diff options
Diffstat (limited to 'arch/i386/kernel/cpu/amd.c')
| -rw-r--r-- | arch/i386/kernel/cpu/amd.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c new file mode 100644 index 00000000000..ae94585d044 --- /dev/null +++ b/arch/i386/kernel/cpu/amd.c @@ -0,0 +1,249 @@ +#include <linux/init.h> +#include <linux/bitops.h> +#include <linux/mm.h> +#include <asm/io.h> +#include <asm/processor.h> + +#include "cpu.h" + +/* + * B step AMD K6 before B 9730xxxx have hardware bugs that can cause + * misexecution of code under Linux. Owners of such processors should + * contact AMD for precise details and a CPU swap. + * + * See http://www.multimania.com/poulot/k6bug.html + * http://www.amd.com/K6/k6docs/revgd.html + * + * The following test is erm.. interesting. AMD neglected to up + * the chip setting when fixing the bug but they also tweaked some + * performance at the same time.. + */ + +extern void vide(void); +__asm__(".align 4\nvide: ret"); + +static void __init init_amd(struct cpuinfo_x86 *c) +{ + u32 l, h; + int mbytes = num_physpages >> (20-PAGE_SHIFT); + int r; + + /* + * FIXME: We should handle the K5 here. Set up the write + * range and also turn on MSR 83 bits 4 and 31 (write alloc, + * no bus pipeline) + */ + + /* Bit 31 in normal CPUID used for nonstandard 3DNow ID; + 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */ + clear_bit(0*32+31, c->x86_capability); + + r = get_model_name(c); + + switch(c->x86) + { + case 4: + /* + * General Systems BIOSen alias the cpu frequency registers + * of the Elan at 0x000df000. Unfortuantly, one of the Linux + * drivers subsequently pokes it, and changes the CPU speed. + * Workaround : Remove the unneeded alias. + */ +#define CBAR (0xfffc) /* Configuration Base Address (32-bit) */ +#define CBAR_ENB (0x80000000) +#define CBAR_KEY (0X000000CB) + if (c->x86_model==9 || c->x86_model == 10) { + if (inl (CBAR) & CBAR_ENB) + outl (0 | CBAR_KEY, CBAR); + } + break; + case 5: + if( c->x86_model < 6 ) + { + /* Based on AMD doc 20734R - June 2000 */ + if ( c->x86_model == 0 ) { + clear_bit(X86_FEATURE_APIC, c->x86_capability); + set_bit(X86_FEATURE_PGE, c->x86_capability); + } + break; + } + + if ( c->x86_model == 6 && c->x86_mask == 1 ) { + const int K6_BUG_LOOP = 1000000; + int n; + void (*f_vide)(void); + unsigned long d, d2; + + printk(KERN_INFO "AMD K6 stepping B detected - "); + + /* + * It looks like AMD fixed the 2.6.2 bug and improved indirect + * calls at the same time. + */ + + n = K6_BUG_LOOP; + f_vide = vide; + rdtscl(d); + while (n--) + f_vide(); + rdtscl(d2); + d = d2-d; + + /* Knock these two lines out if it debugs out ok */ + printk(KERN_INFO "AMD K6 stepping B detected - "); + /* -- cut here -- */ + if (d > 20*K6_BUG_LOOP) + printk("system stability may be impaired when more than 32 MB are used.\n"); + else + printk("probably OK (after B9730xxxx).\n"); + printk(KERN_INFO "Please see http://membres.lycos.fr/poulot/k6bug.html\n"); + } + + /* K6 with old style WHCR */ + if (c->x86_model < 8 || + (c->x86_model== 8 && c->x86_mask < 8)) { + /* We can only write allocate on the low 508Mb */ + if(mbytes>508) + mbytes=508; + + rdmsr(MSR_K6_WHCR, l, h); + if ((l&0x0000FFFF)==0) { + unsigned long flags; + l=(1<<0)|((mbytes/4)<<1); + local_irq_save(flags); + wbinvd(); + wrmsr(MSR_K6_WHCR, l, h); + local_irq_restore(flags); + printk(KERN_INFO "Enabling old style K6 write allocation