1 files changed, 495 insertions, 0 deletions
diff --git a/drivers/char/hw_random/rockchip-rng.c b/drivers/char/hw_random/rockchip-rng.c
new file mode 100644
index 000000000000..fb4a30b95507
--- /dev/null
+++ b/drivers/char/hw_random/rockchip-rng.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * rockchip-rng.c True Random Number Generator driver for Rockchip SoCs
+ *
+ * Copyright (c) 2018, Fuzhou Rockchip Electronics Co., Ltd.
+ * Copyright (c) 2022, Aurelien Jarno
+ * Copyright (c) 2025, Collabora Ltd.
+ * Authors:
+ *  Lin Jinhan <troy.lin@rock-chips.com>
+ *  Aurelien Jarno <aurelien@aurel32.net>
+ *  Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
+ */
+#include <linux/clk.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#define RK_RNG_AUTOSUSPEND_DELAY	100
+#define RK_RNG_MAX_BYTE			32
+#define RK_RNG_POLL_PERIOD_US		100
+#define RK_RNG_POLL_TIMEOUT_US		10000
+
+/*
+ * TRNG collects osc ring output bit every RK_RNG_SAMPLE_CNT time. The value is
+ * a tradeoff between speed and quality and has been adjusted to get a quality
+ * of ~900 (~87.5% of FIPS 140-2 successes).
+ */
+#define RK_RNG_SAMPLE_CNT		1000
+
+/* after how many bytes of output TRNGv1 implementations should be reseeded */
+#define RK_TRNG_V1_AUTO_RESEED_CNT	16000
+
+/* TRNG registers from RK3568 TRM-Part2, section 5.4.1 */
+#define TRNG_RST_CTL			0x0004
+#define TRNG_RNG_CTL			0x0400
+#define TRNG_RNG_CTL_LEN_64_BIT		(0x00 << 4)
+#define TRNG_RNG_CTL_LEN_128_BIT	(0x01 << 4)
+#define TRNG_RNG_CTL_LEN_192_BIT	(0x02 << 4)
+#define TRNG_RNG_CTL_LEN_256_BIT	(0x03 << 4)
+#define TRNG_RNG_CTL_OSC_RING_SPEED_0	(0x00 << 2)
+#define TRNG_RNG_CTL_OSC_RING_SPEED_1	(0x01 << 2)
+#define TRNG_RNG_CTL_OSC_RING_SPEED_2	(0x02 << 2)
+#define TRNG_RNG_CTL_OSC_RING_SPEED_3	(0x03 << 2)
+#define TRNG_RNG_CTL_MASK		GENMASK(15, 0)
+#define TRNG_RNG_CTL_ENABLE		BIT(1)
+#define TRNG_RNG_CTL_START		BIT(0)
+#define TRNG_RNG_SAMPLE_CNT		0x0404
+#define TRNG_RNG_DOUT			0x0410
+
+/*
+ * TRNG V1 register definitions
+ * The TRNG V1 IP is a stand-alone TRNG implementation (not part of a crypto IP)
+ * and can be found in the Rockchip RK3588 SoC
+ */
+#define TRNG_V1_CTRL				0x0000
+#define TRNG_V1_CTRL_NOP			0x00
+#define TRNG_V1_CTRL_RAND			0x01
+#define TRNG_V1_CTRL_SEED			0x02
+
+#define TRNG_V1_STAT				0x0004
+#define TRNG_V1_STAT_SEEDED			BIT(9)
+#define TRNG_V1_STAT_GENERATING			BIT(30)
+#define TRNG_V1_STAT_RESEEDING			BIT(31)
+
+#define TRNG_V1_MODE				0x0008
+#define TRNG_V1_MODE_128_BIT			(0x00 << 3)
+#define TRNG_V1_MODE_256_BIT			(0x01 << 3)
+
+/* Interrupt Enable register; unused because polling is faster */
+#define TRNG_V1_IE				0x0010
+#define TRNG_V1_IE_GLBL_EN			BIT(31)
+#define TRNG_V1_IE_SEED_DONE_EN			BIT(1)
+#define TRNG_V1_IE_RAND_RDY_EN			BIT(0)
+
+#define TRNG_V1_ISTAT				0x0014
+#define TRNG_V1_ISTAT_RAND_RDY			BIT(0)
+
+/* RAND0 ~ RAND7 */
+#define TRNG_V1_RAND0				0x0020
+#define TRNG_V1_RAND7				0x003C
+
+/* Auto Reseed Register */
+#define TRNG_V1_AUTO_RQSTS			0x0060
+
+#define TRNG_V1_VERSION				0x00F0
+#define TRNG_v1_VERSION_CODE			0x46bc
+/* end of TRNG_V1 register definitions */
+
+/*
+ * RKRNG register definitions
+ * The RKRNG IP is a stand-alone TRNG implementation (not part of a crypto IP)
+ * and can be found in the Rockchip RK3576, Rockchip RK3562 and Rockchip RK3528
+ * SoCs. It can either output true randomness (TRNG) or "deterministic"
+ * randomness derived from hashing the true entropy (DRNG). This driver
+ * implementation uses just the true entropy, and leaves stretching the entropy
+ * up to Linux.
