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

Chris Morgan
2023-04-06T16:18:12Z

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.

Signed-off-by: Lin Jinhan <troy.lin@rock-chips.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
drivers/rng/rockchip_rng.c | 120 ++++++++++++++++++++++++++++++++++---
1 file changed, 111 insertions(+), 9 deletions(-)

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