tjh.dev
Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Dummy driver for Intel's Image Signal Processor found on Bay and Cherry
4 * Trail devices. The sole purpose of this driver is to allow the ISP to
5 * be put in D3.
6 *
7 * Copyright (C) 2018 Hans de Goede <hdegoede@redhat.com>
8 *
9 * Based on various non upstream patches for ISP support:
10 * Copyright (C) 2010-2017 Intel Corporation. All rights reserved.
11 * Copyright (c) 2010 Silicon Hive www.siliconhive.com.
12 */
13
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/mod_devicetable.h>
17#include <linux/pci.h>
18#include <linux/pm_runtime.h>
19#include <asm/iosf_mbi.h>
20
21/* PCI configuration regs */
22#define PCI_INTERRUPT_CTRL 0x9c
23
24#define PCI_CSI_CONTROL 0xe8
25#define PCI_CSI_CONTROL_PORTS_OFF_MASK 0x7
26
27/* IOSF BT_MBI_UNIT_PMC regs */
28#define ISPSSPM0 0x39
29#define ISPSSPM0_ISPSSC_OFFSET 0
30#define ISPSSPM0_ISPSSC_MASK 0x00000003
31#define ISPSSPM0_ISPSSS_OFFSET 24
32#define ISPSSPM0_ISPSSS_MASK 0x03000000
33#define ISPSSPM0_IUNIT_POWER_ON 0x0
34#define ISPSSPM0_IUNIT_POWER_OFF 0x3
35
36static int isp_set_power(struct pci_dev *dev, bool enable)
37{
38 unsigned long timeout;
39 u32 val = enable ? ISPSSPM0_IUNIT_POWER_ON :
40 ISPSSPM0_IUNIT_POWER_OFF;
41
42 /* Write to ISPSSPM0 bit[1:0] to power on/off the IUNIT */
43 iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, ISPSSPM0,
44 val, ISPSSPM0_ISPSSC_MASK);
45
46 /*
47 * There should be no IUNIT access while power-down is
48 * in progress HW sighting: 4567865
49 * Wait up to 50 ms for the IUNIT to shut down.
50 * And we do the same for power on.
51 */
52 timeout = jiffies + msecs_to_jiffies(50);
53 while (1) {
54 u32 tmp;
55
56 /* Wait until ISPSSPM0 bit[25:24] shows the right value */
57 iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, ISPSSPM0, &tmp);
58 tmp = (tmp & ISPSSPM0_ISPSSS_MASK) >> ISPSSPM0_ISPSSS_OFFSET;
59 if (tmp == val)
60 break;
61
62 if (time_after(jiffies, timeout)) {
63 dev_err(&dev->dev, "IUNIT power-%s timeout.\n",
64 enable ? "on" : "off");
65 return -EBUSY;
66 }
67 usleep_range(1000, 2000);
68 }
69
70 return 0;
71}
72
73static int isp_probe(struct pci_dev *dev, const struct pci_device_id *id)
74{
75 pm_runtime_allow(&dev->dev);
76 pm_runtime_put_sync_suspend(&dev->dev);
77
78 return 0;
79}
80
81static void isp_remove(struct pci_dev *dev)
82{
83 pm_runtime_get_sync(&dev->dev);
84 pm_runtime_forbid(&dev->dev);
85}
86
87static int isp_pci_suspend(struct device *dev)
88{
89 struct pci_dev *pdev = to_pci_dev(dev);
90 u32 val;
91
92 pci_write_config_dword(pdev, PCI_INTERRUPT_CTRL, 0);
93
94 /*
95 * MRFLD IUNIT DPHY is located in an always-power-on island
96 * MRFLD HW design need all CSI ports are disabled before
97 * powering down the IUNIT.
98 */
99 pci_read_config_dword(pdev, PCI_CSI_CONTROL, &val);
100 val |= PCI_CSI_CONTROL_PORTS_OFF_MASK;
101 pci_write_config_dword(pdev, PCI_CSI_CONTROL, val);
102
103 /*
104 * We lose config space access when punit power gates
105 * the ISP. Can't use pci_set_power_state() because
106 * pmcsr won't actually change when we write to it.
107 */
108 pci_save_state(pdev);
109 pdev->current_state = PCI_D3cold;
110 isp_set_power(pdev, false);
111
112 return 0;
113}
114
115static int isp_pci_resume(struct device *dev)
116{
117 struct pci_dev *pdev = to_pci_dev(dev);
118
119 isp_set_power(pdev, true);
120 pdev->current_state = PCI_D0;
121 pci_restore_state(pdev);
122
123 return 0;
124}
125
126static UNIVERSAL_DEV_PM_OPS(isp_pm_ops, isp_pci_suspend,
127 isp_pci_resume, NULL);
128
129static const struct pci_device_id isp_id_table[] = {
130 { PCI_VDEVICE(INTEL, 0x0f38), },
131 { PCI_VDEVICE(INTEL, 0x22b8), },
132 { 0, }
133};
134MODULE_DEVICE_TABLE(pci, isp_id_table);
135
136static struct pci_driver isp_pci_driver = {
137 .name = "intel_atomisp2_pm",
138 .id_table = isp_id_table,
139 .probe = isp_probe,
140 .remove = isp_remove,
141 .driver.pm = &isp_pm_ops,
142};
143
144module_pci_driver(isp_pci_driver);
145
146MODULE_DESCRIPTION("Intel AtomISP2 dummy / power-management drv (for suspend)");
147MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
148MODULE_LICENSE("GPL v2");