On 11/1/23 15:49, Alexey Romanov wrote:
Add dm_rng_read_default() function, which obtain a series
of random bytes. In some cases, such function would be
useful because it allows the caller to abstract away from
RNG device.
Signed-off-by: Alexey Romanov <avroma...@salutedevices.com>
---
drivers/rng/rng-uclass.c | 20 ++++++++++++++++++++
include/rng.h | 10 ++++++++++
2 files changed, 30 insertions(+)
diff --git a/drivers/rng/rng-uclass.c b/drivers/rng/rng-uclass.c
index 53108e1b31..3a8fb7d276 100644
--- a/drivers/rng/rng-uclass.c
+++ b/drivers/rng/rng-uclass.c
@@ -19,6 +19,26 @@ int dm_rng_read(struct udevice *dev, void *buffer, size_t
size)
return ops->read(dev, buffer, size);
}
+int dm_rng_read_default(void *buffer, size_t size)
+{
+ struct udevice *rng;
+ int ret;
+
+ ret = uclass_get_device(UCLASS_RNG, 0, &rng);
This function will give you the first RNG device and not the first
successfully probed RNG device.
We already have a weak function platform_get_rng_device() which allows a
board to provide a different device. I think we should move
platform_get_rng_device() to rng-uclass.c and use it here.
platform_get_rng_device should be re-implemented to provide the first
successfully probed RNG device.
+ if (ret) {
+ pr_err("Can't get RNG device (%d)\n", ret);
+ return ret;
+ }
+
+ ret = dm_rng_read(rng, buffer, size);
Here you are using a device which may not have been probed yet.
Best regards
Heinrich
+ if (ret) {
+ pr_err("Can't read from RNG device (%d)\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
UCLASS_DRIVER(rng) = {
.name = "rng",
.id = UCLASS_RNG,
diff --git a/include/rng.h b/include/rng.h
index 37af554363..5537daae88 100644
--- a/include/rng.h
+++ b/include/rng.h
@@ -20,6 +20,16 @@ struct udevice;
*/
int dm_rng_read(struct udevice *dev, void *buffer, size_t size);
+/**
+ * dm_rng_read_default() - same as dm_rng_read(), except that caller
+ * don't need to pass an argument with RNG udevice.
+ * @buffer: input buffer to put the read random seed into
+ * @size: number of bytes of random seed read
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int dm_rng_read_default(void *buffer, size_t size);
+
/**
* struct dm_rng_ops - operations for the hwrng uclass
*
