// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2018 Oleksij Rempel <linux@rempel-privat.de>
 *
 * Driver for Alcor Micro AU6601 and AU6621 controllers
 */

#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/pm.h>

#include <linux/alcor_pci.h>

#define DRV_NAME_ALCOR_PCI			"alcor_pci"

static DEFINE_IDA(alcor_pci_idr);

static struct mfd_cell alcor_pci_cells[] = {
	[ALCOR_SD_CARD] = {
		.name = DRV_NAME_ALCOR_PCI_SDMMC,
	},
	[ALCOR_MS_CARD] = {
		.name = DRV_NAME_ALCOR_PCI_MS,
	},
};

static const struct alcor_dev_cfg alcor_cfg = {
	.dma = 0,
};

static const struct alcor_dev_cfg au6621_cfg = {
	.dma = 1,
};

static const struct alcor_dev_cfg au6625_cfg = {
	.dma = 0,
};

static const struct pci_device_id pci_ids[] = {
	{ PCI_DEVICE(PCI_ID_ALCOR_MICRO, PCI_ID_AU6601),
		.driver_data = (kernel_ulong_t)&alcor_cfg },
	{ PCI_DEVICE(PCI_ID_ALCOR_MICRO, PCI_ID_AU6621),
		.driver_data = (kernel_ulong_t)&au6621_cfg },
	{ PCI_DEVICE(PCI_ID_ALCOR_MICRO, PCI_ID_AU6625),
		.driver_data = (kernel_ulong_t)&au6625_cfg },
	{},
};
MODULE_DEVICE_TABLE(pci, pci_ids);

void alcor_write8(struct alcor_pci_priv *priv, u8 val, unsigned int addr)
{
	writeb(val, priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_write8);

void alcor_write16(struct alcor_pci_priv *priv, u16 val, unsigned int addr)
{
	writew(val, priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_write16);

void alcor_write32(struct alcor_pci_priv *priv, u32 val, unsigned int addr)
{
	writel(val, priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_write32);

void alcor_write32be(struct alcor_pci_priv *priv, u32 val, unsigned int addr)
{
	iowrite32be(val, priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_write32be);

u8 alcor_read8(struct alcor_pci_priv *priv, unsigned int addr)
{
	return readb(priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_read8);

u32 alcor_read32(struct alcor_pci_priv *priv, unsigned int addr)
{
	return readl(priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_read32);

u32 alcor_read32be(struct alcor_pci_priv *priv, unsigned int addr)
{
	return ioread32be(priv->iobase + addr);
}
EXPORT_SYMBOL_GPL(alcor_read32be);

static int alcor_pci_find_cap_offset(struct alcor_pci_priv *priv,
				     struct pci_dev *pci)
{
	int where;
	u8 val8;
	u32 val32;

	where = ALCOR_CAP_START_OFFSET;
	pci_read_config_byte(pci, where, &val8);
	if (!val8)
		return 0;

	where = (int)val8;
	while (1) {
		pci_read_config_dword(pci, where, &val32);
		if (val32 == 0xffffffff) {
			dev_dbg(priv->dev, "find_cap_offset invalid value %x.\n",
				val32);
			return 0;
		}

		if ((val32 & 0xff) == 0x10) {
			dev_dbg(priv->dev, "pcie cap offset: %x\n", where);
			return where;
		}

		if ((val32 & 0xff00) == 0x00) {
			dev_dbg(priv->dev, "pci_find_cap_offset invalid value %x.\n",
				val32);
			break;
		}
		where = (int)((val32 >> 8) & 0xff);
	}

	return 0;
}

static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv)
{
	struct pci_dev *pci;
	int where;
	u32 val32;

	priv->pdev_cap_off    = alcor_pci_find_cap_offset(priv, priv->pdev);
	/*
	 * A device might be attached to root complex directly and
	 * priv->parent_pdev will be NULL. In this case we don't check its
	 * capability and disable ASPM completely.
	 */
	if (priv->parent_pdev)
		priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
							 priv->parent_pdev);

	if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) {
		dev_dbg(priv->dev, "pci_cap_off: %x, parent_cap_off: %x\n",
			priv->pdev_cap_off, priv->parent_cap_off);
		return;
	}

