spi.c

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/*
 * This file is part of wl1271
 *
 * Copyright (C) 2008-2009 Nokia Corporation
 *
 * Contact: Luciano Coelho <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/crc7.h>
#include <linux/spi/spi.h>
#include <linux/wl12xx.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include "wlcore.h"
#include "wl12xx_80211.h"
#include "io.h"

#define WSPI_CMD_READ                 0x40000000
#define WSPI_CMD_WRITE                0x00000000
#define WSPI_CMD_FIXED                0x20000000
#define WSPI_CMD_BYTE_LENGTH          0x1FFE0000
#define WSPI_CMD_BYTE_LENGTH_OFFSET   17
#define WSPI_CMD_BYTE_ADDR            0x0001FFFF

#define WSPI_INIT_CMD_CRC_LEN       5

#define WSPI_INIT_CMD_START         0x00
#define WSPI_INIT_CMD_TX            0x40
/* the extra bypass bit is sampled by the TNET as '1' */
#define WSPI_INIT_CMD_BYPASS_BIT    0x80
#define WSPI_INIT_CMD_FIXEDBUSY_LEN 0x07
#define WSPI_INIT_CMD_EN_FIXEDBUSY  0x80
#define WSPI_INIT_CMD_DIS_FIXEDBUSY 0x00
#define WSPI_INIT_CMD_IOD           0x40
#define WSPI_INIT_CMD_IP            0x20
#define WSPI_INIT_CMD_CS            0x10
#define WSPI_INIT_CMD_WS            0x08
#define WSPI_INIT_CMD_WSPI          0x01
#define WSPI_INIT_CMD_END           0x01

#define WSPI_INIT_CMD_LEN           8

#define HW_ACCESS_WSPI_FIXED_BUSY_LEN \
        ((WL1271_BUSY_WORD_LEN - 4) / sizeof(u32))
#define HW_ACCESS_WSPI_INIT_CMD_MASK  0

/* HW limitation: maximum possible chunk size is 4095 bytes */
#define WSPI_MAX_CHUNK_SIZE    4092

/*
 * only support SPI for 12xx - this code should be reworked when 18xx
 * support is introduced
 */
#define SPI_AGGR_BUFFER_SIZE (4 * PAGE_SIZE)

#define WSPI_MAX_NUM_OF_CHUNKS (SPI_AGGR_BUFFER_SIZE / WSPI_MAX_CHUNK_SIZE)

struct wl12xx_spi_glue {
    struct device *dev;
    struct platform_device *core;
};

static void wl12xx_spi_reset(struct device *child)
{
    struct wl12xx_spi_glue *glue = dev_get_drvdata(child->parent);
    u8 *cmd;
    struct spi_transfer t;
    struct spi_message m;

    cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
    if (!cmd) {
        dev_err(child->parent,
            "could not allocate cmd for spi reset\n");
        return;
    }

    memset(&t, 0, sizeof(t));
    spi_message_init(&m);

    memset(cmd, 0xff, WSPI_INIT_CMD_LEN);

    t.tx_buf = cmd;
    t.len = WSPI_INIT_CMD_LEN;
    spi_message_add_tail(&t, &m);

    spi_sync(to_spi_device(glue->dev), &m);

    kfree(cmd);
}

static void wl12xx_spi_init(struct device *child)
{
    struct wl12xx_spi_glue *glue = dev_get_drvdata(child->parent);
    u8 crc[WSPI_INIT_CMD_CRC_LEN], *cmd;
    struct spi_transfer t;
    struct spi_message m;

    cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
    if (!cmd) {
        dev_err(child->parent,
            "could not allocate cmd for spi init\n");
        return;
    }

    memset(crc, 0, sizeof(crc));
    memset(&t, 0, sizeof(t));
    spi_message_init(&m);

    /*
     * Set WSPI_INIT_COMMAND
     * the data is being send from the MSB to LSB
     */
    cmd[2] = 0xff;
    cmd[3] = 0xff;
    cmd[1] = WSPI_INIT_CMD_START | WSPI_INIT_CMD_TX;
    cmd[0] = 0;
    cmd[7] = 0;
    cmd[6] |= HW_ACCESS_WSPI_INIT_CMD_MASK << 3;
    cmd[6] |= HW_ACCESS_WSPI_FIXED_BUSY_LEN & WSPI_INIT_CMD_FIXEDBUSY_LEN;

    if (HW_ACCESS_WSPI_FIXED_BUSY_LEN == 0)
        cmd[5] |=  WSPI_INIT_CMD_DIS_FIXEDBUSY;
    else
        cmd[5] |= WSPI_INIT_CMD_EN_FIXEDBUSY;

