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-rw-r--r--arch/mips/dec/ecc-berr.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/arch/mips/dec/ecc-berr.c b/arch/mips/dec/ecc-berr.c
new file mode 100644
index 000000000..1eb356fdd
--- /dev/null
+++ b/arch/mips/dec/ecc-berr.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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
+ */
+
+#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/cpu-type.h>
+#include <asm/irq_regs.h>
+#include <asm/processor.h>
+#include <asm/ptrace.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();
+}
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