// SPDX-License-Identifier: GPL-2.0
/*
 * SGI IOC3 multifunction device driver
 *
 * Copyright (C) 2018, 2019 Thomas Bogendoerfer <tbogendoerfer@suse.de>
 *
 * Based on work by:
 *   Stanislaw Skowronek <skylark@unaligned.org>
 *   Joshua Kinard <kumba@gentoo.org>
 *   Brent Casavant <bcasavan@sgi.com> - IOC4 master driver
 *   Pat Gefre <pfg@sgi.com> - IOC3 serial port IRQ demuxer
 */

#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/platform_data/sgi-w1.h>
#include <linux/rtc/ds1685.h>

#include <asm/pci/bridge.h>
#include <asm/sn/ioc3.h>

#define IOC3_IRQ_SERIAL_A	6
#define IOC3_IRQ_SERIAL_B	15
#define IOC3_IRQ_KBD		22

/* Bitmask for selecting which IRQs are level triggered */
#define IOC3_LVL_MASK	(BIT(IOC3_IRQ_SERIAL_A) | BIT(IOC3_IRQ_SERIAL_B))

#define M48T35_REG_SIZE	32768	/* size of m48t35 registers */

/* 1.2 us latency timer (40 cycles at 33 MHz) */
#define IOC3_LATENCY	40

struct ioc3_priv_data {
	struct irq_domain *domain;
	struct ioc3 __iomem *regs;
	struct pci_dev *pdev;
	int domain_irq;
};

static void ioc3_irq_ack(struct irq_data *d)
{
	struct ioc3_priv_data *ipd = irq_data_get_irq_chip_data(d);
	unsigned int hwirq = irqd_to_hwirq(d);

	writel(BIT(hwirq), &ipd->regs->sio_ir);
}

static void ioc3_irq_mask(struct irq_data *d)
{
	struct ioc3_priv_data *ipd = irq_data_get_irq_chip_data(d);
	unsigned int hwirq = irqd_to_hwirq(d);

	writel(BIT(hwirq), &ipd->regs->sio_iec);
}

static void ioc3_irq_unmask(struct irq_data *d)
{
	struct ioc3_priv_data *ipd = irq_data_get_irq_chip_data(d);
	unsigned int hwirq = irqd_to_hwirq(d);

	writel(BIT(hwirq), &ipd->regs->sio_ies);
}

static struct irq_chip ioc3_irq_chip = {
	.name		= "IOC3",
	.irq_ack	= ioc3_irq_ack,
	.irq_mask	= ioc3_irq_mask,
	.irq_unmask	= ioc3_irq_unmask,
};

static int ioc3_irq_domain_map(struct irq_domain *d, unsigned int irq,
			      irq_hw_number_t hwirq)
{
	/* Set level IRQs for every interrupt contained in IOC3_LVL_MASK */
	if (BIT(hwirq) & IOC3_LVL_MASK)
		irq_set_chip_and_handler(irq, &ioc3_irq_chip, handle_level_irq);
	else
		irq_set_chip_and_handler(irq, &ioc3_irq_chip, handle_edge_irq);

	irq_set_chip_data(irq, d->host_data);
	return 0;
}

static void ioc3_irq_domain_unmap(struct irq_domain *d, unsigned int irq)
{
	irq_set_chip_and_handler(irq, NULL, NULL);
	irq_set_chip_data(irq, NULL);
}

static const struct irq_domain_ops ioc3_irq_domain_ops = {
	.map = ioc3_irq_domain_map,
	.unmap = ioc3_irq_domain_unmap,
};

static void ioc3_irq_handler(struct irq_desc *desc)
{
	struct irq_domain *domain = irq_desc_get_handler_data(desc);
	struct ioc3_priv_data *ipd = domain->host_data;
	struct ioc3 __iomem *regs = ipd->regs;
	u32 pending, mask;
	unsigned int irq;

	pending = readl(&regs->sio_ir);
	mask = readl(&regs->sio_ies);
	pending &= mask; /* Mask off not enabled interrupts */

	if (pending) {
		irq = irq_find_mapping(domain, __ffs(pending));
		if (irq)
			generic_handle_irq(irq);
	} else  {
		spurious_interrupt();
	}
}

