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/*
* Handle async block request by crypto hardware engine.
*
* Copyright (C) 2016 Linaro, Inc.
*
* Author: Baolin Wang <baolin.wang@linaro.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; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/err.h>
#include <linux/delay.h>
#include "internal.h"
#define CRYPTO_ENGINE_MAX_QLEN 10
void crypto_finalize_request(struct crypto_engine *engine,
struct ablkcipher_request *req, int err);
/**
* crypto_pump_requests - dequeue one request from engine queue to process
* @engine: the hardware engine
* @in_kthread: true if we are in the context of the request pump thread
*
* This function checks if there is any request in the engine queue that
* needs processing and if so call out to the driver to initialize hardware
* and handle each request.
*/
static void crypto_pump_requests(struct crypto_engine *engine,
bool in_kthread)
{
struct crypto_async_request *async_req, *backlog;
struct ablkcipher_request *req;
unsigned long flags;
bool was_busy = false;
int ret;
spin_lock_irqsave(&engine->queue_lock, flags);
/* Make sure we are not already running a request */
if (engine->cur_req)
goto out;
/* If another context is idling then defer */
if (engine->idling) {
queue_kthread_work(&engine->kworker, &engine->pump_requests);
goto out;
}
/* Check if the engine queue is idle */
if (!crypto_queue_len(&engine->queue) || !engine->running) {
if (!engine->busy)
goto out;
/* Only do teardown in the thread */
if (!in_kthread) {
queue_kthread_work(&engine->kworker,
&engine->pump_requests);
goto out;
}
engine->busy = false;
engine->idling = true;
spin_unlock_irqrestore(&engine->queue_lock, flags);
if (engine->unprepare_crypt_hardware &&
engine->unprepare_crypt_hardware(engine))
pr_err("failed to unprepare crypt hardware\n");
spin_lock_irqsave(&engine->queue_lock, flags);
engine->idling = false;
goto out;
}
/* Get the fist request from the engine queue to handle */
backlog = crypto_get_backlog(&engine->queue);
async_req = crypto_dequeue_request(&engine->queue);
if (!async_req)
goto out;
req = ablkcipher_request_cast(async_req);
engine->cur_req = req;
if (backlog)
backlog->complete(backlog, -EINPROGRESS);
if (engine->busy)
was_busy = true;
else
engine->busy = true;
spin_unlock_irqrestore(&engine->queue_lock, flags);
/* Until here we get the request need to be encrypted successfully */
if (!was_busy && engine->prepare_crypt_hardware) {
ret = engine->prepare_crypt_hardware(engine);
if (ret) {
pr_err("failed to prepare crypt hardware\n");
goto req_err;
}
}
if (engine->prepare_request) {
ret = engine->prepare_request(engine, engine->cur_req);
if (ret) {
pr_err("failed to prepare request: %d\n", ret);
goto req_err;
}
engine->cur_req_prepared = true;
}
ret = engine->crypt_one_request(engine, engine->cur_req);
if (ret) {
pr_err("failed to crypt one request from queue\n");
goto req_err;
}
return;
req_err:
crypto_finalize_request(engine, engine->cur_req, ret);
return;
out:
spin_unlock_irqrestore(&engine->queue_lock, flags);
}
static void crypto_pump_work(struct kthread_work *work)
{
struct crypto_engine *engine =
container_of(work, struct crypto_engine, pump_requests);
crypto_pump_requests(engine, true);
}
/**
* crypto_transfer_request - transfer the new request into the engine queue
* @engine: the hardware engine
* @req: the request need to be listed into the engine queue
*/
int crypto_transfer_request(struct crypto_engine *engine,
struct ablkcipher_request *req, bool need_pump)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&engine->queue_lock, flags);
if (!engine->running) {
spin_unlock_irqrestore(&engine->queue_lock, flags);
return -ESHUTDOWN;
}
ret = ablkcipher_enqueue_request(&engine->queue, req);
if (!engine->busy && need_pump)
queue_kthread_work(&engine->kworker, &engine->pump_requests);
