hwrng: cctrng - introduce Arm CryptoCell driver

Introduce low level Arm CryptoCell TRNG HW support.
Signed-off-by: Hadar Gat <hadar.gat@arm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/Kconfig

@@ -474,6 +474,18 @@ config HW_RANDOM_KEYSTONE
 	help
 	  This option enables Keystone's hardware random generator.
 
+config HW_RANDOM_CCTRNG
+	tristate "Arm CryptoCell True Random Number Generator support"
+	default HW_RANDOM
+	help
+	  This driver provides support for the True Random Number
+	  Generator available in Arm TrustZone CryptoCell.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called cctrng.
+
+	  If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

drivers/char/hw_random/Makefile

@@ -41,3 +41,4 @@ obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
 obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o
+obj-$(CONFIG_HW_RANDOM_CCTRNG) += cctrng.o

drivers/char/hw_random/cctrng.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019-2020 ARM Limited or its affiliates. */
+
+#include <linux/bitops.h>
+
+#define POWER_DOWN_ENABLE 0x01
+#define POWER_DOWN_DISABLE 0x00
+
+/* hwrng quality: bits of true entropy per 1024 bits of input */
+#define CC_TRNG_QUALITY	1024
+
+/* CryptoCell TRNG HW definitions */
+#define CC_TRNG_NUM_OF_ROSCS	4
+/* The number of words generated in the entropy holding register (EHR)
+ * 6 words (192 bit) according to HW implementation
+ */
+#define CC_TRNG_EHR_IN_WORDS	6
+#define CC_TRNG_EHR_IN_BITS	(CC_TRNG_EHR_IN_WORDS * BITS_PER_TYPE(u32))
+
+#define CC_HOST_RNG_IRQ_MASK BIT(CC_HOST_RGF_IRR_RNG_INT_BIT_SHIFT)
+
+/* RNG interrupt mask */
+#define CC_RNG_INT_MASK (BIT(CC_RNG_IMR_EHR_VALID_INT_MASK_BIT_SHIFT) | \
+			 BIT(CC_RNG_IMR_AUTOCORR_ERR_INT_MASK_BIT_SHIFT) | \
+			 BIT(CC_RNG_IMR_CRNGT_ERR_INT_MASK_BIT_SHIFT) | \
+			 BIT(CC_RNG_IMR_VN_ERR_INT_MASK_BIT_SHIFT) | \
+			 BIT(CC_RNG_IMR_WATCHDOG_INT_MASK_BIT_SHIFT))
+
+// --------------------------------------
+// BLOCK: RNG
+// --------------------------------------
+#define CC_RNG_IMR_REG_OFFSET	0x0100UL
+#define CC_RNG_IMR_EHR_VALID_INT_MASK_BIT_SHIFT	0x0UL
+#define CC_RNG_IMR_AUTOCORR_ERR_INT_MASK_BIT_SHIFT	0x1UL
+#define CC_RNG_IMR_CRNGT_ERR_INT_MASK_BIT_SHIFT	0x2UL
+#define CC_RNG_IMR_VN_ERR_INT_MASK_BIT_SHIFT	0x3UL
+#define CC_RNG_IMR_WATCHDOG_INT_MASK_BIT_SHIFT	0x4UL
+#define CC_RNG_ISR_REG_OFFSET	0x0104UL
+#define CC_RNG_ISR_EHR_VALID_BIT_SHIFT	0x0UL
+#define CC_RNG_ISR_EHR_VALID_BIT_SIZE	0x1UL
+#define CC_RNG_ISR_AUTOCORR_ERR_BIT_SHIFT	0x1UL
+#define CC_RNG_ISR_AUTOCORR_ERR_BIT_SIZE	0x1UL
+#define CC_RNG_ISR_CRNGT_ERR_BIT_SHIFT	0x2UL
+#define CC_RNG_ISR_CRNGT_ERR_BIT_SIZE	0x1UL
+#define CC_RNG_ISR_WATCHDOG_BIT_SHIFT	0x4UL
+#define CC_RNG_ISR_WATCHDOG_BIT_SIZE	0x1UL
+#define CC_RNG_ICR_REG_OFFSET	0x0108UL
+#define CC_TRNG_CONFIG_REG_OFFSET	0x010CUL
+#define CC_EHR_DATA_0_REG_OFFSET	0x0114UL
+#define CC_RND_SOURCE_ENABLE_REG_OFFSET	0x012CUL
+#define CC_SAMPLE_CNT1_REG_OFFSET	0x0130UL
+#define CC_TRNG_DEBUG_CONTROL_REG_OFFSET	0x0138UL
+#define CC_RNG_SW_RESET_REG_OFFSET	0x0140UL
+#define CC_RNG_CLK_ENABLE_REG_OFFSET	0x01C4UL
+#define CC_RNG_DMA_ENABLE_REG_OFFSET	0x01C8UL
+#define CC_RNG_WATCHDOG_VAL_REG_OFFSET	0x01D8UL
+// --------------------------------------
+// BLOCK: SEC_HOST_RGF
+// --------------------------------------
+#define CC_HOST_RGF_IRR_REG_OFFSET	0x0A00UL
+#define CC_HOST_RGF_IRR_RNG_INT_BIT_SHIFT	0xAUL
+#define CC_HOST_RGF_IMR_REG_OFFSET	0x0A04UL
+#define CC_HOST_RGF_ICR_REG_OFFSET	0x0A08UL
+
+#define CC_HOST_POWER_DOWN_EN_REG_OFFSET	0x0A78UL
+
+// --------------------------------------
+// BLOCK: NVM
+// --------------------------------------
+#define CC_NVM_IS_IDLE_REG_OFFSET	0x0F10UL
+#define CC_NVM_IS_IDLE_VALUE_BIT_SHIFT	0x0UL
+#define CC_NVM_IS_IDLE_VALUE_BIT_SIZE	0x1UL