drivers/crypto/ccp/ccp-dev.c - arm/linux-arm-legacy - Git at Google

 /*
  * AMD Cryptographic Coprocessor (CCP) driver
  *
  * Copyright (C) 2013 Advanced Micro Devices, Inc.
  *
  * Author: Tom Lendacky <thomas.lendacky@amd.com>
  *
  * 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.
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/kthread.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/delay.h>
 #include <linux/hw_random.h>
 #include <linux/cpu.h>
 #include <asm/cpu_device_id.h>
 #include <linux/ccp.h>

 #include "ccp-dev.h"

 MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.0.0");
 MODULE_DESCRIPTION("AMD Cryptographic Coprocessor driver");


 static struct ccp_device *ccp_dev;
 static inline struct ccp_device *ccp_get_device(void)
 {
 	return ccp_dev;
 }

 static inline void ccp_add_device(struct ccp_device *ccp)
 {
 	ccp_dev = ccp;
 }

 static inline void ccp_del_device(struct ccp_device *ccp)
 {
 	ccp_dev = NULL;
 }

 /**
  * ccp_enqueue_cmd - queue an operation for processing by the CCP
  *
  * @cmd: ccp_cmd struct to be processed
  *
  * Queue a cmd to be processed by the CCP. If queueing the cmd
  * would exceed the defined length of the cmd queue the cmd will
  * only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
  * result in a return code of -EBUSY.
  *
  * The callback routine specified in the ccp_cmd struct will be
  * called to notify the caller of completion (if the cmd was not
  * backlogged) or advancement out of the backlog. If the cmd has
  * advanced out of the backlog the "err" value of the callback
  * will be -EINPROGRESS. Any other "err" value during callback is
  * the result of the operation.
  *
  * The cmd has been successfully queued if:
  *   the return code is -EINPROGRESS or
  *   the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
  */
 int ccp_enqueue_cmd(struct ccp_cmd *cmd)
 {
 	struct ccp_device *ccp = ccp_get_device();
 	unsigned long flags;
 	unsigned int i;
 	int ret;

 	if (!ccp)
 		return -ENODEV;

 	/* Caller must supply a callback routine */
 	if (!cmd->callback)
 		return -EINVAL;

 	cmd->ccp = ccp;

 	spin_lock_irqsave(&ccp->cmd_lock, flags);

 	i = ccp->cmd_q_count;

 	if (ccp->cmd_count >= MAX_CMD_QLEN) {
 		ret = -EBUSY;
 		if (cmd->flags & CCP_CMD_MAY_BACKLOG)
 			list_add_tail(&cmd->entry, &ccp->backlog);
 	} else {
 		ret = -EINPROGRESS;
 		ccp->cmd_count++;
 		list_add_tail(&cmd->entry, &ccp->cmd);

 		/* Find an idle queue */
 		if (!ccp->suspending) {
 			for (i = 0; i < ccp->cmd_q_count; i++) {
 				if (ccp->cmd_q[i].active)
 					continue;

 				break;
 			}
 		}
 	}

 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

 	/* If we found an idle queue, wake it up */
 	if (i < ccp->cmd_q_count)
 		wake_up_process(ccp->cmd_q[i].kthread);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);

 static void ccp_do_cmd_backlog(struct work_struct *work)
 {
 	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
 	struct ccp_device *ccp = cmd->ccp;
 	unsigned long flags;
 	unsigned int i;

 	cmd->callback(cmd->data, -EINPROGRESS);

 	spin_lock_irqsave(&ccp->cmd_lock, flags);

 	ccp->cmd_count++;
 	list_add_tail(&cmd->entry, &ccp->cmd);

 	/* Find an idle queue */
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		if (ccp->cmd_q[i].active)
 			continue;

 		break;
 	}

 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

 	/* If we found an idle queue, wake it up */
 	if (i < ccp->cmd_q_count)
 		wake_up_process(ccp->cmd_q[i].kthread);
 }

 static struct ccp_cmd *ccp_dequeue_cmd(struct ccp_cmd_queue *cmd_q)
 {
 	struct ccp_device *ccp = cmd_q->ccp;
 	struct ccp_cmd *cmd = NULL;
 	struct ccp_cmd *backlog = NULL;
 	unsigned long flags;

 	spin_lock_irqsave(&ccp->cmd_lock, flags);

 	cmd_q->active = 0;

 	if (ccp->suspending) {
 		cmd_q->suspended = 1;

 		spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 		wake_up_interruptible(&ccp->suspend_queue);

 		return NULL;
 	}

 	if (ccp->cmd_count) {
 		cmd_q->active = 1;

 		cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
 		list_del(&cmd->entry);

 		ccp->cmd_count--;
 	}

 	if (!list_empty(&ccp->backlog)) {
 		backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
 					   entry);
 		list_del(&backlog->entry);
 	}

