// SPDX-License-Identifier: GPL-2.0-only
//
// HiSilicon SPI NOR V3XX Flash Controller Driver for hi16xx chipsets
//
// Copyright (c) 2019 HiSilicon Technologies Co., Ltd.
// Author: John Garry <john.garry@huawei.com>

#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/dmi.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>

#define HISI_SFC_V3XX_VERSION (0x1f8)

#define HISI_SFC_V3XX_GLB_CFG (0x100)
#define HISI_SFC_V3XX_GLB_CFG_CS0_ADDR_MODE BIT(2)
#define HISI_SFC_V3XX_RAW_INT_STAT (0x120)
#define HISI_SFC_V3XX_INT_STAT (0x124)
#define HISI_SFC_V3XX_INT_MASK (0x128)
#define HISI_SFC_V3XX_INT_CLR (0x12c)
#define HISI_SFC_V3XX_CMD_CFG (0x300)
#define HISI_SFC_V3XX_CMD_CFG_DATA_CNT_OFF 9
#define HISI_SFC_V3XX_CMD_CFG_RW_MSK BIT(8)
#define HISI_SFC_V3XX_CMD_CFG_DATA_EN_MSK BIT(7)
#define HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF 4
#define HISI_SFC_V3XX_CMD_CFG_ADDR_EN_MSK BIT(3)
#define HISI_SFC_V3XX_CMD_CFG_CS_SEL_OFF 1
#define HISI_SFC_V3XX_CMD_CFG_START_MSK BIT(0)
#define HISI_SFC_V3XX_CMD_INS (0x308)
#define HISI_SFC_V3XX_CMD_ADDR (0x30c)
#define HISI_SFC_V3XX_CMD_DATABUF0 (0x400)

/* Common definition of interrupt bit masks */
#define HISI_SFC_V3XX_INT_MASK_ALL (0x1ff)      /* all the masks */
#define HISI_SFC_V3XX_INT_MASK_CPLT BIT(0)      /* command execution complete */
#define HISI_SFC_V3XX_INT_MASK_PP_ERR BIT(2)    /* page program error */
#define HISI_SFC_V3XX_INT_MASK_IACCES BIT(5)    /* error visiting inaccessible/
                                                 * protected address
                                                 */

/* IO Mode definition in HISI_SFC_V3XX_CMD_CFG */
#define HISI_SFC_V3XX_STD (0 << 17)
#define HISI_SFC_V3XX_DIDO (1 << 17)
#define HISI_SFC_V3XX_DIO (2 << 17)
#define HISI_SFC_V3XX_FULL_DIO (3 << 17)
#define HISI_SFC_V3XX_QIQO (5 << 17)
#define HISI_SFC_V3XX_QIO (6 << 17)
#define HISI_SFC_V3XX_FULL_QIO (7 << 17)

/*
 * The IO modes lookup table. hisi_sfc_v3xx_io_modes[(z - 1) / 2][y / 2][x / 2]
 * stands for x-y-z mode, as described in SFDP terminology. -EIO indicates
 * an invalid mode.
 */
static const int hisi_sfc_v3xx_io_modes[2][3][3] = {
        {
                { HISI_SFC_V3XX_DIDO, HISI_SFC_V3XX_DIDO, HISI_SFC_V3XX_DIDO },
                { HISI_SFC_V3XX_DIO, HISI_SFC_V3XX_FULL_DIO, -EIO },
                { -EIO, -EIO, -EIO },
        },
        {
                { HISI_SFC_V3XX_QIQO, HISI_SFC_V3XX_QIQO, HISI_SFC_V3XX_QIQO },
                { -EIO, -EIO, -EIO },
                { HISI_SFC_V3XX_QIO, -EIO, HISI_SFC_V3XX_FULL_QIO },
        },
};

struct hisi_sfc_v3xx_host {
        struct device *dev;
        void __iomem *regbase;
        int max_cmd_dword;
        struct completion *completion;
        u8 address_mode;
        int irq;
};

