spi: reorganize drivers

Sort the SPI makefile and enforce the naming convention spi_*.c for
spi drivers.

This change also rolls the contents of atmel_spi.h into the .c file
since there is only one user of that particular include file.

v2: - Use 'spi-' prefix instead of 'spi_' to match what seems to be
      be the predominant pattern for subsystem prefixes.
    - Clean up filenames in Kconfig and header comment blocks

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 936 insertions, 0 deletions

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
new file mode 100644
index 000000000000..ece5f69deaaf
--- /dev/null
+++ b/drivers/spi/spi-dw.c
@@ -0,0 +1,936 @@
+/*
+ * Designware SPI core controller driver (refer pxa2xx_spi.c)
+ *
+ * Copyright (c) 2009, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/highmem.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "spi-dw.h"
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
+
+#define START_STATE     ((void *)0)
+#define RUNNING_STATE   ((void *)1)
+#define DONE_STATE      ((void *)2)
+#define ERROR_STATE     ((void *)-1)
+
+#define QUEUE_RUNNING   0
+#define QUEUE_STOPPED   1
+
+#define MRST_SPI_DEASSERT       0
+#define MRST_SPI_ASSERT         1
+
+/* Slave spi_dev related */
+struct chip_data {
+        u16 cr0;
+        u8 cs;                  /* chip select pin */
+        u8 n_bytes;             /* current is a 1/2/4 byte op */
+        u8 tmode;               /* TR/TO/RO/EEPROM */
+        u8 type;                /* SPI/SSP/MicroWire */
+
+        u8 poll_mode;           /* 1 means use poll mode */
+
+        u32 dma_width;
+        u32 rx_threshold;
+        u32 tx_threshold;
+        u8 enable_dma;
+        u8 bits_per_word;
+        u16 clk_div;            /* baud rate divider */
+        u32 speed_hz;           /* baud rate */
+        void (*cs_control)(u32 command);
+};
+
+#ifdef CONFIG_DEBUG_FS
+static int spi_show_regs_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+#define SPI_REGS_BUFSIZE        1024
+static ssize_t  spi_show_regs(struct file *file, char __user *user_buf,
+                                size_t count, loff_t *ppos)
+{
+        struct dw_spi *dws;
+        char *buf;
+        u32 len = 0;
+        ssize_t ret;
+
+        dws = file->private_data;
+
+        buf = kzalloc(SPI_REGS_BUFSIZE, GFP_KERNEL);
+        if (!buf)
+                return 0;
+
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "MRST SPI0 registers:\n");
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "=================================\n");
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "CTRL0: \t\t0x%08x\n", dw_readl(dws, ctrl0));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "CTRL1: \t\t0x%08x\n", dw_readl(dws, ctrl1));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "SSIENR: \t0x%08x\n", dw_readl(dws, ssienr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "SER: \t\t0x%08x\n", dw_readl(dws, ser));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "BAUDR: \t\t0x%08x\n", dw_readl(dws, baudr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "TXFTLR: \t0x%08x\n", dw_readl(dws, txfltr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "RXFTLR: \t0x%08x\n", dw_readl(dws, rxfltr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "TXFLR: \t\t0x%08x\n", dw_readl(dws, txflr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "RXFLR: \t\t0x%08x\n", dw_readl(dws, rxflr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "SR: \t\t0x%08x\n", dw_readl(dws, sr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "IMR: \t\t0x%08x\n", dw_readl(dws, imr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "ISR: \t\t0x%08x\n", dw_readl(dws, isr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "DMACR: \t\t0x%08x\n", dw_readl(dws, dmacr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "DMATDLR: \t0x%08x\n", dw_readl(dws, dmatdlr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "DMARDLR: \t0x%08x\n", dw_readl(dws, dmardlr));
+        len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
+                        "=================================\n");
+
+        ret =  simple_read_from_buffer(user_buf, count, ppos, buf, len);
+        kfree(buf);
+        return ret;
+}
+
+static const struct file_operations mrst_spi_regs_ops = {
+        .owner          = THIS_MODULE,
+        .open           = spi_show_regs_open,
+        .read           = spi_show_regs,
+        .llseek         = default_llseek,
+};
+
+static int mrst_spi_debugfs_init(struct dw_spi *dws)
+{
+        dws->debugfs = debugfs_create_dir("mrst_spi", NULL);
+        if (!dws->debugfs)
+                return -ENOMEM;
+
+        debugfs_create_file("registers", S_IFREG | S_IRUGO,
+                dws->debugfs, (void *)dws, &mrst_spi_regs_ops);
+        return 0;
+}
+
+static void mrst_spi_debugfs_remove(struct dw_spi *dws)
+{
+        if (dws->debugfs)
+                debugfs_remove_recursive(dws->debugfs);
+}
+
+#else
+static inline int mrst_spi_debugfs_init(struct dw_spi *dws)
+{
+        return 0;
+}
+
+static inline void mrst_spi_debugfs_remove(struct dw_spi *dws)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+/* Return the max entries we can fill into tx fifo */
+static inline u32 tx_max(struct dw_spi *dws)
+{
+        u32 tx_left, tx_room, rxtx_gap;
+
+        tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
+        tx_room = dws->fifo_len - dw_readw(dws, txflr);
+
+        /*
+         * Another concern is about the tx/rx mismatch, we
+         * though to use (dws->fifo_len - rxflr - txflr) as
+         * one maximum value for tx, but it doesn't cover the
+         * data which is out of tx/rx fifo and inside the
+         * shift registers. So a control from sw point of
+         * view is taken.