 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

 	if (backlog) {
 		INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
 		schedule_work(&backlog->work);
 	}

 	return cmd;
 }

 static void ccp_do_cmd_complete(struct work_struct *work)
 {
 	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);

 	cmd->callback(cmd->data, cmd->ret);
 }

 static int ccp_cmd_queue_thread(void *data)
 {
 	struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
 	struct ccp_cmd *cmd;

 	set_current_state(TASK_INTERRUPTIBLE);
 	while (!kthread_should_stop()) {
 		schedule();

 		set_current_state(TASK_INTERRUPTIBLE);

 		cmd = ccp_dequeue_cmd(cmd_q);
 		if (!cmd)
 			continue;

 		__set_current_state(TASK_RUNNING);

 		/* Execute the command */
 		cmd->ret = ccp_run_cmd(cmd_q, cmd);

 		/* Schedule the completion callback */
 		INIT_WORK(&cmd->work, ccp_do_cmd_complete);
 		schedule_work(&cmd->work);
 	}

 	__set_current_state(TASK_RUNNING);

 	return 0;
 }

 static int ccp_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {
 	struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng);
 	u32 trng_value;
 	int len = min_t(int, sizeof(trng_value), max);

 	/*
 	 * Locking is provided by the caller so we can update device
 	 * hwrng-related fields safely
 	 */
 	trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG);
 	if (!trng_value) {
 		/* Zero is returned if not data is available or if a
 		 * bad-entropy error is present. Assume an error if
 		 * we exceed TRNG_RETRIES reads of zero.
 		 */
 		if (ccp->hwrng_retries++ > TRNG_RETRIES)
 			return -EIO;

 		return 0;
 	}

 	/* Reset the counter and save the rng value */
 	ccp->hwrng_retries = 0;
 	memcpy(data, &trng_value, len);

 	return len;
 }

 /**
  * ccp_alloc_struct - allocate and initialize the ccp_device struct
  *
  * @dev: device struct of the CCP
  */
 struct ccp_device *ccp_alloc_struct(struct device *dev)
 {
 	struct ccp_device *ccp;

 	ccp = kzalloc(sizeof(*ccp), GFP_KERNEL);
 	if (ccp == NULL) {
 		dev_err(dev, "unable to allocate device struct\n");
 		return NULL;
 	}
 	ccp->dev = dev;

 	INIT_LIST_HEAD(&ccp->cmd);
 	INIT_LIST_HEAD(&ccp->backlog);

 	spin_lock_init(&ccp->cmd_lock);
 	mutex_init(&ccp->req_mutex);
 	mutex_init(&ccp->ksb_mutex);
 	ccp->ksb_count = KSB_COUNT;
 	ccp->ksb_start = 0;

 	return ccp;
 }

 /**
  * ccp_init - initialize the CCP device
  *
  * @ccp: ccp_device struct
  */
 int ccp_init(struct ccp_device *ccp)
 {
 	struct device *dev = ccp->dev;
 	struct ccp_cmd_queue *cmd_q;
 	struct dma_pool *dma_pool;
 	char dma_pool_name[MAX_DMAPOOL_NAME_LEN];
 	unsigned int qmr, qim, i;
 	int ret;

 	/* Find available queues */
 	qim = 0;
 	qmr = ioread32(ccp->io_regs + Q_MASK_REG);
 	for (i = 0; i < MAX_HW_QUEUES; i++) {
 		if (!(qmr & (1 << i)))
 			continue;

 		/* Allocate a dma pool for this queue */
 		snprintf(dma_pool_name, sizeof(dma_pool_name), "ccp_q%d", i);
 		dma_pool = dma_pool_create(dma_pool_name, dev,
 					   CCP_DMAPOOL_MAX_SIZE,
 					   CCP_DMAPOOL_ALIGN, 0);
 		if (!dma_pool) {
 			dev_err(dev, "unable to allocate dma pool\n");
 			ret = -ENOMEM;
 			goto e_pool;
 		}

 		cmd_q = &ccp->cmd_q[ccp->cmd_q_count];
 		ccp->cmd_q_count++;

 		cmd_q->ccp = ccp;
 		cmd_q->id = i;
 		cmd_q->dma_pool = dma_pool;

