/* * Bus error event handling code for systems equipped with ECC * handling logic, i.e. DECstation/DECsystem 5000/200 (KN02), * 5000/240 (KN03), 5000/260 (KN05) and DECsystem 5900 (KN03), * 5900/260 (KN05) systems. * * Copyright (c) 2003, 2005 Maciej W. Rozycki * * 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. */ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/types.h> #include <asm/addrspace.h> #include <asm/bootinfo.h> #include <asm/cpu.h> #include <asm/irq_regs.h> #include <asm/processor.h> #include <asm/ptrace.h> #include <asm/system.h> #include <asm/traps.h> #include <asm/dec/ecc.h> #include <asm/dec/kn02.h> #include <asm/dec/kn03.h> #include <asm/dec/kn05.h> static volatile u32 *kn0x_erraddr; static volatile u32 *kn0x_chksyn; static inline void dec_ecc_be_ack(void) { *kn0x_erraddr = 0; /* any write clears the IRQ */ iob(); } static int dec_ecc_be_backend(struct pt_regs *regs, int is_fixup, int invoker) { static const char excstr[] = "exception"; static const char intstr[] = "interrupt"; static const char cpustr[] = "CPU"; static const char dmastr[] = "DMA"; static const char readstr[] = "read"; static const char mreadstr[] = "memory read"; static const char writestr[] = "write"; static const char mwritstr[] = "partial memory write"; static const char timestr[] = "timeout"; static const char overstr[] = "overrun"; static const char eccstr[] = "ECC error"; const char *kind, *agent, *cycle, *event; const char *status = "", *xbit = "", *fmt = ""; unsigned long address; u16 syn = 0, sngl; int i = 0; u32 erraddr = *kn0x_erraddr; u32 chksyn = *kn0x_chksyn; int action = MIPS_BE_FATAL; /* For non-ECC ack ASAP, so that any subsequent errors get caught. */ if ((erraddr & (KN0X_EAR_VALID | KN0X_EAR_ECCERR)) == KN0X_EAR_VALID) dec_ecc_be_ack(); kind = invoker ? intstr : excstr; if (!(erraddr & KN0X_EAR_VALID)) { /* No idea what happened. */ printk(KERN_ALERT "Unidentified bus error %s\n", kind); return action; } agent = (erraddr & KN0X_EAR_CPU) ? cpustr : dmastr; if (erraddr & KN0X_EAR_ECCERR) { /* An ECC error on a CPU or DMA transaction. */ cycle = (erraddr & KN0X_EAR_WRITE) ? mwritstr : mreadstr; event = eccstr; } else { /* A CPU timeout or a DMA overrun. */ cycle = (erraddr & KN0X_EAR_WRITE) ? writestr : readstr; event = (erraddr & KN0X_EAR_CPU) ? timestr : overstr; } address = erraddr & KN0X_EAR_ADDRESS; /* For ECC errors on reads adjust for MT pipelining. */ if ((erraddr & (KN0X_EAR_WRITE | KN0X_EAR_ECCERR)) == KN0X_EAR_ECCERR) address = (address & ~0xfffLL) | ((address - 5) & 0xfffLL); address <<= 2; /* Only CPU errors are fixable. */ if (erraddr & KN0X_EAR_CPU && is_fixup) action = MIPS_BE_FIXUP; if (erraddr & KN0X_EAR_ECCERR) { static const u8 data_sbit[32] = { 0x4f, 0x4a, 0x52, 0x54, 0x57, 0x58, 0x5b, 0x5d, 0x23, 0x25, 0x26, 0x29, 0x2a, 0x2c, 0x31, 0x34, 0x0e, 0x0b, 0x13, 0x15, 0x16, 0x19, 0x1a, 0x1c, 0x62, 0x64, 0x67, 0x68, 0x6b, 0x6d, 0x70, 0x75, }; static const u8 data_mbit[25] = { 0x07, 0x0d, 0x1f, 0x2f, 0x32, 0x37, 0x38, 0x3b, 0x3d, 0x3e, 0x43, 0x45, 0x46, 0x49, 0x4c, 0x51, 0x5e, 0x61, 0x6e, 0x73, 0x76, 0x79, 0x7a, 0x7c, 0x7f, }; static const char sbestr[] = "corrected single"; static const char dbestr[] = "uncorrectable double"; static const char mbestr[] = "uncorrectable multiple"; if (!(address & 0x4)) syn = chksyn; /* Low bank. */ else syn = chksyn >> 16; /* High bank. */ if (!