bus_watcher.c

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/*
 * Copyright (C) 2002,2003 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/*
 * The Bus Watcher monitors internal bus transactions and maintains
 * counts of transactions with error status, logging details and
 * causing one of several interrupts.  This driver provides a handler
 * for those interrupts which aggregates the counts (to avoid
 * saturating the 8-bit counters) and provides a presence in
 * /proc/bus_watcher if PROC_FS is on.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <asm/io.h>

#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250_scd.h>


struct bw_stats_struct {
    uint64_t status;
    uint32_t l2_err;
    uint32_t memio_err;
    int status_printed;
    unsigned long l2_cor_d;
    unsigned long l2_bad_d;
    unsigned long l2_cor_t;
    unsigned long l2_bad_t;
    unsigned long mem_cor_d;
    unsigned long mem_bad_d;
    unsigned long bus_error;
} bw_stats;


static void print_summary(uint32_t status, uint32_t l2_err,
              uint32_t memio_err)
{
    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));
}

/*
 * check_bus_watcher is exported for use in situations where we want
 * to see the most recent status of the bus watcher, which might have
 * already been destructively read out of the registers.
 *
 * notes: this is currently used by the cache error handler
 *        should provide locking against the interrupt handler
 */
void check_bus_watcher(void)
{
    u32 status, l2_err, memio_err;

#ifdef CONFIG_SB1_PASS_1_WORKAROUNDS
    /* Destructive read, clears register and interrupt */
    status = csr_in32(IOADDR(A_SCD_BUS_ERR_STATUS));
#else
    /* Use non-destructive register */
    status = csr_in32(IOADDR(A_SCD_BUS_ERR_STATUS_DEBUG));
#endif
    if (!(status & 0x7fffffff)) {
        printk("Using last values reaped by bus watcher driver\n");
        status = bw_stats.status;
        l2_err = bw_stats.l2_err;
        memio_err = bw_stats.memio_err;
    } else {
        l2_err = csr_in32(IOADDR(A_BUS_L2_ERRORS));
        memio_err = csr_in32(IOADDR(A_BUS_MEM_IO_ERRORS));
    }
    if (status & ~(1UL << 31))
        print_summary(status, l2_err, memio_err);
    else
        printk("Bus watcher indicates no error\n");
}

static int bw_print_buffer(char *page, struct bw_stats_struct *stats)
{
    int len;

    len = sprintf(page, "SiByte Bus Watcher statistics\n");
    len += sprintf(page+len, "-----------------------------\n");
    len += sprintf(page+len, "L2-d-cor %8ld\nL2-d-bad %8ld\n",
               stats->l2_cor_d, stats->l2_bad_d);
    len += sprintf(page+len, "L2-t-cor %8ld\nL2-t-bad %8ld\n",
               stats->l2_cor_t, stats->l2_bad_t);
    len += sprintf(page+len, "MC-d-cor %8ld\nMC-d-bad %8ld\n",
               stats->mem_cor_d, stats->mem_bad_d);
    len += sprintf(page+len, "IO-err   %8ld\n", stats->bus_error);
    len += sprintf(page+len, "\nLast recorded signature:\n");
    len += sprintf(page+len, "Request %02x from %d, answered by %d with Dcode %d\n",
               (unsigned int)(G_SCD_BERR_TID(stats->status) & 0x3f),
               (int)(G_SCD_BERR_TID(stats->status) >> 6),
               (int)G_SCD_BERR_RID(stats->status),
               (int)G_SCD_BERR_DCODE(stats->status));
    /* XXXKW indicate multiple errors between printings, or stats
           collection (or both)? */
    if (stats->status & M_SCD_BERR_MULTERRS)
        len += sprintf(page+len, "Multiple errors observed since last check.\n");
    if (stats->status_printed) {
        len += sprintf(page+len, "(no change since last printing)\n");
    } else {
        stats->status_printed = 1;
    }

    return len;
}

#ifdef CONFIG_PROC_FS

/* For simplicity, I want to assume a single read is required each
   time */
static int bw_read_proc(char *page, char **start, off_t off,
            int count, int *eof, void *data)
{
    int len;

    if (off == 0) {
        len = bw_print_buffer(page, data);
        *start = page;
    } else {
        len = 0;
        *eof = 1;
    }
    return len;
}

static void create_proc_decoder(struct bw_stats_struct *stats)
{
    struct proc_dir_entry *ent;

    ent = create_proc_read_entry("bus_watcher", S_IWUSR | S_IRUGO, NULL,
                     bw_read_proc, stats);
    if (!ent) {
        printk(KERN_INFO "Unable to initialize bus_watcher /proc entry\n");
        return;
    }
}

