root/drivers/mmc/host/tifm_sd.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  tifm_sd.c - TI FlashMedia driver
 *
 *  Copyright (C) 2006 Alex Dubov <oakad@yahoo.com>
 *
 * Special thanks to Brad Campbell for extensive testing of this driver.
 */


#include <linux/tifm.h>
#include <linux/mmc/host.h>
#include <linux/highmem.h>
#include <linux/scatterlist.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <asm/io.h>

#define DRIVER_NAME "tifm_sd"
#define DRIVER_VERSION "0.8"

static bool no_dma = 0;
static bool fixed_timeout = 0;
module_param(no_dma, bool, 0644);
module_param(fixed_timeout, bool, 0644);

/* Constants here are mostly from OMAP5912 datasheet */
#define TIFM_MMCSD_RESET      0x0002
#define TIFM_MMCSD_CLKMASK    0x03ff
#define TIFM_MMCSD_POWER      0x0800
#define TIFM_MMCSD_4BBUS      0x8000
#define TIFM_MMCSD_RXDE       0x8000   /* rx dma enable */
#define TIFM_MMCSD_TXDE       0x0080   /* tx dma enable */
#define TIFM_MMCSD_BUFINT     0x0c00   /* set bits: AE, AF */
#define TIFM_MMCSD_DPE        0x0020   /* data timeout counted in kilocycles */
#define TIFM_MMCSD_INAB       0x0080   /* abort / initialize command */
#define TIFM_MMCSD_READ       0x8000

#define TIFM_MMCSD_ERRMASK    0x01e0   /* set bits: CCRC, CTO, DCRC, DTO */
#define TIFM_MMCSD_EOC        0x0001   /* end of command phase  */
#define TIFM_MMCSD_CD         0x0002   /* card detect           */
#define TIFM_MMCSD_CB         0x0004   /* card enter busy state */
#define TIFM_MMCSD_BRS        0x0008   /* block received/sent   */
#define TIFM_MMCSD_EOFB       0x0010   /* card exit busy state  */
#define TIFM_MMCSD_DTO        0x0020   /* data time-out         */
#define TIFM_MMCSD_DCRC       0x0040   /* data crc error        */
#define TIFM_MMCSD_CTO        0x0080   /* command time-out      */
#define TIFM_MMCSD_CCRC       0x0100   /* command crc error     */
#define TIFM_MMCSD_AF         0x0400   /* fifo almost full      */
#define TIFM_MMCSD_AE         0x0800   /* fifo almost empty     */
#define TIFM_MMCSD_OCRB       0x1000   /* OCR busy              */
#define TIFM_MMCSD_CIRQ       0x2000   /* card irq (cmd40/sdio) */
#define TIFM_MMCSD_CERR       0x4000   /* card status error     */

#define TIFM_MMCSD_ODTO       0x0040   /* open drain / extended timeout */
#define TIFM_MMCSD_CARD_RO    0x0200   /* card is read-only     */

#define TIFM_MMCSD_FIFO_SIZE  0x0020

#define TIFM_MMCSD_RSP_R0     0x0000
#define TIFM_MMCSD_RSP_R1     0x0100
#define TIFM_MMCSD_RSP_R2     0x0200
#define TIFM_MMCSD_RSP_R3     0x0300
#define TIFM_MMCSD_RSP_R4     0x0400
#define TIFM_MMCSD_RSP_R5     0x0500
#define TIFM_MMCSD_RSP_R6     0x0600

#define TIFM_MMCSD_RSP_BUSY   0x0800

#define TIFM_MMCSD_CMD_BC     0x0000
#define TIFM_MMCSD_CMD_BCR    0x1000
#define TIFM_MMCSD_CMD_AC     0x2000
#define TIFM_MMCSD_CMD_ADTC   0x3000

#define TIFM_MMCSD_MAX_BLOCK_SIZE  0x0800UL

#define TIFM_MMCSD_REQ_TIMEOUT_MS  1000

enum {
        CMD_READY    = 0x0001,
        FIFO_READY   = 0x0002,
        BRS_READY    = 0x0004,
        SCMD_ACTIVE  = 0x0008,
        SCMD_READY   = 0x0010,
        CARD_BUSY    = 0x0020,
        DATA_CARRY   = 0x0040
};

struct tifm_sd {
        struct tifm_dev       *dev;

        unsigned short        eject:1,
                              open_drain:1,
                              no_dma:1;
        unsigned short        cmd_flags;

        unsigned int          clk_freq;
        unsigned int          clk_div;
        unsigned long         timeout_jiffies;

        struct work_struct    finish_bh_work;
        struct timer_list     timer;
        struct mmc_request    *req;

        int                   sg_len;
        int                   sg_pos;
        unsigned int          block_pos;
        struct scatterlist    bounce_buf;
        unsigned char         bounce_buf_data[TIFM_MMCSD_MAX_BLOCK_SIZE];
};

