root/arch/nios2/kernel/cpuinfo.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2013 Altera Corporation
 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
 *
 * Based on cpuinfo.c from microblaze
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/of.h>
#include <asm/cpuinfo.h>

struct cpuinfo cpuinfo;

#define err_cpu(x) \
        pr_err("ERROR: Nios II " x " different for kernel and DTS\n")

static inline u32 fcpu(struct device_node *cpu, const char *n)
{
        u32 val = 0;

        of_property_read_u32(cpu, n, &val);

        return val;
}

void __init setup_cpuinfo(void)
{
        struct device_node *cpu;
        const char *str;
        int len;

        cpu = of_get_cpu_node(0, NULL);
        if (!cpu)
                panic("%s: No CPU found in devicetree!\n", __func__);

        if (!of_property_read_bool(cpu, "altr,has-initda"))
                panic("initda instruction is unimplemented. Please update your "
                        "hardware system to have more than 4-byte line data "
                        "cache\n");

        cpuinfo.cpu_clock_freq = fcpu(cpu, "clock-frequency");

        str = of_get_property(cpu, "altr,implementation", &len);
        strscpy(cpuinfo.cpu_impl, str ?: "<unknown>");

        cpuinfo.has_div = of_property_read_bool(cpu, "altr,has-div");
        cpuinfo.has_mul = of_property_read_bool(cpu, "altr,has-mul");
        cpuinfo.has_mulx = of_property_read_bool(cpu, "altr,has-mulx");
        cpuinfo.has_bmx = of_property_read_bool(cpu, "altr,has-bmx");
        cpuinfo.has_cdx = of_property_read_bool(cpu, "altr,has-cdx");
        cpuinfo.mmu = of_property_read_bool(cpu, "altr,has-mmu");

        if (IS_ENABLED(CONFIG_NIOS2_HW_DIV_SUPPORT) && !cpuinfo.has_div)
                err_cpu("DIV");

        if (IS_ENABLED(CONFIG_NIOS2_HW_MUL_SUPPORT) && !cpuinfo.has_mul)
                err_cpu("MUL");

        if (IS_ENABLED(CONFIG_NIOS2_HW_MULX_SUPPORT) && !cpuinfo.has_mulx)
                err_cpu("MULX");

        if (IS_ENABLED(CONFIG_NIOS2_BMX_SUPPORT) && !cpuinfo.has_bmx)
                err_cpu("BMX");

        if (IS_ENABLED(CONFIG_NIOS2_CDX_SUPPORT) && !cpuinfo.has_cdx)
                err_cpu("CDX");

        cpuinfo.tlb_num_ways = fcpu(cpu, "altr,tlb-num-ways");
        if (!cpuinfo.tlb_num_ways)
                panic("altr,tlb-num-ways can't be 0. Please check your hardware "
                        "system\n");
        cpuinfo.icache_line_size = fcpu(cpu, "icache-line-size");
        cpuinfo.icache_size = fcpu(cpu, "icache-size");
        if (CONFIG_NIOS2_ICACHE_SIZE != cpuinfo.icache_size)
                pr_warn("Warning: icache size configuration mismatch "
                "(0x%x vs 0x%x) of CONFIG_NIOS2_ICACHE_SIZE vs "
                "device tree icache-size\n",
                CONFIG_NIOS2_ICACHE_SIZE, cpuinfo.icache_size);

        cpuinfo.dcache_line_size = fcpu(cpu, "dcache-line-size");
        if (CONFIG_NIOS2_DCACHE_LINE_SIZE != cpuinfo.dcache_line_size)
                pr_warn("Warning: dcache line size configuration mismatch "
                "(0x%x vs 0x%x) of CONFIG_NIOS2_DCACHE_LINE_SIZE vs "
                "device tree dcache-line-size\n",
                CONFIG_NIOS2_DCACHE_LINE_SIZE, cpuinfo.dcache_line_size);
        cpuinfo.dcache_size = fcpu(cpu, "dcache-size");
        if (CONFIG_NIOS2_DCACHE_SIZE != cpuinfo.dcache_size)
                pr_warn("Warning: dcache size configuration mismatch "
                        "(0x%x vs 0x%x) of CONFIG_NIOS2_DCACHE_SIZE vs "
                        "device tree dcache-size\n",
                        CONFIG_NIOS2_DCACHE_SIZE, cpuinfo.dcache_size);

