File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/blackfin/kernel/irqchip.c b/arch/blackfin/kernel/irqchip.c
new file mode 100644
index 0000000..052cde5
--- /dev/null
+++ b/arch/blackfin/kernel/irqchip.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright 2005-2009 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/seq_file.h>
+#include <asm/irq_handler.h>
+#include <asm/trace.h>
+#include <asm/pda.h>
+
+static atomic_t irq_err_count;
+void ack_bad_irq(unsigned int irq)
+{
+ atomic_inc(&irq_err_count);
+ printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
+}
+
+static struct irq_desc bad_irq_desc = {
+ .handle_irq = handle_bad_irq,
+ .lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
+};
+
+#ifdef CONFIG_CPUMASK_OFFSTACK
+/* We are not allocating a variable-sized bad_irq_desc.affinity */
+#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
+#endif
+
+#ifdef CONFIG_PROC_FS
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+ int j;
+
+ seq_printf(p, "%*s: ", prec, "NMI");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
+ seq_printf(p, " CORE Non Maskable Interrupt\n");
+ seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+ return 0;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+static void check_stack_overflow(int irq)
+{
+ /* Debugging check for stack overflow: is there less than STACK_WARN free? */
+ long sp = __get_SP() & (THREAD_SIZE - 1);
+
+ if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
+ dump_stack();
+ pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
+ irq, sp - sizeof(struct thread_info));
+ }
+}
+#else
+static inline void check_stack_overflow(int irq) { }
+#endif
+
+#ifndef CONFIG_IPIPE
+static void maybe_lower_to_irq14(void)
+{
+ unsigned short pending, other_ints;
+
+ /*
+ * If we're the only interrupt running (ignoring IRQ15 which
+ * is for syscalls), lower our priority to IRQ14 so that
+ * softirqs run at that level. If there's another,
+ * lower-level interrupt, irq_exit will defer softirqs to
+ * that. If the interrupt pipeline is enabled, we are already
+ * running at IRQ14 priority, so we don't need this code.
+ */
+ CSYNC();
+ pending = bfin_read_IPEND() & ~0x8000;
+ other_ints = pending & (pending - 1);
+ if (other_ints == 0)
+ lower_to_irq14();
+}
+#else
+static inline void maybe_lower_to_irq14(void) { }
+#endif
+
+/*
+ * do_IRQ handles all hardware IRQs. Decoded IRQs should not
+ * come via this function. Instead, they should provide their
+ * own 'handler'
+ */
+#ifdef CONFIG_DO_IRQ_L1
+__attribute__((l1_text))
+#endif
+asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+
+ irq_enter();
+
+ check_stack_overflow(irq);
+
+ /*
+ * Some hardware gives randomly wrong interrupts. Rather
+ * than crashing, do something sensible.
+ */
+ if (irq >= NR_IRQS)
+ handle_bad_irq(&bad_irq_desc);
+ else
+ generic_handle_irq(irq);
+
+ maybe_lower_to_irq14();
+
+ irq_exit();
+
+ set_irq_regs(old_regs);
+}
+
+void __init init_IRQ(void)
+{
+ init_arch_irq();
+
+#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
+ /* Now that evt_ivhw is set up, turn this on */
+ trace_buff_offset = 0;
+ bfin_write_TBUFCTL(BFIN_TRACE_ON);
+ printk(KERN_INFO "Hardware Trace expanded to %ik\n",
+ 1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
+#endif
+}