 		/* Reserve 2 KSB regions for the queue */
 		cmd_q->ksb_key = KSB_START + ccp->ksb_start++;
 		cmd_q->ksb_ctx = KSB_START + ccp->ksb_start++;
 		ccp->ksb_count -= 2;

 		/* Preset some register values and masks that are queue
 		 * number dependent
 		 */
 		cmd_q->reg_status = ccp->io_regs + CMD_Q_STATUS_BASE +
 				    (CMD_Q_STATUS_INCR * i);
 		cmd_q->reg_int_status = ccp->io_regs + CMD_Q_INT_STATUS_BASE +
 					(CMD_Q_STATUS_INCR * i);
 		cmd_q->int_ok = 1 << (i * 2);
 		cmd_q->int_err = 1 << ((i * 2) + 1);

 		cmd_q->free_slots = CMD_Q_DEPTH(ioread32(cmd_q->reg_status));

 		init_waitqueue_head(&cmd_q->int_queue);

 		/* Build queue interrupt mask (two interrupts per queue) */
 		qim |= cmd_q->int_ok | cmd_q->int_err;

 		dev_dbg(dev, "queue #%u available\n", i);
 	}
 	if (ccp->cmd_q_count == 0) {
 		dev_notice(dev, "no command queues available\n");
 		ret = -EIO;
 		goto e_pool;
 	}
 	dev_notice(dev, "%u command queues available\n", ccp->cmd_q_count);

 	/* Disable and clear interrupts until ready */
 	iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		cmd_q = &ccp->cmd_q[i];

 		ioread32(cmd_q->reg_int_status);
 		ioread32(cmd_q->reg_status);
 	}
 	iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);

 	/* Request an irq */
 	ret = ccp->get_irq(ccp);
 	if (ret) {
 		dev_err(dev, "unable to allocate an IRQ\n");
 		goto e_pool;
 	}

 	/* Initialize the queues used to wait for KSB space and suspend */
 	init_waitqueue_head(&ccp->ksb_queue);
 	init_waitqueue_head(&ccp->suspend_queue);

 	/* Create a kthread for each queue */
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		struct task_struct *kthread;

 		cmd_q = &ccp->cmd_q[i];

 		kthread = kthread_create(ccp_cmd_queue_thread, cmd_q,
 					 "ccp-q%u", cmd_q->id);
 		if (IS_ERR(kthread)) {
 			dev_err(dev, "error creating queue thread (%ld)\n",
 				PTR_ERR(kthread));
 			ret = PTR_ERR(kthread);
 			goto e_kthread;
 		}

 		cmd_q->kthread = kthread;
 		wake_up_process(kthread);
 	}

 	/* Register the RNG */
 	ccp->hwrng.name = "ccp-rng";
 	ccp->hwrng.read = ccp_trng_read;
 	ret = hwrng_register(&ccp->hwrng);
 	if (ret) {
 		dev_err(dev, "error registering hwrng (%d)\n", ret);
 		goto e_kthread;
 	}

 	/* Make the device struct available before enabling interrupts */
 	ccp_add_device(ccp);

 	/* Enable interrupts */
 	iowrite32(qim, ccp->io_regs + IRQ_MASK_REG);

 	return 0;

 e_kthread:
 	for (i = 0; i < ccp->cmd_q_count; i++)
 		if (ccp->cmd_q[i].kthread)
 			kthread_stop(ccp->cmd_q[i].kthread);

 	ccp->free_irq(ccp);

 e_pool:
 	for (i = 0; i < ccp->cmd_q_count; i++)
 		dma_pool_destroy(ccp->cmd_q[i].dma_pool);

 	return ret;
 }

 /**
  * ccp_destroy - tear down the CCP device
  *
  * @ccp: ccp_device struct
  */
 void ccp_destroy(struct ccp_device *ccp)
 {
 	struct ccp_cmd_queue *cmd_q;
 	struct ccp_cmd *cmd;
 	unsigned int qim, i;

 	/* Remove general access to the device struct */
 	ccp_del_device(ccp);

