rockchip: rng: Add a driver for random number generator(rng) device

Add a driver for the rng device found on rockchip platforms.
Support rng module of crypto v1 and crypto v2.

Signed-off-by: Lin Jinhan <troy.lin@rock-chips.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

drivers/rng/Kconfig

@@ -31,4 +31,12 @@ config RNG_STM32MP1
 	help
 	  Enable STM32MP1 rng driver.
 
+config RNG_ROCKCHIP
+	bool "Enable random number generator for rockchip crypto rng"
+	depends on ARCH_ROCKCHIP && DM_RNG
+	default n
+	help
+	  Enable random number generator for rockchip.This driver is
+	  support rng module of crypto v1 and crypto v2.
+
 endif

drivers/rng/Makefile

@@ -7,3 +7,4 @@ obj-$(CONFIG_DM_RNG) += rng-uclass.o
 obj-$(CONFIG_RNG_MESON) += meson-rng.o
 obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
 obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
+obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o

drivers/rng/rockchip_rng.c

@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 Fuzhou Rockchip Electronics Co., Ltd
+ */
+#include <asm/arch-rockchip/hardware.h>
+#include <asm/io.h>
+#include <common.h>
+#include <dm.h>
+#include <linux/iopoll.h>
+#include <linux/string.h>
+#include <rng.h>
+
+#define RK_HW_RNG_MAX 32
+
+#define _SBF(s, v)	((v) << (s))
+
+/* start of CRYPTO V1 register define */
+#define CRYPTO_V1_CTRL				0x0008
+#define CRYPTO_V1_RNG_START			BIT(8)
+#define CRYPTO_V1_RNG_FLUSH			BIT(9)
+
+#define CRYPTO_V1_TRNG_CTRL			0x0200
+#define CRYPTO_V1_OSC_ENABLE			BIT(16)
+#define CRYPTO_V1_TRNG_SAMPLE_PERIOD(x)		(x)
+
+#define CRYPTO_V1_TRNG_DOUT_0			0x0204
+/* end of CRYPTO V1 register define */
+
+/* start of CRYPTO V2 register define */
+#define CRYPTO_V2_RNG_CTL			0x0400
+#define CRYPTO_V2_RNG_64_BIT_LEN		_SBF(4, 0x00)
+#define CRYPTO_V2_RNG_128_BIT_LEN		_SBF(4, 0x01)
+#define CRYPTO_V2_RNG_192_BIT_LEN		_SBF(4, 0x02)
+#define CRYPTO_V2_RNG_256_BIT_LEN		_SBF(4, 0x03)
+#define CRYPTO_V2_RNG_FATESY_SOC_RING		_SBF(2, 0x00)
+#define CRYPTO_V2_RNG_SLOWER_SOC_RING_0		_SBF(2, 0x01)
+#define CRYPTO_V2_RNG_SLOWER_SOC_RING_1		_SBF(2, 0x02)
+#define CRYPTO_V2_RNG_SLOWEST_SOC_RING		_SBF(2, 0x03)
+#define CRYPTO_V2_RNG_ENABLE			BIT(1)
+#define CRYPTO_V2_RNG_START			BIT(0)
+#define CRYPTO_V2_RNG_SAMPLE_CNT		0x0404
+#define CRYPTO_V2_RNG_DOUT_0			0x0410
+/* end of CRYPTO V2 register define */
+
+#define RK_RNG_TIME_OUT	50000  /* max 50ms */
+
+struct rk_rng_soc_data {
+	int (*rk_rng_read)(struct udevice *dev, void *data, size_t len);
+};
+
+struct rk_rng_platdata {
+	fdt_addr_t base;
+	struct rk_rng_soc_data *soc_data;
+};
+
+static int rk_rng_read_regs(fdt_addr_t addr, void *buf, size_t size)
+{
+	u32 count = RK_HW_RNG_MAX / sizeof(u32);
+	u32 reg, tmp_len;
+
+	if (size > RK_HW_RNG_MAX)
+		return -EINVAL;
+
+	while (size && count) {
+		reg = readl(addr);
+		tmp_len = min(size, sizeof(u32));
+		memcpy(buf, &reg, tmp_len);
+		addr += sizeof(u32);
+		buf += tmp_len;
+		size -= tmp_len;
+		count--;
+	}
+
+	return 0;
+}
+
+static int rk_v1_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	struct rk_rng_platdata *pdata = dev_get_priv(dev);
+	u32 reg = 0;
+	int retval;
+
+	if (len > RK_HW_RNG_MAX)
+		return -EINVAL;
+
+	/* enable osc_ring to get entropy, sample period is set as 100 */
