root/arch/mips/mm/cerr-sb1.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001,2002,2003 Broadcom Corporation
 */
#include <linux/sched.h>
#include <asm/mipsregs.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>

#if !defined(CONFIG_SIBYTE_BUS_WATCHER) || defined(CONFIG_SIBYTE_BW_TRACE)
#include <asm/io.h>
#include <asm/sibyte/sb1250_scd.h>
#endif

/*
 * We'd like to dump the L2_ECC_TAG register on errors, but errata make
 * that unsafe... So for now we don't.  (BCM1250/BCM112x erratum SOC-48.)
 */
#undef DUMP_L2_ECC_TAG_ON_ERROR

/* SB1 definitions */

/* XXX should come from config1 XXX */
#define SB1_CACHE_INDEX_MASK   0x1fe0

#define CP0_ERRCTL_RECOVERABLE (1 << 31)
#define CP0_ERRCTL_DCACHE      (1 << 30)
#define CP0_ERRCTL_ICACHE      (1 << 29)
#define CP0_ERRCTL_MULTIBUS    (1 << 23)
#define CP0_ERRCTL_MC_TLB      (1 << 15)
#define CP0_ERRCTL_MC_TIMEOUT  (1 << 14)

#define CP0_CERRI_TAG_PARITY   (1 << 29)
#define CP0_CERRI_DATA_PARITY  (1 << 28)
#define CP0_CERRI_EXTERNAL     (1 << 26)

#define CP0_CERRI_IDX_VALID(c) (!((c) & CP0_CERRI_EXTERNAL))
#define CP0_CERRI_DATA         (CP0_CERRI_DATA_PARITY)

#define CP0_CERRD_MULTIPLE     (1 << 31)
#define CP0_CERRD_TAG_STATE    (1 << 30)
#define CP0_CERRD_TAG_ADDRESS  (1 << 29)
#define CP0_CERRD_DATA_SBE     (1 << 28)
#define CP0_CERRD_DATA_DBE     (1 << 27)
#define CP0_CERRD_EXTERNAL     (1 << 26)
#define CP0_CERRD_LOAD         (1 << 25)
#define CP0_CERRD_STORE        (1 << 24)
#define CP0_CERRD_FILLWB       (1 << 23)
#define CP0_CERRD_COHERENCY    (1 << 22)
#define CP0_CERRD_DUPTAG       (1 << 21)

#define CP0_CERRD_DPA_VALID(c) (!((c) & CP0_CERRD_EXTERNAL))
#define CP0_CERRD_IDX_VALID(c) \
   (((c) & (CP0_CERRD_LOAD | CP0_CERRD_STORE)) ? (!((c) & CP0_CERRD_EXTERNAL)) : 0)
#define CP0_CERRD_CAUSES \
   (CP0_CERRD_LOAD | CP0_CERRD_STORE | CP0_CERRD_FILLWB | CP0_CERRD_COHERENCY | CP0_CERRD_DUPTAG)
#define CP0_CERRD_TYPES \
   (CP0_CERRD_TAG_STATE | CP0_CERRD_TAG_ADDRESS | CP0_CERRD_DATA_SBE | CP0_CERRD_DATA_DBE | CP0_CERRD_EXTERNAL)
#define CP0_CERRD_DATA         (CP0_CERRD_DATA_SBE | CP0_CERRD_DATA_DBE)

static uint32_t extract_ic(unsigned short addr, int data);
static uint32_t extract_dc(unsigned short addr, int data);

static inline void breakout_errctl(unsigned int val)
{
        if (val & CP0_ERRCTL_RECOVERABLE)
                printk(" recoverable");
        if (val & CP0_ERRCTL_DCACHE)
                printk(" dcache");
        if (val & CP0_ERRCTL_ICACHE)
                printk(" icache");
        if (val & CP0_ERRCTL_MULTIBUS)
                printk(" multiple-buserr");
        printk("\n");
}

static inline void breakout_cerri(unsigned int val)
{
        if (val & CP0_CERRI_TAG_PARITY)
                printk(" tag-parity");
        if (val & CP0_CERRI_DATA_PARITY)
                printk(" data-parity");
        if (val & CP0_CERRI_EXTERNAL)
                printk(" external");
        printk("\n");
}