+         */
+        rxtx_gap =  ((dws->rx_end - dws->rx) - (dws->tx_end - dws->tx))
+                        / dws->n_bytes;
+
+        return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
+}
+
+/* Return the max entries we should read out of rx fifo */
+static inline u32 rx_max(struct dw_spi *dws)
+{
+        u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
+
+        return min(rx_left, (u32)dw_readw(dws, rxflr));
+}
+
+static void dw_writer(struct dw_spi *dws)
+{
+        u32 max = tx_max(dws);
+        u16 txw = 0;
+
+        while (max--) {
+                /* Set the tx word if the transfer's original "tx" is not null */
+                if (dws->tx_end - dws->len) {
+                        if (dws->n_bytes == 1)
+                                txw = *(u8 *)(dws->tx);
+                        else
+                                txw = *(u16 *)(dws->tx);
+                }
+                dw_writew(dws, dr, txw);
+                dws->tx += dws->n_bytes;
+        }
+}
+
+static void dw_reader(struct dw_spi *dws)
+{
+        u32 max = rx_max(dws);
+        u16 rxw;
+
+        while (max--) {
+                rxw = dw_readw(dws, dr);
+                /* Care rx only if the transfer's original "rx" is not null */
+                if (dws->rx_end - dws->len) {
+                        if (dws->n_bytes == 1)
+                                *(u8 *)(dws->rx) = rxw;
+                        else
+                                *(u16 *)(dws->rx) = rxw;
+                }
+                dws->rx += dws->n_bytes;
+        }
+}
+
+static void *next_transfer(struct dw_spi *dws)
+{
+        struct spi_message *msg = dws->cur_msg;
+        struct spi_transfer *trans = dws->cur_transfer;
+
+        /* Move to next transfer */
+        if (trans->transfer_list.next != &msg->transfers) {
+                dws->cur_transfer =
+                        list_entry(trans->transfer_list.next,
+                                        struct spi_transfer,
+                                        transfer_list);
+                return RUNNING_STATE;
+        } else
+                return DONE_STATE;
+}
+
+/*
+ * Note: first step is the protocol driver prepares
+ * a dma-capable memory, and this func just need translate
+ * the virt addr to physical
+ */
+static int map_dma_buffers(struct dw_spi *dws)
+{
+        if (!dws->cur_msg->is_dma_mapped
+                || !dws->dma_inited
+                || !dws->cur_chip->enable_dma
+                || !dws->dma_ops)
+                return 0;
+
+        if (dws->cur_transfer->tx_dma)
+                dws->tx_dma = dws->cur_transfer->tx_dma;
+
+        if (dws->cur_transfer->rx_dma)
+                dws->rx_dma = dws->cur_transfer->rx_dma;
+
+        return 1;
+}
+
+/* Caller already set message->status; dma and pio irqs are blocked */
+static void giveback(struct dw_spi *dws)
+{
+        struct spi_transfer *last_transfer;
+        unsigned long flags;
+        struct spi_message *msg;
+
+        spin_lock_irqsave(&dws->lock, flags);
+        msg = dws->cur_msg;
+        dws->cur_msg = NULL;
+        dws->cur_transfer = NULL;
+        dws->prev_chip = dws->cur_chip;
+        dws->cur_chip = NULL;
+        dws->dma_mapped = 0;
+        queue_work(dws->workqueue, &dws->pump_messages);
+        spin_unlock_irqrestore(&dws->lock, flags);
+
+        last_transfer = list_entry(msg->transfers.prev,
+                                        struct spi_transfer,
+                                        transfer_list);
+
+        if (!last_transfer->cs_change && dws->cs_control)
+                dws->cs_control(MRST_SPI_DEASSERT);
+
+        msg->state = NULL;
+        if (msg->complete)
+                msg->complete(msg->context);
+}
+
+static void int_error_stop(struct dw_spi *dws, const char *msg)
+{
+        /* Stop the hw */
+        spi_enable_chip(dws, 0);
+
