// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * USB SD Host Controller (USHC) controller driver.
 *
 * Copyright (C) 2010 Cambridge Silicon Radio Ltd.
 *
 * Notes:
 *   - Only version 2 devices are supported.
 *   - Version 2 devices only support SDIO cards/devices (R2 response is
 *     unsupported).
 *
 * References:
 *   [USHC] USB SD Host Controller specification (CS-118793-SP)
 */
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/host.h>

enum ushc_request {
        USHC_GET_CAPS  = 0x00,
        USHC_HOST_CTRL = 0x01,
        USHC_PWR_CTRL  = 0x02,
        USHC_CLK_FREQ  = 0x03,
        USHC_EXEC_CMD  = 0x04,
        USHC_READ_RESP = 0x05,
        USHC_RESET     = 0x06,
};

enum ushc_request_type {
        USHC_GET_CAPS_TYPE  = USB_DIR_IN  | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_HOST_CTRL_TYPE = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_PWR_CTRL_TYPE  = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_CLK_FREQ_TYPE  = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_EXEC_CMD_TYPE  = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_READ_RESP_TYPE = USB_DIR_IN  | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        USHC_RESET_TYPE     = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
};

#define USHC_GET_CAPS_VERSION_MASK 0xff
#define USHC_GET_CAPS_3V3      (1 << 8)
#define USHC_GET_CAPS_3V0      (1 << 9)
#define USHC_GET_CAPS_1V8      (1 << 10)
#define USHC_GET_CAPS_HIGH_SPD (1 << 16)

#define USHC_HOST_CTRL_4BIT     (1 << 1)
#define USHC_HOST_CTRL_HIGH_SPD (1 << 0)

#define USHC_PWR_CTRL_OFF 0x00
#define USHC_PWR_CTRL_3V3 0x01
#define USHC_PWR_CTRL_3V0 0x02
#define USHC_PWR_CTRL_1V8 0x03

#define USHC_READ_RESP_BUSY        (1 << 4)
#define USHC_READ_RESP_ERR_TIMEOUT (1 << 3)
#define USHC_READ_RESP_ERR_CRC     (1 << 2)
#define USHC_READ_RESP_ERR_DAT     (1 << 1)
#define USHC_READ_RESP_ERR_CMD     (1 << 0)
#define USHC_READ_RESP_ERR_MASK    0x0f

struct ushc_cbw {
        __u8 signature;
        __u8 cmd_idx;
        __le16 block_size;
        __le32 arg;
} __attribute__((packed));

#define USHC_CBW_SIGNATURE 'C'

struct ushc_csw {
        __u8 signature;
        __u8 status;
        __le32 response;
} __attribute__((packed));

#define USHC_CSW_SIGNATURE 'S'

struct ushc_int_data {
        u8 status;
        u8 reserved[3];
};

#define USHC_INT_STATUS_SDIO_INT     (1 << 1)
#define USHC_INT_STATUS_CARD_PRESENT (1 << 0)


struct ushc_data {
        struct usb_device *usb_dev;
        struct mmc_host *mmc;

        struct urb *int_urb;
        struct ushc_int_data *int_data;

        struct urb *cbw_urb;
        struct ushc_cbw *cbw;

        struct urb *data_urb;

        struct urb *csw_urb;
        struct ushc_csw *csw;

        spinlock_t lock;
        struct mmc_request *current_req;
        u32 caps;
        u16 host_ctrl;
        unsigned long flags;
        u8 last_status;
        int clock_freq;
};

#define DISCONNECTED    0
#define INT_EN          1
#define IGNORE_NEXT_INT 2

static void data_callback(struct urb *urb);

static int ushc_hw_reset(struct ushc_data *ushc)
{
        return usb_control_msg(ushc->usb_dev, usb_sndctrlpipe(ushc->usb_dev, 0),
                               USHC_RESET, USHC_RESET_TYPE,
                               0, 0, NULL, 0, 100);
}

static int ushc_hw_get_caps(struct ushc_data *ushc)
{
        int ret;
        int version;

        ret = usb_control_msg(ushc->usb_dev, usb_rcvctrlpipe(ushc->usb_dev, 0),
                              USHC_GET_CAPS, USHC_GET_CAPS_TYPE,
                              0, 0, &ushc->caps, sizeof(ushc->caps), 100);
        if (ret < 0)
                return ret;

        ushc->caps = le32_to_cpu(ushc->caps);

        version = ushc->caps & USHC_GET_CAPS_VERSION_MASK;
        if (version != 0x02) {
                dev_err(&ushc->usb_dev->dev, "controller version %d is not supported\n", version);
                return -EINVAL;
        }

