diff mbox series

[V2] crypto: qcom-rng - Add hw_random interface support

Message ID 20230905062420.3983268-1-quic_omprsing@quicinc.com
State New
Headers show
Series [V2] crypto: qcom-rng - Add hw_random interface support | expand

Commit Message

Om Prakash Singh Sept. 5, 2023, 6:24 a.m. UTC
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@quicinc.com>
---

Changes in V2:
- Address review comment from Bjorn and Krzysztof

This patch is depends on [1]
[1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@linaro.org/

 drivers/crypto/qcom-rng.c | 65 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 7 deletions(-)

Comments

Konrad Dybcio Sept. 5, 2023, 8:34 a.m. UTC | #1
On 5.09.2023 08:24, 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@quicinc.com>
> ---
> 
> Changes in V2:
> - Address review comment from Bjorn and Krzysztof
"make changes" is not a valid changelog, please be more specific
next time around

Konrad
Bjorn Andersson Sept. 22, 2023, 3:16 p.m. UTC | #2
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@quicinc.com>
> ---
> 
> 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@linaro.org/
> 
>  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...

>  }
>  
>  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.

> +		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@gondor.apana.org.au/

> +
> +	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
diff mbox series

Patch

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;
 }
 
 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)
+		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;
+
+	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,
+};
+
 static int qcom_rng_probe(struct platform_device *pdev)
 {
 	struct qcom_rng *rng;
@@ -177,15 +199,29 @@  static int qcom_rng_probe(struct platform_device *pdev)
 	if (IS_ERR(rng->clk))
 		return PTR_ERR(rng->clk);
 
-	rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev);
+	rng->of_data = (struct qcom_rng_of_data *)of_device_get_match_data(&pdev->dev);
 
 	qcom_rng_dev = rng;
 	ret = crypto_register_rng(&qcom_rng_alg);
 	if (ret) {
 		dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);
 		qcom_rng_dev = NULL;
+		return ret;
+	}
+
+	if (rng->of_data->hwrng_support) {
+		qcom_hwrng.priv = (unsigned long)qcom_rng_dev;
+		ret = devm_hwrng_register(&pdev->dev, &qcom_hwrng);
+		if (ret) {
+			dev_err(&pdev->dev, "Register hwrng failed: %d\n", ret);
+			qcom_rng_dev = NULL;
+			goto fail;
+		}
 	}
 
+	return ret;
+fail:
+	crypto_unregister_rng(&qcom_rng_alg);
 	return ret;
 }
 
@@ -198,6 +234,21 @@  static int qcom_rng_remove(struct platform_device *pdev)
 	return 0;
 }
 
+struct qcom_rng_of_data qcom_prng_of_data = {
+	.skip_init = false,
+	.hwrng_support = false,
+};
+
+struct qcom_rng_of_data qcom_prng_ee_of_data = {
+	.skip_init = true,
+	.hwrng_support = false,
+};
+
+struct qcom_rng_of_data qcom_trng_of_data = {
+	.skip_init = true,
+	.hwrng_support = true,
+};
+
 static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = {
 	{ .id = "QCOM8160", .driver_data = 1 },
 	{}
@@ -205,9 +256,9 @@  static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = {
 MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match);
 
 static const struct of_device_id __maybe_unused qcom_rng_of_match[] = {
-	{ .compatible = "qcom,prng", .data = (void *)0},
-	{ .compatible = "qcom,prng-ee", .data = (void *)1},
-	{ .compatible = "qcom,trng", .data = (void *)1},
+	{ .compatible = "qcom,prng", .data = &qcom_prng_of_data },
+	{ .compatible = "qcom,prng-ee", .data = &qcom_prng_ee_of_data },
+	{ .compatible = "qcom,trng", .data = &qcom_trng_of_data },
 	{}
 };
 MODULE_DEVICE_TABLE(of, qcom_rng_of_match);