	/* link capability */
	pci   = priv->pdev;
	where = priv->pdev_cap_off + ALCOR_PCIE_LINK_CAP_OFFSET;
	pci_read_config_dword(pci, where, &val32);
	priv->pdev_aspm_cap = (u8)(val32 >> 10) & 0x03;

	pci   = priv->parent_pdev;
	where = priv->parent_cap_off + ALCOR_PCIE_LINK_CAP_OFFSET;
	pci_read_config_dword(pci, where, &val32);
	priv->parent_aspm_cap = (u8)(val32 >> 10) & 0x03;

	if (priv->pdev_aspm_cap != priv->parent_aspm_cap) {
		u8 aspm_cap;

		dev_dbg(priv->dev, "pdev_aspm_cap: %x, parent_aspm_cap: %x\n",
			priv->pdev_aspm_cap, priv->parent_aspm_cap);
		aspm_cap = priv->pdev_aspm_cap & priv->parent_aspm_cap;
		priv->pdev_aspm_cap    = aspm_cap;
		priv->parent_aspm_cap = aspm_cap;
	}

	dev_dbg(priv->dev, "ext_config_dev_aspm: %x, pdev_aspm_cap: %x\n",
		priv->ext_config_dev_aspm, priv->pdev_aspm_cap);
	priv->ext_config_dev_aspm &= priv->pdev_aspm_cap;
}

static void alcor_pci_aspm_ctrl(struct alcor_pci_priv *priv, u8 aspm_enable)
{
	struct pci_dev *pci;
	u8 aspm_ctrl, i;
	int where;
	u32 val32;

	if ((!priv->pdev_cap_off) || (!priv->parent_cap_off)) {
		dev_dbg(priv->dev, "pci_cap_off: %x, parent_cap_off: %x\n",
			priv->pdev_cap_off, priv->parent_cap_off);
		return;
	}

	if (!priv->pdev_aspm_cap)
		return;

	aspm_ctrl = 0;
	if (aspm_enable) {
		aspm_ctrl = priv->ext_config_dev_aspm;

		if (!aspm_ctrl) {
			dev_dbg(priv->dev, "aspm_ctrl == 0\n");
			return;
		}
	}

	for (i = 0; i < 2; i++) {

		if (i) {
			pci   = priv->parent_pdev;
			where = priv->parent_cap_off
				+ ALCOR_PCIE_LINK_CTRL_OFFSET;
		} else {
			pci   = priv->pdev;
			where = priv->pdev_cap_off
				+ ALCOR_PCIE_LINK_CTRL_OFFSET;
		}

		pci_read_config_dword(pci, where, &val32);
		val32 &= (~0x03);
		val32 |= (aspm_ctrl & priv->pdev_aspm_cap);
		pci_write_config_byte(pci, where, (u8)val32);
	}

}

static inline void alcor_mask_sd_irqs(struct alcor_pci_priv *priv)
{
	alcor_write32(priv, 0, AU6601_REG_INT_ENABLE);
}

static inline void alcor_unmask_sd_irqs(struct alcor_pci_priv *priv)
{
	alcor_write32(priv, AU6601_INT_CMD_MASK | AU6601_INT_DATA_MASK |
		  AU6601_INT_CARD_INSERT | AU6601_INT_CARD_REMOVE |
		  AU6601_INT_OVER_CURRENT_ERR,
		  AU6601_REG_INT_ENABLE);
}

static inline void alcor_mask_ms_irqs(struct alcor_pci_priv *priv)
{
	alcor_write32(priv, 0, AU6601_MS_INT_ENABLE);
}

static inline void alcor_unmask_ms_irqs(struct alcor_pci_priv *priv)
{
	alcor_write32(priv, 0x3d00fa, AU6601_MS_INT_ENABLE);
}

static int alcor_pci_probe(struct pci_dev *pdev,
			   const struct pci_device_id *ent)
{
	struct alcor_dev_cfg *cfg;
	struct alcor_pci_priv *priv;
	int ret, i, bar = 0;

	cfg = (void *)ent->driver_data;

