1 files changed, 135 insertions, 0 deletions

diff --git a/arch/mips/dec/kn02xa-berr.c b/arch/mips/dec/kn02xa-berr.c
new file mode 100644
index 000000000..9699fc4e6
--- /dev/null
+++ b/arch/mips/dec/kn02xa-berr.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *      Bus error event handling code for 5000-series systems equipped
+ *      with parity error detection logic, i.e. DECstation/DECsystem
+ *      5000/120, /125, /133 (KN02-BA), 5000/150 (KN04-BA) and Personal
+ *      DECstation/DECsystem 5000/20, /25, /33 (KN02-CA), 5000/50
+ *      (KN04-CA) systems.
+ *
+ *      Copyright (c) 2005  Maciej W. Rozycki
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include <asm/addrspace.h>
+#include <asm/cpu-type.h>
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+#include <asm/traps.h>
+
+#include <asm/dec/kn02ca.h>
+#include <asm/dec/kn02xa.h>
+#include <asm/dec/kn05.h>
+
+static inline void dec_kn02xa_be_ack(void)
+{
+        volatile u32 *mer = (void *)CKSEG1ADDR(KN02XA_MER);
+        volatile u32 *mem_intr = (void *)CKSEG1ADDR(KN02XA_MEM_INTR);
+
+        *mer = KN02CA_MER_INTR;         /* Clear errors; keep the ARC IRQ. */
+        *mem_intr = 0;                  /* Any write clears the bus IRQ. */
+        iob();
+}
+
+static int dec_kn02xa_be_backend(struct pt_regs *regs, int is_fixup,
+                                 int invoker)
+{
+        volatile u32 *kn02xa_mer = (void *)CKSEG1ADDR(KN02XA_MER);
+        volatile u32 *kn02xa_ear = (void *)CKSEG1ADDR(KN02XA_EAR);
+
+        static const char excstr[] = "exception";
+        static const char intstr[] = "interrupt";
+        static const char cpustr[] = "CPU";
+        static const char mreadstr[] = "memory read";
+        static const char readstr[] = "read";
+        static const char writestr[] = "write";
+        static const char timestr[] = "timeout";
+        static const char paritystr[] = "parity error";
+        static const char lanestat[][4] = { " OK", "BAD" };
+
+        const char *kind, *agent, *cycle, *event;
+        unsigned long address;
+
+        u32 mer = *kn02xa_mer;
+        u32 ear = *kn02xa_ear;
+        int action = MIPS_BE_FATAL;
+
+        /* Ack ASAP, so that any subsequent errors get caught. */
+        dec_kn02xa_be_ack();
+
+        kind = invoker ? intstr : excstr;
+
+        /* No DMA errors? */
+        agent = cpustr;
+
+        address = ear & KN02XA_EAR_ADDRESS;
+
+        /* Low 256MB is decoded as memory, high -- as TC. */
+        if (address < 0x10000000) {
+                cycle = mreadstr;
+                event = paritystr;
+        } else {
+                cycle = invoker ? writestr : readstr;
+                event = timestr;
+        }
+
+        if (is_fixup)
+                action = MIPS_BE_FIXUP;
+
+        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 && address < 0x10000000)
+                printk(KERN_ALERT "  Byte lane status %#3x -- "
+                       "#3: %s, #2: %s, #1: %s, #0: %s\n",
+                       (mer & KN02XA_MER_BYTERR) >> 8,
+                       lanestat[(mer & KN02XA_MER_BYTERR_3) != 0],
+                       lanestat[(mer & KN02XA_MER_BYTERR_2) != 0],
+                       lanestat[(mer & KN02XA_MER_BYTERR_1) != 0],
+                       lanestat[(mer & KN02XA_MER_BYTERR_0) != 0]);
+
+        return action;
+}
+
+int dec_kn02xa_be_handler(struct pt_regs *regs, int is_fixup)
+{
+        return dec_kn02xa_be_backend(regs, is_fixup, 0);
+}
+
+irqreturn_t dec_kn02xa_be_interrupt(int irq, void *dev_id)
+{
+        struct pt_regs *regs = get_irq_regs();
+        int action = dec_kn02xa_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);
+}
+
+
+void __init dec_kn02xa_be_init(void)
+{
+        volatile u32 *mbcs = (void *)CKSEG1ADDR(KN4K_SLOT_BASE + KN4K_MB_CSR);
+
+        /* For KN04 we need to make sure EE (?) is enabled in the MB.  */
+        if (current_cpu_type() == CPU_R4000SC)
+                *mbcs |= KN4K_MB_CSR_EE;
+        fast_iob();
+
+        /* Clear any leftover errors from the firmware. */
+        dec_kn02xa_be_ack();
+}