crypto: sun4i-ss - support the Security System PRNG

The Security System has a PRNG, this patch adds support for it via
crypto_rng.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 4b75084..5db825a 100644 (file)
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -616,6 +616,14 @@ 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 8f4c7a2..ccb8932 100644 (file)
--- 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 02ad825..1547cbe 100644 (file)
--- 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 @@ error_alg:
                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 (file)
index 0000000..0d01d16
--- /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 a0e1efc..f3ac906 100644 (file)
--- 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);