 	/* Unregister the RNG */
 	hwrng_unregister(&ccp->hwrng);

 	/* Stop the queue kthreads */
 	for (i = 0; i < ccp->cmd_q_count; i++)
 		if (ccp->cmd_q[i].kthread)
 			kthread_stop(ccp->cmd_q[i].kthread);

 	/* Build queue interrupt mask (two interrupt masks per queue) */
 	qim = 0;
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		cmd_q = &ccp->cmd_q[i];
 		qim |= cmd_q->int_ok | cmd_q->int_err;
 	}

 	/* Disable and clear interrupts */
 	iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		cmd_q = &ccp->cmd_q[i];

 		ioread32(cmd_q->reg_int_status);
 		ioread32(cmd_q->reg_status);
 	}
 	iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);

 	ccp->free_irq(ccp);

 	for (i = 0; i < ccp->cmd_q_count; i++)
 		dma_pool_destroy(ccp->cmd_q[i].dma_pool);

 	/* Flush the cmd and backlog queue */
 	while (!list_empty(&ccp->cmd)) {
 		/* Invoke the callback directly with an error code */
 		cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
 		list_del(&cmd->entry);
 		cmd->callback(cmd->data, -ENODEV);
 	}
 	while (!list_empty(&ccp->backlog)) {
 		/* Invoke the callback directly with an error code */
 		cmd = list_first_entry(&ccp->backlog, struct ccp_cmd, entry);
 		list_del(&cmd->entry);
 		cmd->callback(cmd->data, -ENODEV);
 	}
 }

 /**
  * ccp_irq_handler - handle interrupts generated by the CCP device
  *
  * @irq: the irq associated with the interrupt
  * @data: the data value supplied when the irq was created
  */
 irqreturn_t ccp_irq_handler(int irq, void *data)
 {
 	struct device *dev = data;
 	struct ccp_device *ccp = dev_get_drvdata(dev);
 	struct ccp_cmd_queue *cmd_q;
 	u32 q_int, status;
 	unsigned int i;

 	status = ioread32(ccp->io_regs + IRQ_STATUS_REG);

 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		cmd_q = &ccp->cmd_q[i];

 		q_int = status & (cmd_q->int_ok | cmd_q->int_err);
 		if (q_int) {
 			cmd_q->int_status = status;
 			cmd_q->q_status = ioread32(cmd_q->reg_status);
 			cmd_q->q_int_status = ioread32(cmd_q->reg_int_status);

 			/* On error, only save the first error value */
 			if ((q_int & cmd_q->int_err) && !cmd_q->cmd_error)
 				cmd_q->cmd_error = CMD_Q_ERROR(cmd_q->q_status);

 			cmd_q->int_rcvd = 1;

 			/* Acknowledge the interrupt and wake the kthread */
 			iowrite32(q_int, ccp->io_regs + IRQ_STATUS_REG);
 			wake_up_interruptible(&cmd_q->int_queue);
 		}
 	}

 	return IRQ_HANDLED;
 }

 #ifdef CONFIG_PM
 bool ccp_queues_suspended(struct ccp_device *ccp)
 {
 	unsigned int suspended = 0;
 	unsigned long flags;
 	unsigned int i;

 	spin_lock_irqsave(&ccp->cmd_lock, flags);

 	for (i = 0; i < ccp->cmd_q_count; i++)
 		if (ccp->cmd_q[i].suspended)
 			suspended++;

 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

 	return ccp->cmd_q_count == suspended;
 }
 #endif

 static const struct x86_cpu_id ccp_support[] = {
 	{ X86_VENDOR_AMD, 22, },
 };

 static int __init ccp_mod_init(void)
 {
 	struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;
 	int ret;

 	if (!x86_match_cpu(ccp_support))
 		return -ENODEV;

 	switch (cpuinfo->x86) {
 	case 22:
 		if ((cpuinfo->x86_model < 48) || (cpuinfo->x86_model > 63))
 			return -ENODEV;

 		ret = ccp_pci_init();
 		if (ret)
 			return ret;