static inline void breakout_cerrd(unsigned int val)
{
        switch (val & CP0_CERRD_CAUSES) {
        case CP0_CERRD_LOAD:
                printk(" load,");
                break;
        case CP0_CERRD_STORE:
                printk(" store,");
                break;
        case CP0_CERRD_FILLWB:
                printk(" fill/wb,");
                break;
        case CP0_CERRD_COHERENCY:
                printk(" coherency,");
                break;
        case CP0_CERRD_DUPTAG:
                printk(" duptags,");
                break;
        default:
                printk(" NO CAUSE,");
                break;
        }
        if (!(val & CP0_CERRD_TYPES))
                printk(" NO TYPE");
        else {
                if (val & CP0_CERRD_MULTIPLE)
                        printk(" multi-err");
                if (val & CP0_CERRD_TAG_STATE)
                        printk(" tag-state");
                if (val & CP0_CERRD_TAG_ADDRESS)
                        printk(" tag-address");
                if (val & CP0_CERRD_DATA_SBE)
                        printk(" data-SBE");
                if (val & CP0_CERRD_DATA_DBE)
                        printk(" data-DBE");
                if (val & CP0_CERRD_EXTERNAL)
                        printk(" external");
        }
        printk("\n");
}

#ifndef CONFIG_SIBYTE_BUS_WATCHER

static void check_bus_watcher(void)
{
        uint32_t status, l2_err, memio_err;
#ifdef DUMP_L2_ECC_TAG_ON_ERROR
        uint64_t l2_tag;
#endif

        /* Destructive read, clears register and interrupt */
        status = csr_in32(IOADDR(A_SCD_BUS_ERR_STATUS));
        /* Bit 31 is always on, but there's no #define for that */
        if (status & ~(1UL << 31)) {
                l2_err = csr_in32(IOADDR(A_BUS_L2_ERRORS));
#ifdef DUMP_L2_ECC_TAG_ON_ERROR
                l2_tag = in64(IOADDR(A_L2_ECC_TAG));
#endif
                memio_err = csr_in32(IOADDR(A_BUS_MEM_IO_ERRORS));
                printk("Bus watcher error counters: %08x %08x\n", l2_err, memio_err);
                printk("\nLast recorded signature:\n");
                printk("Request %02x from %d, answered by %d with Dcode %d\n",
                       (unsigned int)(G_SCD_BERR_TID(status) & 0x3f),
                       (int)(G_SCD_BERR_TID(status) >> 6),
                       (int)G_SCD_BERR_RID(status),
                       (int)G_SCD_BERR_DCODE(status));
#ifdef DUMP_L2_ECC_TAG_ON_ERROR
                printk("Last L2 tag w/ bad ECC: %016llx\n", l2_tag);
#endif
        } else {
                printk("Bus watcher indicates no error\n");
        }
}
#else
extern void check_bus_watcher(void);
#endif

asmlinkage void sb1_cache_error(void)
{
        uint32_t errctl, cerr_i, cerr_d, dpalo, dpahi, eepc, res;
        unsigned long long cerr_dpa;

#ifdef CONFIG_SIBYTE_BW_TRACE
        /* Freeze the trace buffer now */
        csr_out32(M_SCD_TRACE_CFG_FREEZE, IOADDR(A_SCD_TRACE_CFG));
        printk("Trace buffer frozen\n");
#endif

        printk("Cache error exception on CPU %x:\n",
               (read_c0_prid() >> 25) & 0x7);

        __asm__ __volatile__ (
        "       .set    push\n\t"
        "       .set    mips64\n\t"
        "       .set    noat\n\t"
        "       mfc0    %0, $26\n\t"
        "       mfc0    %1, $27\n\t"
        "       mfc0    %2, $27, 1\n\t"
        "       dmfc0   $1, $27, 3\n\t"
        "       dsrl32  %3, $1, 0 \n\t"
        "       sll     %4, $1, 0 \n\t"
        "       mfc0    %5, $30\n\t"
        "       .set    pop"
        : "=r" (errctl), "=r" (cerr_i), "=r" (cerr_d),
          "=r" (dpahi), "=r" (dpalo), "=r" (eepc));