+ */
+#define RKRNG_CFG				0x0000
+#define RKRNG_CTRL				0x0010
+#define RKRNG_CTRL_REQ_TRNG			BIT(4)
+#define RKRNG_STATE				0x0014
+#define RKRNG_STATE_TRNG_RDY			BIT(4)
+#define RKRNG_TRNG_DATA0			0x0050
+#define RKRNG_TRNG_DATA1			0x0054
+#define RKRNG_TRNG_DATA2			0x0058
+#define RKRNG_TRNG_DATA3			0x005C
+#define RKRNG_TRNG_DATA4			0x0060
+#define RKRNG_TRNG_DATA5			0x0064
+#define RKRNG_TRNG_DATA6			0x0068
+#define RKRNG_TRNG_DATA7			0x006C
+#define RKRNG_READ_LEN				32
+
+/* Before removing this assert, give rk3588_rng_read an upper bound of 32 */
+static_assert(RK_RNG_MAX_BYTE <= (TRNG_V1_RAND7 + 4 - TRNG_V1_RAND0),
+	      "You raised RK_RNG_MAX_BYTE and broke rk3588-rng, congrats.");
+
+struct rk_rng {
+	struct hwrng rng;
+	void __iomem *base;
+	int clk_num;
+	struct clk_bulk_data *clk_bulks;
+	const struct rk_rng_soc_data *soc_data;
+	struct device *dev;
+};
+
+struct rk_rng_soc_data {
+	int (*rk_rng_init)(struct hwrng *rng);
+	int (*rk_rng_read)(struct hwrng *rng, void *buf, size_t max, bool wait);
+	void (*rk_rng_cleanup)(struct hwrng *rng);
+	unsigned short quality;
+	bool reset_optional;
+};
+
+/* The mask in the upper 16 bits determines the bits that are updated */
+static void rk_rng_write_ctl(struct rk_rng *rng, u32 val, u32 mask)
+{
+	writel((mask << 16) | val, rng->base + TRNG_RNG_CTL);
+}
+
+static inline void rk_rng_writel(struct rk_rng *rng, u32 val, u32 offset)
+{
+	writel(val, rng->base + offset);
+}
+
+static inline u32 rk_rng_readl(struct rk_rng *rng, u32 offset)
+{
+	return readl(rng->base + offset);
+}
+
+static int rk_rng_enable_clks(struct rk_rng *rk_rng)
+{
+	int ret;
+	/* start clocks */
+	ret = clk_bulk_prepare_enable(rk_rng->clk_num, rk_rng->clk_bulks);
+	if (ret < 0) {
+		dev_err(rk_rng->dev, "Failed to enable clocks: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rk3568_rng_init(struct hwrng *rng)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+	int ret;
+
+	ret = rk_rng_enable_clks(rk_rng);
+	if (ret < 0)
+		return ret;
+
+	/* set the sample period */
+	writel(RK_RNG_SAMPLE_CNT, rk_rng->base + TRNG_RNG_SAMPLE_CNT);
+
+	/* set osc ring speed and enable it */
+	rk_rng_write_ctl(rk_rng, TRNG_RNG_CTL_LEN_256_BIT |
+				 TRNG_RNG_CTL_OSC_RING_SPEED_0 |
+				 TRNG_RNG_CTL_ENABLE,
+			 TRNG_RNG_CTL_MASK);
+
+	return 0;
+}
+
+static void rk3568_rng_cleanup(struct hwrng *rng)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+
+	/* stop TRNG */
+	rk_rng_write_ctl(rk_rng, 0, TRNG_RNG_CTL_MASK);
+
+	/* stop clocks */
+	clk_bulk_disable_unprepare(rk_rng->clk_num, rk_rng->clk_bulks);
+}
+
+static int rk3568_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+	size_t to_read = min_t(size_t, max, RK_RNG_MAX_BYTE);
+	u32 reg;
