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 <[email protected]>
---
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/[email protected]/
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