/* for some reason, host won't respond correctly to readw/writew */
static void tifm_sd_read_fifo(struct tifm_sd *host, struct page *pg,
                              unsigned int off, unsigned int cnt)
{
        struct tifm_dev *sock = host->dev;
        unsigned char *buf;
        unsigned int pos = 0, val;

        buf = kmap_local_page(pg) + off;
        if (host->cmd_flags & DATA_CARRY) {
                buf[pos++] = host->bounce_buf_data[0];
                host->cmd_flags &= ~DATA_CARRY;
        }

        while (pos < cnt) {
                val = readl(sock->addr + SOCK_MMCSD_DATA);
                buf[pos++] = val & 0xff;
                if (pos == cnt) {
                        host->bounce_buf_data[0] = (val >> 8) & 0xff;
                        host->cmd_flags |= DATA_CARRY;
                        break;
                }
                buf[pos++] = (val >> 8) & 0xff;
        }
        kunmap_local(buf - off);
}

static void tifm_sd_write_fifo(struct tifm_sd *host, struct page *pg,
                               unsigned int off, unsigned int cnt)
{
        struct tifm_dev *sock = host->dev;
        unsigned char *buf;
        unsigned int pos = 0, val;

        buf = kmap_local_page(pg) + off;
        if (host->cmd_flags & DATA_CARRY) {
                val = host->bounce_buf_data[0] | ((buf[pos++] << 8) & 0xff00);
                writel(val, sock->addr + SOCK_MMCSD_DATA);
                host->cmd_flags &= ~DATA_CARRY;
        }

        while (pos < cnt) {
                val = buf[pos++];
                if (pos == cnt) {
                        host->bounce_buf_data[0] = val & 0xff;
                        host->cmd_flags |= DATA_CARRY;
                        break;
                }
                val |= (buf[pos++] << 8) & 0xff00;
                writel(val, sock->addr + SOCK_MMCSD_DATA);
        }
        kunmap_local(buf - off);
}

static void tifm_sd_transfer_data(struct tifm_sd *host)
{
        struct mmc_data *r_data = host->req->cmd->data;
        struct scatterlist *sg = r_data->sg;
        unsigned int off, cnt, t_size = TIFM_MMCSD_FIFO_SIZE * 2;
        unsigned int p_off, p_cnt;
        struct page *pg;

        if (host->sg_pos == host->sg_len)
                return;
        while (t_size) {
                cnt = sg[host->sg_pos].length - host->block_pos;
                if (!cnt) {
                        host->block_pos = 0;
                        host->sg_pos++;
                        if (host->sg_pos == host->sg_len) {
                                if ((r_data->flags & MMC_DATA_WRITE)
                                    && (host->cmd_flags & DATA_CARRY))
                                        writel(host->bounce_buf_data[0],
                                               host->dev->addr
                                               + SOCK_MMCSD_DATA);

                                return;
                        }
                        cnt = sg[host->sg_pos].length;
                }
                off = sg[host->sg_pos].offset + host->block_pos;

                pg = sg_page(&sg[host->sg_pos]) + (off >> PAGE_SHIFT);
                p_off = offset_in_page(off);
                p_cnt = min3(PAGE_SIZE - p_off, cnt, t_size);

                if (r_data->flags & MMC_DATA_READ)
                        tifm_sd_read_fifo(host, pg, p_off, p_cnt);
                else if (r_data->flags & MMC_DATA_WRITE)
                        tifm_sd_write_fifo(host, pg, p_off, p_cnt);

                t_size -= p_cnt;
                host->block_pos += p_cnt;
        }
}

static void tifm_sd_copy_page(struct page *dst, unsigned int dst_off,
                              struct page *src, unsigned int src_off,
                              unsigned int count)
{
        unsigned char *src_buf = kmap_local_page(src) + src_off;
        unsigned char *dst_buf = kmap_local_page(dst) + dst_off;

        memcpy(dst_buf, src_buf, count);

        kunmap_local(dst_buf - dst_off);
        kunmap_local(src_buf - src_off);
}

static void tifm_sd_bounce_block(struct tifm_sd *host, struct mmc_data *r_data)
{
        struct scatterlist *sg = r_data->sg;
        unsigned int t_size = r_data->blksz;
        unsigned int off, cnt;
        unsigned int p_off, p_cnt;
        struct page *pg;

        dev_dbg(&host->dev->dev, "bouncing block\n");
        while (t_size) {
                cnt = sg[host->sg_pos].length - host->block_pos;
                if (!cnt) {
                        host->block_pos = 0;
                        host->sg_pos++;
                        if (host->sg_pos == host->sg_len)
                                return;
                        cnt = sg[host->sg_pos].length;
                }
                off = sg[host->sg_pos].offset + host->block_pos;

                pg = sg_page(&sg[host->sg_pos]) + (off >> PAGE_SHIFT);
                p_off = offset_in_page(off);
                p_cnt = PAGE_SIZE - p_off;
                p_cnt = min(p_cnt, cnt);
                p_cnt = min(p_cnt, t_size);

                if (r_data->flags & MMC_DATA_WRITE)
                        tifm_sd_copy_page(sg_page(&host->bounce_buf),
                                          r_data->blksz - t_size,
                                          pg, p_off, p_cnt);
                else if (r_data->flags & MMC_DATA_READ)
                        tifm_sd_copy_page(pg, p_off, sg_page(&host->bounce_buf),
                                          r_data->blksz - t_size, p_cnt);

