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Commit | Line | Data |
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894acb2f DB |
1 | /* |
2 | * Intel BayTrail PMIC I2C bus semaphore implementaion | |
3 | * Copyright (c) 2014, Intel Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | */ | |
894acb2f DB |
14 | #include <linux/delay.h> |
15 | #include <linux/device.h> | |
16 | #include <linux/acpi.h> | |
17 | #include <linux/i2c.h> | |
18 | #include <linux/interrupt.h> | |
086cb4af | 19 | #include <linux/pm_qos.h> |
c8e043e6 | 20 | |
894acb2f | 21 | #include <asm/iosf_mbi.h> |
c8e043e6 | 22 | |
894acb2f DB |
23 | #include "i2c-designware-core.h" |
24 | ||
78c43af2 | 25 | #define SEMAPHORE_TIMEOUT 500 |
894acb2f | 26 | #define PUNIT_SEMAPHORE 0x7 |
fd476fa2 | 27 | #define PUNIT_SEMAPHORE_CHT 0x10e |
9b5c9f04 AS |
28 | #define PUNIT_SEMAPHORE_BIT BIT(0) |
29 | #define PUNIT_SEMAPHORE_ACQUIRE BIT(1) | |
894acb2f DB |
30 | |
31 | static unsigned long acquired; | |
32 | ||
fd476fa2 HG |
33 | static u32 get_sem_addr(struct dw_i2c_dev *dev) |
34 | { | |
35 | if (dev->flags & MODEL_CHERRYTRAIL) | |
36 | return PUNIT_SEMAPHORE_CHT; | |
37 | else | |
38 | return PUNIT_SEMAPHORE; | |
39 | } | |
40 | ||
62aee937 | 41 | static int get_sem(struct dw_i2c_dev *dev, u32 *sem) |
894acb2f | 42 | { |
fd476fa2 | 43 | u32 addr = get_sem_addr(dev); |
9b5c9f04 | 44 | u32 data; |
894acb2f DB |
45 | int ret; |
46 | ||
fd476fa2 | 47 | ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &data); |
894acb2f | 48 | if (ret) { |
62aee937 | 49 | dev_err(dev->dev, "iosf failed to read punit semaphore\n"); |
894acb2f DB |
50 | return ret; |
51 | } | |
52 | ||
9b5c9f04 | 53 | *sem = data & PUNIT_SEMAPHORE_BIT; |
894acb2f DB |
54 | |
55 | return 0; | |
56 | } | |
57 | ||
62aee937 | 58 | static void reset_semaphore(struct dw_i2c_dev *dev) |
894acb2f | 59 | { |
fd476fa2 | 60 | if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, get_sem_addr(dev), |
519e23a7 | 61 | 0, PUNIT_SEMAPHORE_BIT)) |
62aee937 | 62 | dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n"); |
086cb4af HG |
63 | |
64 | pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE); | |
5b2cacce | 65 | |
d93a6ed3 HG |
66 | iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_END, |
67 | NULL); | |
5b2cacce | 68 | iosf_mbi_punit_release(); |
894acb2f DB |
69 | } |
70 | ||
c8e043e6 | 71 | static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) |
894acb2f | 72 | { |
c7f82ea8 | 73 | u32 addr; |
4077a387 | 74 | u32 sem = PUNIT_SEMAPHORE_ACQUIRE; |
894acb2f DB |
75 | int ret; |
76 | unsigned long start, end; | |
77 | ||
ebf2ef8f AS |
78 | might_sleep(); |
79 | ||
894acb2f DB |
80 | if (!dev || !dev->dev) |
81 | return -ENODEV; | |
82 | ||
30be774b | 83 | if (!dev->release_lock) |
894acb2f DB |
84 | return 0; |
85 | ||
5b2cacce | 86 | iosf_mbi_punit_acquire(); |
d93a6ed3 HG |
87 | iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_BEGIN, |
88 | NULL); | |
5b2cacce | 89 | |
086cb4af HG |
90 | /* |
91 | * Disallow the CPU to enter C6 or C7 state, entering these states | |
92 | * requires the punit to talk to the pmic and if this happens while | |
93 | * we're holding the semaphore, the SoC hangs. | |
94 | */ | |
