// SPDX-License-Identifier: GPL-2.0+
  /*
   * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
   * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
   * Author: Zou Rongrong <zourongrong@huawei.com>
   * Author: John Garry <john.garry@huawei.com>
   */
  
  #include <linux/acpi.h>
  #include <linux/console.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/logic_pio.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  #include <linux/of_platform.h>
  #include <linux/pci.h>

  #include <linux/serial_8250.h>

  #include <linux/slab.h>
  
  #define DRV_NAME "hisi-lpc"
  
  /*
   * Setting this bit means each IO operation will target a different port
   * address; 0 means repeated IO operations will use the same port,
   * such as BT.
   */
  #define FG_INCRADDR_LPC		0x02
  
  struct lpc_cycle_para {
  	unsigned int opflags;
  	unsigned int csize; /* data length of each operation */
  };
  
  struct hisi_lpc_dev {
  	spinlock_t cycle_lock;
  	void __iomem  *membase;
  	struct logic_pio_hwaddr *io_host;
  };
  
  /* The max IO cycle counts supported is four per operation at maximum */
  #define LPC_MAX_DWIDTH	4
  
  #define LPC_REG_STARTUP_SIGNAL		0x00
  #define LPC_REG_STARTUP_SIGNAL_START	BIT(0)
  #define LPC_REG_OP_STATUS		0x04
  #define LPC_REG_OP_STATUS_IDLE		BIT(0)
  #define LPC_REG_OP_STATUS_FINISHED	BIT(1)
  #define LPC_REG_OP_LEN			0x10 /* LPC cycles count per start */
  #define LPC_REG_CMD			0x14
  #define LPC_REG_CMD_OP			BIT(0) /* 0: read, 1: write */
  #define LPC_REG_CMD_SAMEADDR		BIT(3)
  #define LPC_REG_ADDR			0x20 /* target address */
  #define LPC_REG_WDATA			0x24 /* write FIFO */
  #define LPC_REG_RDATA			0x28 /* read FIFO */
  
  /* The minimal nanosecond interval for each query on LPC cycle status */
  #define LPC_NSEC_PERWAIT	100
  
  /*
   * The maximum waiting time is about 128us.  It is specific for stream I/O,
   * such as ins.
   *
   * The fastest IO cycle time is about 390ns, but the worst case will wait
   * for extra 256 lpc clocks, so (256 + 13) * 30ns = 8 us. The maximum burst
   * cycles is 16. So, the maximum waiting time is about 128us under worst
   * case.
   *
   * Choose 1300 as the maximum.
   */
  #define LPC_MAX_WAITCNT		1300
  
  /* About 10us. This is specific for single IO operations, such as inb */
  #define LPC_PEROP_WAITCNT	100
  
  static int wait_lpc_idle(unsigned char *mbase, unsigned int waitcnt)
  {
  	u32 status;
  
  	do {
  		status = readl(mbase + LPC_REG_OP_STATUS);
  		if (status & LPC_REG_OP_STATUS_IDLE)
  			return (status & LPC_REG_OP_STATUS_FINISHED) ? 0 : -EIO;
  		ndelay(LPC_NSEC_PERWAIT);
  	} while (--waitcnt);
  
  	return -ETIME;
  }
  
  /*
   * hisi_lpc_target_in - trigger a series of LPC cycles for read operation
   * @lpcdev: pointer to hisi lpc device
   * @para: some parameters used to control the lpc I/O operations
   * @addr: the lpc I/O target port address
   * @buf: where the read back data is stored
   * @opcnt: how many I/O operations required, i.e. data width
   *
   * Returns 0 on success, non-zero on fail.
   */
  static int hisi_lpc_target_in(struct hisi_lpc_dev *lpcdev,
  			      struct lpc_cycle_para *para, unsigned long addr,
  			      unsigned char *buf, unsigned long opcnt)
  {
  	unsigned int cmd_word;
  	unsigned int waitcnt;
  	unsigned long flags;
  	int ret;
  
  	if (!buf || !opcnt || !para || !para->csize || !lpcdev)
  		return -EINVAL;
  
  	cmd_word = 0; /* IO mode, Read */
  	waitcnt = LPC_PEROP_WAITCNT;
  	if (!(para->opflags & FG_INCRADDR_LPC)) {
  		cmd_word |= LPC_REG_CMD_SAMEADDR;
  		waitcnt = LPC_MAX_WAITCNT;
  	}
  
