// 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;
}

/*
 * 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\n");
                return -EIO;
        }

        if (acpi_device_enumerated(adev)) {
                dev_dbg(child, "has been enumerated\n");
                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\n");
                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\n",
                         count);
                acpi_dev_free_resource_list(&resource_list);
                return -ENOMEM;
        }
        count = 0;
        list_for_each_entry(rentry, &resource_list, node)
                resources[count++] = *rentry->res;

        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)\n",
                                &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)\n", 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\n",
                                 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)!\n", 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]\n",
                 &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);