// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * X-Gene SLIMpro I2C Driver
 *
 * Copyright (c) 2014, Applied Micro Circuits Corporation
 * Author: Feng Kan <fkan@apm.com>
 * Author: Hieu Le <hnle@apm.com>
 *
 * This driver provides support for X-Gene SLIMpro I2C device access
 * using the APM X-Gene SLIMpro mailbox driver.
 */
#include <acpi/pcc.h>
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#define MAILBOX_OP_TIMEOUT              1000    /* Operation time out in ms */
#define MAILBOX_I2C_INDEX               0
#define SLIMPRO_IIC_BUS                 1       /* Use I2C bus 1 only */

#define SMBUS_CMD_LEN                   1
#define BYTE_DATA                       1
#define WORD_DATA                       2
#define BLOCK_DATA                      3

#define SLIMPRO_IIC_I2C_PROTOCOL        0
#define SLIMPRO_IIC_SMB_PROTOCOL        1

#define SLIMPRO_IIC_READ                0
#define SLIMPRO_IIC_WRITE               1

#define IIC_SMB_WITHOUT_DATA_LEN        0
#define IIC_SMB_WITH_DATA_LEN           1

#define SLIMPRO_DEBUG_MSG               0
#define SLIMPRO_MSG_TYPE_SHIFT          28
#define SLIMPRO_DBG_SUBTYPE_I2C1READ    4
#define SLIMPRO_DBGMSG_TYPE_SHIFT       24
#define SLIMPRO_DBGMSG_TYPE_MASK        0x0F000000U
#define SLIMPRO_IIC_DEV_SHIFT           23
#define SLIMPRO_IIC_DEV_MASK            0x00800000U
#define SLIMPRO_IIC_DEVID_SHIFT         13
#define SLIMPRO_IIC_DEVID_MASK          0x007FE000U
#define SLIMPRO_IIC_RW_SHIFT            12
#define SLIMPRO_IIC_RW_MASK             0x00001000U
#define SLIMPRO_IIC_PROTO_SHIFT         11
#define SLIMPRO_IIC_PROTO_MASK          0x00000800U
#define SLIMPRO_IIC_ADDRLEN_SHIFT       8
#define SLIMPRO_IIC_ADDRLEN_MASK        0x00000700U
#define SLIMPRO_IIC_DATALEN_SHIFT       0
#define SLIMPRO_IIC_DATALEN_MASK        0x000000FFU

/*
 * SLIMpro I2C message encode
 *
 * dev          - Controller number (0-based)
 * chip         - I2C chip address
 * op           - SLIMPRO_IIC_READ or SLIMPRO_IIC_WRITE
 * proto        - SLIMPRO_IIC_SMB_PROTOCOL or SLIMPRO_IIC_I2C_PROTOCOL
 * addrlen      - Length of the address field
 * datalen      - Length of the data field
 */
#define SLIMPRO_IIC_ENCODE_MSG(dev, chip, op, proto, addrlen, datalen) \
        ((SLIMPRO_DEBUG_MSG << SLIMPRO_MSG_TYPE_SHIFT) | \
        ((SLIMPRO_DBG_SUBTYPE_I2C1READ << SLIMPRO_DBGMSG_TYPE_SHIFT) & \
        SLIMPRO_DBGMSG_TYPE_MASK) | \
        ((dev << SLIMPRO_IIC_DEV_SHIFT) & SLIMPRO_IIC_DEV_MASK) | \
        ((chip << SLIMPRO_IIC_DEVID_SHIFT) & SLIMPRO_IIC_DEVID_MASK) | \
        ((op << SLIMPRO_IIC_RW_SHIFT) & SLIMPRO_IIC_RW_MASK) | \
        ((proto << SLIMPRO_IIC_PROTO_SHIFT) & SLIMPRO_IIC_PROTO_MASK) | \
        ((addrlen << SLIMPRO_IIC_ADDRLEN_SHIFT) & SLIMPRO_IIC_ADDRLEN_MASK) | \
        ((datalen << SLIMPRO_IIC_DATALEN_SHIFT) & SLIMPRO_IIC_DATALEN_MASK))

#define SLIMPRO_MSG_TYPE(v)             (((v) & 0xF0000000) >> 28)

