2 * mtrr.c: setting MTRR to decent values for cache initialization on P6
4 * Derived from intel_set_mtrr in intel_subr.c and mtrr.c in linux kernel
6 * Copyright 2000 Silicon Integrated System Corporation
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * Reference: Intel Architecture Software Developer's Manual, Volume 3: System Programming
27 2005.1 yhlu add NC support to spare mtrrs for 64G memory above installed
28 2005.6 Eric add address bit in x86_setup_mtrrs
29 2005.6 yhlu split x86_setup_var_mtrrs and x86_setup_fixed_mtrrs,
30 for AMD, it will not use x86_setup_fixed_mtrrs
34 #include <console/console.h>
35 #include <device/device.h>
36 #include <cpu/x86/msr.h>
37 #include <cpu/x86/mtrr.h>
38 #include <cpu/x86/cache.h>
39 #include <cpu/x86/lapic.h>
41 #include <arch/acpi.h>
44 extern uint64_t uma_memory_base, uma_memory_size;
47 static unsigned int mtrr_msr[] = {
48 MTRRfix64K_00000_MSR, MTRRfix16K_80000_MSR, MTRRfix16K_A0000_MSR,
49 MTRRfix4K_C0000_MSR, MTRRfix4K_C8000_MSR, MTRRfix4K_D0000_MSR, MTRRfix4K_D8000_MSR,
50 MTRRfix4K_E0000_MSR, MTRRfix4K_E8000_MSR, MTRRfix4K_F0000_MSR, MTRRfix4K_F8000_MSR,
53 void enable_fixed_mtrr(void)
57 msr = rdmsr(MTRRdefType_MSR);
59 wrmsr(MTRRdefType_MSR, msr);
62 static void enable_var_mtrr(void)
66 msr = rdmsr(MTRRdefType_MSR);
67 msr.lo |= MTRRdefTypeEn;
68 wrmsr(MTRRdefType_MSR, msr);
71 /* setting variable mtrr, comes from linux kernel source */
72 static void set_var_mtrr(
73 unsigned int reg, unsigned long basek, unsigned long sizek,
74 unsigned char type, unsigned address_bits)
77 unsigned address_mask_high;
82 // it is recommended that we disable and enable cache when we
88 zero.lo = zero.hi = 0;
89 /* The invalid bit is kept in the mask, so we simply clear the
90 relevant mask register to disable a range. */
91 wrmsr (MTRRphysMask_MSR(reg), zero);
98 address_mask_high = ((1u << (address_bits - 32u)) - 1u);
100 base.hi = basek >> 22;
101 base.lo = basek << 10;
103 printk(BIOS_SPEW, "ADDRESS_MASK_HIGH=%#x\n", address_mask_high);
105 if (sizek < 4*1024*1024) {
106 mask.hi = address_mask_high;
107 mask.lo = ~((sizek << 10) -1);
110 mask.hi = address_mask_high & (~((sizek >> 22) -1));
114 // it is recommended that we disable and enable cache when we
118 /* Bit 32-35 of MTRRphysMask should be set to 1 */
120 mask.lo |= MTRRphysMaskValid;
121 wrmsr (MTRRphysBase_MSR(reg), base);
122 wrmsr (MTRRphysMask_MSR(reg), mask);
127 /* fms: find most sigificant bit set, stolen from Linux Kernel Source. */
128 static inline unsigned int fms(unsigned int x)
132 __asm__("bsrl %1,%0\n\t"
135 "1:" : "=r" (r) : "g" (x));
139 /* fls: find least sigificant bit set */
140 static inline unsigned int fls(unsigned int x)
144 __asm__("bsfl %1,%0\n\t"
147 "1:" : "=r" (r) : "g" (x));
151 /* setting up variable and fixed mtrr
153 * From Intel Vol. III Section 9.12.4, the Range Size and Base Alignment has some kind of requirement:
154 * 1. The range size must be 2^N byte for N >= 12 (i.e 4KB minimum).
155 * 2. The base address must be 2^N aligned, where the N here is equal to the N in previous
156 * requirement. So a 8K range must be 8K aligned not 4K aligned.
158 * These requirement is meet by "decompositing" the ramsize into Sum(Cn * 2^n, n = [0..N], Cn = [0, 1]).
159 * For Cm = 1, there is a WB range of 2^m size at base address Sum(Cm * 2^m, m = [N..n]).
160 * A 124MB (128MB - 4MB SMA) example:
161 * ramsize = 124MB == 64MB (at 0MB) + 32MB (at 64MB) + 16MB (at 96MB ) + 8MB (at 112MB) + 4MB (120MB).
162 * But this wastes a lot of MTRR registers so we use another more "aggresive" way with Uncacheable Regions.