  	/* whole operation must be atomic */
  	spin_lock_irqsave(&lpcdev->cycle_lock, flags);
  
  	writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
  	writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
  	writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
  
  	writel(LPC_REG_STARTUP_SIGNAL_START,
  	       lpcdev->membase + LPC_REG_STARTUP_SIGNAL);
  
  	/* whether the operation is finished */
  	ret = wait_lpc_idle(lpcdev->membase, waitcnt);
  	if (ret) {
  		spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
  		return ret;
  	}
  
  	readsb(lpcdev->membase + LPC_REG_RDATA, buf, opcnt);
  
  	spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
  
  	return 0;
  }
  
  /*
   * hisi_lpc_target_out - trigger a series of LPC cycles for write operation
   * @lpcdev: pointer to hisi lpc device
   * @para: some parameters used to control the lpc I/O operations
   * @addr: the lpc I/O target port address
   * @buf: where the data to be written is stored
   * @opcnt: how many I/O operations required, i.e. data width
   *
   * Returns 0 on success, non-zero on fail.
   */
  static int hisi_lpc_target_out(struct hisi_lpc_dev *lpcdev,
  			       struct lpc_cycle_para *para, unsigned long addr,
  			       const unsigned char *buf, unsigned long opcnt)
  {
  	unsigned int waitcnt;
  	unsigned long flags;
  	u32 cmd_word;
  	int ret;
  
  	if (!buf || !opcnt || !para || !lpcdev)
  		return -EINVAL;
  
  	/* default is increasing address */
  	cmd_word = LPC_REG_CMD_OP; /* IO mode, write */
  	waitcnt = LPC_PEROP_WAITCNT;
  	if (!(para->opflags & FG_INCRADDR_LPC)) {
  		cmd_word |= LPC_REG_CMD_SAMEADDR;
  		waitcnt = LPC_MAX_WAITCNT;
  	}
  
  	spin_lock_irqsave(&lpcdev->cycle_lock, flags);
  
  	writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
  	writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
  	writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
  
  	writesb(lpcdev->membase + LPC_REG_WDATA, buf, opcnt);
  
  	writel(LPC_REG_STARTUP_SIGNAL_START,
  	       lpcdev->membase + LPC_REG_STARTUP_SIGNAL);
  
  	/* whether the operation is finished */
  	ret = wait_lpc_idle(lpcdev->membase, waitcnt);
  
  	spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
  
  	return ret;
  }
  
  static unsigned long hisi_lpc_pio_to_addr(struct hisi_lpc_dev *lpcdev,
  					  unsigned long pio)
  {
  	return pio - lpcdev->io_host->io_start + lpcdev->io_host->hw_start;
  }
  
  /*
   * hisi_lpc_comm_in - input the data in a single operation
   * @hostdata: pointer to the device information relevant to LPC controller
   * @pio: the target I/O port address
   * @dwidth: the data length required to read from the target I/O port
   *
   * When success, data is returned. Otherwise, ~0 is returned.
   */
  static u32 hisi_lpc_comm_in(void *hostdata, unsigned long pio, size_t dwidth)
  {
  	struct hisi_lpc_dev *lpcdev = hostdata;
  	struct lpc_cycle_para iopara;
  	unsigned long addr;
  	u32 rd_data = 0;
  	int ret;
  
  	if (!lpcdev || !dwidth || dwidth > LPC_MAX_DWIDTH)
  		return ~0;
  