        return 0;
}

static int ushc_hw_set_host_ctrl(struct ushc_data *ushc, u16 mask, u16 val)
{
        u16 host_ctrl;
        int ret;

        host_ctrl = (ushc->host_ctrl & ~mask) | val;
        ret = usb_control_msg(ushc->usb_dev, usb_sndctrlpipe(ushc->usb_dev, 0),
                              USHC_HOST_CTRL, USHC_HOST_CTRL_TYPE,
                              host_ctrl, 0, NULL, 0, 100);
        if (ret < 0)
                return ret;
        ushc->host_ctrl = host_ctrl;
        return 0;
}

static void int_callback(struct urb *urb)
{
        struct ushc_data *ushc = urb->context;
        u8 status, last_status;

        if (urb->status < 0)
                return;

        status = ushc->int_data->status;
        last_status = ushc->last_status;
        ushc->last_status = status;

        /*
         * Ignore the card interrupt status on interrupt transfers that
         * were submitted while card interrupts where disabled.
         *
         * This avoid occasional spurious interrupts when enabling
         * interrupts immediately after clearing the source on the card.
         */

        if (!test_and_clear_bit(IGNORE_NEXT_INT, &ushc->flags)
            && test_bit(INT_EN, &ushc->flags)
            && status & USHC_INT_STATUS_SDIO_INT) {
                mmc_signal_sdio_irq(ushc->mmc);
        }

        if ((status ^ last_status) & USHC_INT_STATUS_CARD_PRESENT)
                mmc_detect_change(ushc->mmc, msecs_to_jiffies(100));

        if (!test_bit(INT_EN, &ushc->flags))
                set_bit(IGNORE_NEXT_INT, &ushc->flags);
        usb_submit_urb(ushc->int_urb, GFP_ATOMIC);
}

static void cbw_callback(struct urb *urb)
{
        struct ushc_data *ushc = urb->context;

        if (urb->status != 0) {
                usb_unlink_urb(ushc->data_urb);
                usb_unlink_urb(ushc->csw_urb);
        }
}

static void data_callback(struct urb *urb)
{
        struct ushc_data *ushc = urb->context;

        if (urb->status != 0)
                usb_unlink_urb(ushc->csw_urb);
}

static void csw_callback(struct urb *urb)
{
        struct ushc_data *ushc = urb->context;
        struct mmc_request *req = ushc->current_req;
        int status;

        status = ushc->csw->status;

        if (urb->status != 0) {
                req->cmd->error = urb->status;
        } else if (status & USHC_READ_RESP_ERR_CMD) {
                if (status & USHC_READ_RESP_ERR_CRC)
                        req->cmd->error = -EIO;
                else
                        req->cmd->error = -ETIMEDOUT;
        }
        if (req->data) {
                if (status & USHC_READ_RESP_ERR_DAT) {
                        if (status & USHC_READ_RESP_ERR_CRC)
                                req->data->error = -EIO;
                        else
                                req->data->error = -ETIMEDOUT;
                        req->data->bytes_xfered = 0;
                } else {
                        req->data->bytes_xfered = req->data->blksz * req->data->blocks;
                }
        }

        req->cmd->resp[0] = le32_to_cpu(ushc->csw->response);

        mmc_request_done(ushc->mmc, req);
}

static void ushc_request(struct mmc_host *mmc, struct mmc_request *req)
{
        struct ushc_data *ushc = mmc_priv(mmc);
        int ret;
        unsigned long flags;

        spin_lock_irqsave(&ushc->lock, flags);

        if (test_bit(DISCONNECTED, &ushc->flags)) {
                ret = -ENODEV;
                goto out;
        }

        /* Version 2 firmware doesn't support the R2 response format. */
        if (req->cmd->flags & MMC_RSP_136) {
                ret = -EINVAL;
                goto out;
        }

        /* The Astoria's data FIFOs don't work with clock speeds < 5MHz so
           limit commands with data to 6MHz or more. */
        if (req->data && ushc->clock_freq < 6000000) {
                ret = -EINVAL;
                goto out;
        }

        ushc->current_req = req;

        /* Start cmd with CBW. */
        ushc->cbw->cmd_idx = cpu_to_le16(req->cmd->opcode);
        if (req->data)
                ushc->cbw->block_size = cpu_to_le16(req->data->blksz);
        else
                ushc->cbw->block_size = 0;
        ushc->cbw->arg = cpu_to_le32(req->cmd->arg);

        ret = usb_submit_urb(ushc->cbw_urb, GFP_ATOMIC);
        if (ret < 0)
                goto out;

