ipack.c

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/*
 * Industry-pack bus support functions.
 *
 * (C) 2011 Samuel Iglesias Gonsalvez <[email protected]>, CERN
 * (C) 2012 Samuel Iglesias Gonsalvez <[email protected]>, Igalia
 *
 * 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; version 2 of the License.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <asm/io.h>
#include "ipack.h"

#define to_ipack_dev(device) container_of(device, struct ipack_device, dev)
#define to_ipack_driver(drv) container_of(drv, struct ipack_driver, driver)

static DEFINE_IDA(ipack_ida);

static void ipack_device_release(struct device *dev)
{
    struct ipack_device *device = to_ipack_dev(dev);
    kfree(device->id);
    kfree(device);
}

static inline const struct ipack_device_id *
ipack_match_one_device(const struct ipack_device_id *id,
               const struct ipack_device *device)
{
    if ((id->format == IPACK_ANY_FORMAT ||
                id->format == device->id_format) &&
        (id->vendor == IPACK_ANY_ID || id->vendor == device->id_vendor) &&
        (id->device == IPACK_ANY_ID || id->device == device->id_device))
        return id;
    return NULL;
}

static const struct ipack_device_id *
ipack_match_id(const struct ipack_device_id *ids, struct ipack_device *idev)
{
    if (ids) {
        while (ids->vendor || ids->device) {
            if (ipack_match_one_device(ids, idev))
                return ids;
            ids++;
        }
    }
    return NULL;
}

static int ipack_bus_match(struct device *dev, struct device_driver *drv)
{
    struct ipack_device *idev = to_ipack_dev(dev);
    struct ipack_driver *idrv = to_ipack_driver(drv);
    const struct ipack_device_id *found_id;

    found_id = ipack_match_id(idrv->id_table, idev);
    return found_id ? 1 : 0;
}

static int ipack_bus_probe(struct device *device)
{
    struct ipack_device *dev = to_ipack_dev(device);
    struct ipack_driver *drv = to_ipack_driver(device->driver);

    if (!drv->ops->probe)
        return -EINVAL;

    return drv->ops->probe(dev);
}

static int ipack_bus_remove(struct device *device)
{
    struct ipack_device *dev = to_ipack_dev(device);
    struct ipack_driver *drv = to_ipack_driver(device->driver);

    if (!drv->ops->remove)
        return -EINVAL;

    drv->ops->remove(dev);
    return 0;
}

#ifdef CONFIG_HOTPLUG

static int ipack_uevent(struct device *dev, struct kobj_uevent_env *env)
{
    struct ipack_device *idev;

    if (!dev)
        return -ENODEV;

    idev = to_ipack_dev(dev);

    if (add_uevent_var(env,
               "MODALIAS=ipack:f%02Xv%08Xd%08X", idev->id_format,
               idev->id_vendor, idev->id_device))
        return -ENOMEM;

    return 0;
}

#else /* !CONFIG_HOTPLUG */

#define ipack_uevent NULL

#endif /* !CONFIG_HOTPLUG */

#define ipack_device_attr(field, format_string)             \
static ssize_t                              \
field##_show(struct device *dev, struct device_attribute *attr,     \
        char *buf)                      \
{                                   \
    struct ipack_device *idev = to_ipack_dev(dev);          \
    return sprintf(buf, format_string, idev->field);        \
}

static ssize_t id_show(struct device *dev,
               struct device_attribute *attr, char *buf)
{
    unsigned int i, c, l, s;
    struct ipack_device *idev = to_ipack_dev(dev);


    switch (idev->id_format) {
    case IPACK_ID_VERSION_1:
        l = 0x7; s = 1; break;
    case IPACK_ID_VERSION_2:
        l = 0xf; s = 2; break;
    default:
        return -EIO;
    }
    c = 0;
    for (i = 0; i < idev->id_avail; i++) {
        if (i > 0) {
            if ((i & l) == 0)
                buf[c++] = '\n';
            else if ((i & s) == 0)
                buf[c++] = ' ';
        }
        sprintf(&buf[c], "%02x", idev->id[i]);
        c += 2;
    }
    buf[c++] = '\n';
    return c;
}

