[PATCH v3] rng: Add Turris Mox rTWM RNG driver

[Max Resch <resch.max@gmail.com>]

A RNG driver for Armada 3720 boards running the Turris Mox rWTM firmware
from CZ.NIC in the secure processor.

Signed-off-by: Max Resch <resch.max@gmail.com>
---

Changes in v3:
 - More meaningful variable names in accordance with review

Changes in v2:
 - Removed ring buffer implementation

 drivers/rng/turris_rwtm_rng.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/rng/turris_rwtm_rng.c b/drivers/rng/turris_rwtm_rng.c
index 143fe0b47f..ec2cb0bca3 100644
--- a/drivers/rng/turris_rwtm_rng.c
+++ b/drivers/rng/turris_rwtm_rng.c
@@ -41,18 +41,19 @@ static int turris_rwtm_rng_fill_entropy(phys_addr_t entropy, size_t size)
 
 static int turris_rwtm_rng_random_read(struct udevice *dev, void *data, size_t count)
 {
-	phys_addr_t p;
+	struct turris_rwtm_rng_priv *priv = dev_get_priv(dev);
+	phys_addr_t phys;
 	size_t size;
 	int ret;
 
-	p = ((struct turris_rwtm_rng_priv *)dev_get_priv(dev))->buffer;
+	phys = priv->buffer;
 
 	while (count) {
 		size = min_t(size_t, RNG_BUFFER_SIZE, count);
 
-		ret = turris_rwtm_rng_fill_entropy(p, size);
+		ret = turris_rwtm_rng_fill_entropy(phys, size);
 
-		memcpy(data, (void *)p, size);
+		memcpy(data, (void *)phys, size);
 		count -= size;
 		data = (u8 *)data + size;
 	}
@@ -62,7 +63,7 @@ static int turris_rwtm_rng_random_read(struct udevice *dev, void *data, size_t c
 
 static int turris_rwtm_rng_probe(struct udevice *dev)
 {
-	struct turris_rwtm_rng_priv *priv;
+	struct turris_rwtm_rng_priv *priv = dev_get_priv(dev);
 	u32 args[] = { 0 };
 	int ret;
 
@@ -76,7 +77,6 @@ static int turris_rwtm_rng_probe(struct udevice *dev)
 		return ret;
 
 	/* entropy buffer */
-	priv = (struct turris_rwtm_rng_priv *)dev_get_priv(dev);
 	priv->buffer = 0;
 
 	/* buffer address need to be aligned */
@@ -89,10 +89,10 @@ static int turris_rwtm_rng_probe(struct udevice *dev)
 
 static int turris_rwtm_rng_remove(struct udevice *dev)
 {
-	phys_addr_t p;
+	struct turris_rwtm_rng_priv *priv = dev_get_priv(dev);
+	phys_addr_t phys = priv->buffer;
 
-	p = ((struct turris_rwtm_rng_priv *)dev_get_priv(dev))->buffer;
-	dma_free_coherent((void *)p);
+	dma_free_coherent((void *)phys);
 
 	return 0;
 }
-- 
2.43.0