1 files changed, 202 insertions, 0 deletions

diff --git a/arch/arm26/kernel/fiq.c b/arch/arm26/kernel/fiq.c
new file mode 100644
index 000000000000..08a97c9498ff
--- /dev/null
+++ b/arch/arm26/kernel/fiq.c
@@ -0,0 +1,202 @@
+/*
+ *  linux/arch/arm26/kernel/fiq.c
+ *
+ *  Copyright (C) 1998 Russell King
+ *  Copyright (C) 1998, 1999 Phil Blundell
+ *  Copyright (C) 2003 Ian Molton
+ *
+ *  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/module.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+
+#include <asm/fiq.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/pgalloc.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define FIQ_VECTOR (vectors_base() + 0x1c)
+
+static unsigned long no_fiq_insn;
+
+#define unprotect_page_0()
+#define protect_page_0()
+
+/* Default reacquire function
+ * - we always relinquish FIQ control
+ * - we always reacquire FIQ control
+ */
+static int fiq_def_op(void *ref, int relinquish)
+{
+        if (!relinquish) {
+                unprotect_page_0();
+                *(unsigned long *)FIQ_VECTOR = no_fiq_insn;
+                protect_page_0();
+        }
+
+        return 0;
+}
+
+static struct fiq_handler default_owner = {
+        .name   = "default",
+        .fiq_op = fiq_def_op,
+};
+
+static struct fiq_handler *current_fiq = &default_owner;
+
+int show_fiq_list(struct seq_file *p, void *v)
+{
+        if (current_fiq != &default_owner)
+                seq_printf(p, "FIQ:              %s\n", current_fiq->name);
+
+        return 0;
+}
+
+void set_fiq_handler(void *start, unsigned int length)
+{
+        unprotect_page_0();
+
+        memcpy((void *)FIQ_VECTOR, start, length);
+
+        protect_page_0();
+}
+
+/*
+ * Taking an interrupt in FIQ mode is death, so both these functions
+ * disable irqs for the duration. 
+ */
+void set_fiq_regs(struct pt_regs *regs)
+{
+        register unsigned long tmp, tmp2;
+        __asm__ volatile (
+        "mov    %0, pc
+        bic     %1, %0, #0x3
+        orr     %1, %1, %3
+        teqp    %1, #0          @ select FIQ mode
+        mov     r0, r0
+        ldmia   %2, {r8 - r14}
+        teqp    %0, #0          @ return to SVC mode
+        mov     r0, r0"
+        : "=&r" (tmp), "=&r" (tmp2)
+        : "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | MODE_FIQ26)
+        /* These registers aren't modified by the above code in a way
+           visible to the compiler, but we mark them as clobbers anyway
+           so that GCC won't put any of the input or output operands in
+           them.  */
+        : "r8", "r9", "r10", "r11", "r12", "r13", "r14");
+}
+
+void get_fiq_regs(struct pt_regs *regs)
+{
+        register unsigned long tmp, tmp2;
+        __asm__ volatile (
+        "mov    %0, pc
+        bic     %1, %0, #0x3
+        orr     %1, %1, %3
+        teqp    %1, #0          @ select FIQ mode
+        mov     r0, r0
+        stmia   %2, {r8 - r14}
+        teqp    %0, #0          @ return to SVC mode
+        mov     r0, r0"
+        : "=&r" (tmp), "=&r" (tmp2)
+        : "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | MODE_FIQ26)
+        /* These registers aren't modified by the above code in a way
+           visible to the compiler, but we mark them as clobbers anyway
+           so that GCC won't put any of the input or output operands in
+           them.  */
+        : "r8", "r9", "r10", "r11", "r12", "r13", "r14");
+}
+
+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));
+}
+
+void enable_fiq(int fiq)
+{
+        enable_irq(fiq + FIQ_START);
+}
+
+void disable_fiq(int fiq)
+{
+        disable_irq(fiq + FIQ_START);
+}
+
+EXPORT_SYMBOL(set_fiq_handler);
+EXPORT_SYMBOL(set_fiq_regs);
+EXPORT_SYMBOL(get_fiq_regs);
+EXPORT_SYMBOL(claim_fiq);
+EXPORT_SYMBOL(release_fiq);
+EXPORT_SYMBOL(enable_fiq);
+EXPORT_SYMBOL(disable_fiq);
+
+void __init init_FIQ(void)
+{
+        no_fiq_insn = *(unsigned long *)FIQ_VECTOR;
+        set_fs(get_fs());
+}