164 * In the Uncacheable Region scheme, we try to cover the whole ramsize by one WB region as possible,
165 * If (an only if) this can not be done we will try to decomposite the ramesize, the mathematical formula
166 * whould be ramsize = Sum(Cn * 2^n, n = [0..N], Cn = [-1, 0, 1]). For Cn = -1, a Uncachable Region is used.
167 * The same 124MB example:
168 * ramsize = 124MB == 128MB WB (at 0MB) + 4MB UC (at 124MB)
169 * or a 156MB (128MB + 32MB - 4MB SMA) example:
170 * ramsize = 156MB == 128MB WB (at 0MB) + 32MB WB (at 128MB) + 4MB UC (at 156MB)
172 /* 2 MTRRS are reserved for the operating system */
180 #define MTRRS (BIOS_MTRRS + OS_MTRRS)
182 static int total_mtrrs = MTRRS;
183 static int bios_mtrrs = BIOS_MTRRS;
185 static void detect_var_mtrrs(void)
189 msr = rdmsr(MTRRcap_MSR);
191 total_mtrrs = msr.lo & 0xff;
192 bios_mtrrs = total_mtrrs - 2;
195 static void set_fixed_mtrrs(unsigned int first, unsigned int last, unsigned char type)
198 unsigned int fixed_msr = NUM_FIXED_RANGES >> 3;
200 msr.lo = msr.hi = 0; /* Shut up gcc */
201 for(i = first; i < last; i++) {
202 /* When I switch to a new msr read it in */
203 if (fixed_msr != i >> 3) {
204 /* But first write out the old msr */
205 if (fixed_msr < (NUM_FIXED_RANGES >> 3)) {
207 wrmsr(mtrr_msr[fixed_msr], msr);
211 msr = rdmsr(mtrr_msr[fixed_msr]);
214 msr.lo &= ~(0xff << ((i&3)*8));
215 msr.lo |= type << ((i&3)*8);
217 msr.hi &= ~(0xff << ((i&3)*8));
218 msr.hi |= type << ((i&3)*8);
221 /* Write out the final msr */
222 if (fixed_msr < (NUM_FIXED_RANGES >> 3)) {
224 wrmsr(mtrr_msr[fixed_msr], msr);
229 static unsigned fixed_mtrr_index(unsigned long addrk)
232 index = (addrk - 0) >> 6;
234 index = ((addrk - 8*64) >> 4) + 8;
237 index = ((addrk - (8*64 + 16*16)) >> 2) + 24;
239 if (index > NUM_FIXED_RANGES) {
240 index = NUM_FIXED_RANGES;
245 static unsigned int range_to_mtrr(unsigned int reg,
246 unsigned long range_startk, unsigned long range_sizek,
247 unsigned long next_range_startk, unsigned char type,
248 unsigned int address_bits, unsigned int above4gb)
250 unsigned long hole_startk = 0, hole_sizek = 0;
253 /* If there's no MTRR hole, this function will bail out
254 * here when called for the hole.
256 printk(BIOS_SPEW, "Zero-sized MTRR range @%ldKB\n", range_startk);
260 if (reg >= bios_mtrrs) {
261 printk(BIOS_ERR, "Warning: Out of MTRRs for base: %4ldMB, range: %ldMB, type %s\n",
262 range_startk >>10, range_sizek >> 10,
263 (type==MTRR_TYPE_UNCACHEABLE)?"UC":
264 ((type==MTRR_TYPE_WRBACK)?"WB":"Other") );
268 #define MIN_ALIGN 0x10000 /* 64MB */
270 if (above4gb == 2 && type == MTRR_TYPE_WRBACK &&
271 range_sizek > MIN_ALIGN && range_sizek % MIN_ALIGN) {
273 * If this range is not divisible then instead
274 * make a larger range and carve out an uncached hole.