        cerr_dpa = (((uint64_t)dpahi) << 32) | dpalo;
        printk(" c0_errorepc ==   %08x\n", eepc);
        printk(" c0_errctl   ==   %08x", errctl);
        breakout_errctl(errctl);
        if (errctl & CP0_ERRCTL_ICACHE) {
                printk(" c0_cerr_i   ==   %08x", cerr_i);
                breakout_cerri(cerr_i);
                if (CP0_CERRI_IDX_VALID(cerr_i)) {
                        /* Check index of EPC, allowing for delay slot */
                        if (((eepc & SB1_CACHE_INDEX_MASK) != (cerr_i & SB1_CACHE_INDEX_MASK)) &&
                            ((eepc & SB1_CACHE_INDEX_MASK) != ((cerr_i & SB1_CACHE_INDEX_MASK) - 4)))
                                printk(" cerr_i idx doesn't match eepc\n");
                        else {
                                res = extract_ic(cerr_i & SB1_CACHE_INDEX_MASK,
                                                 (cerr_i & CP0_CERRI_DATA) != 0);
                                if (!(res & cerr_i))
                                        printk("...didn't see indicated icache problem\n");
                        }
                }
        }
        if (errctl & CP0_ERRCTL_DCACHE) {
                printk(" c0_cerr_d   ==   %08x", cerr_d);
                breakout_cerrd(cerr_d);
                if (CP0_CERRD_DPA_VALID(cerr_d)) {
                        printk(" c0_cerr_dpa == %010llx\n", cerr_dpa);
                        if (!CP0_CERRD_IDX_VALID(cerr_d)) {
                                res = extract_dc(cerr_dpa & SB1_CACHE_INDEX_MASK,
                                                 (cerr_d & CP0_CERRD_DATA) != 0);
                                if (!(res & cerr_d))
                                        printk("...didn't see indicated dcache problem\n");
                        } else {
                                if ((cerr_dpa & SB1_CACHE_INDEX_MASK) != (cerr_d & SB1_CACHE_INDEX_MASK))
                                        printk(" cerr_d idx doesn't match cerr_dpa\n");
                                else {
                                        res = extract_dc(cerr_d & SB1_CACHE_INDEX_MASK,
                                                         (cerr_d & CP0_CERRD_DATA) != 0);
                                        if (!(res & cerr_d))
                                                printk("...didn't see indicated problem\n");
                                }
                        }
                }
        }

        check_bus_watcher();

        /*
         * Calling panic() when a fatal cache error occurs scrambles the
         * state of the system (and the cache), making it difficult to
         * investigate after the fact.  However, if you just stall the CPU,
         * the other CPU may keep on running, which is typically very
         * undesirable.
         */
#ifdef CONFIG_SB1_CERR_STALL
        while (1)
                ;
#else
        panic("unhandled cache error");
#endif
}


/* Parity lookup table. */
static const uint8_t parity[256] = {
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
        0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0
};

/* Masks to select bits for Hamming parity, mask_72_64[i] for bit[i] */
static const uint64_t mask_72_64[8] = {
        0x0738C808099264FFULL,
        0x38C808099264FF07ULL,
        0xC808099264FF0738ULL,
        0x08099264FF0738C8ULL,
        0x099264FF0738C808ULL,
        0x9264FF0738C80809ULL,
        0x64FF0738C8080992ULL,
        0xFF0738C808099264ULL
};

/* Calculate the parity on a range of bits */
static char range_parity(uint64_t dword, int max, int min)
{
        char parity = 0;
        int i;
        dword >>= min;
        for (i=max-min; i>=0; i--) {
                if (dword & 0x1)
                        parity = !parity;
                dword >>= 1;
        }
        return parity;
}

/* Calculate the 4-bit even byte-parity for an instruction */
static unsigned char inst_parity(uint32_t word)
{
        int i, j;
        char parity = 0;
        for (j=0; j<4; j++) {
                char byte_parity = 0;
                for (i=0; i<8; i++) {
                        if (word & 0x80000000)
                                byte_parity = !byte_parity;
                        word <<= 1;
                }
                parity <<= 1;
                parity |= byte_parity;
        }
        return parity;
}

static uint32_t extract_ic(unsigned short addr, int data)
{
        unsigned short way;
        int valid;
        uint32_t taghi, taglolo, taglohi;
        unsigned long long taglo, va;
        uint64_t tlo_tmp;
        uint8_t lru;
        int res = 0;

        printk("Icache index 0x%04x  ", addr);
        for (way = 0; way < 4; way++) {
                /* Index-load-tag-I */
                __asm__ __volatile__ (
                "       .set    push            \n\t"
                "       .set    noreorder       \n\t"
                "       .set    mips64          \n\t"
                "       .set    noat            \n\t"
                "       cache   4, 0(%3)        \n\t"
                "       mfc0    %0, $29         \n\t"
                "       dmfc0   $1, $28         \n\t"
                "       dsrl32  %1, $1, 0       \n\t"
                "       sll     %2, $1, 0       \n\t"
                "       .set    pop"
                : "=r" (taghi), "=r" (taglohi), "=r" (taglolo)
                : "r" ((way << 13) | addr));