  	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
  
  	iopara.opflags = FG_INCRADDR_LPC;
  	iopara.csize = dwidth;
  
  	ret = hisi_lpc_target_in(lpcdev, &iopara, addr,
  				 (unsigned char *)&rd_data, dwidth);
  	if (ret)
  		return ~0;
  
  	return le32_to_cpu(rd_data);
  }
  
  /*
   * hisi_lpc_comm_out - output the data in a single operation
   * @hostdata: pointer to the device information relevant to LPC controller
   * @pio: the target I/O port address
   * @val: a value to be output from caller, maximum is four bytes
   * @dwidth: the data width required writing to the target I/O port
   *
   * This function corresponds to out(b,w,l) only.
   */
  static void hisi_lpc_comm_out(void *hostdata, unsigned long pio,
  			      u32 val, size_t dwidth)
  {
  	struct hisi_lpc_dev *lpcdev = hostdata;
  	struct lpc_cycle_para iopara;
  	const unsigned char *buf;
  	unsigned long addr;
  
  	if (!lpcdev || !dwidth || dwidth > LPC_MAX_DWIDTH)
  		return;
  
  	val = cpu_to_le32(val);
  
  	buf = (const unsigned char *)&val;
  	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
  
  	iopara.opflags = FG_INCRADDR_LPC;
  	iopara.csize = dwidth;
  
  	hisi_lpc_target_out(lpcdev, &iopara, addr, buf, dwidth);
  }
  
  /*
   * hisi_lpc_comm_ins - input the data in the buffer in multiple operations
   * @hostdata: pointer to the device information relevant to LPC controller
   * @pio: the target I/O port address
   * @buffer: a buffer where read/input data bytes are stored
   * @dwidth: the data width required writing to the target I/O port
   * @count: how many data units whose length is dwidth will be read
   *
   * When success, the data read back is stored in buffer pointed by buffer.
   * Returns 0 on success, -errno otherwise.
   */
  static u32 hisi_lpc_comm_ins(void *hostdata, unsigned long pio, void *buffer,
  			     size_t dwidth, unsigned int count)
  {
  	struct hisi_lpc_dev *lpcdev = hostdata;
  	unsigned char *buf = buffer;
  	struct lpc_cycle_para iopara;
  	unsigned long addr;
  
  	if (!lpcdev || !buf || !count || !dwidth || dwidth > LPC_MAX_DWIDTH)
  		return -EINVAL;
  
  	iopara.opflags = 0;
  	if (dwidth > 1)
  		iopara.opflags |= FG_INCRADDR_LPC;
  	iopara.csize = dwidth;
  
  	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
  
  	do {
  		int ret;
  
  		ret = hisi_lpc_target_in(lpcdev, &iopara, addr, buf, dwidth);
  		if (ret)
  			return ret;
  		buf += dwidth;
  	} while (--count);
  
  	return 0;
  }
  
  /*
   * hisi_lpc_comm_outs - output the data in the buffer in multiple operations
   * @hostdata: pointer to the device information relevant to LPC controller
   * @pio: the target I/O port address
   * @buffer: a buffer where write/output data bytes are stored
   * @dwidth: the data width required writing to the target I/O port
   * @count: how many data units whose length is dwidth will be written
   */
  static void hisi_lpc_comm_outs(void *hostdata, unsigned long pio,
  			       const void *buffer, size_t dwidth,
  			       unsigned int count)
  {
  	struct hisi_lpc_dev *lpcdev = hostdata;
  	struct lpc_cycle_para iopara;
  	const unsigned char *buf = buffer;
  	unsigned long addr;
  
  	if (!lpcdev || !buf || !count || !dwidth || dwidth > LPC_MAX_DWIDTH)
  		return;
  
  	iopara.opflags = 0;
  	if (dwidth > 1)
  		iopara.opflags |= FG_INCRADDR_LPC;
  	iopara.csize = dwidth;
  
