summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/cpu-r3k-probe.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/kernel/cpu-r3k-probe.c')
-rw-r--r--arch/mips/kernel/cpu-r3k-probe.c152
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/mips/kernel/cpu-r3k-probe.c b/arch/mips/kernel/cpu-r3k-probe.c
new file mode 100644
index 0000000000..be93469c0e
--- /dev/null
+++ b/arch/mips/kernel/cpu-r3k-probe.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Processor capabilities determination functions.
+ *
+ * Copyright (C) xxxx the Anonymous
+ * Copyright (C) 1994 - 2006 Ralf Baechle
+ * Copyright (C) 2003, 2004 Maciej W. Rozycki
+ * Copyright (C) 2001, 2004, 2011, 2012 MIPS Technologies, Inc.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/smp.h>
+#include <linux/stddef.h>
+#include <linux/export.h>
+
+#include <asm/bugs.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
+#include <asm/fpu.h>
+#include <asm/mipsregs.h>
+#include <asm/elf.h>
+#include <asm/traps.h>
+
+#include "fpu-probe.h"
+
+/* Hardware capabilities */
+unsigned int elf_hwcap __read_mostly;
+EXPORT_SYMBOL_GPL(elf_hwcap);
+
+void __init check_bugs32(void)
+{
+
+}
+
+/*
+ * Probe whether cpu has config register by trying to play with
+ * alternate cache bit and see whether it matters.
+ * It's used by cpu_probe to distinguish between R3000A and R3081.
+ */
+static inline int cpu_has_confreg(void)
+{
+#ifdef CONFIG_CPU_R3000
+ extern unsigned long r3k_cache_size(unsigned long);
+ unsigned long size1, size2;
+ unsigned long cfg = read_c0_conf();
+
+ size1 = r3k_cache_size(ST0_ISC);
+ write_c0_conf(cfg ^ R30XX_CONF_AC);
+ size2 = r3k_cache_size(ST0_ISC);
+ write_c0_conf(cfg);
+ return size1 != size2;
+#else
+ return 0;
+#endif
+}
+
+static inline void set_elf_platform(int cpu, const char *plat)
+{
+ if (cpu == 0)
+ __elf_platform = plat;
+}
+
+const char *__cpu_name[NR_CPUS];
+const char *__elf_platform;
+const char *__elf_base_platform;
+
+void cpu_probe(void)
+{
+ struct cpuinfo_mips *c = &current_cpu_data;
+ unsigned int cpu = smp_processor_id();
+
+ /*
+ * Set a default elf platform, cpu probe may later
+ * overwrite it with a more precise value
+ */
+ set_elf_platform(cpu, "mips");
+
+ c->processor_id = PRID_IMP_UNKNOWN;
+ c->fpu_id = FPIR_IMP_NONE;
+ c->cputype = CPU_UNKNOWN;
+ c->writecombine = _CACHE_UNCACHED;
+
+ c->fpu_csr31 = FPU_CSR_RN;
+ c->fpu_msk31 = FPU_CSR_RSVD | FPU_CSR_ABS2008 | FPU_CSR_NAN2008 |
+ FPU_CSR_CONDX | FPU_CSR_FS;
+
+ c->srsets = 1;
+
+ c->processor_id = read_c0_prid();
+ switch (c->processor_id & (PRID_COMP_MASK | PRID_IMP_MASK)) {
+ case PRID_COMP_LEGACY | PRID_IMP_R2000:
+ c->cputype = CPU_R2000;
+ __cpu_name[cpu] = "R2000";
+ c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
+ MIPS_CPU_NOFPUEX;
+ if (__cpu_has_fpu())
+ c->options |= MIPS_CPU_FPU;
+ c->tlbsize = 64;
+ break;
+ case PRID_COMP_LEGACY | PRID_IMP_R3000:
+ if ((c->processor_id & PRID_REV_MASK) == PRID_REV_R3000A) {
+ if (cpu_has_confreg()) {
+ c->cputype = CPU_R3081E;
+ __cpu_name[cpu] = "R3081";
+ } else {
+ c->cputype = CPU_R3000A;
+ __cpu_name[cpu] = "R3000A";
+ }
+ } else {
+ c->cputype = CPU_R3000;
+ __cpu_name[cpu] = "R3000";
+ }
+ c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
+ MIPS_CPU_NOFPUEX;
+ if (__cpu_has_fpu())
+ c->options |= MIPS_CPU_FPU;
+ c->tlbsize = 64;
+ break;
+ }
+
+ BUG_ON(!__cpu_name[cpu]);
+ BUG_ON(c->cputype == CPU_UNKNOWN);
+
+ /*
+ * Platform code can force the cpu type to optimize code
+ * generation. In that case be sure the cpu type is correctly
+ * manually setup otherwise it could trigger some nasty bugs.
+ */
+ BUG_ON(current_cpu_type() != c->cputype);
+
+ if (mips_fpu_disabled)
+ c->options &= ~MIPS_CPU_FPU;
+
+ if (c->options & MIPS_CPU_FPU)
+ cpu_set_fpu_opts(c);
+ else
+ cpu_set_nofpu_opts(c);
+
+ reserve_exception_space(0, 0x400);
+}
+
+void cpu_report(void)
+{
+ struct cpuinfo_mips *c = &current_cpu_data;
+
+ pr_info("CPU%d revision is: %08x (%s)\n",
+ smp_processor_id(), c->processor_id, cpu_name_string());
+ if (c->options & MIPS_CPU_FPU)
+ pr_info("FPU revision is: %08x\n", c->fpu_id);
+}