                t_size -= p_cnt;
                host->block_pos += p_cnt;
        }
}

static int tifm_sd_set_dma_data(struct tifm_sd *host, struct mmc_data *r_data)
{
        struct tifm_dev *sock = host->dev;
        unsigned int t_size = TIFM_DMA_TSIZE * r_data->blksz;
        unsigned int dma_len, dma_blk_cnt, dma_off;
        struct scatterlist *sg = NULL;

        if (host->sg_pos == host->sg_len)
                return 1;

        if (host->cmd_flags & DATA_CARRY) {
                host->cmd_flags &= ~DATA_CARRY;
                tifm_sd_bounce_block(host, r_data);
                if (host->sg_pos == host->sg_len)
                        return 1;
        }

        dma_len = sg_dma_len(&r_data->sg[host->sg_pos]) - host->block_pos;
        if (!dma_len) {
                host->block_pos = 0;
                host->sg_pos++;
                if (host->sg_pos == host->sg_len)
                        return 1;
                dma_len = sg_dma_len(&r_data->sg[host->sg_pos]);
        }

        if (dma_len < t_size) {
                dma_blk_cnt = dma_len / r_data->blksz;
                dma_off = host->block_pos;
                host->block_pos += dma_blk_cnt * r_data->blksz;
        } else {
                dma_blk_cnt = TIFM_DMA_TSIZE;
                dma_off = host->block_pos;
                host->block_pos += t_size;
        }

        if (dma_blk_cnt)
                sg = &r_data->sg[host->sg_pos];
        else if (dma_len) {
                if (r_data->flags & MMC_DATA_WRITE)
                        tifm_sd_bounce_block(host, r_data);
                else
                        host->cmd_flags |= DATA_CARRY;

                sg = &host->bounce_buf;
                dma_off = 0;
                dma_blk_cnt = 1;
        } else
                return 1;

        dev_dbg(&sock->dev, "setting dma for %d blocks\n", dma_blk_cnt);
        writel(sg_dma_address(sg) + dma_off, sock->addr + SOCK_DMA_ADDRESS);
        if (r_data->flags & MMC_DATA_WRITE)
                writel((dma_blk_cnt << 8) | TIFM_DMA_TX | TIFM_DMA_EN,
                       sock->addr + SOCK_DMA_CONTROL);
        else
                writel((dma_blk_cnt << 8) | TIFM_DMA_EN,
                       sock->addr + SOCK_DMA_CONTROL);

        return 0;
}

static unsigned int tifm_sd_op_flags(struct mmc_command *cmd)
{
        unsigned int rc = 0;

        switch (mmc_resp_type(cmd)) {
        case MMC_RSP_NONE:
                rc |= TIFM_MMCSD_RSP_R0;
                break;
        case MMC_RSP_R1B:
                rc |= TIFM_MMCSD_RSP_BUSY;
                fallthrough;
        case MMC_RSP_R1:
                rc |= TIFM_MMCSD_RSP_R1;
                break;
        case MMC_RSP_R2:
                rc |= TIFM_MMCSD_RSP_R2;
                break;
        case MMC_RSP_R3:
                rc |= TIFM_MMCSD_RSP_R3;
                break;
        default:
                BUG();
        }

        switch (mmc_cmd_type(cmd)) {
        case MMC_CMD_BC:
                rc |= TIFM_MMCSD_CMD_BC;
                break;
        case MMC_CMD_BCR:
                rc |= TIFM_MMCSD_CMD_BCR;
                break;
        case MMC_CMD_AC:
                rc |= TIFM_MMCSD_CMD_AC;
                break;
        case MMC_CMD_ADTC:
                rc |= TIFM_MMCSD_CMD_ADTC;
                break;
        default:
                BUG();
        }
        return rc;
}

static void tifm_sd_exec(struct tifm_sd *host, struct mmc_command *cmd)
{
        struct tifm_dev *sock = host->dev;
        unsigned int cmd_mask = tifm_sd_op_flags(cmd);

        if (host->open_drain)
                cmd_mask |= TIFM_MMCSD_ODTO;

        if (cmd->data && (cmd->data->flags & MMC_DATA_READ))
                cmd_mask |= TIFM_MMCSD_READ;

        dev_dbg(&sock->dev, "executing opcode 0x%x, arg: 0x%x, mask: 0x%x\n",
                cmd->opcode, cmd->arg, cmd_mask);

        writel((cmd->arg >> 16) & 0xffff, sock->addr + SOCK_MMCSD_ARG_HIGH);
        writel(cmd->arg & 0xffff, sock->addr + SOCK_MMCSD_ARG_LOW);
        writel(cmd->opcode | cmd_mask, sock->addr + SOCK_MMCSD_COMMAND);
}

static void tifm_sd_fetch_resp(struct mmc_command *cmd, struct tifm_dev *sock)
{
        cmd->resp[0] = (readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x1c) << 16)
                       | readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x18);
        cmd->resp[1] = (readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x14) << 16)
                       | readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x10);
        cmd->resp[2] = (readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x0c) << 16)
                       | readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x08);
        cmd->resp[3] = (readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x04) << 16)
                       | readl(sock->addr + SOCK_MMCSD_RESPONSE + 0x00);
}

static void tifm_sd_check_status(struct tifm_sd *host)
{
        struct tifm_dev *sock = host->dev;
        struct mmc_command *cmd = host->req->cmd;

        if (cmd->error)
                goto finish_request;

        if (!(host->cmd_flags & CMD_READY))
                return;

        if (cmd->data) {
                if (cmd->data->error) {
                        if ((host->cmd_flags & SCMD_ACTIVE)
                            && !(host->cmd_flags & SCMD_READY))
                                return;

