[PATCH V2 1/2] rockchip: rng: add trngv1 for rk3588

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

This adds support for the TRNG found in the RK3588 SoC to the
rockchip_rng driver so that it can be used for things such as
seeding randomness to Linux.

This code was taken wholesale from the Rockchip BSP U-Boot source
located here:
https://github.com/rockchip-linux/u-boot/commit/09f31aed858c36a8a5ee20789712e65bb4762068

Tested on an Indiedroid Nova with an RK3588s.

Changes in V2:
 - Modified Kconfig to note that the Rockchip RNG driver supports all
   versions of the hardware (v1, v2, and the trng in the rk3588).

Signed-off-by: Lin Jinhan <troy.lin@rock-chips.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/rng/Kconfig        |   5 +-
 drivers/rng/rockchip_rng.c | 120 ++++++++++++++++++++++++++++++++++---
 2 files changed, 114 insertions(+), 11 deletions(-)

diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index 5dcf68176a..5deb5db5b7 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -58,8 +58,9 @@ config RNG_ROCKCHIP
 	bool "Enable random number generator for rockchip crypto rng"
 	depends on ARCH_ROCKCHIP && DM_RNG
 	help
-	  Enable random number generator for rockchip.This driver is
-	  support rng module of crypto v1 and crypto v2.
+	  Enable random number generator for rockchip. This driver
+	  supports the rng module of crypto v1, crypto v2, and the
+	  trng module of the rk3588 series.
 
 config RNG_IPROC200
 	bool "Broadcom iProc RNG200 random number generator"
diff --git a/drivers/rng/rockchip_rng.c b/drivers/rng/rockchip_rng.c
index 800150f114..705b424cf3 100644
--- a/drivers/rng/rockchip_rng.c
+++ b/drivers/rng/rockchip_rng.c
@@ -43,9 +43,41 @@
 #define CRYPTO_V2_RNG_DOUT_0			0x0410
 /* end of CRYPTO V2 register define */
 
+/* start of TRNG V1 register define */
+#define TRNG_V1_CTRL				0x0000
+#define TRNG_V1_CTRL_NOP			_SBF(0, 0x00)
+#define TRNG_V1_CTRL_RAND			_SBF(0, 0x01)
+#define TRNG_V1_CTRL_SEED			_SBF(0, 0x02)
+
+#define TRNG_V1_MODE				0x0008
+#define TRNG_V1_MODE_128_BIT			_SBF(3, 0x00)
+#define TRNG_V1_MODE_256_BIT			_SBF(3, 0x01)
+
+#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
+
+#define TRNG_V1_AUTO_RQSTS			0x0060
+
+#define TRNG_V1_VERSION				0x00F0
+#define TRNG_v1_VERSION_CODE			0x46BC
+/* end of TRNG V1 register define */
+
 #define RK_RNG_TIME_OUT	50000  /* max 50ms */
 
+#define trng_write(pdata, pos, val)	writel(val, (pdata)->base + (pos))
+#define trng_read(pdata, pos)		readl((pdata)->base + (pos))
+
 struct rk_rng_soc_data {
+	int (*rk_rng_init)(struct udevice *dev);
 	int (*rk_rng_read)(struct udevice *dev, void *data, size_t len);
 };
 
@@ -75,7 +107,7 @@ static int rk_rng_read_regs(fdt_addr_t addr, void *buf, size_t size)
 	return 0;
 }
 
-static int rk_v1_rng_read(struct udevice *dev, void *data, size_t len)
+static int rk_cryptov1_rng_read(struct udevice *dev, void *data, size_t len)
 {
 	struct rk_rng_plat *pdata = dev_get_priv(dev);
 	u32 reg = 0;
@@ -106,7 +138,7 @@ exit:
 	return 0;
 }
 
-static int rk_v2_rng_read(struct udevice *dev, void *data, size_t len)
+static int rk_cryptov2_rng_read(struct udevice *dev, void *data, size_t len)
 {
 	struct rk_rng_plat *pdata = dev_get_priv(dev);
 	u32 reg = 0;
@@ -140,6 +172,63 @@ exit:
 	return retval;
 }
 
