diff options
Diffstat (limited to 'arch/mips/kernel/cpu-r3k-probe.c')
| -rw-r--r-- | arch/mips/kernel/cpu-r3k-probe.c | 152 |
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 = ¤t_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 = ¤t_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); +} |