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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/kernel/fiq.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm/kernel/fiq.c')
-rw-r--r--arch/arm/kernel/fiq.c181
1 files changed, 181 insertions, 0 deletions
diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c
new file mode 100644
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+++ b/arch/arm/kernel/fiq.c
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+/*
+ * linux/arch/arm/kernel/fiq.c
+ *
+ * Copyright (C) 1998 Russell King
+ * Copyright (C) 1998, 1999 Phil Blundell
+ *
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+
+#include <asm/cacheflush.h>
+#include <asm/fiq.h>
+#include <asm/irq.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+static unsigned long no_fiq_insn;
+
+/* Default reacquire function
+ * - we always relinquish FIQ control
+ * - we always reacquire FIQ control
+ */
+static int fiq_def_op(void *ref, int relinquish)
+{
+ if (!relinquish)
+ set_fiq_handler(&no_fiq_insn, sizeof(no_fiq_insn));
+
+ 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)
+{
+ memcpy((void *)0xffff001c, start, length);
+ flush_icache_range(0xffff001c, 0xffff001c + length);
+ if (!vectors_high())
+ flush_icache_range(0x1c, 0x1c + length);
+}
+
+/*
+ * Taking an interrupt in FIQ mode is death, so both these functions
+ * disable irqs for the duration. Note - these functions are almost
+ * entirely coded in assembly.
+ */
+void __attribute__((naked)) set_fiq_regs(struct pt_regs *regs)
+{
+ register unsigned long tmp;
+ asm volatile (
+ "mov ip, sp\n\
+ stmfd sp!, {fp, ip, lr, pc}\n\
+ sub fp, ip, #4\n\
+ mrs %0, cpsr\n\
+ msr cpsr_c, %2 @ select FIQ mode\n\
+ mov r0, r0\n\
+ ldmia %1, {r8 - r14}\n\
+ msr cpsr_c, %0 @ return to SVC mode\n\
+ mov r0, r0\n\
+ ldmea fp, {fp, sp, pc}"
+ : "=&r" (tmp)
+ : "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
+}
+
+void __attribute__((naked)) get_fiq_regs(struct pt_regs *regs)
+{
+ register unsigned long tmp;
+ asm volatile (
+ "mov ip, sp\n\
+ stmfd sp!, {fp, ip, lr, pc}\n\
+ sub fp, ip, #4\n\
+ mrs %0, cpsr\n\
+ msr cpsr_c, %2 @ select FIQ mode\n\
+ mov r0, r0\n\
+ stmia %1, {r8 - r14}\n\
+ msr cpsr_c, %0 @ return to SVC mode\n\
+ mov r0, r0\n\
+ ldmea fp, {fp, sp, pc}"
+ : "=&r" (tmp)
+ : "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
+}
+
+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);
+ dump_stack();
+ 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 *)0xffff001c;
+}