static void hisi_sfc_v3xx_disable_int(struct hisi_sfc_v3xx_host *host)
{
        writel(0, host->regbase + HISI_SFC_V3XX_INT_MASK);
}

static void hisi_sfc_v3xx_enable_int(struct hisi_sfc_v3xx_host *host)
{
        writel(HISI_SFC_V3XX_INT_MASK_ALL, host->regbase + HISI_SFC_V3XX_INT_MASK);
}

static void hisi_sfc_v3xx_clear_int(struct hisi_sfc_v3xx_host *host)
{
        writel(HISI_SFC_V3XX_INT_MASK_ALL, host->regbase + HISI_SFC_V3XX_INT_CLR);
}

/*
 * The interrupt status register indicates whether an error occurs
 * after per operation. Check it, and clear the interrupts for
 * next time judgement.
 */
static int hisi_sfc_v3xx_handle_completion(struct hisi_sfc_v3xx_host *host)
{
        u32 reg;

        reg = readl(host->regbase + HISI_SFC_V3XX_RAW_INT_STAT);
        hisi_sfc_v3xx_clear_int(host);

        if (reg & HISI_SFC_V3XX_INT_MASK_IACCES) {
                dev_err(host->dev, "fail to access protected address\n");
                return -EIO;
        }

        if (reg & HISI_SFC_V3XX_INT_MASK_PP_ERR) {
                dev_err(host->dev, "page program operation failed\n");
                return -EIO;
        }

        /*
         * The other bits of the interrupt registers is not currently
         * used and probably not be triggered in this driver. When it
         * happens, we regard it as an unsupported error here.
         */
        if (!(reg & HISI_SFC_V3XX_INT_MASK_CPLT)) {
                dev_err(host->dev, "unsupported error occurred, status=0x%x\n", reg);
                return -EIO;
        }

        return 0;
}

#define HISI_SFC_V3XX_WAIT_TIMEOUT_US           1000000
#define HISI_SFC_V3XX_WAIT_POLL_INTERVAL_US     10

static int hisi_sfc_v3xx_wait_cmd_idle(struct hisi_sfc_v3xx_host *host)
{
        u32 reg;

        return readl_poll_timeout(host->regbase + HISI_SFC_V3XX_CMD_CFG, reg,
                                  !(reg & HISI_SFC_V3XX_CMD_CFG_START_MSK),
                                  HISI_SFC_V3XX_WAIT_POLL_INTERVAL_US,
                                  HISI_SFC_V3XX_WAIT_TIMEOUT_US);
}

static int hisi_sfc_v3xx_adjust_op_size(struct spi_mem *mem,
                                        struct spi_mem_op *op)
{
        struct spi_device *spi = mem->spi;
        struct hisi_sfc_v3xx_host *host;
        uintptr_t addr = (uintptr_t)op->data.buf.in;
        int max_byte_count;

        host = spi_controller_get_devdata(spi->controller);

        max_byte_count = host->max_cmd_dword * 4;

        if (!IS_ALIGNED(addr, 4) && op->data.nbytes >= 4)
                op->data.nbytes = 4 - (addr % 4);
        else if (op->data.nbytes > max_byte_count)
                op->data.nbytes = max_byte_count;

        return 0;
}

/*
 * The controller only supports Standard SPI mode, Dual mode and
 * Quad mode. Double sanitize the ops here to avoid OOB access.
 */
static bool hisi_sfc_v3xx_supports_op(struct spi_mem *mem,
                                      const struct spi_mem_op *op)
{
        struct spi_device *spi = mem->spi;
        struct hisi_sfc_v3xx_host *host;

        host = spi_controller_get_devdata(spi->controller);

        if (op->data.buswidth > 4 || op->dummy.buswidth > 4 ||
            op->addr.buswidth > 4 || op->cmd.buswidth > 4)
                return false;

        if (op->addr.nbytes != host->address_mode && op->addr.nbytes)
                return false;