/*
 * System boards/BaseIOs use more interrupt pins of the bridge ASIC
 * to which the IOC3 is connected. Since the IOC3 MFD driver
 * knows wiring of these extra pins, we use the map_irq function
 * to get interrupts activated
 */
static int ioc3_map_irq(struct pci_dev *pdev, int slot, int pin)
{
	struct pci_host_bridge *hbrg = pci_find_host_bridge(pdev->bus);

	return hbrg->map_irq(pdev, slot, pin);
}

static int ioc3_irq_domain_setup(struct ioc3_priv_data *ipd, int irq)
{
	struct irq_domain *domain;
	struct fwnode_handle *fn;

	fn = irq_domain_alloc_named_fwnode("IOC3");
	if (!fn)
		goto err;

	domain = irq_domain_create_linear(fn, 24, &ioc3_irq_domain_ops, ipd);
	if (!domain) {
		irq_domain_free_fwnode(fn);
		goto err;
	}

	ipd->domain = domain;

	irq_set_chained_handler_and_data(irq, ioc3_irq_handler, domain);
	ipd->domain_irq = irq;
	return 0;

err:
	dev_err(&ipd->pdev->dev, "irq domain setup failed\n");
	return -ENOMEM;
}

static const struct resource ioc3_uarta_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, sregs.uarta),
		       sizeof_field(struct ioc3, sregs.uarta)),
	DEFINE_RES_IRQ(IOC3_IRQ_SERIAL_A)
};

static const struct resource ioc3_uartb_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, sregs.uartb),
		       sizeof_field(struct ioc3, sregs.uartb)),
	DEFINE_RES_IRQ(IOC3_IRQ_SERIAL_B)
};

static struct mfd_cell ioc3_serial_cells[] = {
	{
		.name = "ioc3-serial8250",
		.resources = ioc3_uarta_resources,
		.num_resources = ARRAY_SIZE(ioc3_uarta_resources),
	},
	{
		.name = "ioc3-serial8250",
		.resources = ioc3_uartb_resources,
		.num_resources = ARRAY_SIZE(ioc3_uartb_resources),
	}
};

static int ioc3_serial_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	/* Set gpio pins for RS232/RS422 mode selection */
	writel(GPCR_UARTA_MODESEL | GPCR_UARTB_MODESEL,
		&ipd->regs->gpcr_s);
	/* Select RS232 mode for uart a */
	writel(0, &ipd->regs->gppr[6]);
	/* Select RS232 mode for uart b */
	writel(0, &ipd->regs->gppr[7]);

	/* Switch both ports to 16650 mode */
	writel(readl(&ipd->regs->port_a.sscr) & ~SSCR_DMA_EN,
	       &ipd->regs->port_a.sscr);
	writel(readl(&ipd->regs->port_b.sscr) & ~SSCR_DMA_EN,
	       &ipd->regs->port_b.sscr);
	udelay(1000); /* Wait until mode switch is done */

	ret = mfd_add_devices(&ipd->pdev->dev, PLATFORM_DEVID_AUTO,
			      ioc3_serial_cells, ARRAY_SIZE(ioc3_serial_cells),
			      &ipd->pdev->resource[0], 0, ipd->domain);
	if (ret) {
		dev_err(&ipd->pdev->dev, "Failed to add 16550 subdevs\n");
		return ret;
	}

	return 0;
}

static const struct resource ioc3_kbd_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, serio),
		       sizeof_field(struct ioc3, serio)),
	DEFINE_RES_IRQ(IOC3_IRQ_KBD)
};

static struct mfd_cell ioc3_kbd_cells[] = {
	{
		.name = "ioc3-kbd",
		.resources = ioc3_kbd_resources,
		.num_resources = ARRAY_SIZE(ioc3_kbd_resources),
	}
};

static int ioc3_kbd_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	ret = mfd_add_devices(&ipd->pdev->dev, PLATFORM_DEVID_AUTO,
			      ioc3_kbd_cells, ARRAY_SIZE(ioc3_kbd_cells),
			      &ipd->pdev->resource[0], 0, ipd->domain);
	if (ret) {
		dev_err(&ipd->pdev->dev, "Failed to add 16550 subdevs\n");
		return ret;
	}

	return 0;
}

static const struct resource ioc3_eth_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, eth),
		       sizeof_field(struct ioc3, eth)),
	DEFINE_RES_MEM(offsetof(struct ioc3, ssram),
		       sizeof_field(struct ioc3, ssram)),
	DEFINE_RES_IRQ(0)
};

static const struct resource ioc3_w1_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, mcr),
		       sizeof_field(struct ioc3, mcr)),
};
static struct sgi_w1_platform_data ioc3_w1_platform_data;

static struct mfd_cell ioc3_eth_cells[] = {
	{
		.name = "ioc3-eth",
		.resources = ioc3_eth_resources,
		.num_resources = ARRAY_SIZE(ioc3_eth_resources),
	},
	{
		.name = "sgi_w1",
		.resources = ioc3_w1_resources,
		.num_resources = ARRAY_SIZE(ioc3_w1_resources),
		.platform_data = &ioc3_w1_platform_data,
		.pdata_size = sizeof(ioc3_w1_platform_data),
	}
};

static int ioc3_eth_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	/* Enable One-Wire bus */
	writel(GPCR_MLAN_EN, &ipd->regs->gpcr_s);