+static int rk_trngv1_init(struct udevice *dev)
+{
+	u32 status, version;
+	u32 auto_reseed_cnt = 1000;
+	struct rk_rng_plat *pdata = dev_get_priv(dev);
+
+	version = trng_read(pdata, TRNG_V1_VERSION);
+	if (version != TRNG_v1_VERSION_CODE) {
+		printf("wrong trng version, expected = %08x, actual = %08x",
+		       TRNG_V1_VERSION, version);
+		return -EFAULT;
+	}
+
+	/* wait in case of RND_RDY triggered at firs power on */
+	readl_poll_timeout(pdata->base + TRNG_V1_ISTAT, status,
+			   (status & TRNG_V1_ISTAT_RAND_RDY),
+			   RK_RNG_TIME_OUT);
+
+	/* clear RAND_RDY flag for first power on */
+	trng_write(pdata, TRNG_V1_ISTAT, status);
+
+	/* auto reseed after (auto_reseed_cnt * 16) byte rand generate */
+	trng_write(pdata, TRNG_V1_AUTO_RQSTS, auto_reseed_cnt);
+
+	return 0;
+}
+
+static int rk_trngv1_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	struct rk_rng_plat *pdata = dev_get_priv(dev);
+	u32 reg = 0;
+	int retval;
+
+	if (len > RK_HW_RNG_MAX)
+		return -EINVAL;
+
+	trng_write(pdata, TRNG_V1_MODE, TRNG_V1_MODE_256_BIT);
+	trng_write(pdata, TRNG_V1_CTRL, TRNG_V1_CTRL_RAND);
+
+	retval = readl_poll_timeout(pdata->base + TRNG_V1_ISTAT, reg,
+				    (reg & TRNG_V1_ISTAT_RAND_RDY),
+				    RK_RNG_TIME_OUT);
+	/* clear ISTAT */
+	trng_write(pdata, TRNG_V1_ISTAT, reg);
+
+	if (retval)
+		goto exit;
+
+	rk_rng_read_regs(pdata->base + TRNG_V1_RAND0, data, len);
+
+exit:
+	/* close TRNG */
+	trng_write(pdata, TRNG_V1_CTRL, TRNG_V1_CTRL_NOP);
+
+	return retval;
+}
+
 static int rockchip_rng_read(struct udevice *dev, void *data, size_t len)
 {
 	unsigned char *buf = data;
@@ -184,18 +273,27 @@ static int rockchip_rng_of_to_plat(struct udevice *dev)
 static int rockchip_rng_probe(struct udevice *dev)
 {
 	struct rk_rng_plat *pdata = dev_get_priv(dev);
+	int ret = 0;
 
 	pdata->soc_data = (struct rk_rng_soc_data *)dev_get_driver_data(dev);
 
-	return 0;
+	if (pdata->soc_data->rk_rng_init)
+		ret = pdata->soc_data->rk_rng_init(dev);
+
+	return ret;
 }
 
-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_cryptov1_soc_data = {
+	.rk_rng_read = rk_cryptov1_rng_read,
+};
+
+static const struct rk_rng_soc_data rk_cryptov2_soc_data = {
+	.rk_rng_read = rk_cryptov2_rng_read,
 };
 
-static const struct rk_rng_soc_data rk_rng_v2_soc_data = {
-	.rk_rng_read = rk_v2_rng_read,
+static const struct rk_rng_soc_data rk_trngv1_soc_data = {
+	.rk_rng_init = rk_trngv1_init,
+	.rk_rng_read = rk_trngv1_rng_read,
 };
 
 static const struct dm_rng_ops rockchip_rng_ops = {
@@ -205,11 +303,15 @@ static const struct dm_rng_ops rockchip_rng_ops = {
 static const struct udevice_id rockchip_rng_match[] = {
 	{
 		.compatible = "rockchip,cryptov1-rng",
-		.data = (ulong)&rk_rng_v1_soc_data,
+		.data = (ulong)&rk_cryptov1_soc_data,
 	},
 	{
 		.compatible = "rockchip,cryptov2-rng",
-		.data = (ulong)&rk_rng_v2_soc_data,
+		.data = (ulong)&rk_cryptov2_soc_data,
+	},
+	{
+		.compatible = "rockchip,trngv1",
+		.data = (ulong)&rk_trngv1_soc_data,
 	},
 	{},
 };
-- 
2.34.1