+	int ret = 0;
+
+	ret = pm_runtime_resume_and_get(rk_rng->dev);
+	if (ret < 0)
+		return ret;
+
+	/* Start collecting random data */
+	rk_rng_write_ctl(rk_rng, TRNG_RNG_CTL_START, TRNG_RNG_CTL_START);
+
+	ret = readl_poll_timeout(rk_rng->base + TRNG_RNG_CTL, reg,
+				 !(reg & TRNG_RNG_CTL_START),
+				 RK_RNG_POLL_PERIOD_US,
+				 RK_RNG_POLL_TIMEOUT_US);
+	if (ret < 0)
+		goto out;
+
+	/* Read random data stored in the registers */
+	memcpy_fromio(buf, rk_rng->base + TRNG_RNG_DOUT, to_read);
+out:
+	pm_runtime_mark_last_busy(rk_rng->dev);
+	pm_runtime_put_sync_autosuspend(rk_rng->dev);
+
+	return (ret < 0) ? ret : to_read;
+}
+
+static int rk3576_rng_init(struct hwrng *rng)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+
+	return rk_rng_enable_clks(rk_rng);
+}
+
+static int rk3576_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+	size_t to_read = min_t(size_t, max, RKRNG_READ_LEN);
+	int ret = 0;
+	u32 val;
+
+	ret = pm_runtime_resume_and_get(rk_rng->dev);
+	if (ret < 0)
+		return ret;
+
+	rk_rng_writel(rk_rng, RKRNG_CTRL_REQ_TRNG | (RKRNG_CTRL_REQ_TRNG << 16),
+		      RKRNG_CTRL);
+
+	if (readl_poll_timeout(rk_rng->base + RKRNG_STATE, val,
+			       (val & RKRNG_STATE_TRNG_RDY), RK_RNG_POLL_PERIOD_US,
+			       RK_RNG_POLL_TIMEOUT_US)) {
+		dev_err(rk_rng->dev, "timed out waiting for data\n");
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	rk_rng_writel(rk_rng, RKRNG_STATE_TRNG_RDY, RKRNG_STATE);
+
+	memcpy_fromio(buf, rk_rng->base + RKRNG_TRNG_DATA0, to_read);
+
+out:
+	pm_runtime_mark_last_busy(rk_rng->dev);
+	pm_runtime_put_sync_autosuspend(rk_rng->dev);
+
+	return (ret < 0) ? ret : to_read;
+}
+
+static int rk3588_rng_init(struct hwrng *rng)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+	u32 version, status, mask, istat;
+	int ret;
+
+	ret = rk_rng_enable_clks(rk_rng);
+	if (ret < 0)
+		return ret;
+
+	version = rk_rng_readl(rk_rng, TRNG_V1_VERSION);
+	if (version != TRNG_v1_VERSION_CODE) {
+		dev_err(rk_rng->dev,
+			"wrong trng version, expected = %08x, actual = %08x\n",
+			TRNG_V1_VERSION, version);
+		ret = -EFAULT;
+		goto err_disable_clk;
+	}
+
+	mask = TRNG_V1_STAT_SEEDED | TRNG_V1_STAT_GENERATING |
+	       TRNG_V1_STAT_RESEEDING;
+	if (readl_poll_timeout(rk_rng->base + TRNG_V1_STAT, status,
+			       (status & mask) == TRNG_V1_STAT_SEEDED,
+			       RK_RNG_POLL_PERIOD_US, RK_RNG_POLL_TIMEOUT_US) < 0) {
+		dev_err(rk_rng->dev, "timed out waiting for hwrng to reseed\n");
+		ret = -ETIMEDOUT;
+		goto err_disable_clk;
+	}
+
+	/*
+	 * clear ISTAT flag, downstream advises to do this to avoid
+	 * auto-reseeding "on power on"
+	 */
+	istat = rk_rng_readl(rk_rng, TRNG_V1_ISTAT);
+	rk_rng_writel(rk_rng, istat, TRNG_V1_ISTAT);
