drivers: bcm_hwrng: add HWRNG driver

low level driver for Broadcom random number generator IP.

Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Bharat Kumar Reddy Gooty <bharat.gooty@broadcom.com>
Signed-off-by: Sandeep Tripathy <sandeep.tripathy@broadcom.com>

3 files changed, 96 insertions, 0 deletions

diff --git a/core/drivers/bcm_hwrng.c b/core/drivers/bcm_hwrng.c
new file mode 100644
index 00000000..75fda00a
--- /dev/null
+++ b/core/drivers/bcm_hwrng.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright 2019 Broadcom.
+ */
+
+#include <drivers/bcm_hwrng.h>
+#include <initcall.h>
+#include <io.h>
+#include <kernel/delay.h>
+#include <mm/core_memprot.h>
+#include <platform_config.h>
+#include <trace.h>
+
+/* Registers */
+#define RNG_CTRL_OFFSET         0x00
+#define RNG_CTRL_MASK           0x00001fff
+#define RNG_CTRL_DISABLE        0x00000000
+#define RNG_CTRL_ENABLE         0x00000001
+
+#define RNG_SOFT_RESET_OFFSET   0x04
+#define RNG_SOFT_RESET_MASK     0x00000001
+
+#define RNG_FIFO_DATA_OFFSET    0x20
+
+#define RNG_FIFO_COUNT_OFFSET   0x24
+
+#define RNG_FIFO_COUNT_MASK     0x000000ff
+#define RNG_TIMEOUT_US		10000
+
+static vaddr_t bcm_hwrng_base;
+
+static void bcm_hwrng_reset(void)
+{
+	/* Disable RBG */
+	io_clrsetbits32(bcm_hwrng_base + RNG_CTRL_OFFSET,
+			RNG_CTRL_MASK, RNG_CTRL_DISABLE);
+	/* Reset RNG and RBG */
+	io_setbits32(bcm_hwrng_base +
+		     RNG_SOFT_RESET_OFFSET, RNG_SOFT_RESET_MASK);
+	io_clrbits32(bcm_hwrng_base +
+		     RNG_SOFT_RESET_OFFSET, RNG_SOFT_RESET_MASK);
+	/* Enable RBG */
+	io_clrsetbits32(bcm_hwrng_base + RNG_CTRL_OFFSET,
+			RNG_CTRL_MASK, RNG_CTRL_ENABLE);
+}
+
+uint32_t bcm_hwrng_read_rng(uint32_t *p_out, uint32_t words_to_read)
+{
+	uint32_t available_words = 0;
+	uint32_t num_words = 0;
+	uint32_t i = 0;
+	uint64_t timeout = timeout_init_us(RNG_TIMEOUT_US);
+
+	assert(bcm_hwrng_base);
+
+	do {
+		available_words = io_read32(bcm_hwrng_base +
+					    RNG_FIFO_COUNT_OFFSET);
+		available_words = available_words & RNG_FIFO_COUNT_MASK;
+	} while (!available_words && !timeout_elapsed(timeout));
+
+	if ((available_words > 0) && (words_to_read > 0)) {
+		num_words =  MIN(available_words, words_to_read);
+		for (i = 0; i < num_words; i++)
+			p_out[i] = io_read32(bcm_hwrng_base +
+					     RNG_FIFO_DATA_OFFSET);
+	}
+
+	return num_words;
+}
+
+static TEE_Result bcm_hwrng_init(void)
+{
+	bcm_hwrng_base = (vaddr_t)phys_to_virt(HWRNG_BASE, MEM_AREA_IO_SEC);
+
+	bcm_hwrng_reset();
+
+	DMSG("bcm_hwrng init done\n");
+	return TEE_SUCCESS;
+}
+
+driver_init(bcm_hwrng_init);
diff --git a/core/drivers/sub.mk b/core/drivers/sub.mk
index eaf0e570..e0cf05ae 100644
--- a/core/drivers/sub.mk
+++ b/core/drivers/sub.mk
@@ -25,3 +25,4 @@ srcs-$(CFG_STM32_GPIO) += stm32_gpio.c
 srcs-$(CFG_STM32_RNG) += stm32_rng.c
 srcs-$(CFG_STM32_UART) += stm32_uart.c
 srcs-$(CFG_STM32_I2C) += stm32_i2c.c
+srcs-$(CFG_BCM_HWRNG) += bcm_hwrng.c
diff --git a/core/include/drivers/bcm_hwrng.h b/core/include/drivers/bcm_hwrng.h
new file mode 100644
index 00000000..abf213df
--- /dev/null
+++ b/core/include/drivers/bcm_hwrng.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright 2019 Broadcom.
+ */
+
+#ifndef BCM_HWRNG_H
+#define BCM_HWRNG_H
+
+#include <stdlib.h>
+
+uint32_t bcm_hwrng_read_rng(uint32_t *p_out, uint32_t words_to_read);
+
+#endif /* BCM_HWRNG_H */