpu_bug(c
, X86_BUG_COMA
);
326 tmp
= (!(dir0_lsn
& 7) || dir0_lsn
& 1) ? 2 : 0;
327 Cx86_cb
[tmp
] = cyrix_model_mult2
[dir0_lsn
& 7];
329 if (((dir1
& 0x0f) > 4) || ((dir1
& 0xf0) == 0x20))
331 /* Emulate MTRRs using Cyrix's ARRs. */
332 set_cpu_cap(c
, X86_FEATURE_CYRIX_ARR
);
335 case 0xf: /* Cyrix 486 without DEVID registers */
337 case 0xd: /* either a 486SLC or DLC w/o DEVID */
339 p
= Cx486_name
[!!boot_cpu_has(X86_FEATURE_FPU
)];
342 case 0xe: /* a 486S A step */
349 default: /* unknown (shouldn't happen, we know everyone ;-) */
353 strcpy(buf
, Cx86_model
[dir0_msn
& 7]);
360 * Handle National Semiconductor branded processors
362 static void init_nsc(struct cpuinfo_x86
*c
)
365 * There may be GX1 processors in the wild that are branded
368 * This function only handles the GX processor, and kicks every
369 * thing else to the Cyrix init function above - that should
370 * cover any processors that might have been branded differently
371 * after NSC acquired Cyrix.
373 * If this breaks your GX1 horribly, please e-mail
374 * info-linux@ldcmail.amd.com to tell us.
377 /* Handle the GX (Formally known as the GX2) */
379 if (c
->x86
== 5 && c
->x86_model
== 5)
380 cpu_detect_cache_sizes(c
);
386 * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
387 * by the fact that they preserve the flags across the division of 5/2.
388 * PII and PPro exhibit this behavior too, but they have cpuid available.
392 * Perform the Cyrix 5/2 test. A Cyrix won't change
393 * the flags, while other 486 chips will.
395 static inline int test_cyrix_52div(void)
399 __asm__
__volatile__(
400 "sahf\n\t" /* clear flags (%eax = 0x0005) */
401 "div %b2\n\t" /* divide 5 by 2 */
402 "lahf" /* store flags into %ah */
407 /* AH is 0x02 on Cyrix after the divide.. */
408 return (unsigned char) (test
>> 8) == 0x02;
411 static void cyrix_identify(struct cpuinfo_x86
*c
)
413 /* Detect Cyrix with disabled CPUID */
414 if (c
->x86
== 4 && test_cyrix_52div()) {
415 unsigned char dir0
, dir1
;
417 strcpy(c
->x86_vendor_id
, "CyrixInstead");
418 c
->x86_vendor
= X86_VENDOR_CYRIX
;
420 /* Actually enable cpuid on the older cyrix */
422 /* Retrieve CPU revisions */
424 do_cyrix_devid(&dir0
, &dir1
);
428 /* Check it is an affected model */
430 if (dir0
== 5 || dir0
== 3) {
433 pr_info("Enabling CPUID on Cyrix processor.\n");
434 local_irq_save(flags
);
435 ccr3
= getCx86(CX86_CCR3
);
437 setCx86(CX86_CCR3
, (ccr3
& 0x0f) | 0x10);
439 setCx86_old(CX86_CCR4
, getCx86_old(CX86_CCR4
) | 0x80);
441 setCx86(CX86_CCR3
, ccr3
);
442 local_irq_restore(flags
);
447 static const struct cpu_dev cyrix_cpu_dev
= {
449 .c_ident
= { "CyrixInstead" },
450 .c_early_init
= early_init_cyrix
,
451 .c_init
= init_cyrix
,
452 .c_identify
= cyrix_identify
,
453 .c_x86_vendor
= X86_VENDOR_CYRIX
,
456 cpu_dev_register(cyrix_cpu_dev
);
458 static const struct cpu_dev nsc_cpu_dev
= {
460 .c_ident
= { "Geode by NSC" },
462 .c_x86_vendor
= X86_VENDOR_NSC
,
465 cpu_dev_register(nsc_cpu_dev
);