arch/arm/mach-omap2/omap_hwmod_reset.c

   1 /*
   2  * OMAP IP block custom reset and preprogramming stubs
   3  *
   4  * Copyright (C) 2012 Texas Instruments, Inc.
   5  * Paul Walmsley
   6  *
   7  * A small number of IP blocks need custom reset and preprogramming
   8  * functions.  The stubs in this file provide a standard way for the
   9  * hwmod code to call these functions, which are to be located under
  10  * drivers/.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation version 2.
  15  *
  16  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  17  * kind, whether express or implied; without even the implied warranty
  18  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  24  * 02110-1301 USA
  25  */
  26 #include <linux/kernel.h>
  27 #include <linux/errno.h>
  28
  29 #include <sound/aess.h>
  30
  31 #include "omap_hwmod.h"
  32 #include "common.h"
  33
  34 #define OMAP_RTC_STATUS_REG     0x44
  35 #define OMAP_RTC_KICK0_REG      0x6c
  36 #define OMAP_RTC_KICK1_REG      0x70
  37
  38 #define OMAP_RTC_KICK0_VALUE    0x83E70B13
  39 #define OMAP_RTC_KICK1_VALUE    0x95A4F1E0
  40 #define OMAP_RTC_STATUS_BUSY    BIT(0)
  41 #define OMAP_RTC_MAX_READY_TIME 50
  42
  43 /**
  44  * omap_hwmod_aess_preprogram - enable AESS internal autogating
  45  * @oh: struct omap_hwmod *
  46  *
  47  * The AESS will not IdleAck to the PRCM until its internal autogating
  48  * is enabled.  Since internal autogating is disabled by default after
  49  * AESS reset, we must enable autogating after the hwmod code resets
  50  * the AESS.  Returns 0.
  51  */
  52 int omap_hwmod_aess_preprogram(struct omap_hwmod *oh)
  53 {
  54         void __iomem *va;
  55
  56         va = omap_hwmod_get_mpu_rt_va(oh);
  57         if (!va)
  58                 return -EINVAL;
  59
  60         aess_enable_autogating(va);
  61
  62         return 0;
  63 }
  64
  65 /**
  66  * omap_rtc_wait_not_busy - Wait for the RTC BUSY flag
  67  * @oh: struct omap_hwmod *
  68  *
  69  * For updating certain RTC registers, the MPU must wait
  70  * for the BUSY status in OMAP_RTC_STATUS_REG to become zero.
  71  * Once the BUSY status is zero, there is a 15 microseconds access
  72  * period in which the MPU can program.
  73  */
  74 static void omap_rtc_wait_not_busy(struct omap_hwmod *oh)
  75 {
  76         int i;
  77
  78         /* BUSY may stay active for 1/32768 second (~30 usec) */
  79         omap_test_timeout(omap_hwmod_read(oh, OMAP_RTC_STATUS_REG)
  80                           & OMAP_RTC_STATUS_BUSY, OMAP_RTC_MAX_READY_TIME, i);
  81         /* now we have ~15 microseconds to read/write various registers */
  82 }
  83
  84 /**
  85  * omap_hwmod_rtc_unlock - Unlock the Kicker mechanism.
  86  * @oh: struct omap_hwmod *
  87  *
  88  * RTC IP have kicker feature. This prevents spurious writes to its registers.
  89  * In order to write into any of the RTC registers, KICK values has te be
  90  * written in respective KICK registers. This is needed for hwmod to write into
  91  * sysconfig register.
  92  */
  93 void omap_hwmod_rtc_unlock(struct omap_hwmod *oh)
  94 {
  95         unsigned long flags;
  96
  97         local_irq_save(flags);
  98         omap_rtc_wait_not_busy(oh);
  99         omap_hwmod_write(OMAP_RTC_KICK0_VALUE, oh, OMAP_RTC_KICK0_REG);
 100         omap_hwmod_write(OMAP_RTC_KICK1_VALUE, oh, OMAP_RTC_KICK1_REG);
 101         local_irq_restore(flags);
 102 }
 103
 104 /**
 105  * omap_hwmod_rtc_lock - Lock the Kicker mechanism.
 106  * @oh: struct omap_hwmod *
 107  *
 108  * RTC IP have kicker feature. This prevents spurious writes to its registers.
 109  * Once the RTC registers are written, KICK mechanism needs to be locked,
 110  * in order to prevent any spurious writes. This function locks back the RTC
 111  * registers once hwmod completes its write into sysconfig register.
 112  */
 113 void omap_hwmod_rtc_lock(struct omap_hwmod *oh)
 114 {
 115         unsigned long flags;
 116
 117         local_irq_save(flags);
 118         omap_rtc_wait_not_busy(oh);
 119         omap_hwmod_write(0x0, oh, OMAP_RTC_KICK0_REG);
 120         omap_hwmod_write(0x0, oh, OMAP_RTC_KICK1_REG);
 121         local_irq_restore(flags);
 122 }