+
+	/* auto reseed after RK_TRNG_V1_AUTO_RESEED_CNT bytes */
+	rk_rng_writel(rk_rng, RK_TRNG_V1_AUTO_RESEED_CNT / 16, TRNG_V1_AUTO_RQSTS);
+
+	return 0;
+err_disable_clk:
+	clk_bulk_disable_unprepare(rk_rng->clk_num, rk_rng->clk_bulks);
+	return ret;
+}
+
+static void rk3588_rng_cleanup(struct hwrng *rng)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+
+	clk_bulk_disable_unprepare(rk_rng->clk_num, rk_rng->clk_bulks);
+}
+
+static int rk3588_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
+	size_t to_read = min_t(size_t, max, RK_RNG_MAX_BYTE);
+	int ret = 0;
+	u32 reg;
+
+	ret = pm_runtime_resume_and_get(rk_rng->dev);
+	if (ret < 0)
+		return ret;
+
+	/* Clear ISTAT, even without interrupts enabled, this will be updated */
+	reg = rk_rng_readl(rk_rng, TRNG_V1_ISTAT);
+	rk_rng_writel(rk_rng, reg, TRNG_V1_ISTAT);
+
+	/* generate 256 bits of random data */
+	rk_rng_writel(rk_rng, TRNG_V1_MODE_256_BIT, TRNG_V1_MODE);
+	rk_rng_writel(rk_rng, TRNG_V1_CTRL_RAND, TRNG_V1_CTRL);
+
+	ret = readl_poll_timeout_atomic(rk_rng->base + TRNG_V1_ISTAT, reg,
+					(reg & TRNG_V1_ISTAT_RAND_RDY), 0,
+					RK_RNG_POLL_TIMEOUT_US);
+	if (ret < 0)
+		goto out;
+
+	/* Read random data that's in registers TRNG_V1_RAND0 through RAND7 */
+	memcpy_fromio(buf, rk_rng->base + TRNG_V1_RAND0, to_read);
+
+out:
+	/* Clear ISTAT */
+	rk_rng_writel(rk_rng, reg, TRNG_V1_ISTAT);
+	/* close the TRNG */
+	rk_rng_writel(rk_rng, TRNG_V1_CTRL_NOP, TRNG_V1_CTRL);
+
+	pm_runtime_mark_last_busy(rk_rng->dev);
+	pm_runtime_put_sync_autosuspend(rk_rng->dev);
+
+	return (ret < 0) ? ret : to_read;
+}
+
+static const struct rk_rng_soc_data rk3568_soc_data = {
+	.rk_rng_init = rk3568_rng_init,
+	.rk_rng_read = rk3568_rng_read,
+	.rk_rng_cleanup = rk3568_rng_cleanup,
+	.quality = 900,
+	.reset_optional = false,
+};
+
+static const struct rk_rng_soc_data rk3576_soc_data = {
+	.rk_rng_init = rk3576_rng_init,
+	.rk_rng_read = rk3576_rng_read,
+	.rk_rng_cleanup = rk3588_rng_cleanup,
+	.quality = 999,		/* as determined by actual testing */
+	.reset_optional = true,
+};
+
+static const struct rk_rng_soc_data rk3588_soc_data = {
+	.rk_rng_init = rk3588_rng_init,
+	.rk_rng_read = rk3588_rng_read,
+	.rk_rng_cleanup = rk3588_rng_cleanup,
+	.quality = 999,		/* as determined by actual testing */
+	.reset_optional = true,
+};
+
+static int rk_rng_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct reset_control *rst;
+	struct rk_rng *rk_rng;
+	int ret;
+
+	rk_rng = devm_kzalloc(dev, sizeof(*rk_rng), GFP_KERNEL);
+	if (!rk_rng)
+		return -ENOMEM;
+
+	rk_rng->soc_data = of_device_get_match_data(dev);
+	rk_rng->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rk_rng->base))
+		return PTR_ERR(rk_rng->base);
+