        return spi_mem_default_supports_op(mem, op);
}

/*
 * memcpy_{to,from}io doesn't gurantee 32b accesses - which we require for the
 * DATABUF registers -so use __io{read,write}32_copy when possible. For
 * trailing bytes, copy them byte-by-byte from the DATABUF register, as we
 * can't clobber outside the source/dest buffer.
 *
 * For efficient data read/write, we try to put any start 32b unaligned data
 * into a separate transaction in hisi_sfc_v3xx_adjust_op_size().
 */
static void hisi_sfc_v3xx_read_databuf(struct hisi_sfc_v3xx_host *host,
                                       u8 *to, unsigned int len)
{
        void __iomem *from;
        int i;

        from = host->regbase + HISI_SFC_V3XX_CMD_DATABUF0;

        if (IS_ALIGNED((uintptr_t)to, 4)) {
                int words = len / 4;

                __ioread32_copy(to, from, words);

                len -= words * 4;
                if (len) {
                        u32 val;

                        to += words * 4;
                        from += words * 4;

                        val = __raw_readl(from);

                        for (i = 0; i < len; i++, val >>= 8, to++)
                                *to = (u8)val;
                }
        } else {
                for (i = 0; i < DIV_ROUND_UP(len, 4); i++, from += 4) {
                        u32 val = __raw_readl(from);
                        int j;

                        for (j = 0; j < 4 && (j + (i * 4) < len);
                             to++, val >>= 8, j++)
                                *to = (u8)val;
                }
        }
}

static void hisi_sfc_v3xx_write_databuf(struct hisi_sfc_v3xx_host *host,
                                        const u8 *from, unsigned int len)
{
        void __iomem *to;
        int i;

        to = host->regbase + HISI_SFC_V3XX_CMD_DATABUF0;

        if (IS_ALIGNED((uintptr_t)from, 4)) {
                int words = len / 4;

                __iowrite32_copy(to, from, words);

                len -= words * 4;
                if (len) {
                        u32 val = 0;

                        to += words * 4;
                        from += words * 4;

                        for (i = 0; i < len; i++, from++)
                                val |= *from << i * 8;
                        __raw_writel(val, to);
                }

        } else {
                for (i = 0; i < DIV_ROUND_UP(len, 4); i++, to += 4) {
                        u32 val = 0;
                        int j;

                        for (j = 0; j < 4 && (j + (i * 4) < len);
                             from++, j++)
                                val |= *from << j * 8;
                        __raw_writel(val, to);
                }
        }
}

static int hisi_sfc_v3xx_start_bus(struct hisi_sfc_v3xx_host *host,
                                   const struct spi_mem_op *op,
                                   u8 chip_select)
{
        int len = op->data.nbytes, buswidth_mode;
        u32 config = 0;

        if (op->addr.nbytes)
                config |= HISI_SFC_V3XX_CMD_CFG_ADDR_EN_MSK;

        if (op->data.buswidth == 0 || op->data.buswidth == 1) {
                buswidth_mode = HISI_SFC_V3XX_STD;
        } else {
                int data_idx, addr_idx, cmd_idx;

                data_idx = (op->data.buswidth - 1) / 2;
                addr_idx = op->addr.buswidth / 2;
                cmd_idx = op->cmd.buswidth / 2;
                buswidth_mode = hisi_sfc_v3xx_io_modes[data_idx][addr_idx][cmd_idx];
        }
        if (buswidth_mode < 0)
                return buswidth_mode;
        config |= buswidth_mode;

        if (op->data.dir != SPI_MEM_NO_DATA) {
                config |= (len - 1) << HISI_SFC_V3XX_CMD_CFG_DATA_CNT_OFF;
                config |= HISI_SFC_V3XX_CMD_CFG_DATA_EN_MSK;
        }

        if (op->data.dir == SPI_MEM_DATA_IN)
                config |= HISI_SFC_V3XX_CMD_CFG_RW_MSK;