  	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
  	do {
  		if (hisi_lpc_target_out(lpcdev, &iopara, addr, buf, dwidth))
  			break;
  		buf += dwidth;
  	} while (--count);
  }
  
  static const struct logic_pio_host_ops hisi_lpc_ops = {
  	.in = hisi_lpc_comm_in,
  	.out = hisi_lpc_comm_out,
  	.ins = hisi_lpc_comm_ins,
  	.outs = hisi_lpc_comm_outs,
  };

  #ifdef CONFIG_ACPI

  static int hisi_lpc_acpi_xlat_io_res(struct acpi_device *adev,
  				     struct acpi_device *host,
  				     struct resource *res)
  {
  	unsigned long sys_port;
  	resource_size_t len = resource_size(res);
  
  	sys_port = logic_pio_trans_hwaddr(&host->fwnode, res->start, len);
  	if (sys_port == ~0UL)
  		return -EFAULT;
  
  	res->start = sys_port;
  	res->end = sys_port + len;
  
  	return 0;
  }
  
  /*

   * Released firmware describes the IO port max address as 0x3fff, which is
   * the max host bus address. Fixup to a proper range. This will probably
   * never be fixed in firmware.
   */
  static void hisi_lpc_acpi_fixup_child_resource(struct device *hostdev,
  					       struct resource *r)
  {
  	if (r->end != 0x3fff)
  		return;
  
  	if (r->start == 0xe4)
  		r->end = 0xe4 + 0x04 - 1;
  	else if (r->start == 0x2f8)
  		r->end = 0x2f8 + 0x08 - 1;
  	else
  		dev_warn(hostdev, "unrecognised resource %pR to fixup, ignoring
  ",
  			 r);
  }
  
  /*

   * hisi_lpc_acpi_set_io_res - set the resources for a child

   * @child: the device node to be updated the I/O resource
   * @hostdev: the device node associated with host controller
   * @res: double pointer to be set to the address of translated resources
   * @num_res: pointer to variable to hold the number of translated resources
   *
   * Returns 0 when successful, and a negative value for failure.
   *
   * For a given host controller, each child device will have an associated
   * host-relative address resource.  This function will return the translated
   * logical PIO addresses for each child devices resources.
   */
  static int hisi_lpc_acpi_set_io_res(struct device *child,
  				    struct device *hostdev,
  				    const struct resource **res, int *num_res)
  {
  	struct acpi_device *adev;
  	struct acpi_device *host;
  	struct resource_entry *rentry;
  	LIST_HEAD(resource_list);
  	struct resource *resources;
  	int count;
  	int i;
  
  	if (!child || !hostdev)
  		return -EINVAL;
  
  	host = to_acpi_device(hostdev);
  	adev = to_acpi_device(child);
  
  	if (!adev->status.present) {
  		dev_dbg(child, "device is not present
  ");
  		return -EIO;
  	}
  
  	if (acpi_device_enumerated(adev)) {
  		dev_dbg(child, "has been enumerated
  ");
  		return -EIO;
  	}
  
  	/*
  	 * The following code segment to retrieve the resources is common to
  	 * acpi_create_platform_device(), so consider a common helper function
  	 * in future.
  	 */
  	count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  	if (count <= 0) {
  		dev_dbg(child, "failed to get resources
  ");
  		return count ? count : -EIO;
  	}
  
  	resources = devm_kcalloc(hostdev, count, sizeof(*resources),
  				 GFP_KERNEL);
  	if (!resources) {
  		dev_warn(hostdev, "could not allocate memory for %d resources
  ",
  			 count);
  		acpi_dev_free_resource_list(&resource_list);
  		return -ENOMEM;
  	}
  	count = 0;

  	list_for_each_entry(rentry, &resource_list, node) {
  		resources[count] = *rentry->res;
  		hisi_lpc_acpi_fixup_child_resource(hostdev, &resources[count]);
  		count++;
  	}

  
  	acpi_dev_free_resource_list(&resource_list);
  