/*
 * Encode for upper address for block data
 */
#define SLIMPRO_IIC_ENCODE_FLAG_BUFADDR                 0x80000000
#define SLIMPRO_IIC_ENCODE_FLAG_WITH_DATA_LEN(a)        ((u32) (((a) << 30) \
                                                                & 0x40000000))
#define SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(a)             ((u32) (((a) >> 12) \
                                                                & 0x3FF00000))
#define SLIMPRO_IIC_ENCODE_ADDR(a)                      ((a) & 0x000FFFFF)

#define SLIMPRO_IIC_MSG_DWORD_COUNT                     3

struct slimpro_i2c_dev {
        struct i2c_adapter adapter;
        struct device *dev;
        struct mbox_chan *mbox_chan;
        struct pcc_mbox_chan *pcc_chan;
        struct mbox_client mbox_client;
        int mbox_idx;
        struct completion rd_complete;
        u8 dma_buffer[I2C_SMBUS_BLOCK_MAX + 1]; /* dma_buffer[0] is used for length */
        u32 *resp_msg;
};

#define to_slimpro_i2c_dev(cl)  \
                container_of(cl, struct slimpro_i2c_dev, mbox_client)

enum slimpro_i2c_version {
        XGENE_SLIMPRO_I2C_V1 = 0,
        XGENE_SLIMPRO_I2C_V2 = 1,
};

/*
 * This function tests and clears a bitmask then returns its old value
 */
static u16 xgene_word_tst_and_clr(u16 *addr, u16 mask)
{
        u16 ret, val;

        val = le16_to_cpu(READ_ONCE(*addr));
        ret = val & mask;
        val &= ~mask;
        WRITE_ONCE(*addr, cpu_to_le16(val));

        return ret;
}

static void slimpro_i2c_rx_cb(struct mbox_client *cl, void *mssg)
{
        struct slimpro_i2c_dev *ctx = to_slimpro_i2c_dev(cl);

        /*
         * Response message format:
         * mssg[0] is the return code of the operation
         * mssg[1] is the first data word
         * mssg[2] is NOT used
         */
        if (ctx->resp_msg)
                *ctx->resp_msg = ((u32 *)mssg)[1];

        if (ctx->mbox_client.tx_block)
                complete(&ctx->rd_complete);
}

static void slimpro_i2c_pcc_rx_cb(struct mbox_client *cl, void *msg)
{
        struct slimpro_i2c_dev *ctx = to_slimpro_i2c_dev(cl);
        struct acpi_pcct_shared_memory __iomem *generic_comm_base =
                                                        ctx->pcc_chan->shmem;

        /* Check if platform sends interrupt */
        if (!xgene_word_tst_and_clr(&generic_comm_base->status,
                                    PCC_STATUS_SCI_DOORBELL))
                return;

        if (xgene_word_tst_and_clr(&generic_comm_base->status,
                                   PCC_STATUS_CMD_COMPLETE)) {
                msg = generic_comm_base + 1;

                /* Response message msg[1] contains the return value. */
                if (ctx->resp_msg)
                        *ctx->resp_msg = ((u32 *)msg)[1];

                complete(&ctx->rd_complete);
        }
}

static void slimpro_i2c_pcc_tx_prepare(struct slimpro_i2c_dev *ctx, u32 *msg)
{
        struct acpi_pcct_shared_memory __iomem *generic_comm_base =
                                                        ctx->pcc_chan->shmem;
        u32 *ptr = (void *)(generic_comm_base + 1);
        u16 status;
        int i;

        WRITE_ONCE(generic_comm_base->signature,
                   cpu_to_le32(PCC_SIGNATURE | ctx->mbox_idx));

        WRITE_ONCE(generic_comm_base->command,
                   cpu_to_le16(SLIMPRO_MSG_TYPE(msg[0]) | PCC_CMD_GENERATE_DB_INTR));

        status = le16_to_cpu(READ_ONCE(generic_comm_base->status));
        status &= ~PCC_STATUS_CMD_COMPLETE;
        WRITE_ONCE(generic_comm_base->status, cpu_to_le16(status));

        /* Copy the message to the PCC comm space */
        for (i = 0; i < SLIMPRO_IIC_MSG_DWORD_COUNT; i++)
                WRITE_ONCE(ptr[i], cpu_to_le32(msg[i]));
}

static int start_i2c_msg_xfer(struct slimpro_i2c_dev *ctx)
{
        if (ctx->mbox_client.tx_block || !acpi_disabled) {
                if (!wait_for_completion_timeout(&ctx->rd_complete,
                                                 msecs_to_jiffies(MAILBOX_OP_TIMEOUT)))
                        return -ETIMEDOUT;
        }

