In preparation for SHA support, replace the tasklets with a kthread that
manages one crypto_queue for the core.
As the Sahara can only process one AES or SHA request at a time, we make
sure that the queue serializes all requests from userspace. Instead of a
watchdog timer we now use a completion mechanism in the queue manager
thread.
This makes the control flow more obvious and guarantees, that only one
request is dequeued until the completion is completed.
Signed-off-by: Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx>
---
drivers/crypto/sahara.c | 152 +++++++++++++++++++++---------------------------
1 file changed, 66 insertions(+), 86 deletions(-)
diff --git a/drivers/crypto/sahara.c b/drivers/crypto/sahara.c
index 55c0d2bea426..04d3b4309e4c 100644
--- a/drivers/crypto/sahara.c
+++ b/drivers/crypto/sahara.c
@@ -22,7 +22,9 @@
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
+#include <linux/kthread.h>
#include <linux/module.h>
+#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
@@ -38,7 +40,6 @@
#define FLAGS_ENCRYPT BIT(0)
#define FLAGS_CBC BIT(1)
#define FLAGS_NEW_KEY BIT(3)
-#define FLAGS_BUSY 4
#define SAHARA_HDR_BASE 0x00800000
#define SAHARA_HDR_SKHA_ALG_AES 0
@@ -119,7 +120,6 @@ struct sahara_hw_link {
};
struct sahara_ctx {
- struct sahara_dev *dev;
unsigned long flags;
int keylen;
u8 key[AES_KEYSIZE_128];
@@ -136,15 +136,15 @@ struct sahara_dev {
void __iomem *regs_base;
struct clk *clk_ipg;
struct clk *clk_ahb;
+ struct mutex queue_mutex;
+ struct task_struct *kthread;
+ struct completion dma_completion;
struct sahara_ctx *ctx;
spinlock_t lock;
struct crypto_queue queue;
unsigned long flags;
- struct tasklet_struct done_task;
- struct tasklet_struct queue_task;
-
struct sahara_hw_desc *hw_desc[SAHARA_MAX_HW_DESC];
dma_addr_t hw_phys_desc[SAHARA_MAX_HW_DESC];
@@ -157,7 +157,6 @@ struct sahara_dev {
struct sahara_hw_link *hw_link[SAHARA_MAX_HW_LINK];
dma_addr_t hw_phys_link[SAHARA_MAX_HW_LINK];
- struct ablkcipher_request *req;
size_t total;
struct scatterlist *in_sg;
unsigned int nb_in_sg;
@@ -165,7 +164,6 @@ struct sahara_dev {
unsigned int nb_out_sg;
u32 error;
- struct timer_list watchdog;
};
static struct sahara_dev *dev_ptr;
@@ -404,34 +402,6 @@ static void sahara_dump_links(struct sahara_dev *dev)
dev_dbg(dev->device, "\n");
}
-static void sahara_aes_done_task(unsigned long data)
-{
- struct sahara_dev *dev = (struct sahara_dev *)data;
-
- dma_unmap_sg(dev->device, dev->out_sg, dev->nb_out_sg,
- DMA_TO_DEVICE);
- dma_unmap_sg(dev->device, dev->in_sg, dev->nb_in_sg,
- DMA_FROM_DEVICE);
-
- spin_lock(&dev->lock);
- clear_bit(FLAGS_BUSY, &dev->flags);
- spin_unlock(&dev->lock);
-
- dev->req->base.complete(&dev->req->base, dev->error);
-}
-
-static void sahara_watchdog(unsigned long data)
-{
- struct sahara_dev *dev = (struct sahara_dev *)data;
- unsigned int err = sahara_read(dev, SAHARA_REG_ERRSTATUS);
- unsigned int stat = sahara_read(dev, SAHARA_REG_STATUS);
-
- sahara_decode_status(dev, stat);