  	/* translate the I/O resources */
  	for (i = 0; i < count; i++) {
  		int ret;
  
  		if (!(resources[i].flags & IORESOURCE_IO))
  			continue;
  		ret = hisi_lpc_acpi_xlat_io_res(adev, host, &resources[i]);
  		if (ret) {
  			dev_err(child, "translate IO range %pR failed (%d)
  ",
  				&resources[i], ret);
  			return ret;
  		}
  	}
  	*res = resources;
  	*num_res = count;
  
  	return 0;
  }

  static int hisi_lpc_acpi_remove_subdev(struct device *dev, void *unused)
  {
  	platform_device_unregister(to_platform_device(dev));
  	return 0;
  }
  
  struct hisi_lpc_acpi_cell {
  	const char *hid;
  	const char *name;
  	void *pdata;
  	size_t pdata_size;
  };

  static void hisi_lpc_acpi_remove(struct device *hostdev)
  {
  	struct acpi_device *adev = ACPI_COMPANION(hostdev);
  	struct acpi_device *child;
  
  	device_for_each_child(hostdev, NULL, hisi_lpc_acpi_remove_subdev);
  
  	list_for_each_entry(child, &adev->children, node)
  		acpi_device_clear_enumerated(child);
  }

  /*
   * hisi_lpc_acpi_probe - probe children for ACPI FW
   * @hostdev: LPC host device pointer
   *
   * Returns 0 when successful, and a negative value for failure.
   *

   * Create a platform device per child, fixing up the resources
   * from bus addresses to Logical PIO addresses.
   *

   */
  static int hisi_lpc_acpi_probe(struct device *hostdev)
  {
  	struct acpi_device *adev = ACPI_COMPANION(hostdev);

  	struct acpi_device *child;

  	int ret;

  	/* Only consider the children of the host */
  	list_for_each_entry(child, &adev->children, node) {

  		const char *hid = acpi_device_hid(child);
  		const struct hisi_lpc_acpi_cell *cell;
  		struct platform_device *pdev;

  		const struct resource *res;

  		bool found = false;

  		int num_res;
  
  		ret = hisi_lpc_acpi_set_io_res(&child->dev, &adev->dev, &res,
  					       &num_res);

  		if (ret) {

  			dev_warn(hostdev, "set resource fail (%d)
  ", ret);

  			goto fail;
  		}
  
  		cell = (struct hisi_lpc_acpi_cell []){
  			/* ipmi */
  			{
  				.hid = "IPI0001",
  				.name = "hisi-lpc-ipmi",
  			},

  			/* 8250-compatible uart */
  			{
  				.hid = "HISI1031",
  				.name = "serial8250",
  				.pdata = (struct plat_serial8250_port []) {
  					{
  						.iobase = res->start,
  						.uartclk = 1843200,
  						.iotype = UPIO_PORT,
  						.flags = UPF_BOOT_AUTOCONF,
  					},
  					{}
  				},
  				.pdata_size = 2 *
  					sizeof(struct plat_serial8250_port),
  			},

  			{}
  		};
  
  		for (; cell && cell->name; cell++) {
  			if (!strcmp(cell->hid, hid)) {
  				found = true;
  				break;
  			}

  		}

  
  		if (!found) {
  			dev_warn(hostdev,

  				 "could not find cell for child device (%s), discarding
  ",

  				 hid);

  			continue;

  		}
  
  		pdev = platform_device_alloc(cell->name, PLATFORM_DEVID_AUTO);
  		if (!pdev) {
  			ret = -ENOMEM;
  			goto fail;
  		}
  
  		pdev->dev.parent = hostdev;
  		ACPI_COMPANION_SET(&pdev->dev, child);
  
  		ret = platform_device_add_resources(pdev, res, num_res);
  		if (ret)
  			goto fail;
  
  		ret = platform_device_add_data(pdev, cell->pdata,
  					       cell->pdata_size);
  		if (ret)
  			goto fail;
  
  		ret = platform_device_add(pdev);
  		if (ret)
  			goto fail;
  
  		acpi_device_set_enumerated(child);