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

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	ret = ida_simple_get(&alcor_pci_idr, 0, 0, GFP_KERNEL);
	if (ret < 0)
		return ret;
	priv->id = ret;

	priv->pdev = pdev;
	priv->parent_pdev = pdev->bus->self;
	priv->dev = &pdev->dev;
	priv->cfg = cfg;
	priv->irq = pdev->irq;

	ret = pci_request_regions(pdev, DRV_NAME_ALCOR_PCI);
	if (ret) {
		dev_err(&pdev->dev, "Cannot request region\n");
		return -ENOMEM;
	}

	if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
		dev_err(&pdev->dev, "BAR %d is not iomem. Aborting.\n", bar);
		ret = -ENODEV;
		goto error_release_regions;
	}

	priv->iobase = pcim_iomap(pdev, bar, 0);
	if (!priv->iobase) {
		ret = -ENOMEM;
		goto error_release_regions;
	}

	/* make sure irqs are disabled */
	alcor_write32(priv, 0, AU6601_REG_INT_ENABLE);
	alcor_write32(priv, 0, AU6601_MS_INT_ENABLE);

	ret = dma_set_mask_and_coherent(priv->dev, AU6601_SDMA_MASK);
	if (ret) {
		dev_err(priv->dev, "Failed to set DMA mask\n");
		goto error_release_regions;
	}

	pci_set_master(pdev);
	pci_set_drvdata(pdev, priv);
	alcor_pci_init_check_aspm(priv);

	for (i = 0; i < ARRAY_SIZE(alcor_pci_cells); i++) {
		alcor_pci_cells[i].platform_data = priv;
		alcor_pci_cells[i].pdata_size = sizeof(*priv);
	}
	ret = mfd_add_devices(&pdev->dev, priv->id, alcor_pci_cells,
			ARRAY_SIZE(alcor_pci_cells), NULL, 0, NULL);
	if (ret < 0)
		goto error_release_regions;

	alcor_pci_aspm_ctrl(priv, 0);

	return 0;

error_release_regions:
	pci_release_regions(pdev);
	return ret;
}

static void alcor_pci_remove(struct pci_dev *pdev)
{
	struct alcor_pci_priv *priv;

	priv = pci_get_drvdata(pdev);

	alcor_pci_aspm_ctrl(priv, 1);

	mfd_remove_devices(&pdev->dev);

	ida_simple_remove(&alcor_pci_idr, priv->id);

	pci_release_regions(pdev);
	pci_set_drvdata(pdev, NULL);
}

#ifdef CONFIG_PM_SLEEP
static int alcor_suspend(struct device *dev)
{
	struct alcor_pci_priv *priv = dev_get_drvdata(dev);

	alcor_pci_aspm_ctrl(priv, 1);
	return 0;
}

static int alcor_resume(struct device *dev)
{

	struct alcor_pci_priv *priv = dev_get_drvdata(dev);

	alcor_pci_aspm_ctrl(priv, 0);
	return 0;
}
#endif /* CONFIG_PM_SLEEP */

static SIMPLE_DEV_PM_OPS(alcor_pci_pm_ops, alcor_suspend, alcor_resume);

static struct pci_driver alcor_driver = {
	.name	=	DRV_NAME_ALCOR_PCI,
	.id_table =	pci_ids,
	.probe	=	alcor_pci_probe,
	.remove =	alcor_pci_remove,
	.driver	=	{
		.pm	= &alcor_pci_pm_ops
	},
};

module_pci_driver(alcor_driver);

MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
MODULE_DESCRIPTION("PCI driver for Alcor Micro AU6601 Secure Digital Host Controller Interface");
MODULE_LICENSE("GPL");