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 V4: - Fixed email address of author - Removed extra space added in qcom_hwrng_read() Changes in V3: - Fix qcom_rng_read() implementation to account for remaining bytes read - Update qcom_rng_generate() return condition for success case - Added hwrng structure as part of qcom_rng structure Changes in V2: - Updated patch to fix the return value from qcom_rng_generate() to be consistent with current implementation - 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 | 66 ++++++++++++++++++++++++++++++++++----- 1 file changed, 58 insertions(+), 8 deletions(-) diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c index fb54b8cfc35f..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 }, {} @@ -205,9 +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,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); -- 2.25.1
