kbuild: document howto build external modules using several directories

[linux-2.6/verdex.git] / drivers / char / tpm / tpm.c

/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Maintained by: <tpmdd_devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org       
 *
 * 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.
 * 
 * Note, the TPM chip is not interrupt driven (only polling)
 * and can have very long timeouts (minutes!). Hence the unusual
 * calls to msleep.
 *
 */

#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include "tpm.h"

enum tpm_const {
        TPM_MINOR = 224,        /* officially assigned */
        TPM_BUFSIZE = 2048,
        TPM_NUM_DEVICES = 256,
        TPM_NUM_MASK_ENTRIES = TPM_NUM_DEVICES / (8 * sizeof(int))
};

static LIST_HEAD(tpm_chip_list);
static DEFINE_SPINLOCK(driver_lock);
static int dev_mask[TPM_NUM_MASK_ENTRIES];

static void user_reader_timeout(unsigned long ptr)
{
        struct tpm_chip *chip = (struct tpm_chip *) ptr;

        schedule_work(&chip->work);
}

static void timeout_work(void * ptr)
{
        struct tpm_chip *chip = ptr;

        down(&chip->buffer_mutex);
        atomic_set(&chip->data_pending, 0);
        memset(chip->data_buffer, 0, TPM_BUFSIZE);
        up(&chip->buffer_mutex);
}

/*
 * Internal kernel interface to transmit TPM commands
 */
static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
                            size_t bufsiz)
{
        ssize_t rc;
        u32 count;
        unsigned long stop;

        count = be32_to_cpu(*((__be32 *) (buf + 2)));

        if (count == 0)
                return -ENODATA;
        if (count > bufsiz) {
                dev_err(chip->dev,
                        "invalid count value %x %zx \n", count, bufsiz);
                return -E2BIG;
        }

        down(&chip->tpm_mutex);

        if ((rc = chip->vendor->send(chip, (u8 *) buf, count)) < 0) {
                dev_err(chip->dev,
                        "tpm_transmit: tpm_send: error %zd\n", rc);
                goto out;
        }

        stop = jiffies + 2 * 60 * HZ;
        do {
                u8 status = chip->vendor->status(chip);
                if ((status & chip->vendor->req_complete_mask) ==
                    chip->vendor->req_complete_val) {
                        goto out_recv;
                }

                if ((status == chip->vendor->req_canceled)) {
                        dev_err(chip->dev, "Operation Canceled\n");
                        rc = -ECANCELED;
                        goto out;
                }

                msleep(TPM_TIMEOUT);    /* CHECK */
                rmb();
        } while (time_before(jiffies, stop));


        chip->vendor->cancel(chip);
        dev_err(chip->dev, "Operation Timed out\n");
        rc = -ETIME;
        goto out;

out_recv:
        rc = chip->vendor->recv(chip, (u8 *) buf, bufsiz);
        if (rc < 0)
                dev_err(chip->dev,
                        "tpm_transmit: tpm_recv: error %zd\n", rc);
out:
        up(&chip->tpm_mutex);
        return rc;
}

#define TPM_DIGEST_SIZE 20
#define CAP_PCR_RESULT_SIZE 18
static const u8 cap_pcr[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 22,            /* length */
        0, 0, 0, 101,           /* TPM_ORD_GetCapability */
        0, 0, 0, 5,
        0, 0, 0, 4,
        0, 0, 1, 1
};

#define READ_PCR_RESULT_SIZE 30
static const u8 pcrread[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 14,            /* length */
        0, 0, 0, 21,            /* TPM_ORD_PcrRead */
        0, 0, 0, 0              /* PCR index */
};

ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
                      char *buf)
{
        u8 data[READ_PCR_RESULT_SIZE];
        ssize_t len;
        int i, j, num_pcrs;
        __be32 index;
        char *str = buf;

        struct tpm_chip *chip = dev_get_drvdata(dev);
        if (chip == NULL)
                return -ENODEV;

        memcpy(data, cap_pcr, sizeof(cap_pcr));
        if ((len = tpm_transmit(chip, data, sizeof(data)))
            < CAP_PCR_RESULT_SIZE) {
                dev_dbg(chip->dev, "A TPM error (%d) occurred "
                                "attempting to determine the number of PCRS\n",
                        be32_to_cpu(*((__be32 *) (data + 6))));
                return 0;
        }