        /* Check of invalid data or no device */
        if (*ctx->resp_msg == 0xffffffff)
                return -ENODEV;

        return 0;
}

static int slimpro_i2c_send_msg(struct slimpro_i2c_dev *ctx,
                                u32 *msg,
                                u32 *data)
{
        int rc;

        ctx->resp_msg = data;

        if (!acpi_disabled) {
                reinit_completion(&ctx->rd_complete);
                slimpro_i2c_pcc_tx_prepare(ctx, msg);
        }

        rc = mbox_send_message(ctx->mbox_chan, msg);
        if (rc < 0)
                goto err;

        rc = start_i2c_msg_xfer(ctx);

err:
        if (!acpi_disabled)
                mbox_chan_txdone(ctx->mbox_chan, 0);

        ctx->resp_msg = NULL;

        return rc;
}

static int slimpro_i2c_rd(struct slimpro_i2c_dev *ctx, u32 chip,
                          u32 addr, u32 addrlen, u32 protocol,
                          u32 readlen, u32 *data)
{
        u32 msg[3];

        msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip,
                                        SLIMPRO_IIC_READ, protocol, addrlen, readlen);
        msg[1] = SLIMPRO_IIC_ENCODE_ADDR(addr);
        msg[2] = 0;

        return slimpro_i2c_send_msg(ctx, msg, data);
}

static int slimpro_i2c_wr(struct slimpro_i2c_dev *ctx, u32 chip,
                          u32 addr, u32 addrlen, u32 protocol, u32 writelen,
                          u32 data)
{
        u32 msg[3];

        msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip,
                                        SLIMPRO_IIC_WRITE, protocol, addrlen, writelen);
        msg[1] = SLIMPRO_IIC_ENCODE_ADDR(addr);
        msg[2] = data;

        return slimpro_i2c_send_msg(ctx, msg, msg);
}

static int slimpro_i2c_blkrd(struct slimpro_i2c_dev *ctx, u32 chip, u32 addr,
                             u32 addrlen, u32 protocol, u32 readlen,
                             u32 with_data_len, void *data)
{
        dma_addr_t paddr;
        u32 msg[3];
        int rc;

        paddr = dma_map_single(ctx->dev, ctx->dma_buffer, readlen, DMA_FROM_DEVICE);
        if (dma_mapping_error(ctx->dev, paddr)) {
                dev_err(&ctx->adapter.dev, "Error in mapping dma buffer %p\n",
                        ctx->dma_buffer);
                return -ENOMEM;
        }

        msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip, SLIMPRO_IIC_READ,
                                        protocol, addrlen, readlen);
        msg[1] = SLIMPRO_IIC_ENCODE_FLAG_BUFADDR |
                 SLIMPRO_IIC_ENCODE_FLAG_WITH_DATA_LEN(with_data_len) |
                 SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(paddr) |
                 SLIMPRO_IIC_ENCODE_ADDR(addr);
        msg[2] = (u32)paddr;

        rc = slimpro_i2c_send_msg(ctx, msg, msg);

        /* Copy to destination */
        memcpy(data, ctx->dma_buffer, readlen);

        dma_unmap_single(ctx->dev, paddr, readlen, DMA_FROM_DEVICE);
        return rc;
}

static int slimpro_i2c_blkwr(struct slimpro_i2c_dev *ctx, u32 chip,
                             u32 addr, u32 addrlen, u32 protocol, u32 writelen,
                             void *data)
{
        dma_addr_t paddr;
        u32 msg[3];
        int rc;

        if (writelen > I2C_SMBUS_BLOCK_MAX)
                return -EINVAL;

        memcpy(ctx->dma_buffer, data, writelen);
        paddr = dma_map_single(ctx->dev, ctx->dma_buffer, writelen,
                               DMA_TO_DEVICE);
        if (dma_mapping_error(ctx->dev, paddr)) {
                dev_err(&ctx->adapter.dev, "Error in mapping dma buffer %p\n",
                        ctx->dma_buffer);
                return -ENOMEM;
        }

        msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip, SLIMPRO_IIC_WRITE,
                                        protocol, addrlen, writelen);
        msg[1] = SLIMPRO_IIC_ENCODE_FLAG_BUFADDR |
                 SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(paddr) |
                 SLIMPRO_IIC_ENCODE_ADDR(addr);
        msg[2] = (u32)paddr;

        if (ctx->mbox_client.tx_block)
                reinit_completion(&ctx->rd_complete);

