[CRYPTO] hifn795x: Disallow built-in hifn795x when HW_RANDOM is m

Currently it is possible to select HW_RANDOM as a module and have
hifn795x built-in.  This causes a build problem because hifn795x
will then call hwrng_register which isn't built-in.

This patch introduces a new config option to control the hifn795x
RNG which lets us avoid this problem.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 10 insertions, 4 deletions

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 74bd599dfb0c..8a70a9edabda 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -88,10 +88,16 @@ config CRYPTO_DEV_HIFN_795X
         select CRYPTO_DES
         select CRYPTO_ALGAPI
         select CRYPTO_BLKCIPHER
+        select HW_RANDOM if CRYPTO_DEV_HIFN_795X_RNG
         depends on PCI
         help
           This option allows you to have support for HIFN 795x crypto adapters.
 
-
+config CRYPTO_DEV_HIFN_795X_RNG
+        bool "HIFN 795x random number generator"
+        depends on CRYPTO_DEV_HIFN_795X
+        help
+          Select this option if you want to enable the random number generator
+          on the HIFN 795x crypto adapters.
 
 endif # CRYPTO_HW
diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
index 16413e57597c..dfbf24c4033c 100644
--- a/drivers/crypto/hifn_795x.c
+++ b/drivers/crypto/hifn_795x.c
@@ -463,7 +463,7 @@ struct hifn_device
 
         unsigned int            pk_clk_freq;
 
-#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+#ifdef CRYPTO_DEV_HIFN_795X_RNG
         unsigned int            rng_wait_time;
         ktime_t                 rngtime;
         struct hwrng            rng;
@@ -795,7 +795,7 @@ static struct pci2id {
         }
 };
 
-#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+#ifdef CRYPTO_DEV_HIFN_795X_RNG
 static int hifn_rng_data_present(struct hwrng *rng, int wait)
 {
         struct hifn_device *dev = (struct hifn_device *)rng->priv;
@@ -880,7 +880,7 @@ static int hifn_init_pubrng(struct hifn_device *dev)
         dprintk("Chip %s: RNG engine has been successfully initialised.\n",
                         dev->name);
 
-#if defined(CONFIG_HW_RANDOM) || defined(CONFIG_HW_RANDOM_MODULE)
+#ifdef CRYPTO_DEV_HIFN_795X_RNG
         /* First value must be discarded */
         hifn_read_1(dev, HIFN_1_RNG_DATA);
         dev->rngtime = ktime_get();