                taglo = ((unsigned long long)taglohi << 32) | taglolo;
                if (way == 0) {
                        lru = (taghi >> 14) & 0xff;
                        printk("[Bank %d Set 0x%02x]  LRU > %d %d %d %d > MRU\n",
                                    ((addr >> 5) & 0x3), /* bank */
                                    ((addr >> 7) & 0x3f), /* index */
                                    (lru & 0x3),
                                    ((lru >> 2) & 0x3),
                                    ((lru >> 4) & 0x3),
                                    ((lru >> 6) & 0x3));
                }
                va = (taglo & 0xC0000FFFFFFFE000ULL) | addr;
                if ((taglo & (1 << 31)) && (((taglo >> 62) & 0x3) == 3))
                        va |= 0x3FFFF00000000000ULL;
                valid = ((taghi >> 29) & 1);
                if (valid) {
                        tlo_tmp = taglo & 0xfff3ff;
                        if (((taglo >> 10) & 1) ^ range_parity(tlo_tmp, 23, 0)) {
                                printk("   ** bad parity in VTag0/G/ASID\n");
                                res |= CP0_CERRI_TAG_PARITY;
                        }
                        if (((taglo >> 11) & 1) ^ range_parity(taglo, 63, 24)) {
                                printk("   ** bad parity in R/VTag1\n");
                                res |= CP0_CERRI_TAG_PARITY;
                        }
                }
                if (valid ^ ((taghi >> 27) & 1)) {
                        printk("   ** bad parity for valid bit\n");
                        res |= CP0_CERRI_TAG_PARITY;
                }
                printk(" %d  [VA %016llx]  [Vld? %d]  raw tags: %08X-%016llX\n",
                            way, va, valid, taghi, taglo);

                if (data) {
                        uint32_t datahi, insta, instb;
                        uint8_t predecode;
                        int offset;

                        /* (hit all banks and ways) */
                        for (offset = 0; offset < 4; offset++) {
                                /* Index-load-data-I */
                                __asm__ __volatile__ (
                                "       .set    push\n\t"
                                "       .set    noreorder\n\t"
                                "       .set    mips64\n\t"
                                "       .set    noat\n\t"
                                "       cache   6, 0(%3)  \n\t"
                                "       mfc0    %0, $29, 1\n\t"
                                "       dmfc0  $1, $28, 1\n\t"
                                "       dsrl32 %1, $1, 0 \n\t"
                                "       sll    %2, $1, 0 \n\t"
                                "       .set    pop         \n"
                                : "=r" (datahi), "=r" (insta), "=r" (instb)
                                : "r" ((way << 13) | addr | (offset << 3)));
                                predecode = (datahi >> 8) & 0xff;
                                if (((datahi >> 16) & 1) != (uint32_t)range_parity(predecode, 7, 0)) {
                                        printk("   ** bad parity in predecode\n");
                                        res |= CP0_CERRI_DATA_PARITY;
                                }
                                /* XXXKW should/could check predecode bits themselves */
                                if (((datahi >> 4) & 0xf) ^ inst_parity(insta)) {
                                        printk("   ** bad parity in instruction a\n");
                                        res |= CP0_CERRI_DATA_PARITY;
                                }
                                if ((datahi & 0xf) ^ inst_parity(instb)) {
                                        printk("   ** bad parity in instruction b\n");
                                        res |= CP0_CERRI_DATA_PARITY;
                                }
                                printk("  %05X-%08X%08X", datahi, insta, instb);
                        }
                        printk("\n");
                }
        }
        return res;
}

/* Compute the ECC for a data doubleword */
static uint8_t dc_ecc(uint64_t dword)
{
        uint64_t t;
        uint32_t w;
        uint8_t  p;
        int      i;

        p = 0;
        for (i = 7; i >= 0; i--)
        {
                p <<= 1;
                t = dword & mask_72_64[i];
                w = (uint32_t)(t >> 32);
                p ^= (parity[w>>24] ^ parity[(w>>16) & 0xFF]
                      ^ parity[(w>>8) & 0xFF] ^ parity[w & 0xFF]);
                w = (uint32_t)(t & 0xFFFFFFFF);
                p ^= (parity[w>>24] ^ parity[(w>>16) & 0xFF]
                      ^ parity[(w>>8) & 0xFF] ^ parity[w & 0xFF]);
        }
        return p;
}

struct dc_state {
        unsigned char val;
        char *name;
};

static struct dc_state dc_states[] = {
        { 0x00, "INVALID" },
        { 0x0f, "COH-SHD" },
        { 0x13, "NCO-E-C" },
        { 0x19, "NCO-E-D" },
        { 0x16, "COH-E-C" },
        { 0x1c, "COH-E-D" },
        { 0xff, "*ERROR*" }
};