 		/* Don't leave the driver loaded if init failed */
 		if (!ccp_get_device()) {
 			ccp_pci_exit();
 			return -ENODEV;
 		}

 		return 0;

 		break;
 	}

 	return -ENODEV;
 }

 static void __exit ccp_mod_exit(void)
 {
 	struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;

 	switch (cpuinfo->x86) {
 	case 22:
 		ccp_pci_exit();
 		break;
 	}
 }

 module_init(ccp_mod_init);
 module_exit(ccp_mod_exit);
	/*
	* AMD Cryptographic Coprocessor (CCP) driver
	*
	* Copyright (C) 2013 Advanced Micro Devices, Inc.
	*
	* Author: Tom Lendacky <thomas.lendacky@amd.com>
	*
	* 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.
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/kthread.h>
	#include <linux/sched.h>
	#include <linux/interrupt.h>
	#include <linux/spinlock.h>
	#include <linux/mutex.h>
	#include <linux/delay.h>
	#include <linux/hw_random.h>
	#include <linux/cpu.h>
	#include <asm/cpu_device_id.h>
	#include <linux/ccp.h>

	#include "ccp-dev.h"

	MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
	MODULE_LICENSE("GPL");
	MODULE_VERSION("1.0.0");
	MODULE_DESCRIPTION("AMD Cryptographic Coprocessor driver");


	static struct ccp_device *ccp_dev;
	static inline struct ccp_device *ccp_get_device(void)
	{
	return ccp_dev;
	}

	static inline void ccp_add_device(struct ccp_device *ccp)
	{
	ccp_dev = ccp;
	}

	static inline void ccp_del_device(struct ccp_device *ccp)
	{
	ccp_dev = NULL;
	}

	/**
	* ccp_enqueue_cmd - queue an operation for processing by the CCP
	*
	* @cmd: ccp_cmd struct to be processed
	*
	* Queue a cmd to be processed by the CCP. If queueing the cmd
	* would exceed the defined length of the cmd queue the cmd will
	* only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
	* result in a return code of -EBUSY.
	*
	* The callback routine specified in the ccp_cmd struct will be
	* called to notify the caller of completion (if the cmd was not
	* backlogged) or advancement out of the backlog. If the cmd has
	* advanced out of the backlog the "err" value of the callback
	* will be -EINPROGRESS. Any other "err" value during callback is
	* the result of the operation.
	*
	* The cmd has been successfully queued if:
	* the return code is -EINPROGRESS or
	* the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
	*/
	int ccp_enqueue_cmd(struct ccp_cmd *cmd)
	{
	struct ccp_device *ccp = ccp_get_device();
	unsigned long flags;
	unsigned int i;
	int ret;

	if (!ccp)
	return -ENODEV;

	/* Caller must supply a callback routine */
	if (!cmd->callback)
	return -EINVAL;

	cmd->ccp = ccp;

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	i = ccp->cmd_q_count;

	if (ccp->cmd_count >= MAX_CMD_QLEN) {
	ret = -EBUSY;
	if (cmd->flags & CCP_CMD_MAY_BACKLOG)
	list_add_tail(&cmd->entry, &ccp->backlog);
	} else {
	ret = -EINPROGRESS;
	ccp->cmd_count++;
	list_add_tail(&cmd->entry, &ccp->cmd);

	/* Find an idle queue */
	if (!ccp->suspending) {
	for (i = 0; i < ccp->cmd_q_count; i++) {
	if (ccp->cmd_q[i].active)
	continue;

	break;
	}
	}
	}

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	/* If we found an idle queue, wake it up */
	if (i < ccp->cmd_q_count)
	wake_up_process(ccp->cmd_q[i].kthread);

	return ret;
	}
	EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);

	static void ccp_do_cmd_backlog(struct work_struct *work)
	{
	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
	struct ccp_device *ccp = cmd->ccp;
	unsigned long flags;
	unsigned int i;

	cmd->callback(cmd->data, -EINPROGRESS);

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	ccp->cmd_count++;
	list_add_tail(&cmd->entry, &ccp->cmd);

	/* Find an idle queue */
	for (i = 0; i < ccp->cmd_q_count; i++) {
	if (ccp->cmd_q[i].active)
	continue;

	break;
	}

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	/* If we found an idle queue, wake it up */
	if (i < ccp->cmd_q_count)
	wake_up_process(ccp->cmd_q[i].kthread);
	}

	static struct ccp_cmd ccp_dequeue_cmd(struct ccp_cmd_queue cmd_q)
	{
	struct ccp_device *ccp = cmd_q->ccp;
	struct ccp_cmd *cmd = NULL;
	struct ccp_cmd *backlog = NULL;
	unsigned long flags;