	/* Generate unique identifier */
	snprintf(ioc3_w1_platform_data.dev_id,
		 sizeof(ioc3_w1_platform_data.dev_id), "ioc3-%012llx",
		 ipd->pdev->resource->start);

	ret = mfd_add_devices(&ipd->pdev->dev, PLATFORM_DEVID_AUTO,
			      ioc3_eth_cells, ARRAY_SIZE(ioc3_eth_cells),
			      &ipd->pdev->resource[0], ipd->pdev->irq, NULL);
	if (ret) {
		dev_err(&ipd->pdev->dev, "Failed to add ETH/W1 subdev\n");
		return ret;
	}

	return 0;
}

static const struct resource ioc3_m48t35_resources[] = {
	DEFINE_RES_MEM(IOC3_BYTEBUS_DEV0, M48T35_REG_SIZE)
};

static struct mfd_cell ioc3_m48t35_cells[] = {
	{
		.name = "rtc-m48t35",
		.resources = ioc3_m48t35_resources,
		.num_resources = ARRAY_SIZE(ioc3_m48t35_resources),
	}
};

static int ioc3_m48t35_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	ret = mfd_add_devices(&ipd->pdev->dev, PLATFORM_DEVID_AUTO,
			      ioc3_m48t35_cells, ARRAY_SIZE(ioc3_m48t35_cells),
			      &ipd->pdev->resource[0], 0, ipd->domain);
	if (ret)
		dev_err(&ipd->pdev->dev, "Failed to add M48T35 subdev\n");

	return ret;
}

static struct ds1685_rtc_platform_data ip30_rtc_platform_data = {
	.bcd_mode = false,
	.no_irq = false,
	.uie_unsupported = true,
	.access_type = ds1685_reg_indirect,
};

static const struct resource ioc3_rtc_ds1685_resources[] = {
	DEFINE_RES_MEM(IOC3_BYTEBUS_DEV1, 1),
	DEFINE_RES_MEM(IOC3_BYTEBUS_DEV2, 1),
	DEFINE_RES_IRQ(0)
};

static struct mfd_cell ioc3_ds1685_cells[] = {
	{
		.name = "rtc-ds1685",
		.resources = ioc3_rtc_ds1685_resources,
		.num_resources = ARRAY_SIZE(ioc3_rtc_ds1685_resources),
		.platform_data = &ip30_rtc_platform_data,
		.pdata_size = sizeof(ip30_rtc_platform_data),
		.id = PLATFORM_DEVID_NONE,
	}
};

static int ioc3_ds1685_setup(struct ioc3_priv_data *ipd)
{
	int ret, irq;

	irq = ioc3_map_irq(ipd->pdev, 6, 0);

	ret = mfd_add_devices(&ipd->pdev->dev, 0, ioc3_ds1685_cells,
			      ARRAY_SIZE(ioc3_ds1685_cells),
			      &ipd->pdev->resource[0], irq, NULL);
	if (ret)
		dev_err(&ipd->pdev->dev, "Failed to add DS1685 subdev\n");

	return ret;
};


static const struct resource ioc3_leds_resources[] = {
	DEFINE_RES_MEM(offsetof(struct ioc3, gppr[0]),
		       sizeof_field(struct ioc3, gppr[0])),
	DEFINE_RES_MEM(offsetof(struct ioc3, gppr[1]),
		       sizeof_field(struct ioc3, gppr[1])),
};

static struct mfd_cell ioc3_led_cells[] = {
	{
		.name = "ip30-leds",
		.resources = ioc3_leds_resources,
		.num_resources = ARRAY_SIZE(ioc3_leds_resources),
		.id = PLATFORM_DEVID_NONE,
	}
};

static int ioc3_led_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	ret = mfd_add_devices(&ipd->pdev->dev, 0, ioc3_led_cells,
			      ARRAY_SIZE(ioc3_led_cells),
			      &ipd->pdev->resource[0], 0, ipd->domain);
	if (ret)
		dev_err(&ipd->pdev->dev, "Failed to add LED subdev\n");

