1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Dummy driver for Intel's Image Signal Processor found on Bay Trail
  4 * and Cherry Trail devices. The sole purpose of this driver is to allow
  5 * the ISP to 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 : ISPSSPM0_IUNIT_POWER_OFF;
 40
 41	/* Write to ISPSSPM0 bit[1:0] to power on/off the IUNIT */
 42	iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, ISPSSPM0,
 43			val, ISPSSPM0_ISPSSC_MASK);
 44
 45	/*
 46	 * There should be no IUNIT access while power-down is
 47	 * in progress. HW sighting: 4567865.
 48	 * Wait up to 50 ms for the IUNIT to shut down.
 49	 * And we do the same for power on.
 50	 */
 51	timeout = jiffies + msecs_to_jiffies(50);
 52	do {
 53		u32 tmp;
 54
 55		/* Wait until ISPSSPM0 bit[25:24] shows the right value */
 56		iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, ISPSSPM0, &tmp);
 57		tmp = (tmp & ISPSSPM0_ISPSSS_MASK) >> ISPSSPM0_ISPSSS_OFFSET;
 58		if (tmp == val)
 59			return 0;
 60
 61		usleep_range(1000, 2000);
 62	} while (time_before(jiffies, timeout));
 63
 64	dev_err(&dev->dev, "IUNIT power-%s timeout.\n", enable ? "on" : "off");
 65	return -EBUSY;
 66}
 67
 68static int isp_probe(struct pci_dev *dev, const struct pci_device_id *id)
 69{
 70	pm_runtime_allow(&dev->dev);
 71	pm_runtime_put_sync_suspend(&dev->dev);
 72
 73	return 0;
 74}
 75
 76static void isp_remove(struct pci_dev *dev)
 77{
 78	pm_runtime_get_sync(&dev->dev);
 79	pm_runtime_forbid(&dev->dev);
 80}
 81
 82static int isp_pci_suspend(struct device *dev)
 83{
 84	struct pci_dev *pdev = to_pci_dev(dev);
 85	u32 val;
 86
 87	pci_write_config_dword(pdev, PCI_INTERRUPT_CTRL, 0);
 88
 89	/*
 90	 * MRFLD IUNIT DPHY is located in an always-power-on island
 91	 * MRFLD HW design need all CSI ports are disabled before
 92	 * powering down the IUNIT.
 93	 */
 94	pci_read_config_dword(pdev, PCI_CSI_CONTROL, &val);
 95	val |= PCI_CSI_CONTROL_PORTS_OFF_MASK;
 96	pci_write_config_dword(pdev, PCI_CSI_CONTROL, val);
 97
 98	/*
 99	 * We lose config space access when punit power gates
100	 * the ISP. Can't use pci_set_power_state() because
101	 * pmcsr won't actually change when we write to it.
102	 */
103	pci_save_state(pdev);
104	pdev->current_state = PCI_D3cold;
105	isp_set_power(pdev, false);
106
107	return 0;
108}
109
110static int isp_pci_resume(struct device *dev)
111{
112	struct pci_dev *pdev = to_pci_dev(dev);
113
114	isp_set_power(pdev, true);
115	pdev->current_state = PCI_D0;
116	pci_restore_state(pdev);
117
118	return 0;
119}
120
121static UNIVERSAL_DEV_PM_OPS(isp_pm_ops, isp_pci_suspend,
122			    isp_pci_resume, NULL);
123
124static const struct pci_device_id isp_id_table[] = {
125	{ PCI_VDEVICE(INTEL, 0x0f38), },
126	{ PCI_VDEVICE(INTEL, 0x22b8), },
127	{ 0, }
128};
129MODULE_DEVICE_TABLE(pci, isp_id_table);
130
131static struct pci_driver isp_pci_driver = {
132	.name = "intel_atomisp2_pm",
133	.id_table = isp_id_table,
134	.probe = isp_probe,
135	.remove = isp_remove,
136	.driver.pm = &isp_pm_ops,
137};
138
139module_pci_driver(isp_pci_driver);
140
141MODULE_DESCRIPTION("Intel AtomISP2 dummy / power-management drv (for suspend)");
142MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
143MODULE_LICENSE("GPL v2");