        /* Submit data (if any). */
        if (req->data) {
                struct mmc_data *data = req->data;
                int pipe;

                if (data->flags & MMC_DATA_READ)
                        pipe = usb_rcvbulkpipe(ushc->usb_dev, 6);
                else
                        pipe = usb_sndbulkpipe(ushc->usb_dev, 2);

                usb_fill_bulk_urb(ushc->data_urb, ushc->usb_dev, pipe,
                                  NULL, data->sg->length,
                                  data_callback, ushc);
                ushc->data_urb->num_sgs = 1;
                ushc->data_urb->sg = data->sg;
                ret = usb_submit_urb(ushc->data_urb, GFP_ATOMIC);
                if (ret < 0)
                        goto out;
        }

        /* Submit CSW. */
        ret = usb_submit_urb(ushc->csw_urb, GFP_ATOMIC);

out:
        spin_unlock_irqrestore(&ushc->lock, flags);
        if (ret < 0) {
                usb_unlink_urb(ushc->cbw_urb);
                usb_unlink_urb(ushc->data_urb);
                req->cmd->error = ret;
                mmc_request_done(mmc, req);
        }
}

static int ushc_set_power(struct ushc_data *ushc, unsigned char power_mode)
{
        u16 voltage;

        switch (power_mode) {
        case MMC_POWER_OFF:
                voltage = USHC_PWR_CTRL_OFF;
                break;
        case MMC_POWER_UP:
        case MMC_POWER_ON:
                voltage = USHC_PWR_CTRL_3V3;
                break;
        default:
                return -EINVAL;
        }

        return usb_control_msg(ushc->usb_dev, usb_sndctrlpipe(ushc->usb_dev, 0),
                               USHC_PWR_CTRL, USHC_PWR_CTRL_TYPE,
                               voltage, 0, NULL, 0, 100);
}

static int ushc_set_bus_width(struct ushc_data *ushc, int bus_width)
{
        return ushc_hw_set_host_ctrl(ushc, USHC_HOST_CTRL_4BIT,
                                     bus_width == 4 ? USHC_HOST_CTRL_4BIT : 0);
}

static int ushc_set_bus_freq(struct ushc_data *ushc, int clk, bool enable_hs)
{
        int ret;

        /* Hardware can't detect interrupts while the clock is off. */
        if (clk == 0)
                clk = 400000;

        ret = ushc_hw_set_host_ctrl(ushc, USHC_HOST_CTRL_HIGH_SPD,
                                    enable_hs ? USHC_HOST_CTRL_HIGH_SPD : 0);
        if (ret < 0)
                return ret;

        ret = usb_control_msg(ushc->usb_dev, usb_sndctrlpipe(ushc->usb_dev, 0),
                              USHC_CLK_FREQ, USHC_CLK_FREQ_TYPE,
                              clk & 0xffff, (clk >> 16) & 0xffff, NULL, 0, 100);
        if (ret < 0)
                return ret;

        ushc->clock_freq = clk;
        return 0;
}

static void ushc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct ushc_data *ushc = mmc_priv(mmc);

        ushc_set_power(ushc, ios->power_mode);
        ushc_set_bus_width(ushc, 1 << ios->bus_width);
        ushc_set_bus_freq(ushc, ios->clock, ios->timing == MMC_TIMING_SD_HS);
}

static int ushc_get_cd(struct mmc_host *mmc)
{
        struct ushc_data *ushc = mmc_priv(mmc);

        return !!(ushc->last_status & USHC_INT_STATUS_CARD_PRESENT);
}

static void ushc_enable_sdio_irq(struct mmc_host *mmc, int enable)
{
        struct ushc_data *ushc = mmc_priv(mmc);

        if (enable)
                set_bit(INT_EN, &ushc->flags);
        else
                clear_bit(INT_EN, &ushc->flags);
}

static void ushc_clean_up(struct ushc_data *ushc)
{
        usb_free_urb(ushc->int_urb);
        usb_free_urb(ushc->csw_urb);
        usb_free_urb(ushc->data_urb);
        usb_free_urb(ushc->cbw_urb);

        kfree(ushc->int_data);
        kfree(ushc->cbw);
        kfree(ushc->csw);
}

static const struct mmc_host_ops ushc_ops = {
        .request         = ushc_request,
        .set_ios         = ushc_set_ios,
        .get_cd          = ushc_get_cd,
        .enable_sdio_irq = ushc_enable_sdio_irq,
};