        rc = slimpro_i2c_send_msg(ctx, msg, msg);

        dma_unmap_single(ctx->dev, paddr, writelen, DMA_TO_DEVICE);
        return rc;
}

static int xgene_slimpro_i2c_xfer(struct i2c_adapter *adap, u16 addr,
                                  unsigned short flags, char read_write,
                                  u8 command, int size,
                                  union i2c_smbus_data *data)
{
        struct slimpro_i2c_dev *ctx = i2c_get_adapdata(adap);
        int ret = -EOPNOTSUPP;
        u32 val;

        switch (size) {
        case I2C_SMBUS_BYTE:
                if (read_write == I2C_SMBUS_READ) {
                        ret = slimpro_i2c_rd(ctx, addr, 0, 0,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             BYTE_DATA, &val);
                        data->byte = val;
                } else {
                        ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             0, 0);
                }
                break;
        case I2C_SMBUS_BYTE_DATA:
                if (read_write == I2C_SMBUS_READ) {
                        ret = slimpro_i2c_rd(ctx, addr, command, SMBUS_CMD_LEN,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             BYTE_DATA, &val);
                        data->byte = val;
                } else {
                        val = data->byte;
                        ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             BYTE_DATA, val);
                }
                break;
        case I2C_SMBUS_WORD_DATA:
                if (read_write == I2C_SMBUS_READ) {
                        ret = slimpro_i2c_rd(ctx, addr, command, SMBUS_CMD_LEN,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             WORD_DATA, &val);
                        data->word = val;
                } else {
                        val = data->word;
                        ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
                                             SLIMPRO_IIC_SMB_PROTOCOL,
                                             WORD_DATA, val);
                }
                break;
        case I2C_SMBUS_BLOCK_DATA:
                if (read_write == I2C_SMBUS_READ) {
                        ret = slimpro_i2c_blkrd(ctx, addr, command,
                                                SMBUS_CMD_LEN,
                                                SLIMPRO_IIC_SMB_PROTOCOL,
                                                I2C_SMBUS_BLOCK_MAX + 1,
                                                IIC_SMB_WITH_DATA_LEN,
                                                &data->block[0]);

                } else {
                        ret = slimpro_i2c_blkwr(ctx, addr, command,
                                                SMBUS_CMD_LEN,
                                                SLIMPRO_IIC_SMB_PROTOCOL,
                                                data->block[0] + 1,
                                                &data->block[0]);
                }
                break;
        case I2C_SMBUS_I2C_BLOCK_DATA:
                if (read_write == I2C_SMBUS_READ) {
                        ret = slimpro_i2c_blkrd(ctx, addr,
                                                command,
                                                SMBUS_CMD_LEN,
                                                SLIMPRO_IIC_I2C_PROTOCOL,
                                                I2C_SMBUS_BLOCK_MAX,
                                                IIC_SMB_WITHOUT_DATA_LEN,
                                                &data->block[1]);
                } else {
                        ret = slimpro_i2c_blkwr(ctx, addr, command,
                                                SMBUS_CMD_LEN,
                                                SLIMPRO_IIC_I2C_PROTOCOL,
                                                data->block[0],
                                                &data->block[1]);
                }
                break;
        default:
                break;
        }
        return ret;
}

/*
* Return list of supported functionality.
*/
static u32 xgene_slimpro_i2c_func(struct i2c_adapter *adapter)
{
        return I2C_FUNC_SMBUS_BYTE |
                I2C_FUNC_SMBUS_BYTE_DATA |
                I2C_FUNC_SMBUS_WORD_DATA |
                I2C_FUNC_SMBUS_BLOCK_DATA |
                I2C_FUNC_SMBUS_I2C_BLOCK;
}

static const struct i2c_algorithm xgene_slimpro_i2c_algorithm = {
        .smbus_xfer = xgene_slimpro_i2c_xfer,
        .functionality = xgene_slimpro_i2c_func,
};

static int xgene_slimpro_i2c_probe(struct platform_device *pdev)
{
        struct slimpro_i2c_dev *ctx;
        struct i2c_adapter *adapter;
        struct mbox_client *cl;
        int rc;

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

        ctx->dev = &pdev->dev;
        platform_set_drvdata(pdev, ctx);
        cl = &ctx->mbox_client;

