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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  */
omap_hwmod_aess_preprogram(struct omap_hwmod * oh)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  */
omap_rtc_wait_not_busy(struct omap_hwmod * oh)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  */
omap_hwmod_rtc_unlock(struct omap_hwmod * oh)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  */
omap_hwmod_rtc_lock(struct omap_hwmod * oh)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 }
123