drivers/rambus: add TRNG-IP-76 driver

Add Rambus (InsideSecure) TRNG-IP-76 HW RNG driver.
This IP is part of Marvell Armada CP110/CP115 die integrated
to Armada 7k/8K/CN913x SoCs

Change-Id: I9c5f510ad6728c7ed168da43d85b19d5852cd873
Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Reviewed-by: Stefan Chulski <stefanc@marvell.com>

drivers/rambus/trng_ip_76.c

+/*
+ * Copyright (c) 2020, Marvell Technology Group Ltd. All rights reserved.
+ *
+ * Based on Linux kernel omap-rng.c - RNG driver for TI OMAP CPU family
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2005 (c) MontaVista Software, Inc.
+ *
+ * Mostly based on original driver:
+ *
+ * Copyright (C) 2005 Nokia Corporation
+ * Author: Juha Yrjölä <juha.yrjola@nokia.com>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include <common/debug.h>
+#include <drivers/delay_timer.h>
+#include <drivers/rambus/trng_ip_76.h>
+#include <lib/mmio.h>
+#include <lib/spinlock.h>
+#include <lib/utils.h>
+
+#define RNG_REG_STATUS_RDY			(1 << 0)
+
+#define RNG_REG_INTACK_RDY_MASK			(1 << 0)
+
+#define RNG_CONTROL_ENABLE_TRNG_MASK		(1 << 10)
+
+#define RNG_CONFIG_NOISE_BLOCKS(val)		((0xff & (val)) << 0)
+#define RNG_CONFIG_NOISE_BLK_VAL		0x5
+
+#define RNG_CONFIG_SAMPLE_CYCLES(val)		((0xff & (val)) << 16)
+#define RNG_CONFIG_SAMPLE_CYCLES_VAL		0x22
+
+#define RNG_REG_FRO_ENABLE_MASK			0xffffff
+#define RNG_REG_FRO_DETUNE_MASK			0x0
+
+#define EIP76_RNG_OUTPUT_SIZE			0x10
+#define EIP76_RNG_WAIT_ROUNDS			10
+
+#define RNG_HW_IS_EIP76(ver)			((ver) & (0xff == 0x4C))
+#define RNG_HW_VER_MAJOR(ver)			(((ver) & (0xf << 24)) >> 24)
+#define RNG_HW_VER_MINOR(ver)			(((ver) & (0xf << 20)) >> 20)
+#define RNG_HW_VER_PATCH(ver)			(((ver) & (0xf << 16)) >> 16)
+
+
+enum {
+	RNG_OUTPUT_0_REG = 0,
+	RNG_OUTPUT_1_REG,
+	RNG_OUTPUT_2_REG,
+	RNG_OUTPUT_3_REG,
+	RNG_STATUS_REG,
+	RNG_INTMASK_REG,
+	RNG_INTACK_REG,
+	RNG_CONTROL_REG,
+	RNG_CONFIG_REG,
+	RNG_ALARMCNT_REG,
+	RNG_FROENABLE_REG,
+	RNG_FRODETUNE_REG,
+	RNG_ALARMMASK_REG,
+	RNG_ALARMSTOP_REG,
+	RNG_REV_REG
+};
+
+static uint16_t reg_map_eip76[] = {
+	[RNG_OUTPUT_0_REG]	= 0x0,
+	[RNG_OUTPUT_1_REG]	= 0x4,
+	[RNG_OUTPUT_2_REG]	= 0x8,
+	[RNG_OUTPUT_3_REG]	= 0xc,
+	[RNG_STATUS_REG]	= 0x10,
+	[RNG_INTACK_REG]	= 0x10,
+	[RNG_CONTROL_REG]	= 0x14,
+	[RNG_CONFIG_REG]	= 0x18,
+	[RNG_ALARMCNT_REG]	= 0x1c,
+	[RNG_FROENABLE_REG]	= 0x20,
+	[RNG_FRODETUNE_REG]	= 0x24,
+	[RNG_ALARMMASK_REG]	= 0x28,
+	[RNG_ALARMSTOP_REG]	= 0x2c,
+	[RNG_REV_REG]		= 0x7c,
+};
+
+struct eip76_rng_dev {
+	uintptr_t	base;
+	uint16_t	*regs;
+};
+
+/* Locals */
+static struct eip76_rng_dev eip76_dev;
+static spinlock_t rng_lock;
+
+static inline uint32_t eip76_rng_read(struct eip76_rng_dev *dev, uint16_t reg)
+{
+	return mmio_read_32(dev->base + dev->regs[reg]);
+}
+
+static inline void eip76_rng_write(struct eip76_rng_dev *dev,
+				   uint16_t reg, uint32_t val)
+{
+	mmio_write_32(dev->base + dev->regs[reg], val);
+}
+
+static void eip76_rng_init(struct eip76_rng_dev *dev)
+{
+	uint32_t val;
+
+	/* Return if RNG is already running. */
+	if (eip76_rng_read(dev, RNG_CONTROL_REG) &
+			   RNG_CONTROL_ENABLE_TRNG_MASK) {
+		return;
+	}
+
+	/*  This field sets the number of 512-bit blocks of raw Noise Source
+	 * output data that must be processed by either the Conditioning
+	 * Function or the SP 800-90 DRBG ‘BC_DF’ functionality to yield
+	 * a ‘full entropy’ output value. As according to [SP 800-90B draft]
+	 * the amount of entropy input to this functionality must be twice
+	 * the amount that is output and the 8-bit samples output by the Noise
+	 * Source are supposed to have one bit of entropy each, the settings
+	 * for this field are as follows:
+	 * - SHA-1 Conditioning Function:
+	 *  generates 160 bits output, requiring 2560 sample bits,
+	 *  equivalent to 5 blocks of raw Noise Source input.
