ARM: pxa: add iwmmx support for PJ4

iwmmxt is used in XScale, XScale3, Mohawk and PJ4 core. But the instructions
of accessing CP0 and CP1 is changed in PJ4. Append more files to support
iwmmxt in PJ4 core.

Signed-off-by: Zhou Zhu <zzhu3@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

1 files changed, 94 insertions, 0 deletions

diff --git a/arch/arm/kernel/pj4-cp0.c b/arch/arm/kernel/pj4-cp0.c
new file mode 100644
index 000000000000..a4b1b0748fd3
--- /dev/null
+++ b/arch/arm/kernel/pj4-cp0.c
@@ -0,0 +1,94 @@
+/*
+ * linux/arch/arm/kernel/pj4-cp0.c
+ *
+ * PJ4 iWMMXt coprocessor context switching and handling
+ *
+ * Copyright (c) 2010 Marvell International Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <asm/thread_notify.h>
+
+static int iwmmxt_do(struct notifier_block *self, unsigned long cmd, void *t)
+{
+        struct thread_info *thread = t;
+
+        switch (cmd) {
+        case THREAD_NOTIFY_FLUSH:
+                /*
+                 * flush_thread() zeroes thread->fpstate, so no need
+                 * to do anything here.
+                 *
+                 * FALLTHROUGH: Ensure we don't try to overwrite our newly
+                 * initialised state information on the first fault.
+                 */
+
+        case THREAD_NOTIFY_EXIT:
+                iwmmxt_task_release(thread);
+                break;
+
+        case THREAD_NOTIFY_SWITCH:
+                iwmmxt_task_switch(thread);
+                break;
+        }
+
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block iwmmxt_notifier_block = {
+        .notifier_call  = iwmmxt_do,
+};
+
+
+static u32 __init pj4_cp_access_read(void)
+{
+        u32 value;
+
+        __asm__ __volatile__ (
+                "mrc    p15, 0, %0, c1, c0, 2\n\t"
+                : "=r" (value));
+        return value;
+}
+
+static void __init pj4_cp_access_write(u32 value)
+{
+        u32 temp;
+
+        __asm__ __volatile__ (
+                "mcr    p15, 0, %1, c1, c0, 2\n\t"
+                "mrc    p15, 0, %0, c1, c0, 2\n\t"
+                "mov    %0, %0\n\t"
+                "sub    pc, pc, #4\n\t"
+                : "=r" (temp) : "r" (value));
+}
+
+
+/*
+ * Disable CP0/CP1 on boot, and let call_fpe() and the iWMMXt lazy
+ * switch code handle iWMMXt context switching.
+ */
+static int __init pj4_cp0_init(void)
+{
+        u32 cp_access;
+
+        cp_access = pj4_cp_access_read() & ~0xf;
+        pj4_cp_access_write(cp_access);
+
+        printk(KERN_INFO "PJ4 iWMMXt coprocessor enabled.\n");
+        elf_hwcap |= HWCAP_IWMMXT;
+        thread_register_notifier(&iwmmxt_notifier_block);
+
+        return 0;
+}
+
+late_initcall(pj4_cp0_init);