tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NHI specific operations
4 *
5 * Copyright (C) 2019, Intel Corporation
6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
7 */
8
9#include <linux/delay.h>
10#include <linux/suspend.h>
11
12#include "nhi.h"
13#include "nhi_regs.h"
14#include "tb.h"
15
16/* Ice Lake specific NHI operations */
17
18#define ICL_LC_MAILBOX_TIMEOUT 500 /* ms */
19
20static int check_for_device(struct device *dev, void *data)
21{
22 return tb_is_switch(dev);
23}
24
25static bool icl_nhi_is_device_connected(struct tb_nhi *nhi)
26{
27 struct tb *tb = pci_get_drvdata(nhi->pdev);
28 int ret;
29
30 ret = device_for_each_child(&tb->root_switch->dev, NULL,
31 check_for_device);
32 return ret > 0;
33}
34
35static int icl_nhi_force_power(struct tb_nhi *nhi, bool power)
36{
37 u32 vs_cap;
38
39 /*
40 * The Thunderbolt host controller is present always in Ice Lake
41 * but the firmware may not be loaded and running (depending
42 * whether there is device connected and so on). Each time the
43 * controller is used we need to "Force Power" it first and wait
44 * for the firmware to indicate it is up and running. This "Force
45 * Power" is really not about actually powering on/off the
46 * controller so it is accessible even if "Force Power" is off.
47 *
48 * The actual power management happens inside shared ACPI power
49 * resources using standard ACPI methods.
50 */
51 pci_read_config_dword(nhi->pdev, VS_CAP_22, &vs_cap);
52 if (power) {
53 vs_cap &= ~VS_CAP_22_DMA_DELAY_MASK;
54 vs_cap |= 0x22 << VS_CAP_22_DMA_DELAY_SHIFT;
55 vs_cap |= VS_CAP_22_FORCE_POWER;
56 } else {
57 vs_cap &= ~VS_CAP_22_FORCE_POWER;
58 }
59 pci_write_config_dword(nhi->pdev, VS_CAP_22, vs_cap);
60
61 if (power) {
62 unsigned int retries = 10;
63 u32 val;
64
65 /* Wait until the firmware tells it is up and running */
66 do {
67 pci_read_config_dword(nhi->pdev, VS_CAP_9, &val);
68 if (val & VS_CAP_9_FW_READY)
69 return 0;
70 msleep(250);
71 } while (--retries);
72
73 return -ETIMEDOUT;
74 }
75
76 return 0;
77}
78
79static void icl_nhi_lc_mailbox_cmd(struct tb_nhi *nhi, enum icl_lc_mailbox_cmd cmd)
80{
81 u32 data;
82
83 data = (cmd << VS_CAP_19_CMD_SHIFT) & VS_CAP_19_CMD_MASK;
84 pci_write_config_dword(nhi->pdev, VS_CAP_19, data | VS_CAP_19_VALID);
85}
86
87static int icl_nhi_lc_mailbox_cmd_complete(struct tb_nhi *nhi, int timeout)
88{
89 unsigned long end;
90 u32 data;
91
92 if (!timeout)
93 goto clear;
94
95 end = jiffies + msecs_to_jiffies(timeout);
96 do {
97 pci_read_config_dword(nhi->pdev, VS_CAP_18, &data);
98 if (data & VS_CAP_18_DONE)
99 goto clear;
100 msleep(100);
101 } while (time_before(jiffies, end));
102
103 return -ETIMEDOUT;
104
105clear:
106 /* Clear the valid bit */
107 pci_write_config_dword(nhi->pdev, VS_CAP_19, 0);
108 return 0;
109}
110
111static void icl_nhi_set_ltr(struct tb_nhi *nhi)
112{
113 u32 max_ltr, ltr;
114
115 pci_read_config_dword(nhi->pdev, VS_CAP_16, &max_ltr);
116 max_ltr &= 0xffff;
117 /* Program the same value for both snoop and no-snoop */
118 ltr = max_ltr << 16 | max_ltr;
119 pci_write_config_dword(nhi->pdev, VS_CAP_15, ltr);
120}
121
122static int icl_nhi_suspend(struct tb_nhi *nhi)
123{
124 int ret;
125
126 if (icl_nhi_is_device_connected(nhi))
127 return 0;
128
129 /*
130 * If there is no device connected we need to perform both: a
131 * handshake through LC mailbox and force power down before
132 * entering D3.
133 */
134 icl_nhi_lc_mailbox_cmd(nhi, ICL_LC_PREPARE_FOR_RESET);
135 ret = icl_nhi_lc_mailbox_cmd_complete(nhi, ICL_LC_MAILBOX_TIMEOUT);
136 if (ret)
137 return ret;
138
139 return icl_nhi_force_power(nhi, false);
140}
141
142static int icl_nhi_suspend_noirq(struct tb_nhi *nhi, bool wakeup)
143{
144 enum icl_lc_mailbox_cmd cmd;
145
146 if (!pm_suspend_via_firmware())
147 return icl_nhi_suspend(nhi);
148
149 cmd = wakeup ? ICL_LC_GO2SX : ICL_LC_GO2SX_NO_WAKE;
150 icl_nhi_lc_mailbox_cmd(nhi, cmd);
151 return icl_nhi_lc_mailbox_cmd_complete(nhi, ICL_LC_MAILBOX_TIMEOUT);
152}
153
154static int icl_nhi_resume(struct tb_nhi *nhi)
155{
156 int ret;
157
158 ret = icl_nhi_force_power(nhi, true);
159 if (ret)
160 return ret;
161
162 icl_nhi_set_ltr(nhi);
163 return 0;
164}
165
166static void icl_nhi_shutdown(struct tb_nhi *nhi)
167{
168 icl_nhi_force_power(nhi, false);
169}
170
171const struct tb_nhi_ops icl_nhi_ops = {
172 .init = icl_nhi_resume,
173 .suspend_noirq = icl_nhi_suspend_noirq,
174 .resume_noirq = icl_nhi_resume,
175 .runtime_suspend = icl_nhi_suspend,
176 .runtime_resume = icl_nhi_resume,
177 .shutdown = icl_nhi_shutdown,
178};