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