Eric Lee / smarc-fsl-linux-kernel

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arch/arm/kernel/pj4-cp0.c 1.92 KB
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ef6c84454   Haojian Zhuang   ARM: pxa: add iwm... 
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  /*
   * 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.
   */
ef6c84454   Haojian Zhuang   ARM: pxa: add iwm... 
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  #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
  \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
  \t"
  		"mrc	p15, 0, %0, c1, c0, 2
  \t"
  		"mov	%0, %0
  \t"
  		"sub	pc, pc, #4
  \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.
  ");
  	elf_hwcap |= HWCAP_IWMMXT;
  	thread_register_notifier(&iwmmxt_notifier_block);
  
  	return 0;
  }
  
  late_initcall(pj4_cp0_init);