        num_pcrs = be32_to_cpu(*((__be32 *) (data + 14)));

        for (i = 0; i < num_pcrs; i++) {
                memcpy(data, pcrread, sizeof(pcrread));
                index = cpu_to_be32(i);
                memcpy(data + 10, &index, 4);
                if ((len = tpm_transmit(chip, data, sizeof(data)))
                    < READ_PCR_RESULT_SIZE){
                        dev_dbg(chip->dev, "A TPM error (%d) occurred"
                                " attempting to read PCR %d of %d\n",
                                be32_to_cpu(*((__be32 *) (data + 6))),
                                i, num_pcrs);
                        goto out;
                }
                str += sprintf(str, "PCR-%02d: ", i);
                for (j = 0; j < TPM_DIGEST_SIZE; j++)
                        str += sprintf(str, "%02X ", *(data + 10 + j));
                str += sprintf(str, "\n");
        }
out:
        return str - buf;
}
EXPORT_SYMBOL_GPL(tpm_show_pcrs);

#define  READ_PUBEK_RESULT_SIZE 314
static const u8 readpubek[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 30,            /* length */
        0, 0, 0, 124,           /* TPM_ORD_ReadPubek */
};

ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
                       char *buf)
{
        u8 *data;
        ssize_t len;
        int i, rc;
        char *str = buf;

        struct tpm_chip *chip = dev_get_drvdata(dev);
        if (chip == NULL)
                return -ENODEV;

        data = kzalloc(READ_PUBEK_RESULT_SIZE, GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        memcpy(data, readpubek, sizeof(readpubek));

        if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
            READ_PUBEK_RESULT_SIZE) {
                dev_dbg(chip->dev, "A TPM error (%d) occurred "
                                "attempting to read the PUBEK\n",
                            be32_to_cpu(*((__be32 *) (data + 6))));
                rc = 0;
                goto out;
        }

        /* 
           ignore header 10 bytes
           algorithm 32 bits (1 == RSA )
           encscheme 16 bits
           sigscheme 16 bits
           parameters (RSA 12->bytes: keybit, #primes, expbit)  
           keylenbytes 32 bits
           256 byte modulus
           ignore checksum 20 bytes
         */

        str +=
            sprintf(str,
                    "Algorithm: %02X %02X %02X %02X\nEncscheme: %02X %02X\n"
                    "Sigscheme: %02X %02X\nParameters: %02X %02X %02X %02X"
                    " %02X %02X %02X %02X %02X %02X %02X %02X\n"
                    "Modulus length: %d\nModulus: \n",
                    data[10], data[11], data[12], data[13], data[14],
                    data[15], data[16], data[17], data[22], data[23],
                    data[24], data[25], data[26], data[27], data[28],
                    data[29], data[30], data[31], data[32], data[33],
                    be32_to_cpu(*((__be32 *) (data + 34))));

        for (i = 0; i < 256; i++) {
                str += sprintf(str, "%02X ", data[i + 38]);
                if ((i + 1) % 16 == 0)
                        str += sprintf(str, "\n");
        }
        rc = str - buf;
out:
        kfree(data);
        return rc;
}
EXPORT_SYMBOL_GPL(tpm_show_pubek);

#define CAP_VER_RESULT_SIZE 18
static const u8 cap_version[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 18,            /* length */
        0, 0, 0, 101,           /* TPM_ORD_GetCapability */
        0, 0, 0, 6,
        0, 0, 0, 0
};

#define CAP_MANUFACTURER_RESULT_SIZE 18
static const u8 cap_manufacturer[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 22,            /* length */
        0, 0, 0, 101,           /* TPM_ORD_GetCapability */
        0, 0, 0, 5,
        0, 0, 0, 4,
        0, 0, 1, 3
};

ssize_t tpm_show_caps(struct device *dev, struct device_attribute *attr,
                      char *buf)
{
        u8 data[sizeof(cap_manufacturer)];
        ssize_t len;
        char *str = buf;

        struct tpm_chip *chip = dev_get_drvdata(dev);
        if (chip == NULL)
                return -ENODEV;

        memcpy(data, cap_manufacturer, sizeof(cap_manufacturer));

        if ((len = tpm_transmit(chip, data, sizeof(data))) <
            CAP_MANUFACTURER_RESULT_SIZE)
                return len;

        str += sprintf(str, "Manufacturer: 0x%x\n",
                       be32_to_cpu(*((__be32 *) (data + 14))));