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	cmd_q->active = 0;

	if (ccp->suspending) {
	cmd_q->suspended = 1;

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
	wake_up_interruptible(&ccp->suspend_queue);

	return NULL;
	}

	if (ccp->cmd_count) {
	cmd_q->active = 1;

	cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
	list_del(&cmd->entry);

	ccp->cmd_count--;
	}

	if (!list_empty(&ccp->backlog)) {
	backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
	entry);
	list_del(&backlog->entry);
	}

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	if (backlog) {
	INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
	schedule_work(&backlog->work);
	}

	return cmd;
	}

	static void ccp_do_cmd_complete(struct work_struct *work)
	{
	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);

	cmd->callback(cmd->data, cmd->ret);
	}

	static int ccp_cmd_queue_thread(void *data)
	{
	struct ccp_cmd_queue cmd_q = (struct ccp_cmd_queue )data;
	struct ccp_cmd *cmd;

	set_current_state(TASK_INTERRUPTIBLE);
	while (!kthread_should_stop()) {
	schedule();

	set_current_state(TASK_INTERRUPTIBLE);

	cmd = ccp_dequeue_cmd(cmd_q);
	if (!cmd)
	continue;

	__set_current_state(TASK_RUNNING);

	/* Execute the command */
	cmd->ret = ccp_run_cmd(cmd_q, cmd);

	/* Schedule the completion callback */
	INIT_WORK(&cmd->work, ccp_do_cmd_complete);
	schedule_work(&cmd->work);
	}

	__set_current_state(TASK_RUNNING);

	return 0;
	}

	static int ccp_trng_read(struct hwrng rng, void data, size_t max, bool wait)
	{
	struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng);
	u32 trng_value;
	int len = min_t(int, sizeof(trng_value), max);

	/*
	* Locking is provided by the caller so we can update device
	* hwrng-related fields safely
	*/
	trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG);
	if (!trng_value) {
	/* Zero is returned if not data is available or if a
	* bad-entropy error is present. Assume an error if
	* we exceed TRNG_RETRIES reads of zero.
	*/
	if (ccp->hwrng_retries++ > TRNG_RETRIES)
	return -EIO;

	return 0;
	}

	/* Reset the counter and save the rng value */
	ccp->hwrng_retries = 0;
	memcpy(data, &trng_value, len);

	return len;
	}

	/**
	* ccp_alloc_struct - allocate and initialize the ccp_device struct
	*
	* @dev: device struct of the CCP
	*/
	struct ccp_device ccp_alloc_struct(struct device dev)
	{
	struct ccp_device *ccp;

	ccp = kzalloc(sizeof(*ccp), GFP_KERNEL);
	if (ccp == NULL) {
	dev_err(dev, "unable to allocate device struct\n");
	return NULL;
	}
	ccp->dev = dev;

	INIT_LIST_HEAD(&ccp->cmd);
	INIT_LIST_HEAD(&ccp->backlog);

	spin_lock_init(&ccp->cmd_lock);
	mutex_init(&ccp->req_mutex);
	mutex_init(&ccp->ksb_mutex);
	ccp->ksb_count = KSB_COUNT;
	ccp->ksb_start = 0;

	return ccp;
	}

	/**
	* ccp_init - initialize the CCP device
	*
	* @ccp: ccp_device struct
	*/
	int ccp_init(struct ccp_device *ccp)
	{
	struct device *dev = ccp->dev;
	struct ccp_cmd_queue *cmd_q;
	struct dma_pool *dma_pool;
	char dma_pool_name[MAX_DMAPOOL_NAME_LEN];
	unsigned int qmr, qim, i;
	int ret;

	/* Find available queues */
	qim = 0;
	qmr = ioread32(ccp->io_regs + Q_MASK_REG);
	for (i = 0; i < MAX_HW_QUEUES; i++) {
	if (!(qmr & (1 << i)))
	continue;

	/* Allocate a dma pool for this queue */
	snprintf(dma_pool_name, sizeof(dma_pool_name), "ccp_q%d", i);
	dma_pool = dma_pool_create(dma_pool_name, dev,
	CCP_DMAPOOL_MAX_SIZE,
	CCP_DMAPOOL_ALIGN, 0);
	if (!dma_pool) {
	dev_err(dev, "unable to allocate dma pool\n");
	ret = -ENOMEM;
	goto e_pool;
	}

	cmd_q = &ccp->cmd_q[ccp->cmd_q_count];
	ccp->cmd_q_count++;

	cmd_q->ccp = ccp;
	cmd_q->id = i;
	cmd_q->dma_pool = dma_pool;