  	}
  
  	return 0;

  
  fail:

  	hisi_lpc_acpi_remove(hostdev);

  	return ret;

  }
  
  static const struct acpi_device_id hisi_lpc_acpi_match[] = {
  	{"HISI0191"},
  	{}
  };
  #else
  static int hisi_lpc_acpi_probe(struct device *dev)
  {
  	return -ENODEV;
  }

  
  static void hisi_lpc_acpi_remove(struct device *hostdev)
  {
  }

  #endif // CONFIG_ACPI

  /*
   * hisi_lpc_probe - the probe callback function for hisi lpc host,
   *		   will finish all the initialization.
   * @pdev: the platform device corresponding to hisi lpc host
   *
   * Returns 0 on success, non-zero on fail.
   */
  static int hisi_lpc_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct acpi_device *acpi_device = ACPI_COMPANION(dev);
  	struct logic_pio_hwaddr *range;
  	struct hisi_lpc_dev *lpcdev;
  	resource_size_t io_end;
  	struct resource *res;
  	int ret;
  
  	lpcdev = devm_kzalloc(dev, sizeof(*lpcdev), GFP_KERNEL);
  	if (!lpcdev)
  		return -ENOMEM;
  
  	spin_lock_init(&lpcdev->cycle_lock);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	lpcdev->membase = devm_ioremap_resource(dev, res);
  	if (IS_ERR(lpcdev->membase))
  		return PTR_ERR(lpcdev->membase);
  
  	range = devm_kzalloc(dev, sizeof(*range), GFP_KERNEL);
  	if (!range)
  		return -ENOMEM;
  
  	range->fwnode = dev->fwnode;
  	range->flags = LOGIC_PIO_INDIRECT;
  	range->size = PIO_INDIRECT_SIZE;

  	range->hostdata = lpcdev;
  	range->ops = &hisi_lpc_ops;
  	lpcdev->io_host = range;

  
  	ret = logic_pio_register_range(range);
  	if (ret) {
  		dev_err(dev, "register IO range failed (%d)!
  ", ret);
  		return ret;
  	}

  
  	/* register the LPC host PIO resources */

  	if (acpi_device)
  		ret = hisi_lpc_acpi_probe(dev);
  	else

  		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);

  	if (ret) {
  		logic_pio_unregister_range(range);

  		return ret;

  	}

  	dev_set_drvdata(dev, lpcdev);

  	io_end = lpcdev->io_host->io_start + lpcdev->io_host->size;
  	dev_info(dev, "registered range [%pa - %pa]
  ",
  		 &lpcdev->io_host->io_start, &io_end);
  
  	return ret;
  }

  static int hisi_lpc_remove(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct acpi_device *acpi_device = ACPI_COMPANION(dev);
  	struct hisi_lpc_dev *lpcdev = dev_get_drvdata(dev);
  	struct logic_pio_hwaddr *range = lpcdev->io_host;
  
  	if (acpi_device)
  		hisi_lpc_acpi_remove(dev);
  	else
  		of_platform_depopulate(dev);
  
  	logic_pio_unregister_range(range);
  
  	return 0;
  }

  static const struct of_device_id hisi_lpc_of_match[] = {
  	{ .compatible = "hisilicon,hip06-lpc", },
  	{ .compatible = "hisilicon,hip07-lpc", },
  	{}
  };
  
  static struct platform_driver hisi_lpc_driver = {
  	.driver = {
  		.name           = DRV_NAME,
  		.of_match_table = hisi_lpc_of_match,

  		.acpi_match_table = ACPI_PTR(hisi_lpc_acpi_match),

  	},
  	.probe = hisi_lpc_probe,

  	.remove = hisi_lpc_remove,

  };
  builtin_platform_driver(hisi_lpc_driver);