#define DC_TAG_VALID(state) \
    (((state) == 0x0) || ((state) == 0xf) || ((state) == 0x13) || \
     ((state) == 0x19) || ((state) == 0x16) || ((state) == 0x1c))

static char *dc_state_str(unsigned char state)
{
        struct dc_state *dsc = dc_states;
        while (dsc->val != 0xff) {
                if (dsc->val == state)
                        break;
                dsc++;
        }
        return dsc->name;
}

static uint32_t extract_dc(unsigned short addr, int data)
{
        int valid, way;
        unsigned char state;
        uint32_t taghi, taglolo, taglohi;
        unsigned long long taglo, pa;
        uint8_t ecc, lru;
        int res = 0;

        printk("Dcache index 0x%04x  ", addr);
        for (way = 0; way < 4; way++) {
                __asm__ __volatile__ (
                "       .set    push\n\t"
                "       .set    noreorder\n\t"
                "       .set    mips64\n\t"
                "       .set    noat\n\t"
                "       cache   5, 0(%3)\n\t"   /* Index-load-tag-D */
                "       mfc0    %0, $29, 2\n\t"
                "       dmfc0   $1, $28, 2\n\t"
                "       dsrl32  %1, $1, 0\n\t"
                "       sll     %2, $1, 0\n\t"
                "       .set    pop"
                : "=r" (taghi), "=r" (taglohi), "=r" (taglolo)
                : "r" ((way << 13) | addr));

                taglo = ((unsigned long long)taglohi << 32) | taglolo;
                pa = (taglo & 0xFFFFFFE000ULL) | addr;
                if (way == 0) {
                        lru = (taghi >> 14) & 0xff;
                        printk("[Bank %d Set 0x%02x]  LRU > %d %d %d %d > MRU\n",
                                    ((addr >> 11) & 0x2) | ((addr >> 5) & 1), /* bank */
                                    ((addr >> 6) & 0x3f), /* index */
                                    (lru & 0x3),
                                    ((lru >> 2) & 0x3),
                                    ((lru >> 4) & 0x3),
                                    ((lru >> 6) & 0x3));
                }
                state = (taghi >> 25) & 0x1f;
                valid = DC_TAG_VALID(state);
                printk(" %d  [PA %010llx]  [state %s (%02x)]  raw tags: %08X-%016llX\n",
                            way, pa, dc_state_str(state), state, taghi, taglo);
                if (valid) {
                        if (((taglo >> 11) & 1) ^ range_parity(taglo, 39, 26)) {
                                printk("   ** bad parity in PTag1\n");
                                res |= CP0_CERRD_TAG_ADDRESS;
                        }
                        if (((taglo >> 10) & 1) ^ range_parity(taglo, 25, 13)) {
                                printk("   ** bad parity in PTag0\n");
                                res |= CP0_CERRD_TAG_ADDRESS;
                        }
                } else {
                        res |= CP0_CERRD_TAG_STATE;
                }

                if (data) {
                        uint32_t datalohi, datalolo, datahi;
                        unsigned long long datalo;
                        int offset;
                        char bad_ecc = 0;

                        for (offset = 0; offset < 4; offset++) {
                                /* Index-load-data-D */
                                __asm__ __volatile__ (
                                "       .set    push\n\t"
                                "       .set    noreorder\n\t"
                                "       .set    mips64\n\t"
                                "       .set    noat\n\t"
                                "       cache   7, 0(%3)\n\t" /* Index-load-data-D */
                                "       mfc0    %0, $29, 3\n\t"
                                "       dmfc0   $1, $28, 3\n\t"
                                "       dsrl32  %1, $1, 0 \n\t"
                                "       sll     %2, $1, 0 \n\t"
                                "       .set    pop"
                                : "=r" (datahi), "=r" (datalohi), "=r" (datalolo)
                                : "r" ((way << 13) | addr | (offset << 3)));
                                datalo = ((unsigned long long)datalohi << 32) | datalolo;
                                ecc = dc_ecc(datalo);
                                if (ecc != datahi) {
                                        int bits;
                                        bad_ecc |= 1 << (3-offset);
                                        ecc ^= datahi;
                                        bits = hweight8(ecc);
                                        res |= (bits == 1) ? CP0_CERRD_DATA_SBE : CP0_CERRD_DATA_DBE;
                                }
                                printk("  %02X-%016llX", datahi, datalo);
                        }
                        printk("\n");
                        if (bad_ecc)
                                printk("  dwords w/ bad ECC: %d %d %d %d\n",
                                       !!(bad_ecc & 8), !!(bad_ecc & 4),
                                       !!(bad_ecc & 2), !!(bad_ecc & 1));
                }
        }
        return res;
}