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SubjectRe: [PATCH v4 3/5] crypto: qcom-rng - Add hw_random interface support
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On 10/3/2023 12:40 PM, neil.armstrong@linaro.org wrote:
> From: Om Prakash Singh <quic_omprsing@quicinc.com>
>
> 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>
> Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> ---

Acked-by: Om Prakash Singh <quic_omprsing@quicinc.com>

> 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 825a729f205e..8b506abb934c 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>
> @@ -28,17 +29,25 @@
>
> #define WORD_SZ 4
>
> +#define QCOM_TRNG_QUALITY 1024
> +
> struct qcom_rng {
> struct mutex lock;
> void __iomem *base;
> struct clk *clk;
> - unsigned int skip_init;
> + struct hwrng hwrng;
> + 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)
> @@ -66,11 +75,11 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
> } else {
> /* copy only remaining bytes */
> memcpy(data, &val, max - currsize);
> - break;
> + currsize = max;
> }
> } while (currsize < max);
>
> - return 0;
> + return currsize;
> }
>
> static int qcom_rng_generate(struct crypto_rng *tfm,
> @@ -92,6 +101,9 @@ static int qcom_rng_generate(struct crypto_rng *tfm,
> mutex_unlock(&rng->lock);
> clk_disable_unprepare(rng->clk);
>
> + if (ret >= 0)
> + ret = 0;
> +
> return ret;
> }
>
> @@ -101,6 +113,13 @@ static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
> return 0;
> }
>
> +static int qcom_hwrng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
> +{
> + struct qcom_rng *qrng = container_of(hwrng, struct qcom_rng, hwrng);
> +
> + return qcom_rng_read(qrng, data, max);
> +}
> +
> static int qcom_rng_enable(struct qcom_rng *rng)
> {
> u32 val;
> @@ -136,7 +155,7 @@ 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;
> @@ -177,15 +196,31 @@ 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) {
> + rng->hwrng.name = "qcom_hwrng";
> + rng->hwrng.read = qcom_hwrng_read;
> + rng->hwrng.quality = QCOM_TRNG_QUALITY;
> + ret = devm_hwrng_register(&pdev->dev, &rng->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 +233,21 @@ 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 },
> {}
> @@ -205,8 +255,9 @@ 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,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);
>

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