+	rk_rng->clk_num = devm_clk_bulk_get_all(dev, &rk_rng->clk_bulks);
+	if (rk_rng->clk_num < 0)
+		return dev_err_probe(dev, rk_rng->clk_num,
+				     "Failed to get clks property\n");
+
+	if (rk_rng->soc_data->reset_optional)
+		rst = devm_reset_control_array_get_optional_exclusive(dev);
+	else
+		rst = devm_reset_control_array_get_exclusive(dev);
+
+	if (rst) {
+		if (IS_ERR(rst))
+			return dev_err_probe(dev, PTR_ERR(rst), "Failed to get reset property\n");
+
+		reset_control_assert(rst);
+		udelay(2);
+		reset_control_deassert(rst);
+	}
+
+	platform_set_drvdata(pdev, rk_rng);
+
+	rk_rng->rng.name = dev_driver_string(dev);
+	if (!IS_ENABLED(CONFIG_PM)) {
+		rk_rng->rng.init = rk_rng->soc_data->rk_rng_init;
+		rk_rng->rng.cleanup = rk_rng->soc_data->rk_rng_cleanup;
+	}
+	rk_rng->rng.read = rk_rng->soc_data->rk_rng_read;
+	rk_rng->dev = dev;
+	rk_rng->rng.quality = rk_rng->soc_data->quality;
+
+	pm_runtime_set_autosuspend_delay(dev, RK_RNG_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(dev);
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Runtime pm activation failed.\n");
+
+	ret = devm_hwrng_register(dev, &rk_rng->rng);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register Rockchip hwrng\n");
+
+	return 0;
+}
+
+static int __maybe_unused rk_rng_runtime_suspend(struct device *dev)
+{
+	struct rk_rng *rk_rng = dev_get_drvdata(dev);
+
+	rk_rng->soc_data->rk_rng_cleanup(&rk_rng->rng);
+
+	return 0;
+}
+
+static int __maybe_unused rk_rng_runtime_resume(struct device *dev)
+{
+	struct rk_rng *rk_rng = dev_get_drvdata(dev);
+
+	return rk_rng->soc_data->rk_rng_init(&rk_rng->rng);
+}
+
+static const struct dev_pm_ops rk_rng_pm_ops = {
+	SET_RUNTIME_PM_OPS(rk_rng_runtime_suspend,
+				rk_rng_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
+static const struct of_device_id rk_rng_dt_match[] = {
+	{ .compatible = "rockchip,rk3568-rng", .data = (void *)&rk3568_soc_data },
+	{ .compatible = "rockchip,rk3576-rng", .data = (void *)&rk3576_soc_data },
+	{ .compatible = "rockchip,rk3588-rng", .data = (void *)&rk3588_soc_data },
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, rk_rng_dt_match);
+
+static struct platform_driver rk_rng_driver = {
+	.driver	= {
+		.name	= "rockchip-rng",
+		.pm	= &rk_rng_pm_ops,
+		.of_match_table = rk_rng_dt_match,
+	},
+	.probe	= rk_rng_probe,
+};
+
+module_platform_driver(rk_rng_driver);
+
+MODULE_DESCRIPTION("Rockchip True Random Number Generator driver");
+MODULE_AUTHOR("Lin Jinhan <troy.lin@rock-chips.com>");
+MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
+MODULE_AUTHOR("Daniel Golle <daniel@makrotopia.org>");
+MODULE_AUTHOR("Nicolas Frattaroli <nicolas.frattaroli@collabora.com>");
+MODULE_LICENSE("GPL");