                        goto finish_request;
                }

                if (!(host->cmd_flags & BRS_READY))
                        return;

                if (!(host->no_dma || (host->cmd_flags & FIFO_READY)))
                        return;

                if (cmd->data->flags & MMC_DATA_WRITE) {
                        if (host->req->stop) {
                                if (!(host->cmd_flags & SCMD_ACTIVE)) {
                                        host->cmd_flags |= SCMD_ACTIVE;
                                        writel(TIFM_MMCSD_EOFB
                                               | readl(sock->addr
                                                       + SOCK_MMCSD_INT_ENABLE),
                                               sock->addr
                                               + SOCK_MMCSD_INT_ENABLE);
                                        tifm_sd_exec(host, host->req->stop);
                                        return;
                                } else {
                                        if (!(host->cmd_flags & SCMD_READY)
                                            || (host->cmd_flags & CARD_BUSY))
                                                return;
                                        writel((~TIFM_MMCSD_EOFB)
                                               & readl(sock->addr
                                                       + SOCK_MMCSD_INT_ENABLE),
                                               sock->addr
                                               + SOCK_MMCSD_INT_ENABLE);
                                }
                        } else {
                                if (host->cmd_flags & CARD_BUSY)
                                        return;
                                writel((~TIFM_MMCSD_EOFB)
                                       & readl(sock->addr
                                               + SOCK_MMCSD_INT_ENABLE),
                                       sock->addr + SOCK_MMCSD_INT_ENABLE);
                        }
                } else {
                        if (host->req->stop) {
                                if (!(host->cmd_flags & SCMD_ACTIVE)) {
                                        host->cmd_flags |= SCMD_ACTIVE;
                                        tifm_sd_exec(host, host->req->stop);
                                        return;
                                } else {
                                        if (!(host->cmd_flags & SCMD_READY))
                                                return;
                                }
                        }
                }
        }
finish_request:
        queue_work(system_bh_wq, &host->finish_bh_work);
}

/* Called from interrupt handler */
static void tifm_sd_data_event(struct tifm_dev *sock)
{
        struct tifm_sd *host;
        unsigned int fifo_status = 0;
        struct mmc_data *r_data = NULL;

        spin_lock(&sock->lock);
        host = mmc_priv((struct mmc_host*)tifm_get_drvdata(sock));
        fifo_status = readl(sock->addr + SOCK_DMA_FIFO_STATUS);
        dev_dbg(&sock->dev, "data event: fifo_status %x, flags %x\n",
                fifo_status, host->cmd_flags);

        if (host->req) {
                r_data = host->req->cmd->data;

                if (r_data && (fifo_status & TIFM_FIFO_READY)) {
                        if (tifm_sd_set_dma_data(host, r_data)) {
                                host->cmd_flags |= FIFO_READY;
                                tifm_sd_check_status(host);
                        }
                }
        }

        writel(fifo_status, sock->addr + SOCK_DMA_FIFO_STATUS);
        spin_unlock(&sock->lock);
}

/* Called from interrupt handler */
static void tifm_sd_card_event(struct tifm_dev *sock)
{
        struct tifm_sd *host;
        unsigned int host_status = 0;
        int cmd_error = 0;
        struct mmc_command *cmd = NULL;

        spin_lock(&sock->lock);
        host = mmc_priv((struct mmc_host*)tifm_get_drvdata(sock));
        host_status = readl(sock->addr + SOCK_MMCSD_STATUS);
        dev_dbg(&sock->dev, "host event: host_status %x, flags %x\n",
                host_status, host->cmd_flags);

        if (host->req) {
                cmd = host->req->cmd;

                if (host_status & TIFM_MMCSD_ERRMASK) {
                        writel(host_status & TIFM_MMCSD_ERRMASK,
                               sock->addr + SOCK_MMCSD_STATUS);
                        if (host_status & TIFM_MMCSD_CTO)
                                cmd_error = -ETIMEDOUT;
                        else if (host_status & TIFM_MMCSD_CCRC)
                                cmd_error = -EILSEQ;

                        if (cmd->data) {
                                if (host_status & TIFM_MMCSD_DTO)
                                        cmd->data->error = -ETIMEDOUT;
                                else if (host_status & TIFM_MMCSD_DCRC)
                                        cmd->data->error = -EILSEQ;
                        }

                        writel(TIFM_FIFO_INT_SETALL,
                               sock->addr + SOCK_DMA_FIFO_INT_ENABLE_CLEAR);
                        writel(TIFM_DMA_RESET, sock->addr + SOCK_DMA_CONTROL);

