From 03ba4131783cc9e872f8bb26a03f15bc11f27564 Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Sat, 19 Sep 1998 19:15:08 +0000
Subject:  - Merge with Linux 2.1.121.  - Bugfixes.

---
 arch/arm/kernel/fiq.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 arch/arm/kernel/fiq.c

(limited to 'arch/arm/kernel/fiq.c')

diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c
new file mode 100644
index 000000000..c32fef3c8
--- /dev/null
+++ b/arch/arm/kernel/fiq.c
@@ -0,0 +1,179 @@
+/*
+ *  linux/arch/arm/kernel/fiq.c
+ *
+ *  Copyright (C) 1998 Russell King
+ *  FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
+ *
+ *  FIQ support re-written by Russell King to be more generic
+ *
+ * We now properly support a method by which the FIQ handlers can
+ * be stacked onto the vector.  We still do not support sharing
+ * the FIQ vector itself.
+ *
+ * Operation is as follows:
+ *  1. Owner A claims FIQ:
+ *     - default_fiq relinquishes control.
+ *  2. Owner A:
+ *     - inserts code.
+ *     - sets any registers,
+ *     - enables FIQ.
+ *  3. Owner B claims FIQ:
+ *     - if owner A has a relinquish function.
+ *       - disable FIQs.
+ *       - saves any registers.
+ *       - returns zero.
+ *  4. Owner B:
+ *     - inserts code.
+ *     - sets any registers,
+ *     - enables FIQ.
+ *  5. Owner B releases FIQ:
+ *     - Owner A is asked to reacquire FIQ:
+ *	 - inserts code.
+ *	 - restores saved registers.
+ *	 - enables FIQ.
+ *  6. Goto 3
+ */
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/init.h>
+
+#include <asm/fiq.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define FIQ_VECTOR 0x1c
+
+static unsigned long no_fiq_insn;
+
+#ifdef CONFIG_CPU_32
+static inline void unprotect_page_0(void)
+{
+	__asm__ __volatile__("mcr	p15, 0, %0, c3, c0" :
+			: "r" (DOMAIN_USER_MANAGER |
+			       DOMAIN_KERNEL_CLIENT |
+			       DOMAIN_IO_CLIENT));
+}
+
+static inline void protect_page_0(void)
+{
+	set_fs(get_fs());
+}
+#else
+
+#define unprotect_page_0()
+#define protect_page_0()
+
+#endif
+
+/* Default reacquire function
+ * - we always relinquish FIQ control
+ * - we always reacquire FIQ control
+ */
+int fiq_def_op(void *ref, int relinquish)
+{
+	if (!relinquish) {
+		unprotect_page_0();
+		*(unsigned long *)FIQ_VECTOR = no_fiq_insn;
+		protect_page_0();
+		__flush_entry_to_ram(FIQ_VECTOR);
+	}
+
+	return 0;
+}
+
+static struct fiq_handler default_owner =
+	{ NULL, "default", fiq_def_op, NULL };
+static struct fiq_handler *current_fiq = &default_owner;
+
+int get_fiq_list(char *buf)
+{
+	char *p = buf;
+
+	if (current_fiq != &default_owner)
+		p += sprintf(p, "FIQ:              %s\n",
+			     current_fiq->name);
+
+	return p - buf;
+}
+
+void set_fiq_handler(void *start, unsigned int length)
+{
+	unprotect_page_0();
+
+	memcpy((void *)FIQ_VECTOR, start, length);
+
+	protect_page_0();
+#if 0
+	/* This doesn'w work correctly.  Ok, it's a misuse
+	 * of the DMA flushing code, but it ought to work.
+	 * More investigation required.  Maybe it really
+	 * needs the cache flushed.
+	 */
+	dma_cache_wback(FIQ_VECTOR, length);
+#else
+	processor.u.armv3v4._flush_cache_area(FIQ_VECTOR, FIQ_VECTOR + length, 1);
+#endif
+}
+
+void set_fiq_regs(struct pt_regs *regs)
+{
+	/* not yet -
+	 * this is temporary to get the floppy working
+	 * again on RiscPC.  It *will* become more
+	 * generic.
+	 */
+#ifdef CONFIG_ARCH_ACORN
+	extern void floppy_fiqsetup(unsigned long len, unsigned long addr,
+					     unsigned long port);
+	floppy_fiqsetup(regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
+#endif
+}
+
+void get_fiq_regs(struct pt_regs *regs)
+{
+	/* not yet */
+}
+
+int claim_fiq(struct fiq_handler *f)
+{
+	int ret = 0;
+
+	if (current_fiq) {
+		ret = -EBUSY;
+
+		if (current_fiq->fiq_op != NULL)
+			ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
+	}
+
+	if (!ret) {
+		f->next = current_fiq;
+		current_fiq = f;
+	}
+
+	return ret;
+}
+
+void release_fiq(struct fiq_handler *f)
+{
+	if (current_fiq != f) {
+		printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
+		       f->name, current_fiq->name);
+#ifdef CONFIG_DEBUG_ERRORS
+		__backtrace();
+#endif
+		return;
+	}
+
+	do
+		current_fiq = current_fiq->next;
+	while (current_fiq->fiq_op(current_fiq->dev_id, 0));
+}
+
+__initfunc(void init_FIQ(void))
+{
+	no_fiq_insn = *(unsigned long *)FIQ_VECTOR;
+	set_fs(get_fs());
+}
-- 
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