        memcpy(data, cap_version, sizeof(cap_version));

        if ((len = tpm_transmit(chip, data, sizeof(data))) <
            CAP_VER_RESULT_SIZE)
                return len;

        str +=
            sprintf(str, "TCG version: %d.%d\nFirmware version: %d.%d\n",
                    (int) data[14], (int) data[15], (int) data[16],
                    (int) data[17]);

        return str - buf;
}
EXPORT_SYMBOL_GPL(tpm_show_caps);

ssize_t tpm_store_cancel(struct device *dev, struct device_attribute *attr,
                        const char *buf, size_t count)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);
        if (chip == NULL)
                return 0;

        chip->vendor->cancel(chip);
        return count;
}
EXPORT_SYMBOL_GPL(tpm_store_cancel);

/*
 * Device file system interface to the TPM
 */
int tpm_open(struct inode *inode, struct file *file)
{
        int rc = 0, minor = iminor(inode);
        struct tpm_chip *chip = NULL, *pos;

        spin_lock(&driver_lock);

        list_for_each_entry(pos, &tpm_chip_list, list) {
                if (pos->vendor->miscdev.minor == minor) {
                        chip = pos;
                        break;
                }
        }

        if (chip == NULL) {
                rc = -ENODEV;
                goto err_out;
        }

        if (chip->num_opens) {
                dev_dbg(chip->dev, "Another process owns this TPM\n");
                rc = -EBUSY;
                goto err_out;
        }

        chip->num_opens++;
        get_device(chip->dev);

        spin_unlock(&driver_lock);

        chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);
        if (chip->data_buffer == NULL) {
                chip->num_opens--;
                put_device(chip->dev);
                return -ENOMEM;
        }

        atomic_set(&chip->data_pending, 0);

        file->private_data = chip;
        return 0;

err_out:
        spin_unlock(&driver_lock);
        return rc;
}
EXPORT_SYMBOL_GPL(tpm_open);

int tpm_release(struct inode *inode, struct file *file)
{
        struct tpm_chip *chip = file->private_data;

        spin_lock(&driver_lock);
        file->private_data = NULL;
        chip->num_opens--;
        del_singleshot_timer_sync(&chip->user_read_timer);
        flush_scheduled_work();
        atomic_set(&chip->data_pending, 0);
        put_device(chip->dev);
        kfree(chip->data_buffer);
        spin_unlock(&driver_lock);
        return 0;
}
EXPORT_SYMBOL_GPL(tpm_release);

ssize_t tpm_write(struct file *file, const char __user *buf,
                  size_t size, loff_t * off)
{
        struct tpm_chip *chip = file->private_data;
        int in_size = size, out_size;

        /* cannot perform a write until the read has cleared
           either via tpm_read or a user_read_timer timeout */
        while (atomic_read(&chip->data_pending) != 0)
                msleep(TPM_TIMEOUT);

        down(&chip->buffer_mutex);

        if (in_size > TPM_BUFSIZE)
                in_size = TPM_BUFSIZE;

        if (copy_from_user
            (chip->data_buffer, (void __user *) buf, in_size)) {
                up(&chip->buffer_mutex);
                return -EFAULT;
        }

        /* atomic tpm command send and result receive */
        out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);

        atomic_set(&chip->data_pending, out_size);
        up(&chip->buffer_mutex);

        /* Set a timeout by which the reader must come claim the result */
        mod_timer(&chip->user_read_timer, jiffies + (60 * HZ));

        return in_size;
}

EXPORT_SYMBOL_GPL(tpm_write);

ssize_t tpm_read(struct file * file, char __user *buf,
                 size_t size, loff_t * off)
{
        struct tpm_chip *chip = file->private_data;
        int ret_size;

        del_singleshot_timer_sync(&chip->user_read_timer);
        flush_scheduled_work();
        ret_size = atomic_read(&chip->data_pending);
        atomic_set(&chip->data_pending, 0);
        if (ret_size > 0) {     /* relay data */
                if (size < ret_size)
                        ret_size = size;

                down(&chip->buffer_mutex);
                if (copy_to_user(buf, chip->data_buffer, ret_size))
                        ret_size = -EFAULT;
                up(&chip->buffer_mutex);
        }

        return ret_size;
}
EXPORT_SYMBOL_GPL(tpm_read);