        cpuinfo.tlb_pid_num_bits = fcpu(cpu, "altr,pid-num-bits");
        cpuinfo.tlb_num_ways_log2 = ilog2(cpuinfo.tlb_num_ways);
        cpuinfo.tlb_num_entries = fcpu(cpu, "altr,tlb-num-entries");
        cpuinfo.tlb_num_lines = cpuinfo.tlb_num_entries / cpuinfo.tlb_num_ways;
        cpuinfo.tlb_ptr_sz = fcpu(cpu, "altr,tlb-ptr-sz");

        cpuinfo.reset_addr = fcpu(cpu, "altr,reset-addr");
        cpuinfo.exception_addr = fcpu(cpu, "altr,exception-addr");
        cpuinfo.fast_tlb_miss_exc_addr = fcpu(cpu, "altr,fast-tlb-miss-addr");

        of_node_put(cpu);
}

#ifdef CONFIG_PROC_FS

/*
 * Get CPU information for use by the procfs.
 */
static int show_cpuinfo(struct seq_file *m, void *v)
{
        const u32 clockfreq = cpuinfo.cpu_clock_freq;

        seq_printf(m,
                   "CPU:\t\tNios II/%s\n"
                   "REV:\t\t%i\n"
                   "MMU:\t\t%s\n"
                   "FPU:\t\tnone\n"
                   "Clocking:\t%u.%02u MHz\n"
                   "BogoMips:\t%lu.%02lu\n"
                   "Calibration:\t%lu loops\n",
                   cpuinfo.cpu_impl,
                   CONFIG_NIOS2_ARCH_REVISION,
                   cpuinfo.mmu ? "present" : "none",
                   clockfreq / 1000000, (clockfreq / 100000) % 10,
                   (loops_per_jiffy * HZ) / 500000,
                   ((loops_per_jiffy * HZ) / 5000) % 100,
                   (loops_per_jiffy * HZ));

        seq_printf(m,
                   "HW:\n"
                   " MUL:\t\t%s\n"
                   " MULX:\t\t%s\n"
                   " DIV:\t\t%s\n"
                   " BMX:\t\t%s\n"
                   " CDX:\t\t%s\n",
                   str_yes_no(cpuinfo.has_mul),
                   str_yes_no(cpuinfo.has_mulx),
                   str_yes_no(cpuinfo.has_div),
                   str_yes_no(cpuinfo.has_bmx),
                   str_yes_no(cpuinfo.has_cdx));

        seq_printf(m,
                   "Icache:\t\t%ukB, line length: %u\n",
                   cpuinfo.icache_size >> 10,
                   cpuinfo.icache_line_size);

        seq_printf(m,
                   "Dcache:\t\t%ukB, line length: %u\n",
                   cpuinfo.dcache_size >> 10,
                   cpuinfo.dcache_line_size);

        seq_printf(m,
                   "TLB:\t\t%u ways, %u entries, %u PID bits\n",
                   cpuinfo.tlb_num_ways,
                   cpuinfo.tlb_num_entries,
                   cpuinfo.tlb_pid_num_bits);

        return 0;
}

static void *cpuinfo_start(struct seq_file *m, loff_t *pos)
{
        unsigned long i = *pos;

        return i < num_possible_cpus() ? (void *) (i + 1) : NULL;
}

static void *cpuinfo_next(struct seq_file *m, void *v, loff_t *pos)
{
        ++*pos;
        return cpuinfo_start(m, pos);
}

static void cpuinfo_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
        .start  = cpuinfo_start,
        .next   = cpuinfo_next,
        .stop   = cpuinfo_stop,
        .show   = show_cpuinfo
};

#endif /* CONFIG_PROC_FS */