linux-stable/drivers/crypto/ccp/ccp-dev.c
Tom Lendacky 530abd8938 crypto: ccp - Perform completion callbacks using a tasklet
Change from scheduling work to scheduling a tasklet to perform
the callback operations.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-02-09 09:59:24 +08:00

608 lines
14 KiB
C

/*
* 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");
struct ccp_tasklet_data {
struct completion completion;
struct ccp_cmd *cmd;
};
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(unsigned long data)
{
struct ccp_tasklet_data *tdata = (struct ccp_tasklet_data *)data;
struct ccp_cmd *cmd = tdata->cmd;
cmd->callback(cmd->data, cmd->ret);
complete(&tdata->completion);
}
static int ccp_cmd_queue_thread(void *data)
{
struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
struct ccp_cmd *cmd;
struct ccp_tasklet_data tdata;
struct tasklet_struct tasklet;
tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
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 */
tdata.cmd = cmd;
init_completion(&tdata.completion);
tasklet_schedule(&tasklet);
wait_for_completion(&tdata.completion);
}
__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);