static ssize_t
id_vendor_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct ipack_device *idev = to_ipack_dev(dev);
    switch (idev->id_format) {
    case IPACK_ID_VERSION_1:
        return sprintf(buf, "0x%02x\n", idev->id_vendor);
    case IPACK_ID_VERSION_2:
        return sprintf(buf, "0x%06x\n", idev->id_vendor);
    default:
        return -EIO;
    }
}

static ssize_t
id_device_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct ipack_device *idev = to_ipack_dev(dev);
    switch (idev->id_format) {
    case IPACK_ID_VERSION_1:
        return sprintf(buf, "0x%02x\n", idev->id_device);
    case IPACK_ID_VERSION_2:
        return sprintf(buf, "0x%04x\n", idev->id_device);
    default:
        return -EIO;
    }
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
                 char *buf)
{
    struct ipack_device *idev = to_ipack_dev(dev);

    return sprintf(buf, "ipac:f%02Xv%08Xd%08X", idev->id_format,
               idev->id_vendor, idev->id_device);
}

ipack_device_attr(id_format, "0x%hhu\n");

static struct device_attribute ipack_dev_attrs[] = {
    __ATTR_RO(id),
    __ATTR_RO(id_device),
    __ATTR_RO(id_format),
    __ATTR_RO(id_vendor),
    __ATTR_RO(modalias),
};

static struct bus_type ipack_bus_type = {
    .name      = "ipack",
    .probe     = ipack_bus_probe,
    .match     = ipack_bus_match,
    .remove    = ipack_bus_remove,
    .dev_attrs = ipack_dev_attrs,
    .uevent    = ipack_uevent,
};

struct ipack_bus_device *ipack_bus_register(struct device *parent, int slots,
                        const struct ipack_bus_ops *ops)
{
    int bus_nr;
    struct ipack_bus_device *bus;

    bus = kzalloc(sizeof(struct ipack_bus_device), GFP_KERNEL);
    if (!bus)
        return NULL;

    bus_nr = ida_simple_get(&ipack_ida, 0, 0, GFP_KERNEL);
    if (bus_nr < 0) {
        kfree(bus);
        return NULL;
    }

    bus->bus_nr = bus_nr;
    bus->parent = parent;
    bus->slots = slots;
    bus->ops = ops;
    return bus;
}
EXPORT_SYMBOL_GPL(ipack_bus_register);

static int ipack_unregister_bus_member(struct device *dev, void *data)
{
    struct ipack_device *idev = to_ipack_dev(dev);
    struct ipack_bus_device *bus = data;

    if (idev->bus_nr == bus->bus_nr)
        ipack_device_unregister(idev);

    return 1;
}

int ipack_bus_unregister(struct ipack_bus_device *bus)
{
    bus_for_each_dev(&ipack_bus_type, NULL, bus, ipack_unregister_bus_member);
    ida_simple_remove(&ipack_ida, bus->bus_nr);
    kfree(bus);
    return 0;
}
EXPORT_SYMBOL_GPL(ipack_bus_unregister);

int ipack_driver_register(struct ipack_driver *edrv, struct module *owner,
              const char *name)
{
    edrv->driver.owner = owner;
    edrv->driver.name = name;
    edrv->driver.bus = &ipack_bus_type;
    return driver_register(&edrv->driver);
}
EXPORT_SYMBOL_GPL(ipack_driver_register);

void ipack_driver_unregister(struct ipack_driver *edrv)
{
    driver_unregister(&edrv->driver);
}
EXPORT_SYMBOL_GPL(ipack_driver_unregister);

static u16 ipack_crc_byte(u16 crc, u8 c)
{
    int i;

    crc ^= c << 8;
    for (i = 0; i < 8; i++)
        crc = (crc << 1) ^ ((crc & 0x8000) ? 0x1021 : 0);
    return crc;
}