#endif /* CONFIG_PROC_FS */

/*
 * sibyte_bw_int - handle bus watcher interrupts and accumulate counts
 *
 * notes: possible re-entry due to multiple sources
 *        should check/indicate saturation
 */
static irqreturn_t sibyte_bw_int(int irq, void *data)
{
    struct bw_stats_struct *stats = data;
    unsigned long cntr;
#ifdef CONFIG_SIBYTE_BW_TRACE
    int i;
#endif
#ifndef CONFIG_PROC_FS
    char bw_buf[1024];
#endif

#ifdef CONFIG_SIBYTE_BW_TRACE
    csr_out32(M_SCD_TRACE_CFG_FREEZE, IOADDR(A_SCD_TRACE_CFG));
    csr_out32(M_SCD_TRACE_CFG_START_READ, IOADDR(A_SCD_TRACE_CFG));

    for (i=0; i<256*6; i++)
        printk("%016llx\n",
               (long long)__raw_readq(IOADDR(A_SCD_TRACE_READ)));

    csr_out32(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
    csr_out32(M_SCD_TRACE_CFG_START, IOADDR(A_SCD_TRACE_CFG));
#endif

    /* Destructive read, clears register and interrupt */
    stats->status = csr_in32(IOADDR(A_SCD_BUS_ERR_STATUS));
    stats->status_printed = 0;

    stats->l2_err = cntr = csr_in32(IOADDR(A_BUS_L2_ERRORS));
    stats->l2_cor_d += G_SCD_L2ECC_CORR_D(cntr);
    stats->l2_bad_d += G_SCD_L2ECC_BAD_D(cntr);
    stats->l2_cor_t += G_SCD_L2ECC_CORR_T(cntr);
    stats->l2_bad_t += G_SCD_L2ECC_BAD_T(cntr);
    csr_out32(0, IOADDR(A_BUS_L2_ERRORS));

    stats->memio_err = cntr = csr_in32(IOADDR(A_BUS_MEM_IO_ERRORS));
    stats->mem_cor_d += G_SCD_MEM_ECC_CORR(cntr);
    stats->mem_bad_d += G_SCD_MEM_ECC_BAD(cntr);
    stats->bus_error += G_SCD_MEM_BUSERR(cntr);
    csr_out32(0, IOADDR(A_BUS_MEM_IO_ERRORS));

#ifndef CONFIG_PROC_FS
    bw_print_buffer(bw_buf, stats);
    printk(bw_buf);
#endif

    return IRQ_HANDLED;
}

int __init sibyte_bus_watcher(void)
{
    memset(&bw_stats, 0, sizeof(struct bw_stats_struct));
    bw_stats.status_printed = 1;

    if (request_irq(K_INT_BAD_ECC, sibyte_bw_int, 0, "Bus watcher", &bw_stats)) {
        printk("Failed to register bus watcher BAD_ECC irq\n");
        return -1;
    }
    if (request_irq(K_INT_COR_ECC, sibyte_bw_int, 0, "Bus watcher", &bw_stats)) {
        free_irq(K_INT_BAD_ECC, &bw_stats);
        printk("Failed to register bus watcher COR_ECC irq\n");
        return -1;
    }
    if (request_irq(K_INT_IO_BUS, sibyte_bw_int, 0, "Bus watcher", &bw_stats)) {
        free_irq(K_INT_BAD_ECC, &bw_stats);
        free_irq(K_INT_COR_ECC, &bw_stats);
        printk("Failed to register bus watcher IO_BUS irq\n");
        return -1;
    }

#ifdef CONFIG_PROC_FS
    create_proc_decoder(&bw_stats);
#endif

#ifdef CONFIG_SIBYTE_BW_TRACE
    csr_out32((M_SCD_TRSEQ_ASAMPLE | M_SCD_TRSEQ_DSAMPLE |
           K_SCD_TRSEQ_TRIGGER_ALL),
          IOADDR(A_SCD_TRACE_SEQUENCE_0));
    csr_out32(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
    csr_out32(M_SCD_TRACE_CFG_START, IOADDR(A_SCD_TRACE_CFG));
#endif

    return 0;
}

__initcall(sibyte_bus_watcher);