crypto: mv_cesa - add an expiry timer in case anything goes wrong

The timer triggers when 500ms have gone by after triggering the engine
and no completion interrupt was received. The callback then tries to
sanitise things as well as possible.
Signed-off-by: Phil Sutter <phil.sutter@viprinet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/mv_cesa.c

@@ -24,6 +24,7 @@
 
 #define MV_CESA	"MV-CESA:"
 #define MAX_HW_HASH_SIZE	0xFFFF
+#define MV_CESA_EXPIRE		500 /* msec */
 
 /*
  * STM:
@@ -87,6 +88,7 @@ struct crypto_priv {
 	spinlock_t lock;
 	struct crypto_queue queue;
 	enum engine_status eng_st;
+	struct timer_list completion_timer;
 	struct crypto_async_request *cur_req;
 	struct req_progress p;
 	int max_req_size;
@@ -138,6 +140,29 @@ struct mv_req_hash_ctx {
 	int count_add;
 };
 
+static void mv_completion_timer_callback(unsigned long unused)
+{
+	int active = readl(cpg->reg + SEC_ACCEL_CMD) & SEC_CMD_EN_SEC_ACCL0;
+
+	printk(KERN_ERR MV_CESA
+	       "completion timer expired (CESA %sactive), cleaning up.\n",
+	       active ? "" : "in");
+
+	del_timer(&cpg->completion_timer);
+	writel(SEC_CMD_DISABLE_SEC, cpg->reg + SEC_ACCEL_CMD);
+	while(readl(cpg->reg + SEC_ACCEL_CMD) & SEC_CMD_DISABLE_SEC)
+		printk(KERN_INFO MV_CESA "%s: waiting for engine finishing\n", __func__);
+	cpg->eng_st = ENGINE_W_DEQUEUE;
+	wake_up_process(cpg->queue_th);
+}
+
+static void mv_setup_timer(void)
+{
+	setup_timer(&cpg->completion_timer, &mv_completion_timer_callback, 0);
+	mod_timer(&cpg->completion_timer,
+			jiffies + msecs_to_jiffies(MV_CESA_EXPIRE));
+}
+
 static void compute_aes_dec_key(struct mv_ctx *ctx)
 {
 	struct crypto_aes_ctx gen_aes_key;
@@ -273,12 +298,8 @@ static void mv_process_current_q(int first_block)
 			sizeof(struct sec_accel_config));
 
 	/* GO */
+	mv_setup_timer();
 	writel(SEC_CMD_EN_SEC_ACCL0, cpg->reg + SEC_ACCEL_CMD);
-
-	/*
-	 * XXX: add timer if the interrupt does not occur for some mystery
-	 * reason
-	 */
 }
 
 static void mv_crypto_algo_completion(void)
@@ -357,12 +378,8 @@ static void mv_process_hash_current(int first_block)
 	memcpy(cpg->sram + SRAM_CONFIG, &op, sizeof(struct sec_accel_config));
 
 	/* GO */
+	mv_setup_timer();
 	writel(SEC_CMD_EN_SEC_ACCL0, cpg->reg + SEC_ACCEL_CMD);
-
-	/*
-	* XXX: add timer if the interrupt does not occur for some mystery
-	* reason
-	*/
 }
 
 static inline int mv_hash_import_sha1_ctx(const struct mv_req_hash_ctx *ctx,
@@ -888,6 +905,10 @@ irqreturn_t crypto_int(int irq, void *priv)
 	if (!(val & SEC_INT_ACCEL0_DONE))
 		return IRQ_NONE;
 
+	if (!del_timer(&cpg->completion_timer)) {
+		printk(KERN_WARNING MV_CESA
+		       "got an interrupt but no pending timer?\n");
+	}
 	val &= ~SEC_INT_ACCEL0_DONE;
 	writel(val, cpg->reg + FPGA_INT_STATUS);
 	writel(val, cpg->reg + SEC_ACCEL_INT_STATUS);