- sahara_decode_error(dev, err);
- dev->error = -ETIMEDOUT;
- sahara_aes_done_task(data);
-}
-
static int sahara_hw_descriptor_create(struct sahara_dev *dev)
{
struct sahara_ctx *ctx = dev->ctx;
@@ -515,9 +485,6 @@ static int sahara_hw_descriptor_create(struct sahara_dev *dev)
sahara_dump_descriptors(dev);
sahara_dump_links(dev);
- /* Start processing descriptor chain. */
- mod_timer(&dev->watchdog,
- jiffies + msecs_to_jiffies(SAHARA_TIMEOUT_MS));
sahara_write(dev, dev->hw_phys_desc[0], SAHARA_REG_DAR);
return 0;
@@ -532,37 +499,19 @@ unmap_in:
return -EINVAL;
}
-static void sahara_aes_queue_task(unsigned long data)
+static int sahara_aes_process(struct ablkcipher_request *req)
{
- struct sahara_dev *dev = (struct sahara_dev *)data;
- struct crypto_async_request *async_req, *backlog;
+ struct sahara_dev *dev = dev_ptr;
struct sahara_ctx *ctx;
struct sahara_aes_reqctx *rctx;
- struct ablkcipher_request *req;
int ret;
- spin_lock(&dev->lock);
- backlog = crypto_get_backlog(&dev->queue);
- async_req = crypto_dequeue_request(&dev->queue);
- if (!async_req)
- clear_bit(FLAGS_BUSY, &dev->flags);
- spin_unlock(&dev->lock);
-
- if (!async_req)
- return;
-
- if (backlog)
- backlog->complete(backlog, -EINPROGRESS);
-
- req = ablkcipher_request_cast(async_req);
-
/* Request is ready to be dispatched by the device */
dev_dbg(dev->device,
"dispatch request (nbytes=%d, src=%p, dst=%p)\n",
req->nbytes, req->src, req->dst);
/* assign new request to device */
- dev->req = req;
dev->total = req->nbytes;
dev->in_sg = req->src;
dev->out_sg = req->dst;
@@ -576,16 +525,25 @@ static void sahara_aes_queue_task(unsigned long data)
memcpy(dev->iv_base, req->info, AES_KEYSIZE_128);
/* assign new context to device */
- ctx->dev = dev;
dev->ctx = ctx;
+ reinit_completion(&dev->dma_completion);
+
ret = sahara_hw_descriptor_create(dev);
- if (ret < 0) {
- spin_lock(&dev->lock);
- clear_bit(FLAGS_BUSY, &dev->flags);
- spin_unlock(&dev->lock);
- dev->req->base.complete(&dev->req->base, ret);
+
+ ret = wait_for_completion_timeout(&dev->dma_completion,
+ msecs_to_jiffies(SAHARA_TIMEOUT_MS));
+ if (!ret) {
+ dev_err(dev->device, "AES timeout\n");
+ return -ETIMEDOUT;
}
+
+ dma_unmap_sg(dev->device, dev->out_sg, dev->nb_out_sg,
+ DMA_TO_DEVICE);
+ dma_unmap_sg(dev->device, dev->in_sg, dev->nb_in_sg,
+ DMA_FROM_DEVICE);
+
+ return 0;
}
static int sahara_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
@@ -627,12 +585,9 @@ static int sahara_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
static int sahara_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
{
- struct sahara_ctx *ctx = crypto_ablkcipher_ctx(
- crypto_ablkcipher_reqtfm(req));
struct sahara_aes_reqctx *rctx = ablkcipher_request_ctx(req);
struct sahara_dev *dev = dev_ptr;
int err = 0;
- int busy;
dev_dbg(dev->device, "nbytes: %d, enc: %d, cbc: %d\n",
req->nbytes, !!(mode & FLAGS_ENCRYPT), !!(mode & FLAGS_CBC));
@@ -643,16 +598,13 @@ static int sahara_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
