pismo.c

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/*
 * PISMO memory driver - http://www.pismoworld.org/
 *
 * For ARM Realview and Versatile platforms
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/mtd/physmap.h>
#include <linux/mtd/plat-ram.h>
#include <linux/mtd/pismo.h>

#define PISMO_NUM_CS    5

struct pismo_cs_block {
    u8  type;
    u8  width;
    __le16  access;
    __le32  size;
    u32 reserved[2];
    char    device[32];
} __packed;

struct pismo_eeprom {
    struct pismo_cs_block cs[PISMO_NUM_CS];
    char    board[15];
    u8  sum;
} __packed;

struct pismo_mem {
    phys_addr_t base;
    u32 size;
    u16 access;
    u8  width;
    u8  type;
};

struct pismo_data {
    struct i2c_client   *client;
    void            (*vpp)(void *, int);
    void            *vpp_data;
    struct platform_device  *dev[PISMO_NUM_CS];
};

static void pismo_set_vpp(struct platform_device *pdev, int on)
{
    struct i2c_client *client = to_i2c_client(pdev->dev.parent);
    struct pismo_data *pismo = i2c_get_clientdata(client);

    pismo->vpp(pismo->vpp_data, on);
}

static unsigned int __devinit pismo_width_to_bytes(unsigned int width)
{
    width &= 15;
    if (width > 2)
        return 0;
    return 1 << width;
}

static int __devinit pismo_eeprom_read(struct i2c_client *client, void *buf,
    u8 addr, size_t size)
{
    int ret;
    struct i2c_msg msg[] = {
        {
            .addr = client->addr,
            .len = sizeof(addr),
            .buf = &addr,
        }, {
            .addr = client->addr,
            .flags = I2C_M_RD,
            .len = size,
            .buf = buf,
        },
    };

    ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));

    return ret == ARRAY_SIZE(msg) ? size : -EIO;
}

static int __devinit pismo_add_device(struct pismo_data *pismo, int i,
    struct pismo_mem *region, const char *name, void *pdata, size_t psize)
{
    struct platform_device *dev;
    struct resource res = { };
    phys_addr_t base = region->base;
    int ret;

    if (base == ~0)
        return -ENXIO;

    res.start = base;
    res.end = base + region->size - 1;
    res.flags = IORESOURCE_MEM;

    dev = platform_device_alloc(name, i);
    if (!dev)
        return -ENOMEM;
    dev->dev.parent = &pismo->client->dev;

    do {
        ret = platform_device_add_resources(dev, &res, 1);
        if (ret)
            break;

        ret = platform_device_add_data(dev, pdata, psize);
        if (ret)
            break;

        ret = platform_device_add(dev);
        if (ret)
            break;

        pismo->dev[i] = dev;
        return 0;
    } while (0);

    platform_device_put(dev);
    return ret;
}

static int __devinit pismo_add_nor(struct pismo_data *pismo, int i,
    struct pismo_mem *region)
{
    struct physmap_flash_data data = {
        .width = region->width,
    };

    if (pismo->vpp)
        data.set_vpp = pismo_set_vpp;

    return pismo_add_device(pismo, i, region, "physmap-flash",
        &data, sizeof(data));
}

static int __devinit pismo_add_sram(struct pismo_data *pismo, int i,
    struct pismo_mem *region)
{
    struct platdata_mtd_ram data = {
        .bankwidth = region->width,
    };

    return pismo_add_device(pismo, i, region, "mtd-ram",
        &data, sizeof(data));
}

static void __devinit pismo_add_one(struct pismo_data *pismo, int i,
    const struct pismo_cs_block *cs, phys_addr_t base)
{
    struct device *dev = &pismo->client->dev;
    struct pismo_mem region;

    region.base = base;
    region.type = cs->type;
    region.width = pismo_width_to_bytes(cs->width);
    region.access = le16_to_cpu(cs->access);
    region.size = le32_to_cpu(cs->size);

    if (region.width == 0) {
        dev_err(dev, "cs%u: bad width: %02x, ignoring\n", i, cs->width);
        return;
    }

    /*
     * FIXME: may need to the platforms memory controller here, but at
     * the moment we assume that it has already been correctly setup.
     * The memory controller can also tell us the base address as well.
     */

    dev_info(dev, "cs%u: %.32s: type %02x access %u00ps size %uK\n",
        i, cs->device, region.type, region.access, region.size / 1024);

    switch (region.type) {
    case 0:
        break;
    case 1:
        /* static DOC */
        break;
    case 2:
        /* static NOR */
        pismo_add_nor(pismo, i, &region);
        break;
    case 3:
        /* static RAM */
        pismo_add_sram(pismo, i, &region);
        break;
    }
}

static int __devexit pismo_remove(struct i2c_client *client)
{
    struct pismo_data *pismo = i2c_get_clientdata(client);
    int i;

    for (i = 0; i < ARRAY_SIZE(pismo->dev); i++)
        platform_device_unregister(pismo->dev[i]);

    kfree(pismo);

    return 0;
}

static int __devinit pismo_probe(struct i2c_client *client,
                 const struct i2c_device_id *id)
{
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct pismo_pdata *pdata = client->dev.platform_data;
    struct pismo_eeprom eeprom;
    struct pismo_data *pismo;
    int ret, i;

    if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
        dev_err(&client->dev, "functionality mismatch\n");
        return -EIO;
    }

    pismo = kzalloc(sizeof(*pismo), GFP_KERNEL);
    if (!pismo)
        return -ENOMEM;

    pismo->client = client;
    if (pdata) {
        pismo->vpp = pdata->set_vpp;
        pismo->vpp_data = pdata->vpp_data;
    }
    i2c_set_clientdata(client, pismo);

    ret = pismo_eeprom_read(client, &eeprom, 0, sizeof(eeprom));
    if (ret < 0) {
        dev_err(&client->dev, "error reading EEPROM: %d\n", ret);
        goto exit_free;
    }

    dev_info(&client->dev, "%.15s board found\n", eeprom.board);

    for (i = 0; i < ARRAY_SIZE(eeprom.cs); i++)
        if (eeprom.cs[i].type != 0xff)
            pismo_add_one(pismo, i, &eeprom.cs[i],
                      pdata->cs_addrs[i]);

    return 0;

 exit_free:
    kfree(pismo);
    return ret;
}

static const struct i2c_device_id pismo_id[] = {
    { "pismo" },
    { },
};
MODULE_DEVICE_TABLE(i2c, pismo_id);

static struct i2c_driver pismo_driver = {
    .driver = {
        .name   = "pismo",
        .owner  = THIS_MODULE,
    },
    .probe      = pismo_probe,
    .remove     = __devexit_p(pismo_remove),
    .id_table   = pismo_id,
};

static int __init pismo_init(void)
{
    BUILD_BUG_ON(sizeof(struct pismo_cs_block) != 48);
    BUILD_BUG_ON(sizeof(struct pismo_eeprom) != 256);

    return i2c_add_driver(&pismo_driver);
}
module_init(pismo_init);

static void __exit pismo_exit(void)
{
    i2c_del_driver(&pismo_driver);
}
module_exit(pismo_exit);

MODULE_AUTHOR("Russell King <[email protected]>");
MODULE_DESCRIPTION("PISMO memory driver");
MODULE_LICENSE("GPL");