	return ret;
}

static int ip27_baseio_setup(struct ioc3_priv_data *ipd)
{
	int ret, io_irq;

	io_irq = ioc3_map_irq(ipd->pdev, PCI_SLOT(ipd->pdev->devfn),
			      PCI_INTERRUPT_INTB);
	ret = ioc3_irq_domain_setup(ipd, io_irq);
	if (ret)
		return ret;

	ret = ioc3_eth_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_serial_setup(ipd);
	if (ret)
		return ret;

	return ioc3_m48t35_setup(ipd);
}

static int ip27_baseio6g_setup(struct ioc3_priv_data *ipd)
{
	int ret, io_irq;

	io_irq = ioc3_map_irq(ipd->pdev, PCI_SLOT(ipd->pdev->devfn),
			      PCI_INTERRUPT_INTB);
	ret = ioc3_irq_domain_setup(ipd, io_irq);
	if (ret)
		return ret;

	ret = ioc3_eth_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_serial_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_m48t35_setup(ipd);
	if (ret)
		return ret;

	return ioc3_kbd_setup(ipd);
}

static int ip27_mio_setup(struct ioc3_priv_data *ipd)
{
	int ret;

	ret = ioc3_irq_domain_setup(ipd, ipd->pdev->irq);
	if (ret)
		return ret;

	ret = ioc3_serial_setup(ipd);
	if (ret)
		return ret;

	return ioc3_kbd_setup(ipd);
}

static int ip30_sysboard_setup(struct ioc3_priv_data *ipd)
{
	int ret, io_irq;

	io_irq = ioc3_map_irq(ipd->pdev, PCI_SLOT(ipd->pdev->devfn),
			      PCI_INTERRUPT_INTB);
	ret = ioc3_irq_domain_setup(ipd, io_irq);
	if (ret)
		return ret;

	ret = ioc3_eth_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_serial_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_kbd_setup(ipd);
	if (ret)
		return ret;

	ret = ioc3_ds1685_setup(ipd);
	if (ret)
		return ret;

	return ioc3_led_setup(ipd);
}

static int ioc3_menet_setup(struct ioc3_priv_data *ipd)
{
	int ret, io_irq;

	io_irq = ioc3_map_irq(ipd->pdev, PCI_SLOT(ipd->pdev->devfn),
			      PCI_INTERRUPT_INTB);
	ret = ioc3_irq_domain_setup(ipd, io_irq);
	if (ret)
		return ret;

	ret = ioc3_eth_setup(ipd);
	if (ret)
		return ret;

	return ioc3_serial_setup(ipd);
}

static int ioc3_menet4_setup(struct ioc3_priv_data *ipd)
{
	return ioc3_eth_setup(ipd);
}

static int ioc3_cad_duo_setup(struct ioc3_priv_data *ipd)
{
	int ret, io_irq;

	io_irq = ioc3_map_irq(ipd->pdev, PCI_SLOT(ipd->pdev->devfn),
			      PCI_INTERRUPT_INTB);
	ret = ioc3_irq_domain_setup(ipd, io_irq);
	if (ret)
		return ret;

	ret = ioc3_eth_setup(ipd);
	if (ret)
		return ret;

	return ioc3_kbd_setup(ipd);
}

/* Helper macro for filling ioc3_info array */
#define IOC3_SID(_name, _sid, _setup) \
	{								   \
		.name = _name,						   \
		.sid = PCI_VENDOR_ID_SGI | (IOC3_SUBSYS_ ## _sid << 16),   \
		.setup = _setup,					   \
	}

static struct {
	const char *name;
	u32 sid;
	int (*setup)(struct ioc3_priv_data *ipd);
} ioc3_infos[] = {
	IOC3_SID("IP27 BaseIO6G", IP27_BASEIO6G, &ip27_baseio6g_setup),
	IOC3_SID("IP27 MIO", IP27_MIO, &ip27_mio_setup),
	IOC3_SID("IP27 BaseIO", IP27_BASEIO, &ip27_baseio_setup),
	IOC3_SID("IP29 System Board", IP29_SYSBOARD, &ip27_baseio6g_setup),
	IOC3_SID("IP30 System Board", IP30_SYSBOARD, &ip30_sysboard_setup),
	IOC3_SID("MENET", MENET, &ioc3_menet_setup),
	IOC3_SID("MENET4", MENET4, &ioc3_menet4_setup)
};
#undef IOC3_SID

static int ioc3_setup(struct ioc3_priv_data *ipd)
{
	u32 sid;
	int i;