spin_unlock_irqrestore(&engine->queue_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_transfer_request);
/**
* crypto_transfer_request_to_engine - transfer one request to list into the
* engine queue
* @engine: the hardware engine
* @req: the request need to be listed into the engine queue
*/
int crypto_transfer_request_to_engine(struct crypto_engine *engine,
struct ablkcipher_request *req)
{
return crypto_transfer_request(engine, req, true);
}
EXPORT_SYMBOL_GPL(crypto_transfer_request_to_engine);
/**
* crypto_finalize_request - finalize one request if the request is done
* @engine: the hardware engine
* @req: the request need to be finalized
* @err: error number
*/
void crypto_finalize_request(struct crypto_engine *engine,
struct ablkcipher_request *req, int err)
{
unsigned long flags;
bool finalize_cur_req = false;
int ret;
spin_lock_irqsave(&engine->queue_lock, flags);
if (engine->cur_req == req)
finalize_cur_req = true;
spin_unlock_irqrestore(&engine->queue_lock, flags);
if (finalize_cur_req) {
if (engine->cur_req_prepared && engine->unprepare_request) {
ret = engine->unprepare_request(engine, req);
if (ret)
pr_err("failed to unprepare request\n");
}
spin_lock_irqsave(&engine->queue_lock, flags);
engine->cur_req = NULL;
engine->cur_req_prepared = false;
spin_unlock_irqrestore(&engine->queue_lock, flags);
}
req->base.complete(&req->base, err);
queue_kthread_work(&engine->kworker, &engine->pump_requests);
}
EXPORT_SYMBOL_GPL(crypto_finalize_request);
/**
* crypto_engine_start - start the hardware engine
* @engine: the hardware engine need to be started
*
* Return 0 on success, else on fail.
*/
int crypto_engine_start(struct crypto_engine *engine)
{
unsigned long flags;
spin_lock_irqsave(&engine->queue_lock, flags);
if (engine->running || engine->busy) {
spin_unlock_irqrestore(&engine->queue_lock, flags);
return -EBUSY;
}
engine->running = true;
spin_unlock_irqrestore(&engine->queue_lock, flags);
queue_kthread_work(&engine->kworker, &engine->pump_requests);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_engine_start);
/**
* crypto_engine_stop - stop the hardware engine
* @engine: the hardware engine need to be stopped
*
* Return 0 on success, else on fail.
*/
int crypto_engine_stop(struct crypto_engine *engine)
{
unsigned long flags;
unsigned limit = 500;
int ret = 0;
spin_lock_irqsave(&engine->queue_lock, flags);
/*
* If the engine queue is not empty or the engine is on busy state,
* we need to wait for a while to pump the requests of engine queue.
*/
while ((crypto_queue_len(&engine->queue) || engine->busy) && limit--) {
spin_unlock_irqrestore(&engine->queue_lock, flags);
msleep(20);
spin_lock_irqsave(&engine->queue_lock, flags);
}
if (crypto_queue_len(&engine->queue) || engine->busy)
ret = -EBUSY;
else
engine->running = false;
spin_unlock_irqrestore(&engine->queue_lock, flags);
if (ret)
pr_warn("could not stop engine\n");
return ret;
}
EXPORT_SYMBOL_GPL(crypto_engine_stop);
/**
* crypto_engine_alloc_init - allocate crypto hardware engine structure and
* initialize it.
* @dev: the device attached with one hardware engine
* @rt: whether this queue is set to run as a realtime task
*
* This must be called from context that can sleep.
* Return: the crypto engine structure on success, else NULL.
*/
struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
{
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
struct crypto_engine *engine;
if (!dev)
return NULL;
engine = devm_kzalloc(dev, sizeof(*engine), GFP_KERNEL);
if (!engine)
return NULL;
engine->rt = rt;
engine->running = false;
engine->busy = false;
engine->idling = false;
engine->cur_req_prepared = false;
engine->priv_data = dev;
snprintf(engine->name, sizeof(engine->name),
"%s-engine", dev_name(dev));
crypto_init_queue(&engine->queue, CRYPTO_ENGINE_MAX_QLEN);
spin_lock_init(&engine->queue_lock);
init_kthread_worker(&engine->kworker);
engine
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