                        if (host->req->stop) {
                                if (host->cmd_flags & SCMD_ACTIVE) {
                                        host->req->stop->error = cmd_error;
                                        host->cmd_flags |= SCMD_READY;
                                } else {
                                        cmd->error = cmd_error;
                                        host->cmd_flags |= SCMD_ACTIVE;
                                        tifm_sd_exec(host, host->req->stop);
                                        goto done;
                                }
                        } else
                                cmd->error = cmd_error;
                } else {
                        if (host_status & (TIFM_MMCSD_EOC | TIFM_MMCSD_CERR)) {
                                if (!(host->cmd_flags & CMD_READY)) {
                                        host->cmd_flags |= CMD_READY;
                                        tifm_sd_fetch_resp(cmd, sock);
                                } else if (host->cmd_flags & SCMD_ACTIVE) {
                                        host->cmd_flags |= SCMD_READY;
                                        tifm_sd_fetch_resp(host->req->stop,
                                                           sock);
                                }
                        }
                        if (host_status & TIFM_MMCSD_BRS)
                                host->cmd_flags |= BRS_READY;
                }

                if (host->no_dma && cmd->data) {
                        if (host_status & TIFM_MMCSD_AE)
                                writel(host_status & TIFM_MMCSD_AE,
                                       sock->addr + SOCK_MMCSD_STATUS);

                        if (host_status & (TIFM_MMCSD_AE | TIFM_MMCSD_AF
                                           | TIFM_MMCSD_BRS)) {
                                tifm_sd_transfer_data(host);
                                host_status &= ~TIFM_MMCSD_AE;
                        }
                }

                if (host_status & TIFM_MMCSD_EOFB)
                        host->cmd_flags &= ~CARD_BUSY;
                else if (host_status & TIFM_MMCSD_CB)
                        host->cmd_flags |= CARD_BUSY;

                tifm_sd_check_status(host);
        }
done:
        writel(host_status, sock->addr + SOCK_MMCSD_STATUS);
        spin_unlock(&sock->lock);
}

static void tifm_sd_set_data_timeout(struct tifm_sd *host,
                                     struct mmc_data *data)
{
        struct tifm_dev *sock = host->dev;
        unsigned int data_timeout = data->timeout_clks;

        if (fixed_timeout)
                return;

        data_timeout += data->timeout_ns /
                        ((1000000000UL / host->clk_freq) * host->clk_div);

        if (data_timeout < 0xffff) {
                writel(data_timeout, sock->addr + SOCK_MMCSD_DATA_TO);
                writel((~TIFM_MMCSD_DPE)
                       & readl(sock->addr + SOCK_MMCSD_SDIO_MODE_CONFIG),
                       sock->addr + SOCK_MMCSD_SDIO_MODE_CONFIG);
        } else {
                data_timeout = (data_timeout >> 10) + 1;
                if (data_timeout > 0xffff)
                        data_timeout = 0;       /* set to unlimited */
                writel(data_timeout, sock->addr + SOCK_MMCSD_DATA_TO);
                writel(TIFM_MMCSD_DPE
                       | readl(sock->addr + SOCK_MMCSD_SDIO_MODE_CONFIG),
                       sock->addr + SOCK_MMCSD_SDIO_MODE_CONFIG);
        }
}

static void tifm_sd_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct tifm_sd *host = mmc_priv(mmc);
        struct tifm_dev *sock = host->dev;
        unsigned long flags;
        struct mmc_data *r_data = mrq->cmd->data;

        spin_lock_irqsave(&sock->lock, flags);
        if (host->eject) {
                mrq->cmd->error = -ENOMEDIUM;
                goto err_out;
        }

        if (host->req) {
                pr_err("%s : unfinished request detected\n",
                       dev_name(&sock->dev));
                mrq->cmd->error = -ETIMEDOUT;
                goto err_out;
        }

        host->cmd_flags = 0;
        host->block_pos = 0;
        host->sg_pos = 0;

        if (mrq->data && !is_power_of_2(mrq->data->blksz))
                host->no_dma = 1;
        else
                host->no_dma = no_dma ? 1 : 0;

        if (r_data) {
                tifm_sd_set_data_timeout(host, r_data);

                if ((r_data->flags & MMC_DATA_WRITE) && !mrq->stop)
                         writel(TIFM_MMCSD_EOFB
                                | readl(sock->addr + SOCK_MMCSD_INT_ENABLE),
                                sock->addr + SOCK_MMCSD_INT_ENABLE);

                if (host->no_dma) {
                        writel(TIFM_MMCSD_BUFINT
                               | readl(sock->addr + SOCK_MMCSD_INT_ENABLE),
                               sock->addr + SOCK_MMCSD_INT_ENABLE);
                        writel(((TIFM_MMCSD_FIFO_SIZE - 1) << 8)
                               | (TIFM_MMCSD_FIFO_SIZE - 1),
                               sock->addr + SOCK_MMCSD_BUFFER_CONFIG);

                        host->sg_len = r_data->sg_len;
                } else {
                        sg_init_one(&host->bounce_buf, host->bounce_buf_data,
                                    r_data->blksz);

