On 9/22/2023 8:46 PM, Bjorn Andersson wrote:
On Wed, Sep 20, 2023 at 08:34:08AM +0530, Om Prakash Singh wrote:
Add hw_random interface support in qcom-rng driver as new IP block
in Qualcomm SoC has inbuilt NIST SP800 90B compliant entropic source
to generate true random number.
Keeping current rng_alg interface as well for random number generation
using Kernel Crypto API.
Signed-off-by: Om Prakash Singh <quic_omprsing@xxxxxxxxxxx>
---
Changes in V2:
- Updated patch to fix the return value from qcom_rng_generate() to be
consistent with current implementation
As far as I can tell you didn't change this, see below.
- Updated patch to make it more concise
- Removed unnecessary use local variable and it's initialization
- Updated patch to use devm_hwrng_register() instead of hwrng_register()
- Updated subject line of the patch
This patch is depends on [1]
[1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@xxxxxxxxxx/
drivers/crypto/qcom-rng.c | 65 ++++++++++++++++++++++++++++++++++-----
1 file changed, 58 insertions(+), 7 deletions(-)
diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c
index fb54b8cfc35f..e5a574a3cc59 100644
--- a/drivers/crypto/qcom-rng.c
+++ b/drivers/crypto/qcom-rng.c
@@ -7,6 +7,7 @@
#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/crypto.h>
+#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
@@ -32,13 +33,18 @@ struct qcom_rng {
struct mutex lock;
void __iomem *base;
struct clk *clk;
- unsigned int skip_init;
+ struct qcom_rng_of_data *of_data;
};
struct qcom_rng_ctx {
struct qcom_rng *rng;
};
+struct qcom_rng_of_data {
+ bool skip_init;
+ bool hwrng_support;
+};
+
static struct qcom_rng *qcom_rng_dev;
static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
@@ -70,7 +76,7 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
}
} while (currsize < max);
- return 0;
+ return currsize;
As I pointed out in my previous review, if the qcom_rng_read() is
requested to read a number of bytes (max) that is not evenly divisible
with 4 (WORD_SZ) the loop will exit without accounting for the last
bytes copied...
I will update implementation to account currsize for accounting
remaining bytes
}
static int qcom_rng_generate(struct crypto_rng *tfm,
@@ -92,6 +98,9 @@ static int qcom_rng_generate(struct crypto_rng *tfm,
mutex_unlock(&rng->lock);
clk_disable_unprepare(rng->clk);
+ if (ret == dlen)
...this means that if dlen % 4, you're changing the return value of this
function from 0 to dlen.
I will Update logic for success case return value.
+ ret = 0;
+
return ret;
}
@@ -101,6 +110,13 @@ static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
return 0;
}
+static int qcom_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ struct qcom_rng *qrng = (struct qcom_rng *)rng->priv;
You missed Herbert's request in [1], which I presume implies that
qcom_hwrng should be moved into struct qcom_rng, which would mean that
you can get the qrng by container_of().
[1] https://lore.kernel.org/lkml/ZQQvlXvGy8p01uJS@xxxxxxxxxxxxxxxxxxx/
I will address this comment is my next patch set V3.
+
+ return qcom_rng_read(qrng, data, max);
+}
+
static int qcom_rng_enable(struct qcom_rng *rng)
{
u32 val;
@@ -136,7 +152,7 @@ static int qcom_rng_init(struct crypto_tfm *tfm)
ctx->rng = qcom_rng_dev;
- if (!ctx->rng->skip_init)
+ if (!ctx->rng->of_data->skip_init)
return qcom_rng_enable(ctx->rng);
return 0;
@@ -157,6 +173,12 @@ static struct rng_alg qcom_rng_alg = {
}
};
+static struct hwrng qcom_hwrng = {
+ .name = "qcom-hwrng",
+ .read = qcom_hwrng_read,
+ .quality = 1024,
+};
Which would mean not adding this static global variable...
Regards,
Bjorn