+        dev_err(&dws->master->dev, "%s\n", msg);
+        dws->cur_msg->state = ERROR_STATE;
+        tasklet_schedule(&dws->pump_transfers);
+}
+
+void dw_spi_xfer_done(struct dw_spi *dws)
+{
+        /* Update total byte transferred return count actual bytes read */
+        dws->cur_msg->actual_length += dws->len;
+
+        /* Move to next transfer */
+        dws->cur_msg->state = next_transfer(dws);
+
+        /* Handle end of message */
+        if (dws->cur_msg->state == DONE_STATE) {
+                dws->cur_msg->status = 0;
+                giveback(dws);
+        } else
+                tasklet_schedule(&dws->pump_transfers);
+}
+EXPORT_SYMBOL_GPL(dw_spi_xfer_done);
+
+static irqreturn_t interrupt_transfer(struct dw_spi *dws)
+{
+        u16 irq_status = dw_readw(dws, isr);
+
+        /* Error handling */
+        if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
+                dw_readw(dws, txoicr);
+                dw_readw(dws, rxoicr);
+                dw_readw(dws, rxuicr);
+                int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
+                return IRQ_HANDLED;
+        }
+
+        dw_reader(dws);
+        if (dws->rx_end == dws->rx) {
+                spi_mask_intr(dws, SPI_INT_TXEI);
+                dw_spi_xfer_done(dws);
+                return IRQ_HANDLED;
+        }
+        if (irq_status & SPI_INT_TXEI) {
+                spi_mask_intr(dws, SPI_INT_TXEI);
+                dw_writer(dws);
+                /* Enable TX irq always, it will be disabled when RX finished */
+                spi_umask_intr(dws, SPI_INT_TXEI);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t dw_spi_irq(int irq, void *dev_id)
+{
+        struct dw_spi *dws = dev_id;
+        u16 irq_status = dw_readw(dws, isr) & 0x3f;
+
+        if (!irq_status)
+                return IRQ_NONE;
+
+        if (!dws->cur_msg) {
+                spi_mask_intr(dws, SPI_INT_TXEI);
+                return IRQ_HANDLED;
+        }
+
+        return dws->transfer_handler(dws);
+}
+
+/* Must be called inside pump_transfers() */
+static void poll_transfer(struct dw_spi *dws)
+{
+        do {
+                dw_writer(dws);
+                dw_reader(dws);
+                cpu_relax();
+        } while (dws->rx_end > dws->rx);
+
+        dw_spi_xfer_done(dws);
+}
+
+static void pump_transfers(unsigned long data)
+{
+        struct dw_spi *dws = (struct dw_spi *)data;
+        struct spi_message *message = NULL;
+        struct spi_transfer *transfer = NULL;
+        struct spi_transfer *previous = NULL;
+        struct spi_device *spi = NULL;
+        struct chip_data *chip = NULL;
+        u8 bits = 0;
+        u8 imask = 0;
+        u8 cs_change = 0;
+        u16 txint_level = 0;
+        u16 clk_div = 0;
+        u32 speed = 0;
+        u32 cr0 = 0;
+
+        /* Get current state information */
+        message = dws->cur_msg;
+        transfer = dws->cur_transfer;
+        chip = dws->cur_chip;
+        spi = message->spi;
+
+        if (unlikely(!chip->clk_div))
+                chip->clk_div = dws->max_freq / chip->speed_hz;
+
+        if (message->state == ERROR_STATE) {
+                message->status = -EIO;
+                goto early_exit;
+        }
+
+        /* Handle end of message */
+        if (message->state == DONE_STATE) {
+                message->status = 0;
+                goto early_exit;
+        }
+
+        /* Delay if requested at end of transfer*/
+        if (message->state == RUNNING_STATE) {
+                previous = list_entry(transfer->transfer_list.prev,
+                                        struct spi_transfer,
+                                        transfer_list);
+                if (previous->delay_usecs)
+                        udelay(previous->delay_usecs);
+        }
+
+        dws->n_bytes = chip->n_bytes;
+        dws->dma_width = chip->dma_width;