276 hole_startk = range_startk + range_sizek;
277 hole_sizek = MIN_ALIGN - (range_sizek % MIN_ALIGN);
278 range_sizek += hole_sizek;
282 unsigned long max_align, align;
284 /* Compute the maximum size I can make a range */
285 max_align = fls(range_startk);
286 align = fms(range_sizek);
287 if (align > max_align) {
291 printk(BIOS_DEBUG, "Setting variable MTRR %d, base: %4ldMB, range: %4ldMB, type %s\n",
292 reg, range_startk >>10, sizek >> 10,
293 (type==MTRR_TYPE_UNCACHEABLE)?"UC":
294 ((type==MTRR_TYPE_WRBACK)?"WB":"Other")
297 /* if range is above 4GB, MTRR is needed
298 * only if above4gb flag is set
300 if (range_startk < 0x100000000ull / 1024 || above4gb)
301 set_var_mtrr(reg++, range_startk, sizek, type, address_bits);
302 range_startk += sizek;
303 range_sizek -= sizek;
304 if (reg >= bios_mtrrs) {
305 printk(BIOS_ERR, "Running out of variable MTRRs!\n");
311 printk(BIOS_DEBUG, "Adding hole at %ldMB-%ldMB\n",
312 hole_startk >> 10, (hole_startk + hole_sizek) >> 10);
313 reg = range_to_mtrr(reg, hole_startk, hole_sizek,
314 next_range_startk, MTRR_TYPE_UNCACHEABLE,
315 address_bits, above4gb);
321 static unsigned long resk(uint64_t value)
323 unsigned long resultk;
324 if (value < (1ULL << 42)) {
325 resultk = value >> 10;
328 resultk = 0xffffffff;
333 static void set_fixed_mtrr_resource(void *gp, struct device *dev, struct resource *res)
335 unsigned int start_mtrr;
336 unsigned int last_mtrr;
337 start_mtrr = fixed_mtrr_index(resk(res->base));
338 last_mtrr = fixed_mtrr_index(resk((res->base + res->size)));
339 if (start_mtrr >= NUM_FIXED_RANGES) {
342 printk(BIOS_DEBUG, "Setting fixed MTRRs(%d-%d) Type: WB\n",
343 start_mtrr, last_mtrr);
344 set_fixed_mtrrs(start_mtrr, last_mtrr, MTRR_TYPE_WRBACK);
348 #ifndef CONFIG_VAR_MTRR_HOLE
349 #define CONFIG_VAR_MTRR_HOLE 1
352 struct var_mtrr_state {
353 unsigned long range_startk, range_sizek;
355 unsigned long hole_startk, hole_sizek;
356 unsigned int address_bits;
357 unsigned int above4gb; /* Set if MTRRs are needed for DRAM above 4GB */
360 void set_var_mtrr_resource(void *gp, struct device *dev, struct resource *res)
362 struct var_mtrr_state *state = gp;
363 unsigned long basek, sizek;
364 if (state->reg >= bios_mtrrs)
366 basek = resk(res->base);
367 sizek = resk(res->size);
368 /* See if I can merge with the last range
369 * Either I am below 1M and the fixed mtrrs handle it, or
372 if ((basek <= 1024) || (state->range_startk + state->range_sizek == basek)) {
373 unsigned long endk = basek + sizek;
374 state->range_sizek = endk - state->range_startk;
377 /* Write the range mtrrs */
378 if (state->range_sizek != 0) {
379 #if CONFIG_VAR_MTRR_HOLE
380 if (state->hole_sizek == 0 && state->above4gb != 2) {
381 /* We need to put that on to hole */
382 unsigned long endk = basek + sizek;
383 state->hole_startk = state->range_startk + state->range_sizek;
384 state->hole_sizek = basek - state->hole_startk;
385 state->range_sizek = endk - state->range_startk;
389 state->reg = range_to_mtrr(state->reg, state->range_startk,
390 state->range_sizek, basek, MTRR_TYPE_WRBACK,
391 state->address_bits, state->above4gb);
392 #if CONFIG_VAR_MTRR_HOLE
393 state->reg = range_to_mtrr(state->reg, state->hole_startk,
394 state->hole_sizek, basek, MTRR_TYPE_UNCACHEABLE,
395 state->address_bits, state->above4gb);
397 state->range_startk = 0;
398 state->range_sizek = 0;
399 state->hole_startk = 0;
400 state->hole_sizek = 0;
402 /* Allocate an msr */
403 printk(BIOS_SPEW, " Allocate an msr - basek = %08lx, sizek = %08lx,\n", basek, sizek);
404 state->range_startk = basek;
405 state->range_sizek = sizek;
408 void x86_setup_fixed_mtrrs(void)
410 /* Try this the simple way of incrementally adding together
411 * mtrrs. If this doesn't work out we can get smart again
412 * and clear out the mtrrs.
415 printk(BIOS_DEBUG, "\n");
416 /* Initialized the fixed_mtrrs to uncached */
417 printk(BIOS_DEBUG, "Setting fixed MTRRs(%d-%d) Type: UC\n",
418 0, NUM_FIXED_RANGES);
419 set_fixed_mtrrs(0, NUM_FIXED_RANGES, MTRR_TYPE_UNCACHEABLE);
421 /* Now see which of the fixed mtrrs cover ram.