	/* Reserve 2 KSB regions for the queue */
	cmd_q->ksb_key = KSB_START + ccp->ksb_start++;
	cmd_q->ksb_ctx = KSB_START + ccp->ksb_start++;
	ccp->ksb_count -= 2;

	/* Preset some register values and masks that are queue
	* number dependent
	*/
	cmd_q->reg_status = ccp->io_regs + CMD_Q_STATUS_BASE +
	(CMD_Q_STATUS_INCR * i);
	cmd_q->reg_int_status = ccp->io_regs + CMD_Q_INT_STATUS_BASE +
	(CMD_Q_STATUS_INCR * i);
	cmd_q->int_ok = 1 << (i * 2);
	cmd_q->int_err = 1 << ((i * 2) + 1);

	cmd_q->free_slots = CMD_Q_DEPTH(ioread32(cmd_q->reg_status));

	init_waitqueue_head(&cmd_q->int_queue);

	/* Build queue interrupt mask (two interrupts per queue) */
	qim \|= cmd_q->int_ok \| cmd_q->int_err;

	dev_dbg(dev, "queue #%u available\n", i);
	}
	if (ccp->cmd_q_count == 0) {
	dev_notice(dev, "no command queues available\n");
	ret = -EIO;
	goto e_pool;
	}
	dev_notice(dev, "%u command queues available\n", ccp->cmd_q_count);

	/* Disable and clear interrupts until ready */
	iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
	for (i = 0; i < ccp->cmd_q_count; i++) {
	cmd_q = &ccp->cmd_q[i];

	ioread32(cmd_q->reg_int_status);
	ioread32(cmd_q->reg_status);
	}
	iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);

	/* Request an irq */
	ret = ccp->get_irq(ccp);
	if (ret) {
	dev_err(dev, "unable to allocate an IRQ\n");
	goto e_pool;
	}

	/* Initialize the queues used to wait for KSB space and suspend */
	init_waitqueue_head(&ccp->ksb_queue);
	init_waitqueue_head(&ccp->suspend_queue);

	/* Create a kthread for each queue */
	for (i = 0; i < ccp->cmd_q_count; i++) {
	struct task_struct *kthread;

	cmd_q = &ccp->cmd_q[i];

	kthread = kthread_create(ccp_cmd_queue_thread, cmd_q,
	"ccp-q%u", cmd_q->id);
	if (IS_ERR(kthread)) {
	dev_err(dev, "error creating queue thread (%ld)\n",
	PTR_ERR(kthread));
	ret = PTR_ERR(kthread);
	goto e_kthread;
	}

	cmd_q->kthread = kthread;
	wake_up_process(kthread);
	}

	/* Register the RNG */
	ccp->hwrng.name = "ccp-rng";
	ccp->hwrng.read = ccp_trng_read;
	ret = hwrng_register(&ccp->hwrng);
	if (ret) {
	dev_err(dev, "error registering hwrng (%d)\n", ret);
	goto e_kthread;
	}

	/* Make the device struct available before enabling interrupts */
	ccp_add_device(ccp);

	/* Enable interrupts */
	iowrite32(qim, ccp->io_regs + IRQ_MASK_REG);

	return 0;

	e_kthread:
	for (i = 0; i < ccp->cmd_q_count; i++)
	if (ccp->cmd_q[i].kthread)
	kthread_stop(ccp->cmd_q[i].kthread);

	ccp->free_irq(ccp);

	e_pool:
	for (i = 0; i < ccp->cmd_q_count; i++)
	dma_pool_destroy(ccp->cmd_q[i].dma_pool);

	return ret;
	}

	/**
	* ccp_destroy - tear down the CCP device
	*
	* @ccp: ccp_device struct
	*/
	void ccp_destroy(struct ccp_device *ccp)
	{
	struct ccp_cmd_queue *cmd_q;
	struct ccp_cmd *cmd;
	unsigned int qim, i;

	/* Remove general access to the device struct */
	ccp_del_device(ccp);

	/* Unregister the RNG */
	hwrng_unregister(&ccp->hwrng);