+        dws->cs_control = chip->cs_control;
+
+        dws->rx_dma = transfer->rx_dma;
+        dws->tx_dma = transfer->tx_dma;
+        dws->tx = (void *)transfer->tx_buf;
+        dws->tx_end = dws->tx + transfer->len;
+        dws->rx = transfer->rx_buf;
+        dws->rx_end = dws->rx + transfer->len;
+        dws->cs_change = transfer->cs_change;
+        dws->len = dws->cur_transfer->len;
+        if (chip != dws->prev_chip)
+                cs_change = 1;
+
+        cr0 = chip->cr0;
+
+        /* Handle per transfer options for bpw and speed */
+        if (transfer->speed_hz) {
+                speed = chip->speed_hz;
+
+                if (transfer->speed_hz != speed) {
+                        speed = transfer->speed_hz;
+                        if (speed > dws->max_freq) {
+                                printk(KERN_ERR "MRST SPI0: unsupported"
+                                        "freq: %dHz\n", speed);
+                                message->status = -EIO;
+                                goto early_exit;
+                        }
+
+                        /* clk_div doesn't support odd number */
+                        clk_div = dws->max_freq / speed;
+                        clk_div = (clk_div + 1) & 0xfffe;
+
+                        chip->speed_hz = speed;
+                        chip->clk_div = clk_div;
+                }
+        }
+        if (transfer->bits_per_word) {
+                bits = transfer->bits_per_word;
+
+                switch (bits) {
+                case 8:
+                case 16:
+                        dws->n_bytes = dws->dma_width = bits >> 3;
+                        break;
+                default:
+                        printk(KERN_ERR "MRST SPI0: unsupported bits:"
+                                "%db\n", bits);
+                        message->status = -EIO;
+                        goto early_exit;
+                }
+
+                cr0 = (bits - 1)
+                        | (chip->type << SPI_FRF_OFFSET)
+                        | (spi->mode << SPI_MODE_OFFSET)
+                        | (chip->tmode << SPI_TMOD_OFFSET);
+        }
+        message->state = RUNNING_STATE;
+
+        /*
+         * Adjust transfer mode if necessary. Requires platform dependent
+         * chipselect mechanism.
+         */
+        if (dws->cs_control) {
+                if (dws->rx && dws->tx)
+                        chip->tmode = SPI_TMOD_TR;
+                else if (dws->rx)
+                        chip->tmode = SPI_TMOD_RO;
+                else
+                        chip->tmode = SPI_TMOD_TO;
+
+                cr0 &= ~SPI_TMOD_MASK;
+                cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
+        }
+
+        /* Check if current transfer is a DMA transaction */
+        dws->dma_mapped = map_dma_buffers(dws);
+
+        /*
+         * Interrupt mode
+         * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
+         */
+        if (!dws->dma_mapped && !chip->poll_mode) {
+                int templen = dws->len / dws->n_bytes;
+                txint_level = dws->fifo_len / 2;
+                txint_level = (templen > txint_level) ? txint_level : templen;
+
+                imask |= SPI_INT_TXEI | SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI;
+                dws->transfer_handler = interrupt_transfer;
+        }
+
+        /*
+         * Reprogram registers only if
+         *      1. chip select changes
+         *      2. clk_div is changed
+         *      3. control value changes
+         */
+        if (dw_readw(dws, ctrl0) != cr0 || cs_change || clk_div || imask) {
+                spi_enable_chip(dws, 0);
+
+                if (dw_readw(dws, ctrl0) != cr0)
+                        dw_writew(dws, ctrl0, cr0);
+
+                spi_set_clk(dws, clk_div ? clk_div : chip->clk_div);
+                spi_chip_sel(dws, spi->chip_select);