static int ushc_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        struct usb_device *usb_dev = interface_to_usbdev(intf);
        struct mmc_host *mmc;
        struct ushc_data *ushc;
        int ret;

        if (intf->cur_altsetting->desc.bNumEndpoints < 1)
                return -ENODEV;

        mmc = devm_mmc_alloc_host(&intf->dev, sizeof(*ushc));
        if (mmc == NULL)
                return -ENOMEM;
        ushc = mmc_priv(mmc);
        usb_set_intfdata(intf, ushc);

        ushc->usb_dev = usb_dev;
        ushc->mmc = mmc;

        spin_lock_init(&ushc->lock);

        ret = ushc_hw_reset(ushc);
        if (ret < 0)
                goto err;

        /* Read capabilities. */
        ret = ushc_hw_get_caps(ushc);
        if (ret < 0)
                goto err;

        mmc->ops = &ushc_ops;

        mmc->f_min = 400000;
        mmc->f_max = 50000000;
        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
        mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
        mmc->caps |= (ushc->caps & USHC_GET_CAPS_HIGH_SPD) ? MMC_CAP_SD_HIGHSPEED : 0;

        mmc->max_seg_size  = 512*511;
        mmc->max_segs      = 1;
        mmc->max_req_size  = 512*511;
        mmc->max_blk_size  = 512;
        mmc->max_blk_count = 511;

        ushc->int_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (ushc->int_urb == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        ushc->int_data = kzalloc_obj(struct ushc_int_data);
        if (ushc->int_data == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        usb_fill_int_urb(ushc->int_urb, ushc->usb_dev,
                         usb_rcvintpipe(usb_dev,
                                        intf->cur_altsetting->endpoint[0].desc.bEndpointAddress),
                         ushc->int_data, sizeof(struct ushc_int_data),
                         int_callback, ushc,
                         intf->cur_altsetting->endpoint[0].desc.bInterval);

        ushc->cbw_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (ushc->cbw_urb == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        ushc->cbw = kzalloc_obj(struct ushc_cbw);
        if (ushc->cbw == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        ushc->cbw->signature = USHC_CBW_SIGNATURE;

        usb_fill_bulk_urb(ushc->cbw_urb, ushc->usb_dev, usb_sndbulkpipe(usb_dev, 2),
                          ushc->cbw, sizeof(struct ushc_cbw),
                          cbw_callback, ushc);

        ushc->data_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (ushc->data_urb == NULL) {
                ret = -ENOMEM;
                goto err;
        }

        ushc->csw_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (ushc->csw_urb == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        ushc->csw = kzalloc_obj(struct ushc_csw);
        if (ushc->csw == NULL) {
                ret = -ENOMEM;
                goto err;
        }
        usb_fill_bulk_urb(ushc->csw_urb, ushc->usb_dev, usb_rcvbulkpipe(usb_dev, 6),
                          ushc->csw, sizeof(struct ushc_csw),
                          csw_callback, ushc);

        ret = mmc_add_host(ushc->mmc);
        if (ret)
                goto err;

        ret = usb_submit_urb(ushc->int_urb, GFP_KERNEL);
        if (ret < 0) {
                mmc_remove_host(ushc->mmc);
                goto err;
        }

        return 0;

err:
        ushc_clean_up(ushc);
        return ret;
}

static void ushc_disconnect(struct usb_interface *intf)
{
        struct ushc_data *ushc = usb_get_intfdata(intf);

        spin_lock_irq(&ushc->lock);
        set_bit(DISCONNECTED, &ushc->flags);
        spin_unlock_irq(&ushc->lock);

        usb_kill_urb(ushc->int_urb);
        usb_kill_urb(ushc->cbw_urb);
        usb_kill_urb(ushc->data_urb);
        usb_kill_urb(ushc->csw_urb);

        mmc_remove_host(ushc->mmc);

        ushc_clean_up(ushc);
}

static struct usb_device_id ushc_id_table[] = {
        /* CSR USB SD Host Controller */
        { USB_DEVICE(0x0a12, 0x5d10) },
        { },
};
MODULE_DEVICE_TABLE(usb, ushc_id_table);

static struct usb_driver ushc_driver = {
        .name       = "ushc",
        .id_table   = ushc_id_table,
        .probe      = ushc_probe,
        .disconnect = ushc_disconnect,
};

module_usb_driver(ushc_driver);

MODULE_DESCRIPTION("USB SD Host Controller driver");
MODULE_AUTHOR("David Vrabel <david.vrabel@csr.com>");
MODULE_LICENSE("GPL");