[RFC] crypto: caam: re-init JR on resume

[Matthias Schiffer]

The JR loses its configuration during suspend-to-RAM (at least on
i.MX6UL). Re-initialize the hardware on resume.

Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
---

I've come across the issue that the CAAM would not work anymore after
deep sleep on i.MX6UL. It turned out that the CAAM loses its state
during suspend-to-RAM, so all registers read as zero and need to be
reinitialized.

This patch is my first attempt at fixing the issue. It seems to work
well enough, but I assume I'm missing some synchronization to prevent
that some CAAM operation is currently under way when the suspend
happens? I don't know the PM and crypto subsystems well enough to judge
if this is possible, and if it is, how to prevent it.

I've only compile-tested this version of the patch, as I had to port it
from our board kernel, which is based on the heavily-modified NXP branch.


 drivers/crypto/caam/intern.h |  3 ++
 drivers/crypto/caam/jr.c     | 62 +++++++++++++++++++++++++-----------
 2 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/drivers/crypto/caam/intern.h b/drivers/crypto/caam/intern.h
index c7c10c90464b..5d2e9091d5c2 100644
--- a/drivers/crypto/caam/intern.h
+++ b/drivers/crypto/caam/intern.h
@@ -47,6 +47,9 @@ struct caam_drv_private_jr {
 	struct tasklet_struct irqtask;
 	int irq;			/* One per queue */
 
+	dma_addr_t inpbusaddr;
+	dma_addr_t outbusaddr;
+
 	/* Number of scatterlist crypt transforms active on the JobR */
 	atomic_t tfm_count ____cacheline_aligned;
 
diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c
index fc97cde27059..2dabf5fd7818 100644
--- a/drivers/crypto/caam/jr.c
+++ b/drivers/crypto/caam/jr.c
@@ -418,13 +418,31 @@ int caam_jr_enqueue(struct device *dev, u32 *desc,
 }
 EXPORT_SYMBOL(caam_jr_enqueue);
 
+static void caam_jr_setup_rings(struct caam_drv_private_jr *jrp)
+{
+	jrp->out_ring_read_index = 0;
+	jrp->head = 0;
+	jrp->tail = 0;
+
+	wr_reg64(&jrp->rregs->inpring_base, jrp->inpbusaddr);
+	wr_reg64(&jrp->rregs->outring_base, jrp->outbusaddr);
+	wr_reg32(&jrp->rregs->inpring_size, JOBR_DEPTH);
+	wr_reg32(&jrp->rregs->outring_size, JOBR_DEPTH);
+
+	jrp->inpring_avail = JOBR_DEPTH;
+
+	/* Select interrupt coalescing parameters */
+	clrsetbits_32(&jrp->rregs->rconfig_lo, 0, JOBR_INTC |
+		      (JOBR_INTC_COUNT_THLD << JRCFG_ICDCT_SHIFT) |
+		      (JOBR_INTC_TIME_THLD << JRCFG_ICTT_SHIFT));
+}
+
 /*
  * Init JobR independent of platform property detection
  */
 static int caam_jr_init(struct device *dev)
 {
 	struct caam_drv_private_jr *jrp;
-	dma_addr_t inpbusaddr, outbusaddr;
 	int i, error;
 
 	jrp = dev_get_drvdata(dev);
@@ -434,13 +452,13 @@ static int caam_jr_init(struct device *dev)
 		return error;
 
 	jrp->inpring = dmam_alloc_coherent(dev, SIZEOF_JR_INPENTRY *
-					   JOBR_DEPTH, &inpbusaddr,
+					   JOBR_DEPTH, &jrp->inpbusaddr,
 					   GFP_KERNEL);
 	if (!jrp->inpring)
 		return -ENOMEM;
 
 	jrp->outring = dmam_alloc_coherent(dev, SIZEOF_JR_OUTENTRY *
-					   JOBR_DEPTH, &outbusaddr,
+					   JOBR_DEPTH, &jrp->outbusaddr,
 					   GFP_KERNEL);
 	if (!jrp->outring)
 		return -ENOMEM;
@@ -453,24 +471,9 @@ static int caam_jr_init(struct device *dev)
 	for (i = 0; i < JOBR_DEPTH; i++)
 		jrp->entinfo[i].desc_addr_dma = !0;
 
-	/* Setup rings */
-	jrp->out_ring_read_index = 0;
-	jrp->head = 0;
-	jrp->tail = 0;
-
-	wr_reg64(&jrp->rregs->inpring_base, inpbusaddr);
-	wr_reg64(&jrp->rregs->outring_base, outbusaddr);
-	wr_reg32(&jrp->rregs->inpring_size, JOBR_DEPTH);
-	wr_reg32(&jrp->rregs->outring_size, JOBR_DEPTH);
-
-	jrp->inpring_avail = JOBR_DEPTH;
-
 	spin_lock_init(&jrp->inplock);
 
-	/* Select interrupt coalescing parameters */
-	clrsetbits_32(&jrp->rregs->rconfig_lo, 0, JOBR_INTC |
-		      (JOBR_INTC_COUNT_THLD << JRCFG_ICDCT_SHIFT) |
-		      (JOBR_INTC_TIME_THLD << JRCFG_ICTT_SHIFT));
+	caam_jr_setup_rings(jrp);
 
 	tasklet_init(&jrp->irqtask, caam_jr_dequeue, (unsigned long)dev);
 
@@ -486,6 +489,20 @@ static int caam_jr_init(struct device *dev)
 	return error;
 }
 
+static int caam_jr_reinit(struct device *dev)
+{
+	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
+	int error;
+
+	error = caam_reset_hw_jr(dev);
+	if (error)
+		return error;
+
+	caam_jr_setup_rings(jrp);
+
+	return 0;
+}
+
 static void caam_jr_irq_dispose_mapping(void *data)
 {
 	irq_dispose_mapping((unsigned long)data);
@@ -578,10 +595,17 @@ static const struct of_device_id caam_jr_match[] = {
 };
 MODULE_DEVICE_TABLE(of, caam_jr_match);
 
+#ifdef CONFIG_PM
+static SIMPLE_DEV_PM_OPS(caam_jr_pm_ops, caam_reset_hw_jr, caam_jr_reinit);
+#endif
+
 static struct platform_driver caam_jr_driver = {
 	.driver = {
 		.name = "caam_jr",
 		.of_match_table = caam_jr_match,
+#ifdef CONFIG_PM
+		.pm = &caam_jr_pm_ops,
+#endif
 	},
 	.probe       = caam_jr_probe,
 	.remove      = caam_jr_remove,
-- 
2.17.1