+
+                /* Set the interrupt mask, for poll mode just disable all int */
+                spi_mask_intr(dws, 0xff);
+                if (imask)
+                        spi_umask_intr(dws, imask);
+                if (txint_level)
+                        dw_writew(dws, txfltr, txint_level);
+
+                spi_enable_chip(dws, 1);
+                if (cs_change)
+                        dws->prev_chip = chip;
+        }
+
+        if (dws->dma_mapped)
+                dws->dma_ops->dma_transfer(dws, cs_change);
+
+        if (chip->poll_mode)
+                poll_transfer(dws);
+
+        return;
+
+early_exit:
+        giveback(dws);
+        return;
+}
+
+static void pump_messages(struct work_struct *work)
+{
+        struct dw_spi *dws =
+                container_of(work, struct dw_spi, pump_messages);
+        unsigned long flags;
+
+        /* Lock queue and check for queue work */
+        spin_lock_irqsave(&dws->lock, flags);
+        if (list_empty(&dws->queue) || dws->run == QUEUE_STOPPED) {
+                dws->busy = 0;
+                spin_unlock_irqrestore(&dws->lock, flags);
+                return;
+        }
+
+        /* Make sure we are not already running a message */
+        if (dws->cur_msg) {
+                spin_unlock_irqrestore(&dws->lock, flags);
+                return;
+        }
+
+        /* Extract head of queue */
+        dws->cur_msg = list_entry(dws->queue.next, struct spi_message, queue);
+        list_del_init(&dws->cur_msg->queue);
+
+        /* Initial message state*/
+        dws->cur_msg->state = START_STATE;
+        dws->cur_transfer = list_entry(dws->cur_msg->transfers.next,
+                                                struct spi_transfer,
+                                                transfer_list);
+        dws->cur_chip = spi_get_ctldata(dws->cur_msg->spi);
+
+        /* Mark as busy and launch transfers */
+        tasklet_schedule(&dws->pump_transfers);
+
+        dws->busy = 1;
+        spin_unlock_irqrestore(&dws->lock, flags);
+}
+
+/* spi_device use this to queue in their spi_msg */
+static int dw_spi_transfer(struct spi_device *spi, struct spi_message *msg)
+{
+        struct dw_spi *dws = spi_master_get_devdata(spi->master);
+        unsigned long flags;
+
+        spin_lock_irqsave(&dws->lock, flags);
+
+        if (dws->run == QUEUE_STOPPED) {
+                spin_unlock_irqrestore(&dws->lock, flags);
+                return -ESHUTDOWN;
+        }
+
+        msg->actual_length = 0;
+        msg->status = -EINPROGRESS;
+        msg->state = START_STATE;
+
+        list_add_tail(&msg->queue, &dws->queue);
+
+        if (dws->run == QUEUE_RUNNING && !dws->busy) {
+
+                if (dws->cur_transfer || dws->cur_msg)
+                        queue_work(dws->workqueue,
+                                        &dws->pump_messages);
+                else {
+                        /* If no other data transaction in air, just go */
+                        spin_unlock_irqrestore(&dws->lock, flags);
+                        pump_messages(&dws->pump_messages);
+                        return 0;
+                }
+        }
+
+        spin_unlock_irqrestore(&dws->lock, flags);
+        return 0;
+}
+
+/* This may be called twice for each spi dev */
+static int dw_spi_setup(struct spi_device *spi)
+{
+        struct dw_spi_chip *chip_info = NULL;
+        struct chip_data *chip;
+
+        if (spi->bits_per_word != 8 && spi->bits_per_word != 16)
+                return -EINVAL;
+
+        /* Only alloc on first setup */
+        chip = spi_get_ctldata(spi);
+        if (!chip) {
+                chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
+                if (!chip)
+                        return -ENOMEM;
+        }
+
+        /*
+         * Protocol drivers may change the chip settings, so...