+	 * - SHA-256 Conditioning Function:
+	 *  generates 256 bits output, requiring 4096 sample bits, equivalent
+	 *  to 8 blocks of raw Noise Source input. Note that two blocks of 256
+	 *  bits are needed to start or re-seed the SP 800-90 DRBG
+	 *  (in the EIP-76d-*-SHA2 configurations)
+	 * - SP 800-90 DRBG ‘BC_DF’ functionality:
+	 *  generates 384 bits output, requiring 6144 sample bits, equivalent
+	 *  to 12 blocks of raw Noise Source input.
+	 *  This field can only be modified when ‘enable_trng’ in TRNG_CONTROL
+	 *  is ‘0’ or when either of the ‘test_known_noise’ or ‘test_cond_func’
+	 *  bits in TRNG_TEST is ‘1’. Value 0 in this field selects 256 blocks
+	 *  of 512 bits to be processed.
+	 */
+	val = RNG_CONFIG_NOISE_BLOCKS(RNG_CONFIG_NOISE_BLK_VAL);
+
+	/* This field sets the number of FRO samples that are XOR-ed together
+	 * into one bit to be shifted into the main shift register.
+	 * This value must be such that there is at least one bit of entropy
+	 * (in total) in each 8 bits that are shifted.
+	 * This field can only be modified when ‘enable_trng’ in TRNG_CONTROL
+	 * is ‘0’ or when either of the ‘test_known_noise’ or ‘test_cond_func’
+	 * bits in TRNG_TEST is ‘1’. Value 0 in this field selects 65536 FRO
+	 * samples to be XOR-ed together
+	 */
+	val |= RNG_CONFIG_SAMPLE_CYCLES(RNG_CONFIG_SAMPLE_CYCLES_VAL);
+	eip76_rng_write(dev, RNG_CONFIG_REG, val);
+
+	/* Enable all available FROs */
+	eip76_rng_write(dev, RNG_FRODETUNE_REG, RNG_REG_FRO_DETUNE_MASK);
+	eip76_rng_write(dev, RNG_FROENABLE_REG, RNG_REG_FRO_ENABLE_MASK);
+
+	/* Enable TRNG */
+	eip76_rng_write(dev, RNG_CONTROL_REG, RNG_CONTROL_ENABLE_TRNG_MASK);
+}
+
+int32_t eip76_rng_read_rand_buf(void *data, bool wait)
+{
+	uint32_t i, present;
+
+	if (!eip76_dev.base) /* not initialized */
+		return -1;
+
+	for (i = 0; i < EIP76_RNG_WAIT_ROUNDS; i++) {
+		present = eip76_rng_read(&eip76_dev, RNG_STATUS_REG) &
+					 RNG_REG_STATUS_RDY;
+		if (present || !wait) {
+			break;
+		}
+
+		udelay(10);
+	}
+
+	if (present != 0U) {
+		return 0;
+	}
+
+	memcpy(data,
+	       (void *)(eip76_dev.base + eip76_dev.regs[RNG_OUTPUT_0_REG]),
+	       EIP76_RNG_OUTPUT_SIZE);
+
+	eip76_rng_write(&eip76_dev, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK);
+
+	return EIP76_RNG_OUTPUT_SIZE;
+}
+
+int32_t eip76_rng_probe(uintptr_t base_addr)
+{
+	uint32_t ver;
+
+	eip76_dev.base = base_addr;
+	eip76_dev.regs = reg_map_eip76;
+
+	eip76_rng_init(&eip76_dev);
+
+	ver = eip76_rng_read(&eip76_dev, RNG_REV_REG);
+
+	INFO("%s Random Number Generator HW ver. %01x.%01x.%01x\n",
+	     RNG_HW_IS_EIP76(ver) ? "TRNG-IP-76" : "Unknown",
+	     RNG_HW_VER_MAJOR(ver), RNG_HW_VER_MINOR(ver),
+	     RNG_HW_VER_PATCH(ver));
+
+	return 0;
+}
+
+int32_t eip76_rng_get_random(uint8_t *data, uint32_t len)
+{
+	static uint8_t rand[EIP76_RNG_OUTPUT_SIZE];
+	static uint8_t pos;
+	uint32_t i;
+	int32_t ret = 0;
+
+	if (!data)
+		return -1;
+
+	spin_lock(&rng_lock);
+
+	for (i = 0; i < len; i++) {
+		if (pos >= EIP76_RNG_OUTPUT_SIZE) {
+			pos = 0;
+		}
+
+		if (pos != 0U) {
+			ret = eip76_rng_read_rand_buf(rand, true);
+		}
+
+		/* Only advance FIFO index if it is non zero or
+		 * the update from TRNG HW was successful
+		 */
+		if (pos || ret > 0) {
+			data[i] = rand[pos++];
+			ret = 0;
+		} else {
+			ret = -1;
+			break;
+		}
+	}
+
+	spin_unlock(&rng_lock);
+
+	return ret;
+}

include/drivers/rambus/trng_ip_76.h

+/*
+ * Copyright (c) 2020, Marvell Technology Group Ltd. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+
+#ifndef __TRNG_IP_76_H__
+#define __TRNG_IP_76_H__
+
+#include <stdbool.h>
+#include <stdint.h>
+
+int32_t eip76_rng_read_rand_buf(void *data, bool wait);
+int32_t eip76_rng_probe(uintptr_t base_addr);
+int32_t eip76_rng_get_random(uint8_t *data, uint32_t len);
+
+#endif /* __TRNG_IP_76_H__ */