                        if(1 != tifm_map_sg(sock, &host->bounce_buf, 1,
                                            r_data->flags & MMC_DATA_WRITE
                                            ? DMA_TO_DEVICE
                                            : DMA_FROM_DEVICE)) {
                                pr_err("%s : scatterlist map failed\n",
                                       dev_name(&sock->dev));
                                mrq->cmd->error = -ENOMEM;
                                goto err_out;
                        }
                        host->sg_len = tifm_map_sg(sock, r_data->sg,
                                                   r_data->sg_len,
                                                   r_data->flags
                                                   & MMC_DATA_WRITE
                                                   ? DMA_TO_DEVICE
                                                   : DMA_FROM_DEVICE);
                        if (host->sg_len < 1) {
                                pr_err("%s : scatterlist map failed\n",
                                       dev_name(&sock->dev));
                                tifm_unmap_sg(sock, &host->bounce_buf, 1,
                                              r_data->flags & MMC_DATA_WRITE
                                              ? DMA_TO_DEVICE
                                              : DMA_FROM_DEVICE);
                                mrq->cmd->error = -ENOMEM;
                                goto err_out;
                        }

                        writel(TIFM_FIFO_INT_SETALL,
                               sock->addr + SOCK_DMA_FIFO_INT_ENABLE_CLEAR);
                        writel(ilog2(r_data->blksz) - 2,
                               sock->addr + SOCK_FIFO_PAGE_SIZE);
                        writel(TIFM_FIFO_ENABLE,
                               sock->addr + SOCK_FIFO_CONTROL);
                        writel(TIFM_FIFO_INTMASK,
                               sock->addr + SOCK_DMA_FIFO_INT_ENABLE_SET);

                        if (r_data->flags & MMC_DATA_WRITE)
                                writel(TIFM_MMCSD_TXDE,
                                       sock->addr + SOCK_MMCSD_BUFFER_CONFIG);
                        else
                                writel(TIFM_MMCSD_RXDE,
                                       sock->addr + SOCK_MMCSD_BUFFER_CONFIG);

                        tifm_sd_set_dma_data(host, r_data);
                }

                writel(r_data->blocks - 1,
                       sock->addr + SOCK_MMCSD_NUM_BLOCKS);
                writel(r_data->blksz - 1,
                       sock->addr + SOCK_MMCSD_BLOCK_LEN);
        }

        host->req = mrq;
        mod_timer(&host->timer, jiffies + host->timeout_jiffies);
        writel(TIFM_CTRL_LED | readl(sock->addr + SOCK_CONTROL),
               sock->addr + SOCK_CONTROL);
        tifm_sd_exec(host, mrq->cmd);
        spin_unlock_irqrestore(&sock->lock, flags);
        return;

err_out:
        spin_unlock_irqrestore(&sock->lock, flags);
        mmc_request_done(mmc, mrq);
}

static void tifm_sd_end_cmd(struct work_struct *t)
{
        struct tifm_sd *host = from_work(host, t, finish_bh_work);
        struct tifm_dev *sock = host->dev;
        struct mmc_host *mmc = tifm_get_drvdata(sock);
        struct mmc_request *mrq;
        struct mmc_data *r_data = NULL;
        unsigned long flags;

        spin_lock_irqsave(&sock->lock, flags);

        timer_delete(&host->timer);
        mrq = host->req;
        host->req = NULL;

        if (!mrq) {
                pr_err(" %s : no request to complete?\n",
                       dev_name(&sock->dev));
                spin_unlock_irqrestore(&sock->lock, flags);
                return;
        }

        r_data = mrq->cmd->data;
        if (r_data) {
                if (host->no_dma) {
                        writel((~TIFM_MMCSD_BUFINT)
                               & readl(sock->addr + SOCK_MMCSD_INT_ENABLE),
                               sock->addr + SOCK_MMCSD_INT_ENABLE);
                } else {
                        tifm_unmap_sg(sock, &host->bounce_buf, 1,
                                      (r_data->flags & MMC_DATA_WRITE)
                                      ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
                        tifm_unmap_sg(sock, r_data->sg, r_data->sg_len,
                                      (r_data->flags & MMC_DATA_WRITE)
                                      ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
                }

                r_data->bytes_xfered = r_data->blocks
                        - readl(sock->addr + SOCK_MMCSD_NUM_BLOCKS) - 1;
                r_data->bytes_xfered *= r_data->blksz;
                r_data->bytes_xfered += r_data->blksz
                        - readl(sock->addr + SOCK_MMCSD_BLOCK_LEN) + 1;
        }

        writel((~TIFM_CTRL_LED) & readl(sock->addr + SOCK_CONTROL),
               sock->addr + SOCK_CONTROL);

        spin_unlock_irqrestore(&sock->lock, flags);
        mmc_request_done(mmc, mrq);
}

static void tifm_sd_abort(struct timer_list *t)
{
        struct tifm_sd *host = timer_container_of(host, t, timer);

        pr_err("%s : card failed to respond for a long period of time "
               "(%x, %x)\n",
               dev_name(&host->dev->dev), host->req->cmd->opcode, host->cmd_flags);

        tifm_eject(host->dev);
}

static void tifm_sd_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct tifm_sd *host = mmc_priv(mmc);
        struct tifm_dev *sock = host->dev;
        unsigned int clk_div1, clk_div2;
        unsigned long flags;

        spin_lock_irqsave(&sock->lock, flags);

