Discussion:
[PATCH v5] crypto: sun4i-ss: support the Security System PRNG
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Corentin Labbe
2017-07-03 18:48:48 UTC
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The Security System has a PRNG, this patch adds support for it via
crypto_rng.

Signed-off-by: Corentin Labbe <***@gmail.com>
---

Change since v4
- Fixed some spelling issue in Kconfig and patch description

Changes since v3 (note: the v3 miss changes and version tag sorry)
- Replaced all len values with bits / BITS_PER_LONG or BITS_PER_BYTE

Changes since v2
- converted to crypto_rng

Changes since v1:
- Replaced all spin_lock_bh by simple spin_lock
- Removed handling of size not modulo 4 which will never happen
- Added add_random_ready_callback()

drivers/crypto/Kconfig | 8 +++++
drivers/crypto/sunxi-ss/Makefile | 1 +
drivers/crypto/sunxi-ss/sun4i-ss-core.c | 30 ++++++++++++++++++
drivers/crypto/sunxi-ss/sun4i-ss-prng.c | 56 +++++++++++++++++++++++++++++++++
drivers/crypto/sunxi-ss/sun4i-ss.h | 11 +++++++
5 files changed, 106 insertions(+)
create mode 100644 drivers/crypto/sunxi-ss/sun4i-ss-prng.c

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index ab82536d64e2..99245f9c9d58 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -618,6 +618,14 @@ config CRYPTO_DEV_SUN4I_SS
To compile this driver as a module, choose M here: the module
will be called sun4i-ss.

+config CRYPTO_DEV_SUN4I_SS_PRNG
+ bool "Support for Allwinner Security System PRNG"
+ depends on CRYPTO_DEV_SUN4I_SS
+ select CRYPTO_RNG
+ help
+ Select this option if you want to provide kernel-side support for
+ the Pseudo-Random Number Generator found in the Security System.
+
config CRYPTO_DEV_ROCKCHIP
tristate "Rockchip's Cryptographic Engine driver"
depends on OF && ARCH_ROCKCHIP
diff --git a/drivers/crypto/sunxi-ss/Makefile b/drivers/crypto/sunxi-ss/Makefile
index 8f4c7a273141..ccb893219079 100644
--- a/drivers/crypto/sunxi-ss/Makefile
+++ b/drivers/crypto/sunxi-ss/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_CRYPTO_DEV_SUN4I_SS) += sun4i-ss.o
sun4i-ss-y += sun4i-ss-core.o sun4i-ss-hash.o sun4i-ss-cipher.o
+sun4i-ss-$(CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG) += sun4i-ss-prng.o
diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-core.c b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
index 02ad8256e900..1547cbe13dc2 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss-core.c
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
@@ -213,6 +213,23 @@ static struct sun4i_ss_alg_template ss_algs[] = {
}
}
},
+#ifdef CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG
+{
+ .type = CRYPTO_ALG_TYPE_RNG,
+ .alg.rng = {
+ .base = {
+ .cra_name = "stdrng",
+ .cra_driver_name = "sun4i_ss_rng",
+ .cra_priority = 300,
+ .cra_ctxsize = 0,
+ .cra_module = THIS_MODULE,
+ },
+ .generate = sun4i_ss_prng_generate,
+ .seed = sun4i_ss_prng_seed,
+ .seedsize = SS_SEED_LEN / BITS_PER_BYTE,
+ }
+},
+#endif
};

static int sun4i_ss_probe(struct platform_device *pdev)
@@ -355,6 +372,13 @@ static int sun4i_ss_probe(struct platform_device *pdev)
goto error_alg;
}
break;
+ case CRYPTO_ALG_TYPE_RNG:
+ err = crypto_register_rng(&ss_algs[i].alg.rng);
+ if (err) {
+ dev_err(ss->dev, "Fail to register %s\n",
+ ss_algs[i].alg.rng.base.cra_name);
+ }
+ break;
}
}
platform_set_drvdata(pdev, ss);
@@ -369,6 +393,9 @@ static int sun4i_ss_probe(struct platform_device *pdev)
case CRYPTO_ALG_TYPE_AHASH:
crypto_unregister_ahash(&ss_algs[i].alg.hash);
break;
+ case CRYPTO_ALG_TYPE_RNG:
+ crypto_unregister_rng(&ss_algs[i].alg.rng);
+ break;
}
}
if (ss->reset)
@@ -393,6 +420,9 @@ static int sun4i_ss_remove(struct platform_device *pdev)
case CRYPTO_ALG_TYPE_AHASH:
crypto_unregister_ahash(&ss_algs[i].alg.hash);
break;
+ case CRYPTO_ALG_TYPE_RNG:
+ crypto_unregister_rng(&ss_algs[i].alg.rng);
+ break;
}
}

diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-prng.c b/drivers/crypto/sunxi-ss/sun4i-ss-prng.c
new file mode 100644
index 000000000000..0d01d1624252
--- /dev/null
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-prng.c
@@ -0,0 +1,56 @@
+#include "sun4i-ss.h"
+
+int sun4i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed,
+ unsigned int slen)
+{
+ struct sun4i_ss_alg_template *algt;
+ struct rng_alg *alg = crypto_rng_alg(tfm);
+
+ algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
+ memcpy(algt->ss->seed, seed, slen);
+
+ return 0;
+}
+
+int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int dlen)
+{
+ struct sun4i_ss_alg_template *algt;
+ struct rng_alg *alg = crypto_rng_alg(tfm);
+ int i;
+ u32 v;
+ u32 *data = (u32 *)dst;
+ const u32 mode = SS_OP_PRNG | SS_PRNG_CONTINUE | SS_ENABLED;
+ size_t len;
+ struct sun4i_ss_ctx *ss;
+ unsigned int todo = (dlen / 4) * 4;
+
+ algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
+ ss = algt->ss;
+
+ spin_lock(&ss->slock);
+
+ writel(mode, ss->base + SS_CTL);
+
+ while (todo > 0) {
+ /* write the seed */
+ for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++)
+ writel(ss->seed[i], ss->base + SS_KEY0 + i * 4);
+
+ /* Read the random data */
+ len = min_t(size_t, SS_DATA_LEN / BITS_PER_BYTE, todo);
+ readsl(ss->base + SS_TXFIFO, data, len / 4);
+ data += len / 4;
+ todo -= len;
+
+ /* Update the seed */
+ for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++) {
+ v = readl(ss->base + SS_KEY0 + i * 4);
+ ss->seed[i] = v;
+ }
+ }
+
+ writel(0, ss->base + SS_CTL);
+ spin_unlock(&ss->slock);
+ return dlen;
+}
diff --git a/drivers/crypto/sunxi-ss/sun4i-ss.h b/drivers/crypto/sunxi-ss/sun4i-ss.h
index a0e1efc1cb2a..f3ac90692ac6 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss.h
+++ b/drivers/crypto/sunxi-ss/sun4i-ss.h
@@ -32,6 +32,7 @@
#include <crypto/aes.h>
#include <crypto/des.h>
#include <crypto/internal/rng.h>
+#include <crypto/rng.h>

#define SS_CTL 0x00
#define SS_KEY0 0x04
@@ -127,6 +128,9 @@
#define SS_RXFIFO_EMP_INT_ENABLE (1 << 2)
#define SS_TXFIFO_AVA_INT_ENABLE (1 << 0)

+#define SS_SEED_LEN 192
+#define SS_DATA_LEN 160
+
struct sun4i_ss_ctx {
void __iomem *base;
int irq;
@@ -136,6 +140,9 @@ struct sun4i_ss_ctx {
struct device *dev;
struct resource *res;
spinlock_t slock; /* control the use of the device */
+#ifdef CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG
+ u32 seed[SS_SEED_LEN / BITS_PER_LONG];
+#endif
};

struct sun4i_ss_alg_template {
@@ -144,6 +151,7 @@ struct sun4i_ss_alg_template {
union {
struct skcipher_alg crypto;
struct ahash_alg hash;
+ struct rng_alg rng;
} alg;
struct sun4i_ss_ctx *ss;
};
@@ -201,3 +209,6 @@ int sun4i_ss_des_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen);
int sun4i_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen);
+int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int dlen);
+int sun4i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed, unsigned int slen);
--
2.13.0
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Herbert Xu
2017-07-18 10:37:46 UTC
Permalink
Raw Message
Post by Corentin Labbe
The Security System has a PRNG, this patch adds support for it via
crypto_rng.
Patch applied. Thanks.
--
Email: Herbert Xu <***@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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