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 }