        dev_dbg(&sock->dev, "ios: clock = %u, vdd = %x, bus_mode = %x, "
                "chip_select = %x, power_mode = %x, bus_width = %x\n",
                ios->clock, ios->vdd, ios->bus_mode, ios->chip_select,
                ios->power_mode, ios->bus_width);

        if (ios->bus_width == MMC_BUS_WIDTH_4) {
                writel(TIFM_MMCSD_4BBUS | readl(sock->addr + SOCK_MMCSD_CONFIG),
                       sock->addr + SOCK_MMCSD_CONFIG);
        } else {
                writel((~TIFM_MMCSD_4BBUS)
                       & readl(sock->addr + SOCK_MMCSD_CONFIG),
                       sock->addr + SOCK_MMCSD_CONFIG);
        }

        if (ios->clock) {
                clk_div1 = 20000000 / ios->clock;
                if (!clk_div1)
                        clk_div1 = 1;

                clk_div2 = 24000000 / ios->clock;
                if (!clk_div2)
                        clk_div2 = 1;

                if ((20000000 / clk_div1) > ios->clock)
                        clk_div1++;
                if ((24000000 / clk_div2) > ios->clock)
                        clk_div2++;
                if ((20000000 / clk_div1) > (24000000 / clk_div2)) {
                        host->clk_freq = 20000000;
                        host->clk_div = clk_div1;
                        writel((~TIFM_CTRL_FAST_CLK)
                               & readl(sock->addr + SOCK_CONTROL),
                               sock->addr + SOCK_CONTROL);
                } else {
                        host->clk_freq = 24000000;
                        host->clk_div = clk_div2;
                        writel(TIFM_CTRL_FAST_CLK
                               | readl(sock->addr + SOCK_CONTROL),
                               sock->addr + SOCK_CONTROL);
                }
        } else {
                host->clk_div = 0;
        }
        host->clk_div &= TIFM_MMCSD_CLKMASK;
        writel(host->clk_div
               | ((~TIFM_MMCSD_CLKMASK)
                  & readl(sock->addr + SOCK_MMCSD_CONFIG)),
               sock->addr + SOCK_MMCSD_CONFIG);

        host->open_drain = (ios->bus_mode == MMC_BUSMODE_OPENDRAIN);

        /* chip_select : maybe later */
        //vdd
        //power is set before probe / after remove

        spin_unlock_irqrestore(&sock->lock, flags);
}

static int tifm_sd_ro(struct mmc_host *mmc)
{
        int rc = 0;
        struct tifm_sd *host = mmc_priv(mmc);
        struct tifm_dev *sock = host->dev;
        unsigned long flags;

        spin_lock_irqsave(&sock->lock, flags);
        if (TIFM_MMCSD_CARD_RO & readl(sock->addr + SOCK_PRESENT_STATE))
                rc = 1;
        spin_unlock_irqrestore(&sock->lock, flags);
        return rc;
}

static const struct mmc_host_ops tifm_sd_ops = {
        .request = tifm_sd_request,
        .set_ios = tifm_sd_ios,
        .get_ro  = tifm_sd_ro
};

static int tifm_sd_initialize_host(struct tifm_sd *host)
{
        int rc;
        unsigned int host_status = 0;
        struct tifm_dev *sock = host->dev;

        writel(0, sock->addr + SOCK_MMCSD_INT_ENABLE);
        host->clk_div = 61;
        host->clk_freq = 20000000;
        writel(TIFM_MMCSD_RESET, sock->addr + SOCK_MMCSD_SYSTEM_CONTROL);
        writel(host->clk_div | TIFM_MMCSD_POWER,
               sock->addr + SOCK_MMCSD_CONFIG);

        /* wait up to 0.51 sec for reset */
        for (rc = 32; rc <= 256; rc <<= 1) {
                if (1 & readl(sock->addr + SOCK_MMCSD_SYSTEM_STATUS)) {
                        rc = 0;
                        break;
                }
                msleep(rc);
        }

        if (rc) {
                pr_err("%s : controller failed to reset\n",
                       dev_name(&sock->dev));
                return -ENODEV;
        }

        writel(0, sock->addr + SOCK_MMCSD_NUM_BLOCKS);
        writel(host->clk_div | TIFM_MMCSD_POWER,
               sock->addr + SOCK_MMCSD_CONFIG);
        writel(TIFM_MMCSD_RXDE, sock->addr + SOCK_MMCSD_BUFFER_CONFIG);

        // command timeout fixed to 64 clocks for now
        writel(64, sock->addr + SOCK_MMCSD_COMMAND_TO);
        writel(TIFM_MMCSD_INAB, sock->addr + SOCK_MMCSD_COMMAND);

        for (rc = 16; rc <= 64; rc <<= 1) {
                host_status = readl(sock->addr + SOCK_MMCSD_STATUS);
                writel(host_status, sock->addr + SOCK_MMCSD_STATUS);
                if (!(host_status & TIFM_MMCSD_ERRMASK)
                    && (host_status & TIFM_MMCSD_EOC)) {
                        rc = 0;
                        break;
                }
                msleep(rc);
        }

        if (rc) {
                pr_err("%s : card not ready - probe failed on initialization\n",
                       dev_name(&sock->dev));
                return -ENODEV;
        }