/*
 * The algorithm in lib/crc-ccitt.c does not seem to apply since it uses the
 * opposite bit ordering.
 */
static u8 ipack_calc_crc1(struct ipack_device *dev)
{
    u8 c;
    u16 crc;
    unsigned int i;

    crc = 0xffff;
    for (i = 0; i < dev->id_avail; i++) {
        c = (i != 11) ? dev->id[i] : 0;
        crc = ipack_crc_byte(crc, c);
    }
    crc = ~crc;
    return crc & 0xff;
}

static u16 ipack_calc_crc2(struct ipack_device *dev)
{
    u8 c;
    u16 crc;
    unsigned int i;

    crc = 0xffff;
    for (i = 0; i < dev->id_avail; i++) {
        c = ((i != 0x18) && (i != 0x19)) ? dev->id[i] : 0;
        crc = ipack_crc_byte(crc, c);
    }
    crc = ~crc;
    return crc;
}

static void ipack_parse_id1(struct ipack_device *dev)
{
    u8 *id = dev->id;
    u8 crc;

    dev->id_vendor = id[4];
    dev->id_device = id[5];
    dev->speed_8mhz = 1;
    dev->speed_32mhz = (id[7] == 'H');
    crc = ipack_calc_crc1(dev);
    dev->id_crc_correct = (crc == id[11]);
    if (!dev->id_crc_correct) {
        dev_warn(&dev->dev, "ID CRC invalid found 0x%x, expected 0x%x.\n",
                id[11], crc);
    }
}

static void ipack_parse_id2(struct ipack_device *dev)
{
    __be16 *id = (__be16 *) dev->id;
    u16 flags, crc;

    dev->id_vendor = ((be16_to_cpu(id[3]) & 0xff) << 16)
             + be16_to_cpu(id[4]);
    dev->id_device = be16_to_cpu(id[5]);
    flags = be16_to_cpu(id[10]);
    dev->speed_8mhz = !!(flags & 2);
    dev->speed_32mhz = !!(flags & 4);
    crc = ipack_calc_crc2(dev);
    dev->id_crc_correct = (crc == be16_to_cpu(id[12]));
    if (!dev->id_crc_correct) {
        dev_warn(&dev->dev, "ID CRC invalid found 0x%x, expected 0x%x.\n",
                id[11], crc);
    }
}

static int ipack_device_read_id(struct ipack_device *dev)
{
    u8 __iomem *idmem;
    int i;
    int ret = 0;

    ret = dev->bus->ops->map_space(dev, 0, IPACK_ID_SPACE);
    if (ret) {
        dev_err(&dev->dev, "error mapping memory\n");
        return ret;
    }
    idmem = dev->id_space.address;

    /* Determine ID PROM Data Format.  If we find the ids "IPAC" or "IPAH"
     * we are dealing with a IndustryPack  format 1 device.  If we detect
     * "VITA4 " (16 bit big endian formatted) we are dealing with a
     * IndustryPack format 2 device */
    if ((ioread8(idmem + 1) == 'I') &&
            (ioread8(idmem + 3) == 'P') &&
            (ioread8(idmem + 5) == 'A') &&
            ((ioread8(idmem + 7) == 'C') ||
             (ioread8(idmem + 7) == 'H'))) {
        dev->id_format = IPACK_ID_VERSION_1;
        dev->id_avail = ioread8(idmem + 0x15);
        if ((dev->id_avail < 0x0c) || (dev->id_avail > 0x40)) {
            dev_warn(&dev->dev, "invalid id size");
            dev->id_avail = 0x0c;
        }
    } else if ((ioread8(idmem + 0) == 'I') &&
            (ioread8(idmem + 1) == 'V') &&
            (ioread8(idmem + 2) == 'A') &&
            (ioread8(idmem + 3) == 'T') &&
            (ioread8(idmem + 4) == ' ') &&
            (ioread8(idmem + 5) == '4')) {
        dev->id_format = IPACK_ID_VERSION_2;
        dev->id_avail = ioread16be(idmem + 0x16);
        if ((dev->id_avail < 0x1a) || (dev->id_avail > 0x40)) {
            dev_warn(&dev->dev, "invalid id size");
            dev->id_avail = 0x1a;
        }
    } else {
        dev->id_format = IPACK_ID_VERSION_INVALID;
        dev->id_avail = 0;
    }