for %d Mb\n", + mbytes); + } + break; + } + + if ((c->x86_model == 8 && c->x86_mask >7) || + c->x86_model == 9 || c->x86_model == 13) { + /* The more serious chips .. */ + + if(mbytes>4092) + mbytes=4092; + + rdmsr(MSR_K6_WHCR, l, h); + if ((l&0xFFFF0000)==0) { + unsigned long flags; + l=((mbytes>>2)<<22)|(1<<16); + local_irq_save(flags); + wbinvd(); + wrmsr(MSR_K6_WHCR, l, h); + local_irq_restore(flags); + printk(KERN_INFO "Enabling new style K6 write allocation for %d Mb\n", + mbytes); + } + + /* Set MTRR capability flag if appropriate */ + if (c->x86_model == 13 || c->x86_model == 9 || + (c->x86_model == 8 && c->x86_mask >= 8)) + set_bit(X86_FEATURE_K6_MTRR, c->x86_capability); + break; + } + break; + + case 6: /* An Athlon/Duron */ + + /* Bit 15 of Athlon specific MSR 15, needs to be 0 + * to enable SSE on Palomino/Morgan/Barton CPU's. + * If the BIOS didn't enable it already, enable it here. + */ + if (c->x86_model >= 6 && c->x86_model <= 10) { + if (!cpu_has(c, X86_FEATURE_XMM)) { + printk(KERN_INFO "Enabling disabled K7/SSE Support.\n"); + rdmsr(MSR_K7_HWCR, l, h); + l &= ~0x00008000; + wrmsr(MSR_K7_HWCR, l, h); + set_bit(X86_FEATURE_XMM, c->x86_capability); + } + } + + /* It's been determined by AMD that Athlons since model 8 stepping 1 + * are more robust with CLK_CTL set to 200xxxxx instead of 600xxxxx + * As per AMD technical note 27212 0.2 + */ + if ((c->x86_model == 8 && c->x86_mask>=1) || (c->x86_model > 8)) { + rdmsr(MSR_K7_CLK_CTL, l, h); + if ((l & 0xfff00000) != 0x20000000) { + printk ("CPU: CLK_CTL MSR was %x. Reprogramming to %x\n", l, + ((l & 0x000fffff)|0x20000000)); + wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h); + } + } + break; + } + + switch (c->x86) { + case 15: + set_bit(X86_FEATURE_K8, c->x86_capability); + break; + case 6: + set_bit(X86_FEATURE_K7, c->x86_capability); + break; + } + + display_cacheinfo(c); + detect_ht(c); + +#ifdef CONFIG_X86_HT + /* AMD dual core looks like HT but isn't really. Hide it from the + scheduler. This works around problems with the domain scheduler. + Also probably gives slightly better scheduling and disables + SMT nice which is harmful on dual core. + TBD tune the domain scheduler for dual core. */ + if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) + smp_num_siblings = 1; +#endif + + if (cpuid_eax(0x80000000) >= 0x80000008) { + c->x86_num_cores = (cpuid_ecx(0x80000008) & 0xff) + 1; + if (c->x86_num_cores & (c->x86_num_cores - 1)) + c->x86_num_cores = 1; + } +} + +static unsigned int amd_size_cache(struct cpuinfo_x86 * c, unsigned int size) +{ + /* AMD errata T13 (order #21922) */ + if ((c->x86 == 6)) { + if (c->x86_model == 3 && c->x86_mask == 0) /* Duron Rev A0 */ + size = 64; + if (c->x86_model == 4 && + (c->x86_mask==0 || c->x86_mask==1)) /* Tbird rev A1/A2 */ + size = 256; + } + return size; +} + +static struct cpu_dev amd_cpu_dev __initdata = { + .c_vendor = "AMD", + .c_ident = { "AuthenticAMD" }, + .c_models = { + { .vendor = X86_VENDOR_AMD, .family = 4, .model_names = + { + [3] = "486 DX/2", + [7] = "486 DX/2-WB", + [8] = "486 DX/4", + [9] = "486 DX/4-WB", + [14] = "Am5x86-WT", + [15] = "Am5x86-WB" + } + }, + }, + .c_init = init_amd, + .c_identify = generic_identify, + .c_size_cache = amd_size_cache, +}; + +int __init amd_init_cpu(void) +{ + cpu_devs[X86_VENDOR_AMD] = &amd_cpu_dev; + return 0; +} + +//early_arch_initcall(amd_init_cpu); |