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");