+         * if chip_info exists, use it
+         */
+        chip_info = spi->controller_data;
+
+        /* chip_info doesn't always exist */
+        if (chip_info) {
+                if (chip_info->cs_control)
+                        chip->cs_control = chip_info->cs_control;
+
+                chip->poll_mode = chip_info->poll_mode;
+                chip->type = chip_info->type;
+
+                chip->rx_threshold = 0;
+                chip->tx_threshold = 0;
+
+                chip->enable_dma = chip_info->enable_dma;
+        }
+
+        if (spi->bits_per_word <= 8) {
+                chip->n_bytes = 1;
+                chip->dma_width = 1;
+        } else if (spi->bits_per_word <= 16) {
+                chip->n_bytes = 2;
+                chip->dma_width = 2;
+        } else {
+                /* Never take >16b case for MRST SPIC */
+                dev_err(&spi->dev, "invalid wordsize\n");
+                return -EINVAL;
+        }
+        chip->bits_per_word = spi->bits_per_word;
+
+        if (!spi->max_speed_hz) {
+                dev_err(&spi->dev, "No max speed HZ parameter\n");
+                return -EINVAL;
+        }
+        chip->speed_hz = spi->max_speed_hz;
+
+        chip->tmode = 0; /* Tx & Rx */
+        /* Default SPI mode is SCPOL = 0, SCPH = 0 */
+        chip->cr0 = (chip->bits_per_word - 1)
+                        | (chip->type << SPI_FRF_OFFSET)
+                        | (spi->mode  << SPI_MODE_OFFSET)
+                        | (chip->tmode << SPI_TMOD_OFFSET);
+
+        spi_set_ctldata(spi, chip);
+        return 0;
+}
+
+static void dw_spi_cleanup(struct spi_device *spi)
+{
+        struct chip_data *chip = spi_get_ctldata(spi);
+        kfree(chip);
+}
+
+static int __devinit init_queue(struct dw_spi *dws)
+{
+        INIT_LIST_HEAD(&dws->queue);
+        spin_lock_init(&dws->lock);
+
+        dws->run = QUEUE_STOPPED;
+        dws->busy = 0;
+
+        tasklet_init(&dws->pump_transfers,
+                        pump_transfers, (unsigned long)dws);
+
+        INIT_WORK(&dws->pump_messages, pump_messages);
+        dws->workqueue = create_singlethread_workqueue(
+                                        dev_name(dws->master->dev.parent));
+        if (dws->workqueue == NULL)
+                return -EBUSY;
+
+        return 0;
+}
+
+static int start_queue(struct dw_spi *dws)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&dws->lock, flags);
+
+        if (dws->run == QUEUE_RUNNING || dws->busy) {
+                spin_unlock_irqrestore(&dws->lock, flags);
+                return -EBUSY;
+        }
+
+        dws->run = QUEUE_RUNNING;
+        dws->cur_msg = NULL;
+        dws->cur_transfer = NULL;
+        dws->cur_chip = NULL;
+        dws->prev_chip = NULL;
+        spin_unlock_irqrestore(&dws->lock, flags);
+
+        queue_work(dws->workqueue, &dws->pump_messages);
+
+        return 0;
+}
+
+static int stop_queue(struct dw_spi *dws)
+{
+        unsigned long flags;
+        unsigned limit = 50;
+        int status = 0;
+
+        spin_lock_irqsave(&dws->lock, flags);
+        dws->run = QUEUE_STOPPED;
+        while ((!list_empty(&dws->queue) || dws->busy) && limit--) {
+                spin_unlock_irqrestore(&dws->lock, flags);
+                msleep(10);
+                spin_lock_irqsave(&dws->lock, flags);
+        }
+
+        if (!list_empty(&dws->queue) || dws->busy)
+                status = -EBUSY;
+        spin_unlock_irqrestore(&dws->lock, flags);
+
+        return status;
+}
+
+static int destroy_queue(struct dw_spi *dws)
+{
+        int status;
+
+        status = stop_queue(dws);
+        if (status != 0)
+                return status;
+        destroy_workqueue(dws->workqueue);
+        return 0;
+}
+
+/* Restart the controller, disable all interrupts, clean rx fifo */
+static void spi_hw_init(struct dw_spi *dws)
+{
+        spi_enable_chip(dws, 0);
+        spi_mask_intr(dws, 0xff);
+        spi_enable_chip(dws, 1);
+
+        /*
+         * Try to detect the FIFO depth if not set by interface driver,
+         * the depth could be from 2 to 256 from HW spec
+         */
+        if (!dws->fifo_len) {
+                u32 fifo;
+                for (fifo = 2; fifo <= 257; fifo++) {