+	writel(CRYPTO_V1_OSC_ENABLE | CRYPTO_V1_TRNG_SAMPLE_PERIOD(100),
+	       pdata->base + CRYPTO_V1_TRNG_CTRL);
+
+	rk_clrsetreg(pdata->base + CRYPTO_V1_CTRL, CRYPTO_V1_RNG_START,
+		     CRYPTO_V1_RNG_START);
+
+	retval = readl_poll_timeout(pdata->base + CRYPTO_V1_CTRL, reg,
+				    !(reg & CRYPTO_V1_RNG_START),
+				    RK_RNG_TIME_OUT);
+	if (retval)
+		goto exit;
+
+	rk_rng_read_regs(pdata->base + CRYPTO_V1_TRNG_DOUT_0, data, len);
+
+exit:
+	/* close TRNG */
+	rk_clrreg(pdata->base + CRYPTO_V1_CTRL, CRYPTO_V1_RNG_START);
+
+	return 0;
+}
+
+static int rk_v2_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	struct rk_rng_platdata *pdata = dev_get_priv(dev);
+	u32 reg = 0;
+	int retval;
+
+	if (len > RK_HW_RNG_MAX)
+		return -EINVAL;
+
+	/* enable osc_ring to get entropy, sample period is set as 100 */
+	writel(100, pdata->base + CRYPTO_V2_RNG_SAMPLE_CNT);
+
+	reg |= CRYPTO_V2_RNG_256_BIT_LEN;
+	reg |= CRYPTO_V2_RNG_SLOWER_SOC_RING_0;
+	reg |= CRYPTO_V2_RNG_ENABLE;
+	reg |= CRYPTO_V2_RNG_START;
+
+	rk_clrsetreg(pdata->base + CRYPTO_V2_RNG_CTL, 0xffff, reg);
+
+	retval = readl_poll_timeout(pdata->base + CRYPTO_V2_RNG_CTL, reg,
+				    !(reg & CRYPTO_V2_RNG_START),
+				    RK_RNG_TIME_OUT);
+	if (retval)
+		goto exit;
+
+	rk_rng_read_regs(pdata->base + CRYPTO_V2_RNG_DOUT_0, data, len);
+
+exit:
+	/* close TRNG */
+	rk_clrreg(pdata->base + CRYPTO_V2_RNG_CTL, 0xffff);
+
+	return retval;
+}
+
+static int rockchip_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	unsigned char *buf = data;
+	unsigned int i;
+	int ret = -EIO;
+
+	struct rk_rng_platdata *pdata = dev_get_priv(dev);
+
+	if (!len)
+		return 0;
+
+	if (!pdata->soc_data || !pdata->soc_data->rk_rng_read)
+		return -EINVAL;
+
+	for (i = 0; i < len / RK_HW_RNG_MAX; i++, buf += RK_HW_RNG_MAX) {
+		ret = pdata->soc_data->rk_rng_read(dev, buf, RK_HW_RNG_MAX);
+		if (ret)
+			goto exit;
+	}
+
+	if (len % RK_HW_RNG_MAX)
+		ret = pdata->soc_data->rk_rng_read(dev, buf,
+						   len % RK_HW_RNG_MAX);
+
+exit:
+	return ret;
+}
+
+static int rockchip_rng_ofdata_to_platdata(struct udevice *dev)
+{
+	struct rk_rng_platdata *pdata = dev_get_priv(dev);
+
+	memset(pdata, 0x00, sizeof(*pdata));
+
+	pdata->base = (fdt_addr_t)dev_read_addr_ptr(dev);
+	if (!pdata->base)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int rockchip_rng_probe(struct udevice *dev)
+{
+	struct rk_rng_platdata *pdata = dev_get_priv(dev);
+
+	pdata->soc_data = (struct rk_rng_soc_data *)dev_get_driver_data(dev);
+
+	return 0;
+}
+
+static const struct rk_rng_soc_data rk_rng_v1_soc_data = {
+	.rk_rng_read = rk_v1_rng_read,
+};
+
+static const struct rk_rng_soc_data rk_rng_v2_soc_data = {
+	.rk_rng_read = rk_v2_rng_read,
+};
+
+static const struct dm_rng_ops rockchip_rng_ops = {
+	.read = rockchip_rng_read,
+};
+
+static const struct udevice_id rockchip_rng_match[] = {
+	{
+		.compatible = "rockchip,cryptov1-rng",
+		.data = (ulong)&rk_rng_v1_soc_data,
+	},
+	{
+		.compatible = "rockchip,cryptov2-rng",
+		.data = (ulong)&rk_rng_v2_soc_data,
+	},
+	{},
+};
+
+U_BOOT_DRIVER(rockchip_rng) = {
+	.name = "rockchip-rng",
+	.id = UCLASS_RNG,
+	.of_match = rockchip_rng_match,
+	.ops = &rockchip_rng_ops,
+	.probe = rockchip_rng_probe,
+	.ofdata_to_platdata = rockchip_rng_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct rk_rng_platdata),
+};