	/* Stop the queue kthreads */
	for (i = 0; i < ccp->cmd_q_count; i++)
	if (ccp->cmd_q[i].kthread)
	kthread_stop(ccp->cmd_q[i].kthread);

	/* Build queue interrupt mask (two interrupt masks per queue) */
	qim = 0;
	for (i = 0; i < ccp->cmd_q_count; i++) {
	cmd_q = &ccp->cmd_q[i];
	qim \|= cmd_q->int_ok \| cmd_q->int_err;
	}

	/* Disable and clear interrupts */
	iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
	for (i = 0; i < ccp->cmd_q_count; i++) {
	cmd_q = &ccp->cmd_q[i];

	ioread32(cmd_q->reg_int_status);
	ioread32(cmd_q->reg_status);
	}
	iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);

	ccp->free_irq(ccp);

	for (i = 0; i < ccp->cmd_q_count; i++)
	dma_pool_destroy(ccp->cmd_q[i].dma_pool);

	/* Flush the cmd and backlog queue */
	while (!list_empty(&ccp->cmd)) {
	/* Invoke the callback directly with an error code */
	cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
	list_del(&cmd->entry);
	cmd->callback(cmd->data, -ENODEV);
	}
	while (!list_empty(&ccp->backlog)) {
	/* Invoke the callback directly with an error code */
	cmd = list_first_entry(&ccp->backlog, struct ccp_cmd, entry);
	list_del(&cmd->entry);
	cmd->callback(cmd->data, -ENODEV);
	}
	}

	/**
	* ccp_irq_handler - handle interrupts generated by the CCP device
	*
	* @irq: the irq associated with the interrupt
	* @data: the data value supplied when the irq was created
	*/
	irqreturn_t ccp_irq_handler(int irq, void *data)
	{
	struct device *dev = data;
	struct ccp_device *ccp = dev_get_drvdata(dev);
	struct ccp_cmd_queue *cmd_q;
	u32 q_int, status;
	unsigned int i;

	status = ioread32(ccp->io_regs + IRQ_STATUS_REG);

	for (i = 0; i < ccp->cmd_q_count; i++) {
	cmd_q = &ccp->cmd_q[i];

	q_int = status & (cmd_q->int_ok \| cmd_q->int_err);
	if (q_int) {
	cmd_q->int_status = status;
	cmd_q->q_status = ioread32(cmd_q->reg_status);
	cmd_q->q_int_status = ioread32(cmd_q->reg_int_status);

	/* On error, only save the first error value */
	if ((q_int & cmd_q->int_err) && !cmd_q->cmd_error)
	cmd_q->cmd_error = CMD_Q_ERROR(cmd_q->q_status);

	cmd_q->int_rcvd = 1;

	/* Acknowledge the interrupt and wake the kthread */
	iowrite32(q_int, ccp->io_regs + IRQ_STATUS_REG);
	wake_up_interruptible(&cmd_q->int_queue);
	}
	}

	return IRQ_HANDLED;
	}

	#ifdef CONFIG_PM
	bool ccp_queues_suspended(struct ccp_device *ccp)
	{
	unsigned int suspended = 0;
	unsigned long flags;
	unsigned int i;

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	for (i = 0; i < ccp->cmd_q_count; i++)
	if (ccp->cmd_q[i].suspended)
	suspended++;

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	return ccp->cmd_q_count == suspended;
	}
	#endif

	static const struct x86_cpu_id ccp_support[] = {
	{ X86_VENDOR_AMD, 22, },
	};

	static int __init ccp_mod_init(void)
	{
	struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;
	int ret;

	if (!x86_match_cpu(ccp_support))
	return -ENODEV;

	switch (cpuinfo->x86) {
	case 22:
	if ((cpuinfo->x86_model < 48) \|\| (cpuinfo->x86_model > 63))
	return -ENODEV;

	ret = ccp_pci_init();
	if (ret)
	return ret;

	/* Don't leave the driver loaded if init failed */
	if (!ccp_get_device()) {
	ccp_pci_exit();
	return -ENODEV;
	}

	return 0;

	break;
	}

	return -ENODEV;
	}

	static void __exit ccp_mod_exit(void)
	{
	struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;

	switch (cpuinfo->x86) {
	case 22:
	ccp_pci_exit();
	break;
	}
	}

	module_init(ccp_mod_init);
	module_exit(ccp_mod_exit);