drivers: crypto: ace_sha: add implementation of hardware based lib rand

This patch adds implementation of rand library based on hardware random
number generator of security subsystem in Exynos SOC.

This library includes:
- srand()  - used for seed hardware block
- rand()   - returns random number
- rand_r() - the same as above with given seed

which depends on CONFIG_EXYNOS_ACE_SHA and CONFIG_LIB_HW_RAND.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
cc: Akshay Saraswat <akshay.s@samsung.com>
cc: ARUN MANKUZHI <arun.m@samsung.com>
cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Michael Walle <michael@walle.cc>
Cc: Tom Rini <trini@ti.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>

diff --git a/drivers/crypto/ace_sha.c b/drivers/crypto/ace_sha.c
index acbafde..ed4f541 100644 (file)
--- a/drivers/crypto/ace_sha.c
+++ b/drivers/crypto/ace_sha.c
@@ -5,10 +5,12 @@
  * SPDX-License-Identifier:    GPL-2.0+
  */
 #include <common.h>
+#include "ace_sha.h"
+
+#ifdef CONFIG_SHA_HW_ACCEL
 #include <sha256.h>
 #include <sha1.h>
 #include <asm/errno.h>
-#include "ace_sha.h"
 
 /* SHA1 value for the message of zero length */
 static const unsigned char sha1_digest_emptymsg[SHA1_SUM_LEN] = {
@@ -111,3 +113,72 @@ void hw_sha1(const unsigned char *pbuf, unsigned int buf_len,
        if (ace_sha_hash_digest(pbuf, buf_len, pout, ACE_SHA_TYPE_SHA1))
                debug("ACE was not setup properly or it is faulty\n");
 }
+#endif /* CONFIG_SHA_HW_ACCEL */
+
+#ifdef CONFIG_LIB_HW_RAND
+static unsigned int seed_done;
+
+void srand(unsigned int seed)
+{
+       struct exynos_ace_sfr *reg =
+               (struct exynos_ace_sfr *)samsung_get_base_ace_sfr();
+       int i, status;
+
+       /* Seed data */
+       for (i = 0; i < ACE_HASH_PRNG_REG_NUM; i++)
+               writel(seed << i, &reg->hash_seed[i]);
+
+       /* Wait for seed setup done */
+       while (1) {
+               status = readl(&reg->hash_status);
+               if ((status & ACE_HASH_SEEDSETTING_MASK) ||
+                   (status & ACE_HASH_PRNGERROR_MASK))
+                       break;
+       }
+
+       seed_done = 1;
+}
+
+unsigned int rand(void)
+{
+       struct exynos_ace_sfr *reg =
+               (struct exynos_ace_sfr *)samsung_get_base_ace_sfr();
+       int i, status;
+       unsigned int seed = (unsigned int)&status;
+       unsigned int ret = 0;
+
+       if (!seed_done)
+               srand(seed);
+
+       /* Start PRNG */
+       writel(ACE_HASH_ENGSEL_PRNG | ACE_HASH_STARTBIT_ON, &reg->hash_control);
+
+       /* Wait for PRNG done */
+       while (1) {
+               status = readl(&reg->hash_status);
+               if (status & ACE_HASH_PRNGDONE_MASK)
+                       break;
+               if (status & ACE_HASH_PRNGERROR_MASK) {
+                       seed_done = 0;
+                       return 0;
+               }
+       }
+
+       /* Clear Done IRQ */
+       writel(ACE_HASH_PRNGDONE_MASK, &reg->hash_status);
+
+       /* Read a PRNG result */
+       for (i = 0; i < ACE_HASH_PRNG_REG_NUM; i++)
+               ret += readl(&reg->hash_prng[i]);
+
+       seed_done = 0;
+       return ret;
+}
+
+unsigned int rand_r(unsigned int *seedp)
+{
+       srand(*seedp);
+
+       return rand();
+}
+#endif /* CONFIG_LIB_HW_RAND */

diff --git a/drivers/crypto/ace_sha.h b/drivers/crypto/ace_sha.h
index a426d52..f1097f7 100644 (file)
--- a/drivers/crypto/ace_sha.h
+++ b/drivers/crypto/ace_sha.h
@@ -72,9 +72,10 @@ struct exynos_ace_sfr {
        unsigned char   res12[0x30];
        unsigned int    hash_result[8];
        unsigned char   res13[0x20];
-       unsigned int    hash_seed[8];
-       unsigned int    hash_prng[8];
-       unsigned char   res14[0x180];
+       unsigned int    hash_seed[5];
+       unsigned char   res14[12];
+       unsigned int    hash_prng[5];
+       unsigned char   res15[0x18c];
 
        unsigned int    pka_sfr[5];             /* base + 0x700 */
 };
@@ -291,6 +292,7 @@ struct exynos_ace_sfr {
 #define ACE_HASH_PRNGERROR_MASK        (1 << 7)
 #define ACE_HASH_PRNGERROR_OFF         (0 << 7)
 #define ACE_HASH_PRNGERROR_ON          (1 << 7)
+#define ACE_HASH_PRNG_REG_NUM          5
 
 #define ACE_SHA_TYPE_SHA1              1
 #define ACE_SHA_TYPE_SHA256            2