void tpm_remove_hardware(struct device *dev)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);

        if (chip == NULL) {
                dev_err(dev, "No device data found\n");
                return;
        }

        spin_lock(&driver_lock);

        list_del(&chip->list);

        spin_unlock(&driver_lock);

        dev_set_drvdata(dev, NULL);
        misc_deregister(&chip->vendor->miscdev);
        kfree(chip->vendor->miscdev.name);

        sysfs_remove_group(&dev->kobj, chip->vendor->attr_group);

        dev_mask[chip->dev_num / TPM_NUM_MASK_ENTRIES ] &=
                ~(1 << (chip->dev_num % TPM_NUM_MASK_ENTRIES));

        kfree(chip);

        put_device(dev);
}
EXPORT_SYMBOL_GPL(tpm_remove_hardware);

static u8 savestate[] = {
        0, 193,                 /* TPM_TAG_RQU_COMMAND */
        0, 0, 0, 10,            /* blob length (in bytes) */
        0, 0, 0, 152            /* TPM_ORD_SaveState */
};

/*
 * We are about to suspend. Save the TPM state
 * so that it can be restored.
 */
int tpm_pm_suspend(struct device *dev, pm_message_t pm_state)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);
        if (chip == NULL)
                return -ENODEV;

        tpm_transmit(chip, savestate, sizeof(savestate));
        return 0;
}
EXPORT_SYMBOL_GPL(tpm_pm_suspend);

/*
 * Resume from a power safe. The BIOS already restored
 * the TPM state.
 */
int tpm_pm_resume(struct device *dev)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);

        if (chip == NULL)
                return -ENODEV;

        return 0;
}
EXPORT_SYMBOL_GPL(tpm_pm_resume);

/*
 * Called from tpm_<specific>.c probe function only for devices 
 * the driver has determined it should claim.  Prior to calling
 * this function the specific probe function has called pci_enable_device
 * upon errant exit from this function specific probe function should call
 * pci_disable_device
 */
int tpm_register_hardware(struct device *dev, struct tpm_vendor_specific *entry)
{
#define DEVNAME_SIZE 7

        char *devname;
        struct tpm_chip *chip;
        int i, j;

        /* Driver specific per-device data */
        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (chip == NULL)
                return -ENOMEM;

        init_MUTEX(&chip->buffer_mutex);
        init_MUTEX(&chip->tpm_mutex);
        INIT_LIST_HEAD(&chip->list);

        INIT_WORK(&chip->work, timeout_work, chip);

        init_timer(&chip->user_read_timer);
        chip->user_read_timer.function = user_reader_timeout;
        chip->user_read_timer.data = (unsigned long) chip;

        chip->vendor = entry;

        chip->dev_num = -1;

        for (i = 0; i < TPM_NUM_MASK_ENTRIES; i++)
                for (j = 0; j < 8 * sizeof(int); j++)
                        if ((dev_mask[i] & (1 << j)) == 0) {
                                chip->dev_num =
                                    i * TPM_NUM_MASK_ENTRIES + j;
                                dev_mask[i] |= 1 << j;
                                goto dev_num_search_complete;
                        }

dev_num_search_complete:
        if (chip->dev_num < 0) {
                dev_err(dev, "No available tpm device numbers\n");
                kfree(chip);
                return -ENODEV;
        } else if (chip->dev_num == 0)
                chip->vendor->miscdev.minor = TPM_MINOR;
        else
                chip->vendor->miscdev.minor = MISC_DYNAMIC_MINOR;

        devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);
        scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num);
        chip->vendor->miscdev.name = devname;

        chip->vendor->miscdev.dev = dev;
        chip->dev = get_device(dev);

        if (misc_register(&chip->vendor->miscdev)) {
                dev_err(chip->dev,
                        "unable to misc_register %s, minor %d\n",
                        chip->vendor->miscdev.name,
                        chip->vendor->miscdev.minor);
                put_device(dev);
                kfree(chip);
                dev_mask[i] &= !(1 << j);
                return -ENODEV;
        }

        spin_lock(&driver_lock);

        dev_set_drvdata(dev, chip);

        list_add(&chip->list, &tpm_chip_list);

        spin_unlock(&driver_lock);

        sysfs_create_group(&dev->kobj, chip->vendor->attr_group);

        return 0;
}
EXPORT_SYMBOL_GPL(tpm_register_hardware);

MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");