    cmd[5] |= WSPI_INIT_CMD_IOD | WSPI_INIT_CMD_IP | WSPI_INIT_CMD_CS
        | WSPI_INIT_CMD_WSPI | WSPI_INIT_CMD_WS;

    crc[0] = cmd[1];
    crc[1] = cmd[0];
    crc[2] = cmd[7];
    crc[3] = cmd[6];
    crc[4] = cmd[5];

    cmd[4] |= crc7(0, crc, WSPI_INIT_CMD_CRC_LEN) << 1;
    cmd[4] |= WSPI_INIT_CMD_END;

    t.tx_buf = cmd;
    t.len = WSPI_INIT_CMD_LEN;
    spi_message_add_tail(&t, &m);

    spi_sync(to_spi_device(glue->dev), &m);
    kfree(cmd);
}

#define WL1271_BUSY_WORD_TIMEOUT 1000

static int wl12xx_spi_read_busy(struct device *child)
{
    struct wl12xx_spi_glue *glue = dev_get_drvdata(child->parent);
    struct wl1271 *wl = dev_get_drvdata(child);
    struct spi_transfer t[1];
    struct spi_message m;
    u32 *busy_buf;
    int num_busy_bytes = 0;

    /*
     * Read further busy words from SPI until a non-busy word is
     * encountered, then read the data itself into the buffer.
     */

    num_busy_bytes = WL1271_BUSY_WORD_TIMEOUT;
    busy_buf = wl->buffer_busyword;
    while (num_busy_bytes) {
        num_busy_bytes--;
        spi_message_init(&m);
        memset(t, 0, sizeof(t));
        t[0].rx_buf = busy_buf;
        t[0].len = sizeof(u32);
        t[0].cs_change = true;
        spi_message_add_tail(&t[0], &m);
        spi_sync(to_spi_device(glue->dev), &m);

        if (*busy_buf & 0x1)
            return 0;
    }

    /* The SPI bus is unresponsive, the read failed. */
    dev_err(child->parent, "SPI read busy-word timeout!\n");
    return -ETIMEDOUT;
}

static int __must_check wl12xx_spi_raw_read(struct device *child, int addr,
                        void *buf, size_t len, bool fixed)
{
    struct wl12xx_spi_glue *glue = dev_get_drvdata(child->parent);
    struct wl1271 *wl = dev_get_drvdata(child);
    struct spi_transfer t[2];
    struct spi_message m;
    u32 *busy_buf;
    u32 *cmd;
    u32 chunk_len;

    while (len > 0) {
        chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);

        cmd = &wl->buffer_cmd;
        busy_buf = wl->buffer_busyword;

        *cmd = 0;
        *cmd |= WSPI_CMD_READ;
        *cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
            WSPI_CMD_BYTE_LENGTH;
        *cmd |= addr & WSPI_CMD_BYTE_ADDR;

        if (fixed)
            *cmd |= WSPI_CMD_FIXED;

        spi_message_init(&m);
        memset(t, 0, sizeof(t));

        t[0].tx_buf = cmd;
        t[0].len = 4;
        t[0].cs_change = true;
        spi_message_add_tail(&t[0], &m);

        /* Busy and non busy words read */
        t[1].rx_buf = busy_buf;
        t[1].len = WL1271_BUSY_WORD_LEN;
        t[1].cs_change = true;
        spi_message_add_tail(&t[1], &m);

        spi_sync(to_spi_device(glue->dev), &m);

        if (!(busy_buf[WL1271_BUSY_WORD_CNT - 1] & 0x1) &&
            wl12xx_spi_read_busy(child)) {
            memset(buf, 0, chunk_len);
            return 0;
        }

        spi_message_init(&m);
        memset(t, 0, sizeof(t));

        t[0].rx_buf = buf;
        t[0].len = chunk_len;
        t[0].cs_change = true;
        spi_message_add_tail(&t[0], &m);

        spi_sync(to_spi_device(glue->dev), &m);

        if (!fixed)
            addr += chunk_len;
        buf += chunk_len;
        len -= chunk_len;
    }

    return 0;
}

static int __must_check wl12xx_spi_raw_write(struct device *child, int addr,
                         void *buf, size_t len, bool fixed)
{
    struct wl12xx_spi_glue *glue = dev_get_drvdata(child->parent);
    struct spi_transfer t[2 * WSPI_MAX_NUM_OF_CHUNKS];
    struct spi_message m;
    u32 commands[WSPI_MAX_NUM_OF_CHUNKS];
    u32 *cmd;
    u32 chunk_len;
    int i;