        config |= op->dummy.nbytes << HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF |
                  chip_select << HISI_SFC_V3XX_CMD_CFG_CS_SEL_OFF |
                  HISI_SFC_V3XX_CMD_CFG_START_MSK;

        writel(op->addr.val, host->regbase + HISI_SFC_V3XX_CMD_ADDR);
        writel(op->cmd.opcode, host->regbase + HISI_SFC_V3XX_CMD_INS);

        writel(config, host->regbase + HISI_SFC_V3XX_CMD_CFG);

        return 0;
}

static int hisi_sfc_v3xx_generic_exec_op(struct hisi_sfc_v3xx_host *host,
                                         const struct spi_mem_op *op,
                                         u8 chip_select)
{
        DECLARE_COMPLETION_ONSTACK(done);
        int ret;

        if (host->irq) {
                host->completion = &done;
                hisi_sfc_v3xx_enable_int(host);
        }

        if (op->data.dir == SPI_MEM_DATA_OUT)
                hisi_sfc_v3xx_write_databuf(host, op->data.buf.out, op->data.nbytes);

        ret = hisi_sfc_v3xx_start_bus(host, op, chip_select);
        if (ret)
                return ret;

        if (host->irq) {
                ret = wait_for_completion_timeout(host->completion,
                                                  usecs_to_jiffies(HISI_SFC_V3XX_WAIT_TIMEOUT_US));
                if (!ret)
                        ret = -ETIMEDOUT;
                else
                        ret = 0;

                hisi_sfc_v3xx_disable_int(host);
                synchronize_irq(host->irq);
                host->completion = NULL;
        } else {
                ret = hisi_sfc_v3xx_wait_cmd_idle(host);
        }
        if (hisi_sfc_v3xx_handle_completion(host) || ret)
                return -EIO;

        if (op->data.dir == SPI_MEM_DATA_IN)
                hisi_sfc_v3xx_read_databuf(host, op->data.buf.in, op->data.nbytes);

        return 0;
}

static int hisi_sfc_v3xx_exec_op(struct spi_mem *mem,
                                 const struct spi_mem_op *op)
{
        struct hisi_sfc_v3xx_host *host;
        struct spi_device *spi = mem->spi;
        u8 chip_select = spi_get_chipselect(spi, 0);

        host = spi_controller_get_devdata(spi->controller);

        return hisi_sfc_v3xx_generic_exec_op(host, op, chip_select);
}

static const struct spi_controller_mem_ops hisi_sfc_v3xx_mem_ops = {
        .adjust_op_size = hisi_sfc_v3xx_adjust_op_size,
        .supports_op = hisi_sfc_v3xx_supports_op,
        .exec_op = hisi_sfc_v3xx_exec_op,
};

static irqreturn_t hisi_sfc_v3xx_isr(int irq, void *data)
{
        struct hisi_sfc_v3xx_host *host = data;
        u32 reg;

        reg = readl(host->regbase + HISI_SFC_V3XX_INT_STAT);
        if (!reg)
                return IRQ_NONE;

        hisi_sfc_v3xx_disable_int(host);

        complete(host->completion);

        return IRQ_HANDLED;
}

static int hisi_sfc_v3xx_buswidth_override_bits;

/*
 * ACPI FW does not allow us to currently set the device buswidth, so quirk it
 * depending on the board.
 */
static int __init hisi_sfc_v3xx_dmi_quirk(const struct dmi_system_id *d)
{
        hisi_sfc_v3xx_buswidth_override_bits = SPI_RX_QUAD | SPI_TX_QUAD;

        return 0;
}

static const struct dmi_system_id hisi_sfc_v3xx_dmi_quirk_table[]  = {
        {
        .callback = hisi_sfc_v3xx_dmi_quirk,
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Huawei"),
                DMI_MATCH(DMI_PRODUCT_NAME, "D06"),
        },
        },
        {
        .callback = hisi_sfc_v3xx_dmi_quirk,
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Huawei"),
                DMI_MATCH(DMI_PRODUCT_NAME, "TaiShan 2280 V2"),
        },
        },
        {
        .callback = hisi_sfc_v3xx_dmi_quirk,
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Huawei"),
                DMI_MATCH(DMI_PRODUCT_NAME, "TaiShan 200 (Model 2280)"),
        },
        },
        {}
};

static int hisi_sfc_v3xx_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct hisi_sfc_v3xx_host *host;
        struct spi_controller *ctlr;
        u32 version, glb_config;
        int ret;

        ctlr = spi_alloc_host(&pdev->dev, sizeof(*host));
        if (!ctlr)
                return -ENOMEM;

        ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD |
                          SPI_TX_DUAL | SPI_TX_QUAD;

        ctlr->buswidth_override_bits = hisi_sfc_v3xx_buswidth_override_bits;

        host = spi_controller_get_devdata(ctlr);
        host->dev = dev;

        platform_set_drvdata(pdev, host);

        host->regbase = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(host->regbase)) {
                ret = PTR_ERR(host->regbase);
                goto err_put_host;
        }

        host->irq = platform_get_irq_optional(pdev, 0);
        if (host->irq == -EPROBE_DEFER) {
                ret = -EPROBE_DEFER;
                goto err_put_host;
        }

        hisi_sfc_v3xx_disable_int(host);

        if (host->irq > 0) {
                ret = devm_request_irq(dev, host->irq, hisi_sfc_v3xx_isr, 0,
                                       "hisi-sfc-v3xx", host);

                if (ret) {
                        dev_err(dev, "failed to request irq%d, ret = %d\n", host->irq, ret);
                        host->irq = 0;
                }
        } else {
                host->irq = 0;
        }

        ctlr->bus_num = -1;
        ctlr->num_chipselect = 1;
        ctlr->mem_ops = &hisi_sfc_v3xx_mem_ops;

        /*
         * The address mode of the controller is either 3 or 4,
         * which is indicated by the address mode bit in
         * the global config register. The register is read only
         * for the OS driver.
         */
        glb_config = readl(host->regbase + HISI_SFC_V3XX_GLB_CFG);
        if (glb_config & HISI_SFC_V3XX_GLB_CFG_CS0_ADDR_MODE)
                host->address_mode = 4;
        else
                host->address_mode = 3;

        version = readl(host->regbase + HISI_SFC_V3XX_VERSION);

        if (version >= 0x351)
                host->max_cmd_dword = 64;
        else
                host->max_cmd_dword = 16;

        ret = devm_spi_register_controller(dev, ctlr);
        if (ret)
                goto err_put_host;

        dev_info(&pdev->dev, "hw version 0x%x, %s mode.\n",
                 version, host->irq ? "irq" : "polling");

        return 0;

err_put_host:
        spi_controller_put(ctlr);
        return ret;
}

static const struct acpi_device_id hisi_sfc_v3xx_acpi_ids[] = {
        {"HISI0341", 0},
        {}
};
MODULE_DEVICE_TABLE(acpi, hisi_sfc_v3xx_acpi_ids);

static struct platform_driver hisi_sfc_v3xx_spi_driver = {
        .driver = {
                .name   = "hisi-sfc-v3xx",
                .acpi_match_table = hisi_sfc_v3xx_acpi_ids,
        },
        .probe  = hisi_sfc_v3xx_probe,
};

static int __init hisi_sfc_v3xx_spi_init(void)
{
        dmi_check_system(hisi_sfc_v3xx_dmi_quirk_table);

        return platform_driver_register(&hisi_sfc_v3xx_spi_driver);
}

static void __exit hisi_sfc_v3xx_spi_exit(void)
{
        platform_driver_unregister(&hisi_sfc_v3xx_spi_driver);
}

module_init(hisi_sfc_v3xx_spi_init);
module_exit(hisi_sfc_v3xx_spi_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Garry <john.garry@huawei.com>");
MODULE_DESCRIPTION("HiSilicon SPI NOR V3XX Flash Controller Driver for hi16xx chipsets");