95 | pm_qos_update_request(&dev->pm_qos, 0); | |
96 | ||
c7f82ea8 CIK |
97 | addr = get_sem_addr(dev); |
98 | ||
9b5c9f04 | 99 | /* host driver writes to side band semaphore register */ |
fd476fa2 | 100 | ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, addr, sem); |
894acb2f DB |
101 | if (ret) { |
102 | dev_err(dev->dev, "iosf punit semaphore request failed\n"); | |
086cb4af | 103 | goto out; |
894acb2f DB |
104 | } |
105 | ||
106 | /* host driver waits for bit 0 to be set in semaphore register */ | |
107 | start = jiffies; | |
108 | end = start + msecs_to_jiffies(SEMAPHORE_TIMEOUT); | |
ebf2ef8f | 109 | do { |
62aee937 | 110 | ret = get_sem(dev, &sem); |
894acb2f DB |
111 | if (!ret && sem) { |
112 | acquired = jiffies; | |
113 | dev_dbg(dev->dev, "punit semaphore acquired after %ums\n", | |
114 | jiffies_to_msecs(jiffies - start)); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | usleep_range(1000, 2000); | |
ebf2ef8f | 119 | } while (time_before(jiffies, end)); |
894acb2f DB |
120 | |
121 | dev_err(dev->dev, "punit semaphore timed out, resetting\n"); | |
086cb4af | 122 | out: |
62aee937 | 123 | reset_semaphore(dev); |
894acb2f | 124 | |
fd476fa2 | 125 | ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &sem); |
259aada4 | 126 | if (ret) |
894acb2f DB |
127 | dev_err(dev->dev, "iosf failed to read punit semaphore\n"); |
128 | else | |
129 | dev_err(dev->dev, "PUNIT SEM: %d\n", sem); | |
130 | ||
131 | WARN_ON(1); | |
132 | ||
133 | return -ETIMEDOUT; | |
134 | } | |
894acb2f | 135 | |
c8e043e6 | 136 | static void baytrail_i2c_release(struct dw_i2c_dev *dev) |
894acb2f DB |
137 | { |
138 | if (!dev || !dev->dev) | |
139 | return; | |
140 | ||
141 | if (!dev->acquire_lock) | |
142 | return; | |
143 | ||
62aee937 | 144 | reset_semaphore(dev); |
894acb2f DB |
145 | dev_dbg(dev->dev, "punit semaphore held for %ums\n", |
146 | jiffies_to_msecs(jiffies - acquired)); | |
147 | } | |
894acb2f | 148 | |
086cb4af | 149 | int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) |
894acb2f DB |
150 | { |
151 | acpi_status status; | |
152 | unsigned long long shared_host = 0; | |
153 | acpi_handle handle; | |
154 | ||
155 | if (!dev || !dev->dev) | |
156 | return 0; | |
157 | ||
158 | handle = ACPI_HANDLE(dev->dev); | |
159 | if (!handle) | |
160 | return 0; | |
161 | ||
162 | status = acpi_evaluate_integer(handle, "_SEM", NULL, &shared_host); | |
894acb2f DB |
163 | if (ACPI_FAILURE(status)) |
164 | return 0; | |
165 | ||
e234ed2f HG |
166 | if (!shared_host) |
167 | return 0; | |
894acb2f DB |
168 | |
169 | if (!iosf_mbi_available()) | |
170 | return -EPROBE_DEFER; | |
171 | ||
e234ed2f HG |
172 | dev_info(dev->dev, "I2C bus managed by PUNIT\n"); |
173 | dev->acquire_lock = baytrail_i2c_acquire; | |
174 | dev->release_lock = baytrail_i2c_release; | |
41c80b8a | 175 | dev->pm_disabled = true; |
e234ed2f | 176 | |
086cb4af HG |
177 | pm_qos_add_request(&dev->pm_qos, PM_QOS_CPU_DMA_LATENCY, |
178 | PM_QOS_DEFAULT_VALUE); | |
179 | ||
894acb2f DB |
180 | return 0; |
181 | } | |
086cb4af HG |
182 | |
183 | void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) | |
184 | { | |
185 | if (dev->acquire_lock) | |
186 | pm_qos_remove_request(&dev->pm_qos); | |
187 | } |