return -EINVAL;
}
- ctx->dev = dev;
-
rctx->mode = mode;
- spin_lock_bh(&dev->lock);
+
+ mutex_lock(&dev->queue_mutex);
err = ablkcipher_enqueue_request(&dev->queue, req);
- busy = test_and_set_bit(FLAGS_BUSY, &dev->flags);
- spin_unlock_bh(&dev->lock);
+ mutex_unlock(&dev->queue_mutex);
- if (!busy)
- tasklet_schedule(&dev->queue_task);
+ wake_up_process(dev->kthread);
return err;
}
@@ -755,6 +707,36 @@ static void sahara_aes_cra_exit(struct crypto_tfm *tfm)
ctx->fallback = NULL;
}
+static int sahara_queue_manage(void *data)
+{
+ struct sahara_dev *dev = (struct sahara_dev *)data;
+ struct crypto_async_request *async_req;
+ int ret = 0;
+
+ do {
+ __set_current_state(TASK_INTERRUPTIBLE);
+
+ mutex_lock(&dev->queue_mutex);
+ async_req = crypto_dequeue_request(&dev->queue);
+ mutex_unlock(&dev->queue_mutex);
+
+ if (async_req) {
+ struct ablkcipher_request *req =
+ ablkcipher_request_cast(async_req);
+
+ ret = sahara_aes_process(req);
+
+ async_req->complete(async_req, ret);
+
+ continue;
+ }
+
+ schedule();
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
static struct crypto_alg aes_algs[] = {
{
.cra_name = "ecb(aes)",
@@ -806,8 +788,6 @@ static irqreturn_t sahara_irq_handler(int irq, void *data)
unsigned int stat = sahara_read(dev, SAHARA_REG_STATUS);
unsigned int err = sahara_read(dev, SAHARA_REG_ERRSTATUS);
- del_timer(&dev->watchdog);
-
sahara_write(dev, SAHARA_CMD_CLEAR_INT | SAHARA_CMD_CLEAR_ERR,
SAHARA_REG_CMD);
@@ -822,7 +802,7 @@ static irqreturn_t sahara_irq_handler(int irq, void *data)
dev->error = -EINVAL;
}
- tasklet_schedule(&dev->done_task);
+ complete(&dev->dma_completion);
return IRQ_HANDLED;
}
@@ -961,17 +941,17 @@ static int sahara_probe(struct platform_device *pdev)
crypto_init_queue(&dev->queue, SAHARA_QUEUE_LENGTH);
spin_lock_init(&dev->lock);
+ mutex_init(&dev->queue_mutex);
dev_ptr = dev;
- tasklet_init(&dev->queue_task, sahara_aes_queue_task,
- (unsigned long)dev);
- tasklet_init(&dev->done_task, sahara_aes_done_task,
- (unsigned long)dev);
+ dev->kthread = kthread_run(sahara_queue_manage, dev, "sahara_crypto");
+ if (IS_ERR(dev->kthread)) {
+ err = PTR_ERR(dev->kthread);
+ goto err_link;
+ }
- init_timer(&dev->watchdog);
- dev->watchdog.function = &sahara_watchdog;
- dev->watchdog.data = (unsigned long)dev;
+ init_completion(&dev->dma_completion);
clk_prepare_enable(dev->clk_ipg);
clk_prepare_enable(dev->clk_ahb);
@@ -1016,6 +996,7 @@ err_algs:
dev->hw_link[0], dev->hw_phys_link[0]);
clk_disable_unprepare(dev->clk_ipg);
clk_disable_unprepare(dev->clk_ahb);
+ kthread_stop(dev->kthread);
dev_ptr = NULL;
err_link:
dma_free_coherent(&pdev->dev,
@@ -1043,8 +1024,7 @@ static int sahara_remove(struct platform_device *pdev)
SAHARA_MAX_HW_DESC * sizeof(struct sahara_hw_desc),
dev->hw_desc[0], dev->hw_phys_desc[0]);
- tasklet_kill(&dev->done_task);
- tasklet_kill(&dev->queue_task);
+ kthread_stop(dev->kthread);
sahara_unregister_algs(dev);
--
2.1.3
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