        writel(TIFM_MMCSD_CERR | TIFM_MMCSD_BRS | TIFM_MMCSD_EOC
               | TIFM_MMCSD_ERRMASK,
               sock->addr + SOCK_MMCSD_INT_ENABLE);

        return 0;
}

static int tifm_sd_probe(struct tifm_dev *sock)
{
        struct mmc_host *mmc;
        struct tifm_sd *host;
        int rc = -EIO;

        if (!(TIFM_SOCK_STATE_OCCUPIED
              & readl(sock->addr + SOCK_PRESENT_STATE))) {
                pr_warn("%s : card gone, unexpectedly\n",
                        dev_name(&sock->dev));
                return rc;
        }

        mmc = devm_mmc_alloc_host(&sock->dev, sizeof(*host));
        if (!mmc)
                return -ENOMEM;

        host = mmc_priv(mmc);
        tifm_set_drvdata(sock, mmc);
        host->dev = sock;
        host->timeout_jiffies = msecs_to_jiffies(TIFM_MMCSD_REQ_TIMEOUT_MS);
        /*
         * We use a fixed request timeout of 1s, hence inform the core about it.
         * A future improvement should instead respect the cmd->busy_timeout.
         */
        mmc->max_busy_timeout = TIFM_MMCSD_REQ_TIMEOUT_MS;

        INIT_WORK(&host->finish_bh_work, tifm_sd_end_cmd);
        timer_setup(&host->timer, tifm_sd_abort, 0);

        mmc->ops = &tifm_sd_ops;
        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
        mmc->caps = MMC_CAP_4_BIT_DATA;
        mmc->f_min = 20000000 / 60;
        mmc->f_max = 24000000;

        mmc->max_blk_count = 2048;
        mmc->max_segs = mmc->max_blk_count;
        mmc->max_blk_size = min(TIFM_MMCSD_MAX_BLOCK_SIZE, PAGE_SIZE);
        mmc->max_seg_size = mmc->max_blk_count * mmc->max_blk_size;
        mmc->max_req_size = mmc->max_seg_size;

        sock->card_event = tifm_sd_card_event;
        sock->data_event = tifm_sd_data_event;
        rc = tifm_sd_initialize_host(host);

        if (!rc)
                rc = mmc_add_host(mmc);

        return rc;
}

static void tifm_sd_remove(struct tifm_dev *sock)
{
        struct mmc_host *mmc = tifm_get_drvdata(sock);
        struct tifm_sd *host = mmc_priv(mmc);
        unsigned long flags;

        spin_lock_irqsave(&sock->lock, flags);
        host->eject = 1;
        writel(0, sock->addr + SOCK_MMCSD_INT_ENABLE);
        spin_unlock_irqrestore(&sock->lock, flags);

        cancel_work_sync(&host->finish_bh_work);

        spin_lock_irqsave(&sock->lock, flags);
        if (host->req) {
                writel(TIFM_FIFO_INT_SETALL,
                       sock->addr + SOCK_DMA_FIFO_INT_ENABLE_CLEAR);
                writel(0, sock->addr + SOCK_DMA_FIFO_INT_ENABLE_SET);
                host->req->cmd->error = -ENOMEDIUM;
                if (host->req->stop)
                        host->req->stop->error = -ENOMEDIUM;
                queue_work(system_bh_wq, &host->finish_bh_work);
        }
        spin_unlock_irqrestore(&sock->lock, flags);
        mmc_remove_host(mmc);
        dev_dbg(&sock->dev, "after remove\n");
}

#ifdef CONFIG_PM

static int tifm_sd_suspend(struct tifm_dev *sock, pm_message_t state)
{
        return 0;
}

static int tifm_sd_resume(struct tifm_dev *sock)
{
        struct mmc_host *mmc = tifm_get_drvdata(sock);
        struct tifm_sd *host = mmc_priv(mmc);
        int rc;

        rc = tifm_sd_initialize_host(host);
        dev_dbg(&sock->dev, "resume initialize %d\n", rc);

        if (rc)
                host->eject = 1;

        return rc;
}

#else

#define tifm_sd_suspend NULL
#define tifm_sd_resume NULL

#endif /* CONFIG_PM */

static const struct tifm_device_id tifm_sd_id_tbl[] = {
        { TIFM_TYPE_SD }, { }
};
MODULE_DEVICE_TABLE(tifm, tifm_sd_id_tbl);

static struct tifm_driver tifm_sd_driver = {
        .driver = {
                .name  = DRIVER_NAME,
                .owner = THIS_MODULE
        },
        .id_table = tifm_sd_id_tbl,
        .probe    = tifm_sd_probe,
        .remove   = tifm_sd_remove,
        .suspend  = tifm_sd_suspend,
        .resume   = tifm_sd_resume
};

static int __init tifm_sd_init(void)
{
        return tifm_register_driver(&tifm_sd_driver);
}

static void __exit tifm_sd_exit(void)
{
        tifm_unregister_driver(&tifm_sd_driver);
}

MODULE_AUTHOR("Alex Dubov");
MODULE_DESCRIPTION("TI FlashMedia SD driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRIVER_VERSION);

module_init(tifm_sd_init);
module_exit(tifm_sd_exit);