        /* Request mailbox channel */
        cl->dev = &pdev->dev;
        init_completion(&ctx->rd_complete);
        cl->tx_tout = MAILBOX_OP_TIMEOUT;
        cl->knows_txdone = false;
        if (acpi_disabled) {
                cl->tx_block = true;
                cl->rx_callback = slimpro_i2c_rx_cb;
                ctx->mbox_chan = mbox_request_channel(cl, MAILBOX_I2C_INDEX);
                if (IS_ERR(ctx->mbox_chan))
                        return dev_err_probe(&pdev->dev, PTR_ERR(ctx->mbox_chan),
                                             "i2c mailbox channel request failed\n");
        } else {
                struct pcc_mbox_chan *pcc_chan;
                const struct acpi_device_id *acpi_id;

                acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
                                            &pdev->dev);
                if (!acpi_id)
                        return -EINVAL;

                if (device_property_read_u32(&pdev->dev, "pcc-channel",
                                             &ctx->mbox_idx))
                        ctx->mbox_idx = MAILBOX_I2C_INDEX;

                cl->tx_block = false;
                cl->rx_callback = slimpro_i2c_pcc_rx_cb;
                pcc_chan = pcc_mbox_request_channel(cl, ctx->mbox_idx);
                if (IS_ERR(pcc_chan))
                        return dev_err_probe(&pdev->dev, PTR_ERR(pcc_chan),
                                             "PCC mailbox channel request failed\n");

                ctx->pcc_chan = pcc_chan;
                ctx->mbox_chan = pcc_chan->mchan;

                if (!ctx->mbox_chan->mbox->txdone_irq) {
                        rc = dev_err_probe(&pdev->dev, -ENOENT,
                                           "PCC IRQ not supported\n");
                        goto mbox_err;
                }

        }
        rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
        if (rc)
                dev_warn(&pdev->dev, "Unable to set dma mask\n");

        /* Setup I2C adapter */
        adapter = &ctx->adapter;
        snprintf(adapter->name, sizeof(adapter->name), "MAILBOX I2C");
        adapter->algo = &xgene_slimpro_i2c_algorithm;
        adapter->class = I2C_CLASS_HWMON;
        adapter->dev.parent = &pdev->dev;
        adapter->dev.of_node = pdev->dev.of_node;
        ACPI_COMPANION_SET(&adapter->dev, ACPI_COMPANION(&pdev->dev));
        i2c_set_adapdata(adapter, ctx);
        rc = i2c_add_adapter(adapter);
        if (rc)
                goto mbox_err;

        dev_info(&pdev->dev, "Mailbox I2C Adapter registered\n");
        return 0;

mbox_err:
        if (acpi_disabled)
                mbox_free_channel(ctx->mbox_chan);
        else
                pcc_mbox_free_channel(ctx->pcc_chan);

        return rc;
}

static void xgene_slimpro_i2c_remove(struct platform_device *pdev)
{
        struct slimpro_i2c_dev *ctx = platform_get_drvdata(pdev);

        i2c_del_adapter(&ctx->adapter);

        if (acpi_disabled)
                mbox_free_channel(ctx->mbox_chan);
        else
                pcc_mbox_free_channel(ctx->pcc_chan);
}

static const struct of_device_id xgene_slimpro_i2c_dt_ids[] = {
        {.compatible = "apm,xgene-slimpro-i2c" },
        {},
};
MODULE_DEVICE_TABLE(of, xgene_slimpro_i2c_dt_ids);

#ifdef CONFIG_ACPI
static const struct acpi_device_id xgene_slimpro_i2c_acpi_ids[] = {
        {"APMC0D40", XGENE_SLIMPRO_I2C_V1},
        {"APMC0D8B", XGENE_SLIMPRO_I2C_V2},
        {}
};
MODULE_DEVICE_TABLE(acpi, xgene_slimpro_i2c_acpi_ids);
#endif

static struct platform_driver xgene_slimpro_i2c_driver = {
        .probe  = xgene_slimpro_i2c_probe,
        .remove = xgene_slimpro_i2c_remove,
        .driver = {
                .name   = "xgene-slimpro-i2c",
                .of_match_table = of_match_ptr(xgene_slimpro_i2c_dt_ids),
                .acpi_match_table = ACPI_PTR(xgene_slimpro_i2c_acpi_ids)
        },
};

module_platform_driver(xgene_slimpro_i2c_driver);

MODULE_DESCRIPTION("APM X-Gene SLIMpro I2C driver");
MODULE_AUTHOR("Feng Kan <fkan@apm.com>");
MODULE_AUTHOR("Hieu Le <hnle@apm.com>");
MODULE_LICENSE("GPL");