+                        dw_writew(dws, txfltr, fifo);
+                        if (fifo != dw_readw(dws, txfltr))
+                                break;
+                }
+
+                dws->fifo_len = (fifo == 257) ? 0 : fifo;
+                dw_writew(dws, txfltr, 0);
+        }
+}
+
+int __devinit dw_spi_add_host(struct dw_spi *dws)
+{
+        struct spi_master *master;
+        int ret;
+
+        BUG_ON(dws == NULL);
+
+        master = spi_alloc_master(dws->parent_dev, 0);
+        if (!master) {
+                ret = -ENOMEM;
+                goto exit;
+        }
+
+        dws->master = master;
+        dws->type = SSI_MOTO_SPI;
+        dws->prev_chip = NULL;
+        dws->dma_inited = 0;
+        dws->dma_addr = (dma_addr_t)(dws->paddr + 0x60);
+
+        ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED,
+                        "dw_spi", dws);
+        if (ret < 0) {
+                dev_err(&master->dev, "can not get IRQ\n");
+                goto err_free_master;
+        }
+
+        master->mode_bits = SPI_CPOL | SPI_CPHA;
+        master->bus_num = dws->bus_num;
+        master->num_chipselect = dws->num_cs;
+        master->cleanup = dw_spi_cleanup;
+        master->setup = dw_spi_setup;
+        master->transfer = dw_spi_transfer;
+
+        /* Basic HW init */
+        spi_hw_init(dws);
+
+        if (dws->dma_ops && dws->dma_ops->dma_init) {
+                ret = dws->dma_ops->dma_init(dws);
+                if (ret) {
+                        dev_warn(&master->dev, "DMA init failed\n");
+                        dws->dma_inited = 0;
+                }
+        }
+
+        /* Initial and start queue */
+        ret = init_queue(dws);
+        if (ret) {
+                dev_err(&master->dev, "problem initializing queue\n");
+                goto err_diable_hw;
+        }
+        ret = start_queue(dws);
+        if (ret) {
+                dev_err(&master->dev, "problem starting queue\n");
+                goto err_diable_hw;
+        }
+
+        spi_master_set_devdata(master, dws);
+        ret = spi_register_master(master);
+        if (ret) {
+                dev_err(&master->dev, "problem registering spi master\n");
+                goto err_queue_alloc;
+        }
+
+        mrst_spi_debugfs_init(dws);
+        return 0;
+
+err_queue_alloc:
+        destroy_queue(dws);
+        if (dws->dma_ops && dws->dma_ops->dma_exit)
+                dws->dma_ops->dma_exit(dws);
+err_diable_hw:
+        spi_enable_chip(dws, 0);
+        free_irq(dws->irq, dws);
+err_free_master:
+        spi_master_put(master);
+exit:
+        return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_add_host);
+
+void __devexit dw_spi_remove_host(struct dw_spi *dws)
+{
+        int status = 0;
+
+        if (!dws)
+                return;
+        mrst_spi_debugfs_remove(dws);
+
+        /* Remove the queue */
+        status = destroy_queue(dws);
+        if (status != 0)
+                dev_err(&dws->master->dev, "dw_spi_remove: workqueue will not "
+                        "complete, message memory not freed\n");
+
+        if (dws->dma_ops && dws->dma_ops->dma_exit)
+                dws->dma_ops->dma_exit(dws);
+        spi_enable_chip(dws, 0);
+        /* Disable clk */
+        spi_set_clk(dws, 0);
+        free_irq(dws->irq, dws);
+
+        /* Disconnect from the SPI framework */
+        spi_unregister_master(dws->master);
+}
+EXPORT_SYMBOL_GPL(dw_spi_remove_host);
+
+int dw_spi_suspend_host(struct dw_spi *dws)
+{
+        int ret = 0;
+
+        ret = stop_queue(dws);
+        if (ret)
+                return ret;
+        spi_enable_chip(dws, 0);
+        spi_set_clk(dws, 0);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_suspend_host);
+
+int dw_spi_resume_host(struct dw_spi *dws)
+{
+        int ret;
+
+        spi_hw_init(dws);
+        ret = start_queue(dws);
+        if (ret)
+                dev_err(&dws->master->dev, "fail to start queue (%d)\n", ret);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_resume_host);
+
+MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
+MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
+MODULE_LICENSE("GPL v2");