(syn & KN0X_ESR_VLDLO)) { /* Ack now, no rewrite will happen. */ dec_ecc_be_ack(); fmt = KERN_ALERT "%s" "invalid\n"; } else { sngl = syn & KN0X_ESR_SNGLO; syn &= KN0X_ESR_SYNLO; /* * Multibit errors may be tagged incorrectly; * check the syndrome explicitly. */ for (i = 0; i < 25; i++) if (syn == data_mbit[i]) break; if (i < 25) { status = mbestr; } else if (!sngl) { status = dbestr; } else { volatile u32 *ptr = (void *)CKSEG1ADDR(address); *ptr = *ptr; /* Rewrite. */ iob(); status = sbestr; action = MIPS_BE_DISCARD; } /* Ack now, now we've rewritten (or not). */ dec_ecc_be_ack(); if (syn && syn == (syn & -syn)) { if (syn == 0x01) { fmt = KERN_ALERT "%s" "%#04x -- %s bit error " "at check bit C%s\n"; xbit = "X"; } else { fmt = KERN_ALERT "%s" "%#04x -- %s bit error " "at check bit C%s%u\n"; } i = syn >> 2; } else { for (i = 0; i < 32; i++) if (syn == data_sbit[i]) break; if (i < 32) fmt = KERN_ALERT "%s" "%#04x -- %s bit error " "at data bit D%s%u\n"; else fmt = KERN_ALERT "%s" "%#04x -- %s bit error\n"; } } } if (action != MIPS_BE_FIXUP) printk(KERN_ALERT "Bus error %s: %s %s %s at %#010lx\n", kind, agent, cycle, event, address); if (action != MIPS_BE_FIXUP && erraddr & KN0X_EAR_ECCERR) printk(fmt, " ECC syndrome ", syn, status, xbit, i); return action; } int dec_ecc_be_handler(struct pt_regs *regs, int is_fixup) { return dec_ecc_be_backend(regs, is_fixup, 0); } irqreturn_t dec_ecc_be_interrupt(int irq, void *dev_id) { struct pt_regs *regs = get_irq_regs(); int action = dec_ecc_be_backend(regs, 0, 1); if (action == MIPS_BE_DISCARD) return IRQ_HANDLED; /* * FIXME: Find the affected processes and kill them, otherwise * we must die. * * The interrupt is asynchronously delivered thus EPC and RA * may be irrelevant, but are printed for a reference. */ printk(KERN_ALERT "Fatal bus interrupt, epc == %08lx, ra == %08lx\n", regs->cp0_epc, regs->regs[31]); die("Unrecoverable bus error", regs); } /* * Initialization differs a bit between KN02 and KN03/KN05, so we * need two variants. Once set up, all systems can be handled the * same way. */ static inline void dec_kn02_be_init(void) { volatile u32 *csr = (void *)CKSEG1ADDR(KN02_SLOT_BASE + KN02_CSR); kn0x_erraddr = (void *)CKSEG1ADDR(KN02_SLOT_BASE + KN02_ERRADDR); kn0x_chksyn = (void *)CKSEG1ADDR(KN02_SLOT_BASE + KN02_CHKSYN); /* Preset write-only bits of the Control Register cache. */ cached_kn02_csr = *csr | KN02_CSR_LEDS; /* Set normal ECC detection and generation. */ cached_kn02_csr &= ~(KN02_CSR_DIAGCHK | KN02_CSR_DIAGGEN); /* Enable ECC correction. */ cached_kn02_csr |= KN02_CSR_CORRECT; *csr = cached_kn02_csr; iob(); } static inline void dec_kn03_be_init(void) { volatile u32 *mcr = (void *)CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_MCR); volatile u32 *mbcs = (void *)CKSEG1ADDR(KN4K_SLOT_BASE + KN4K_MB_CSR); kn0x_erraddr = (void *)CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_ERRADDR); kn0x_chksyn = (void *)CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_CHKSYN); /* * Set normal ECC detection and generation, enable ECC correction. * For KN05 we also need to make sure EE (?) is enabled in the MB. * Otherwise DBE/IBE exceptions would be masked but bus error * interrupts would still arrive, resulting in an inevitable crash * if get_dbe() triggers one. */ *mcr = (*mcr & ~(KN03_MCR_DIAGCHK | KN03_MCR_DIAGGEN)) | KN03_MCR_CORRECT; if (current_cpu_type() == CPU_R4400SC) *mbcs |= KN4K_MB_CSR_EE; fast_iob(); } void __init dec_ecc_be_init(void) { if (mips_machtype == MACH_DS5000_200) dec_kn02_be_init(); else dec_kn03_be_init(); /* Clear any leftover errors from the firmware. */ dec_ecc_be_ack(); }