Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / char / tpm / tpm-dev.c

diff --git a/kernel/drivers/char/tpm/tpm-dev.c b/kernel/drivers/char/tpm/tpm-dev.c
new file mode 100644 (file)
index 0000000..de0337e
--- /dev/null
+++ b/kernel/drivers/char/tpm/tpm-dev.c
@@ -0,0 +1,183 @@
+/*
+ * 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>
+ *
+ * Copyright (C) 2013 Obsidian Research Corp
+ * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
+ *
+ * Device file system interface to the TPM
+ *
+ * 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/slab.h>
+#include <linux/uaccess.h>
+#include "tpm.h"
+
+struct file_priv {
+       struct tpm_chip *chip;
+
+       /* Data passed to and from the tpm via the read/write calls */
+       atomic_t data_pending;
+       struct mutex buffer_mutex;
+
+       struct timer_list user_read_timer;      /* user needs to claim result */
+       struct work_struct work;
+
+       u8 data_buffer[TPM_BUFSIZE];
+};
+
+static void user_reader_timeout(unsigned long ptr)
+{
+       struct file_priv *priv = (struct file_priv *)ptr;
+
+       schedule_work(&priv->work);
+}
+
+static void timeout_work(struct work_struct *work)
+{
+       struct file_priv *priv = container_of(work, struct file_priv, work);
+
+       mutex_lock(&priv->buffer_mutex);
+       atomic_set(&priv->data_pending, 0);
+       memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
+       mutex_unlock(&priv->buffer_mutex);
+}
+
+static int tpm_open(struct inode *inode, struct file *file)
+{
+       struct tpm_chip *chip =
+               container_of(inode->i_cdev, struct tpm_chip, cdev);
+       struct file_priv *priv;
+
+       /* It's assured that the chip will be opened just once,
+        * by the check of is_open variable, which is protected
+        * by driver_lock. */
+       if (test_and_set_bit(0, &chip->is_open)) {
+               dev_dbg(chip->pdev, "Another process owns this TPM\n");
+               return -EBUSY;
+       }
+
+       priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+       if (priv == NULL) {
+               clear_bit(0, &chip->is_open);
+               return -ENOMEM;
+       }
+
+       priv->chip = chip;
+       atomic_set(&priv->data_pending, 0);
+       mutex_init(&priv->buffer_mutex);
+       setup_timer(&priv->user_read_timer, user_reader_timeout,
+                       (unsigned long)priv);
+       INIT_WORK(&priv->work, timeout_work);
+
+       file->private_data = priv;
+       get_device(chip->pdev);
+       return 0;
+}
+
+static ssize_t tpm_read(struct file *file, char __user *buf,
+                       size_t size, loff_t *off)
+{
+       struct file_priv *priv = file->private_data;
+       ssize_t ret_size;
+       int rc;
+
+       del_singleshot_timer_sync(&priv->user_read_timer);
+       flush_work(&priv->work);
+       ret_size = atomic_read(&priv->data_pending);
+       if (ret_size > 0) {     /* relay data */
+               ssize_t orig_ret_size = ret_size;
+               if (size < ret_size)
+                       ret_size = size;
+
+               mutex_lock(&priv->buffer_mutex);
+               rc = copy_to_user(buf, priv->data_buffer, ret_size);
+               memset(priv->data_buffer, 0, orig_ret_size);
+               if (rc)
+                       ret_size = -EFAULT;
+
+               mutex_unlock(&priv->buffer_mutex);
+       }
+
+       atomic_set(&priv->data_pending, 0);
+
+       return ret_size;
+}
+
+static ssize_t tpm_write(struct file *file, const char __user *buf,
+                        size_t size, loff_t *off)
+{
+       struct file_priv *priv = file->private_data;
+       size_t in_size = size;
+       ssize_t out_size;
+
+       /* cannot perform a write until the read has cleared
+          either via tpm_read or a user_read_timer timeout.
+          This also prevents splitted buffered writes from blocking here.
+       */
+       if (atomic_read(&priv->data_pending) != 0)
+               return -EBUSY;
+
+       if (in_size > TPM_BUFSIZE)
+               return -E2BIG;
+
+       mutex_lock(&priv->buffer_mutex);
+
+       if (copy_from_user
+           (priv->data_buffer, (void __user *) buf, in_size)) {
+               mutex_unlock(&priv->buffer_mutex);
+               return -EFAULT;
+       }
+
+       /* atomic tpm command send and result receive */
+       out_size = tpm_transmit(priv->chip, priv->data_buffer,
+                               sizeof(priv->data_buffer));
+       if (out_size < 0) {
+               mutex_unlock(&priv->buffer_mutex);
+               return out_size;
+       }
+
+       atomic_set(&priv->data_pending, out_size);
+       mutex_unlock(&priv->buffer_mutex);
+
+       /* Set a timeout by which the reader must come claim the result */
+       mod_timer(&priv->user_read_timer, jiffies + (60 * HZ));
+
+       return in_size;
+}
+
+/*
+ * Called on file close
+ */
+static int tpm_release(struct inode *inode, struct file *file)
+{
+       struct file_priv *priv = file->private_data;
+
+       del_singleshot_timer_sync(&priv->user_read_timer);
+       flush_work(&priv->work);
+       file->private_data = NULL;
+       atomic_set(&priv->data_pending, 0);
+       clear_bit(0, &priv->chip->is_open);
+       put_device(priv->chip->pdev);
+       kfree(priv);
+       return 0;
+}
+
+const struct file_operations tpm_fops = {
+       .owner = THIS_MODULE,
+       .llseek = no_llseek,
+       .open = tpm_open,
+       .read = tpm_read,
+       .write = tpm_write,
+       .release = tpm_release,
+};
+
+