423 search_global_resources(
424 IORESOURCE_MEM | IORESOURCE_CACHEABLE, IORESOURCE_MEM | IORESOURCE_CACHEABLE,
425 set_fixed_mtrr_resource, NULL);
426 printk(BIOS_DEBUG, "DONE fixed MTRRs\n");
428 /* enable fixed MTRR */
429 printk(BIOS_SPEW, "call enable_fixed_mtrr()\n");
434 void x86_setup_var_mtrrs(unsigned int address_bits, unsigned int above4gb)
435 /* this routine needs to know how many address bits a given processor
436 * supports. CPUs get grumpy when you set too many bits in
437 * their mtrr registers :( I would generically call cpuid here
438 * and find out how many physically supported but some cpus are
439 * buggy, and report more bits then they actually support.
440 * If above4gb flag is set, variable MTRR ranges must be used to
441 * set cacheability of DRAM above 4GB. If above4gb flag is clear,
442 * some other mechanism is controlling cacheability of DRAM above 4GB.
445 /* Try this the simple way of incrementally adding together
446 * mtrrs. If this doesn't work out we can get smart again
447 * and clear out the mtrrs.
449 struct var_mtrr_state var_state;
451 /* Cache as many memory areas as possible */
452 /* FIXME is there an algorithm for computing the optimal set of mtrrs?
453 * In some cases it is definitely possible to do better.
455 var_state.range_startk = 0;
456 var_state.range_sizek = 0;
457 var_state.hole_startk = 0;
458 var_state.hole_sizek = 0;
460 var_state.address_bits = address_bits;
461 var_state.above4gb = above4gb;
463 /* Detect number of variable MTRRs */
467 search_global_resources(
468 IORESOURCE_MEM | IORESOURCE_CACHEABLE, IORESOURCE_MEM | IORESOURCE_CACHEABLE,
469 set_var_mtrr_resource, &var_state);
471 #if (CONFIG_GFXUMA == 1) /* UMA or SP. */
472 /* For now we assume the UMA space is at the end of memory below 4GB */
473 if (var_state.hole_startk || var_state.hole_sizek) {
474 printk(BIOS_DEBUG, "Warning: Can't set up MTRR hole for UMA due to pre-existing MTRR hole.\n");
476 #if CONFIG_VAR_MTRR_HOLE
477 // Increase the base range and set up UMA as an UC hole instead
479 var_state.range_sizek += (uma_memory_size >> 10);
481 var_state.hole_startk = (uma_memory_base >> 10);
482 var_state.hole_sizek = (uma_memory_size >> 10);
486 /* Write the last range */
487 var_state.reg = range_to_mtrr(var_state.reg, var_state.range_startk,
488 var_state.range_sizek, 0, MTRR_TYPE_WRBACK,
489 var_state.address_bits, var_state.above4gb);
490 #if CONFIG_VAR_MTRR_HOLE
491 var_state.reg = range_to_mtrr(var_state.reg, var_state.hole_startk,
492 var_state.hole_sizek, 0, MTRR_TYPE_UNCACHEABLE,
493 var_state.address_bits, var_state.above4gb);
495 printk(BIOS_DEBUG, "DONE variable MTRRs\n");
496 printk(BIOS_DEBUG, "Clear out the extra MTRR's\n");
497 /* Clear out the extra MTRR's */
498 while(var_state.reg < total_mtrrs) {
499 set_var_mtrr(var_state.reg++, 0, 0, 0, var_state.address_bits);
503 /* Enable Caching and speculative Reads for the
504 * complete ROM now that we actually have RAM.
506 if (boot_cpu() && (acpi_slp_type != 3)) {
507 set_var_mtrr(total_mtrrs-1, (4096-4)*1024, 4*1024,
508 MTRR_TYPE_WRPROT, address_bits);
512 printk(BIOS_SPEW, "call enable_var_mtrr()\n");
514 printk(BIOS_SPEW, "Leave %s\n", __func__);
519 void x86_setup_mtrrs(void)
522 x86_setup_fixed_mtrrs();
523 address_size = cpu_phys_address_size();
524 printk(BIOS_DEBUG, "CPU physical address size: %d bits\n", address_size);
525 x86_setup_var_mtrrs(address_size, 1);
529 int x86_mtrr_check(void)
531 /* Only Pentium Pro and later have MTRR */
533 printk(BIOS_DEBUG, "\nMTRR check\n");
538 printk(BIOS_DEBUG, "Fixed MTRRs : ");
540 printk(BIOS_DEBUG, "Enabled\n");
542 printk(BIOS_DEBUG, "Disabled\n");
544 printk(BIOS_DEBUG, "Variable MTRRs: ");
546 printk(BIOS_DEBUG, "Enabled\n");
548 printk(BIOS_DEBUG, "Disabled\n");
550 printk(BIOS_DEBUG, "\n");
553 return ((int) msr.lo);