    WARN_ON(len > SPI_AGGR_BUFFER_SIZE);

    spi_message_init(&m);
    memset(t, 0, sizeof(t));

    cmd = &commands[0];
    i = 0;
    while (len > 0) {
        chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);

        *cmd = 0;
        *cmd |= WSPI_CMD_WRITE;
        *cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
            WSPI_CMD_BYTE_LENGTH;
        *cmd |= addr & WSPI_CMD_BYTE_ADDR;

        if (fixed)
            *cmd |= WSPI_CMD_FIXED;

        t[i].tx_buf = cmd;
        t[i].len = sizeof(*cmd);
        spi_message_add_tail(&t[i++], &m);

        t[i].tx_buf = buf;
        t[i].len = chunk_len;
        spi_message_add_tail(&t[i++], &m);

        if (!fixed)
            addr += chunk_len;
        buf += chunk_len;
        len -= chunk_len;
        cmd++;
    }

    spi_sync(to_spi_device(glue->dev), &m);

    return 0;
}

static struct wl1271_if_operations spi_ops = {
    .read       = wl12xx_spi_raw_read,
    .write      = wl12xx_spi_raw_write,
    .reset      = wl12xx_spi_reset,
    .init       = wl12xx_spi_init,
    .set_block_size = NULL,
};

static int __devinit wl1271_probe(struct spi_device *spi)
{
    struct wl12xx_spi_glue *glue;
    struct wl12xx_platform_data *pdata;
    struct resource res[1];
    int ret = -ENOMEM;

    pdata = spi->dev.platform_data;
    if (!pdata) {
        dev_err(&spi->dev, "no platform data\n");
        return -ENODEV;
    }

    pdata->ops = &spi_ops;

    glue = kzalloc(sizeof(*glue), GFP_KERNEL);
    if (!glue) {
        dev_err(&spi->dev, "can't allocate glue\n");
        goto out;
    }

    glue->dev = &spi->dev;

    spi_set_drvdata(spi, glue);

    /* This is the only SPI value that we need to set here, the rest
     * comes from the board-peripherals file */
    spi->bits_per_word = 32;

    ret = spi_setup(spi);
    if (ret < 0) {
        dev_err(glue->dev, "spi_setup failed\n");
        goto out_free_glue;
    }

    glue->core = platform_device_alloc("wl12xx", -1);
    if (!glue->core) {
        dev_err(glue->dev, "can't allocate platform_device\n");
        ret = -ENOMEM;
        goto out_free_glue;
    }

    glue->core->dev.parent = &spi->dev;

    memset(res, 0x00, sizeof(res));

    res[0].start = spi->irq;
    res[0].flags = IORESOURCE_IRQ;
    res[0].name = "irq";

    ret = platform_device_add_resources(glue->core, res, ARRAY_SIZE(res));
    if (ret) {
        dev_err(glue->dev, "can't add resources\n");
        goto out_dev_put;
    }

    ret = platform_device_add_data(glue->core, pdata, sizeof(*pdata));
    if (ret) {
        dev_err(glue->dev, "can't add platform data\n");
        goto out_dev_put;
    }

    ret = platform_device_add(glue->core);
    if (ret) {
        dev_err(glue->dev, "can't register platform device\n");
        goto out_dev_put;
    }

    return 0;

out_dev_put:
    platform_device_put(glue->core);

out_free_glue:
    kfree(glue);
out:
    return ret;
}

static int __devexit wl1271_remove(struct spi_device *spi)
{
    struct wl12xx_spi_glue *glue = spi_get_drvdata(spi);

    platform_device_del(glue->core);
    platform_device_put(glue->core);
    kfree(glue);

    return 0;
}


static struct spi_driver wl1271_spi_driver = {
    .driver = {
        .name       = "wl1271_spi",
        .owner      = THIS_MODULE,
    },

    .probe      = wl1271_probe,
    .remove     = __devexit_p(wl1271_remove),
};

static int __init wl1271_init(void)
{
    return spi_register_driver(&wl1271_spi_driver);
}

static void __exit wl1271_exit(void)
{
    spi_unregister_driver(&wl1271_spi_driver);
}

module_init(wl1271_init);
module_exit(wl1271_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Luciano Coelho <[email protected]>");
MODULE_AUTHOR("Juuso Oikarinen <[email protected]>");
MODULE_ALIAS("spi:wl1271");