crypto/nx: Register and unregister VAS interface on PowerVM

The user space uses /dev/crypto/nx-gzip interface to setup VAS
windows, create paste mapping and close windows. This patch adds
changes to create/remove this interface with VAS register/unregister
functions on PowerVM platform.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/121ea1f4eb3004f3b8f4fe8abefaecc88b292efd.camel@linux.ibm.com

drivers/crypto/nx/Kconfig

@@ -29,6 +29,7 @@ if CRYPTO_DEV_NX_COMPRESS
 config CRYPTO_DEV_NX_COMPRESS_PSERIES
 	tristate "Compression acceleration support on pSeries platform"
 	depends on PPC_PSERIES && IBMVIO
+	depends on PPC_VAS
 	default y
 	help
 	  Support for PowerPC Nest (NX) compression acceleration. This

drivers/crypto/nx/nx-common-pseries.c

@@ -1231,6 +1231,12 @@ static int __init nx842_pseries_init(void)
 		return ret;
 	}
 
+	ret = vas_register_api_pseries(THIS_MODULE, VAS_COP_TYPE_GZIP,
+				       "nx-gzip");
+
+	if (ret)
+		pr_err("NX-GZIP is not supported. Returned=%d\n", ret);
+
 	return 0;
 }
 
@@ -1241,6 +1247,8 @@ static void __exit nx842_pseries_exit(void)
 	struct nx842_devdata *old_devdata;
 	unsigned long flags;
 
+	vas_unregister_api_pseries();
+
 	crypto_unregister_alg(&nx842_pseries_alg);
 
 	spin_lock_irqsave(&devdata_mutex, flags);