    if (!dev->id_avail) {
        ret = -ENODEV;
        goto out;
    }

    /* Obtain the amount of memory required to store a copy of the complete
     * ID ROM contents */
    dev->id = kmalloc(dev->id_avail, GFP_KERNEL);
    if (!dev->id) {
        dev_err(&dev->dev, "dev->id alloc failed.\n");
        ret = -ENOMEM;
        goto out;
    }
    for (i = 0; i < dev->id_avail; i++) {
        if (dev->id_format == IPACK_ID_VERSION_1)
            dev->id[i] = ioread8(idmem + (i << 1) + 1);
        else
            dev->id[i] = ioread8(idmem + i);
    }

    /* now we can finally work with the copy */
    switch (dev->id_format) {
    case IPACK_ID_VERSION_1:
        ipack_parse_id1(dev);
        break;
    case IPACK_ID_VERSION_2:
        ipack_parse_id2(dev);
        break;
    }

out:
    dev->bus->ops->unmap_space(dev, IPACK_ID_SPACE);

    return ret;
}

struct ipack_device *ipack_device_register(struct ipack_bus_device *bus,
                       int slot)
{
    int ret;
    struct ipack_device *dev;

    dev = kzalloc(sizeof(struct ipack_device), GFP_KERNEL);
    if (!dev)
        return NULL;

    dev->dev.bus = &ipack_bus_type;
    dev->dev.release = ipack_device_release;
    dev->dev.parent = bus->parent;
    dev->slot = slot;
    dev->bus_nr = bus->bus_nr;
    dev->bus = bus;
    dev_set_name(&dev->dev,
             "ipack-dev.%u.%u", dev->bus_nr, dev->slot);

    if (bus->ops->set_clockrate(dev, 8))
        dev_warn(&dev->dev, "failed to switch to 8 MHz operation for reading of device ID.\n");
    if (bus->ops->reset_timeout(dev))
        dev_warn(&dev->dev, "failed to reset potential timeout.");

    ret = ipack_device_read_id(dev);
    if (ret < 0) {
        dev_err(&dev->dev, "error reading device id section.\n");
        kfree(dev);
        return NULL;
    }

    /* if the device supports 32 MHz operation, use it. */
    if (dev->speed_32mhz) {
        ret = bus->ops->set_clockrate(dev, 32);
        if (ret < 0)
            dev_err(&dev->dev, "failed to switch to 32 MHz operation.\n");
    }

    ret = device_register(&dev->dev);
    if (ret < 0) {
        kfree(dev->id);
        kfree(dev);
        return NULL;
    }

    return dev;
}
EXPORT_SYMBOL_GPL(ipack_device_register);

void ipack_device_unregister(struct ipack_device *dev)
{
    device_unregister(&dev->dev);
}
EXPORT_SYMBOL_GPL(ipack_device_unregister);

static int __init ipack_init(void)
{
    ida_init(&ipack_ida);
    return bus_register(&ipack_bus_type);
}

static void __exit ipack_exit(void)
{
    bus_unregister(&ipack_bus_type);
    ida_destroy(&ipack_ida);
}

module_init(ipack_init);
module_exit(ipack_exit);

MODULE_AUTHOR("Samuel Iglesias Gonsalvez <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Industry-pack bus core");