	/* Clear IRQs */
	writel(~0, &ipd->regs->sio_iec);
	writel(~0, &ipd->regs->sio_ir);
	writel(0, &ipd->regs->eth.eier);
	writel(~0, &ipd->regs->eth.eisr);

	/* Read subsystem vendor id and subsystem id */
	pci_read_config_dword(ipd->pdev, PCI_SUBSYSTEM_VENDOR_ID, &sid);

	for (i = 0; i < ARRAY_SIZE(ioc3_infos); i++)
		if (sid == ioc3_infos[i].sid) {
			pr_info("ioc3: %s\n", ioc3_infos[i].name);
			return ioc3_infos[i].setup(ipd);
		}

	/* Treat everything not identified by PCI subid as CAD DUO */
	pr_info("ioc3: CAD DUO\n");
	return ioc3_cad_duo_setup(ipd);
}

static int ioc3_mfd_probe(struct pci_dev *pdev,
			  const struct pci_device_id *pci_id)
{
	struct ioc3_priv_data *ipd;
	struct ioc3 __iomem *regs;
	int ret;

	ret = pci_enable_device(pdev);
	if (ret)
		return ret;

	pci_write_config_byte(pdev, PCI_LATENCY_TIMER, IOC3_LATENCY);
	pci_set_master(pdev);

	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
	if (ret) {
		pr_err("%s: No usable DMA configuration, aborting.\n",
		       pci_name(pdev));
		goto out_disable_device;
	}

	/* Set up per-IOC3 data */
	ipd = devm_kzalloc(&pdev->dev, sizeof(struct ioc3_priv_data),
			   GFP_KERNEL);
	if (!ipd) {
		ret = -ENOMEM;
		goto out_disable_device;
	}
	ipd->pdev = pdev;

	/*
	 * Map all IOC3 registers.  These are shared between subdevices
	 * so the main IOC3 module manages them.
	 */
	regs = pci_ioremap_bar(pdev, 0);
	if (!regs) {
		dev_warn(&pdev->dev, "ioc3: Unable to remap PCI BAR for %s.\n",
			 pci_name(pdev));
		ret = -ENOMEM;
		goto out_disable_device;
	}
	ipd->regs = regs;

	/* Track PCI-device specific data */
	pci_set_drvdata(pdev, ipd);

	ret = ioc3_setup(ipd);
	if (ret) {
		/* Remove all already added MFD devices */
		mfd_remove_devices(&ipd->pdev->dev);
		if (ipd->domain) {
			struct fwnode_handle *fn = ipd->domain->fwnode;

			irq_domain_remove(ipd->domain);
			irq_domain_free_fwnode(fn);
			free_irq(ipd->domain_irq, (void *)ipd);
		}
		pci_iounmap(pdev, regs);
		goto out_disable_device;
	}

	return 0;

out_disable_device:
	pci_disable_device(pdev);
	return ret;
}

static void ioc3_mfd_remove(struct pci_dev *pdev)
{
	struct ioc3_priv_data *ipd;

	ipd = pci_get_drvdata(pdev);

	/* Clear and disable all IRQs */
	writel(~0, &ipd->regs->sio_iec);
	writel(~0, &ipd->regs->sio_ir);

	/* Release resources */
	mfd_remove_devices(&ipd->pdev->dev);
	if (ipd->domain) {
		struct fwnode_handle *fn = ipd->domain->fwnode;

		irq_domain_remove(ipd->domain);
		irq_domain_free_fwnode(fn);
		free_irq(ipd->domain_irq, (void *)ipd);
	}
	pci_iounmap(pdev, ipd->regs);
	pci_disable_device(pdev);
}

static struct pci_device_id ioc3_mfd_id_table[] = {
	{ PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC3, PCI_ANY_ID, PCI_ANY_ID },
	{ 0, },
};
MODULE_DEVICE_TABLE(pci, ioc3_mfd_id_table);

static struct pci_driver ioc3_mfd_driver = {
	.name = "IOC3",
	.id_table = ioc3_mfd_id_table,
	.probe = ioc3_mfd_probe,
	.remove = ioc3_mfd_remove,
};

module_pci_driver(ioc3_mfd_driver);

MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
MODULE_DESCRIPTION("SGI IOC3 MFD driver");
MODULE_LICENSE("GPL v2");