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kernel/linux-rt-4.4.41/arch/arm/mach-omap2/omap_hwmod_reset.c 3.73 KB
5113f6f70   김현기   kernel add
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  /*
   * OMAP IP block custom reset and preprogramming stubs
   *
   * Copyright (C) 2012 Texas Instruments, Inc.
   * Paul Walmsley
   *
   * A small number of IP blocks need custom reset and preprogramming
   * functions.  The stubs in this file provide a standard way for the
   * hwmod code to call these functions, which are to be located under
   * drivers/.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation version 2.
   *
   * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   * kind, whether express or implied; without even the implied warranty
   * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   */
  #include <linux/kernel.h>
  #include <linux/errno.h>
  
  #include <sound/aess.h>
  
  #include "omap_hwmod.h"
  #include "common.h"
  
  #define OMAP_RTC_STATUS_REG	0x44
  #define OMAP_RTC_KICK0_REG	0x6c
  #define OMAP_RTC_KICK1_REG	0x70
  
  #define OMAP_RTC_KICK0_VALUE	0x83E70B13
  #define OMAP_RTC_KICK1_VALUE	0x95A4F1E0
  #define OMAP_RTC_STATUS_BUSY	BIT(0)
  #define OMAP_RTC_MAX_READY_TIME	50
  
  /**
   * omap_hwmod_aess_preprogram - enable AESS internal autogating
   * @oh: struct omap_hwmod *
   *
   * The AESS will not IdleAck to the PRCM until its internal autogating
   * is enabled.  Since internal autogating is disabled by default after
   * AESS reset, we must enable autogating after the hwmod code resets
   * the AESS.  Returns 0.
   */
  int omap_hwmod_aess_preprogram(struct omap_hwmod *oh)
  {
  	void __iomem *va;
  
  	va = omap_hwmod_get_mpu_rt_va(oh);
  	if (!va)
  		return -EINVAL;
  
  	aess_enable_autogating(va);
  
  	return 0;
  }
  
  /**
   * omap_rtc_wait_not_busy - Wait for the RTC BUSY flag
   * @oh: struct omap_hwmod *
   *
   * For updating certain RTC registers, the MPU must wait
   * for the BUSY status in OMAP_RTC_STATUS_REG to become zero.
   * Once the BUSY status is zero, there is a 15 microseconds access
   * period in which the MPU can program.
   */
  static void omap_rtc_wait_not_busy(struct omap_hwmod *oh)
  {
  	int i;
  
  	/* BUSY may stay active for 1/32768 second (~30 usec) */
  	omap_test_timeout(omap_hwmod_read(oh, OMAP_RTC_STATUS_REG)
  			  & OMAP_RTC_STATUS_BUSY, OMAP_RTC_MAX_READY_TIME, i);
  	/* now we have ~15 microseconds to read/write various registers */
  }
  
  /**
   * omap_hwmod_rtc_unlock - Unlock the Kicker mechanism.
   * @oh: struct omap_hwmod *
   *
   * RTC IP have kicker feature. This prevents spurious writes to its registers.
   * In order to write into any of the RTC registers, KICK values has te be
   * written in respective KICK registers. This is needed for hwmod to write into
   * sysconfig register.
   */
  void omap_hwmod_rtc_unlock(struct omap_hwmod *oh)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	omap_rtc_wait_not_busy(oh);
  	omap_hwmod_write(OMAP_RTC_KICK0_VALUE, oh, OMAP_RTC_KICK0_REG);
  	omap_hwmod_write(OMAP_RTC_KICK1_VALUE, oh, OMAP_RTC_KICK1_REG);
  	local_irq_restore(flags);
  }
  
  /**
   * omap_hwmod_rtc_lock - Lock the Kicker mechanism.
   * @oh: struct omap_hwmod *
   *
   * RTC IP have kicker feature. This prevents spurious writes to its registers.
   * Once the RTC registers are written, KICK mechanism needs to be locked,
   * in order to prevent any spurious writes. This function locks back the RTC
   * registers once hwmod completes its write into sysconfig register.
   */
  void omap_hwmod_rtc_lock(struct omap_hwmod *oh)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	omap_rtc_wait_not_busy(oh);
  	omap_hwmod_write(0x0, oh, OMAP_RTC_KICK0_REG);
  	omap_hwmod_write(0x0, oh, OMAP_RTC_KICK1_REG);
  	local_irq_restore(flags);
  }