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-rw-r--r--arch/x86/kernel/cpu/cyrix.c467
1 files changed, 467 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c
new file mode 100644
index 000000000..9651275ae
--- /dev/null
+++ b/arch/x86/kernel/cpu/cyrix.c
@@ -0,0 +1,467 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/isa-dma.h>
+#include <linux/pci.h>
+#include <asm/dma.h>
+#include <linux/io.h>
+#include <asm/processor-cyrix.h>
+#include <asm/processor-flags.h>
+#include <linux/timer.h>
+#include <asm/pci-direct.h>
+#include <asm/tsc.h>
+#include <asm/cpufeature.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+
+#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);
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