Adds to support JH7110 TRNG driver which is based on linux kernel's
jh7110-trng.c. This can support to generate 256-bit random numbers and
128-bit but this makes 256-bit default for convenience.

Signed-off-by: Chanho Park <chanho61.p...@samsung.com>
---
 drivers/rng/Kconfig      |   6 +
 drivers/rng/Makefile     |   1 +
 drivers/rng/jh7110_rng.c | 258 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 265 insertions(+)
 create mode 100644 drivers/rng/jh7110_rng.c

diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index 994cc35b2744..0dba1e06b429 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -91,4 +91,10 @@ config TPM_RNG
          functionality. Enable random number generator on TPM
          devices.
 
+config RNG_JH7110
+       bool "StarFive JH7110 Random Number Generator support"
+       depends on DM_RNG && STARFIVE_JH7110
+       help
+         Enable True Random Number Generator in StarFive JH7110 SoCs.
+
 endif
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 47b323e61ee3..9de762c8a1c3 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o
 obj-$(CONFIG_RNG_SMCCC_TRNG) += smccc_trng.o
 obj-$(CONFIG_RNG_ARM_RNDR) += arm_rndr.o
 obj-$(CONFIG_TPM_RNG) += tpm_rng.o
+obj-$(CONFIG_RNG_JH7110) += jh7110_rng.o
diff --git a/drivers/rng/jh7110_rng.c b/drivers/rng/jh7110_rng.c
new file mode 100644
index 000000000000..37ea8cc39945
--- /dev/null
+++ b/drivers/rng/jh7110_rng.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * TRNG driver for the StarFive JH7110 SoC
+ *
+ */
+
+#include <clk.h>
+#include <dm.h>
+#include <reset.h>
+#include <rng.h>
+#include <asm/io.h>
+#include <linux/iopoll.h>
+
+/* trng register offset */
+#define STARFIVE_CTRL                  0x00
+#define STARFIVE_STAT                  0x04
+#define STARFIVE_MODE                  0x08
+#define STARFIVE_SMODE                 0x0C
+#define STARFIVE_IE                    0x10
+#define STARFIVE_ISTAT                 0x14
+#define STARFIVE_RAND0                 0x20
+#define STARFIVE_RAND1                 0x24
+#define STARFIVE_RAND2                 0x28
+#define STARFIVE_RAND3                 0x2C
+#define STARFIVE_RAND4                 0x30
+#define STARFIVE_RAND5                 0x34
+#define STARFIVE_RAND6                 0x38
+#define STARFIVE_RAND7                 0x3C
+#define STARFIVE_AUTO_RQSTS            0x60
+#define STARFIVE_AUTO_AGE              0x64
+
+/* CTRL CMD */
+#define STARFIVE_CTRL_EXEC_NOP         0x0
+#define STARFIVE_CTRL_GENE_RANDNUM     0x1
+#define STARFIVE_CTRL_EXEC_RANDRESEED  0x2
+
+/* STAT */
+#define STARFIVE_STAT_NONCE_MODE       BIT(2)
+#define STARFIVE_STAT_R256             BIT(3)
+#define STARFIVE_STAT_MISSION_MODE     BIT(8)
+#define STARFIVE_STAT_SEEDED           BIT(9)
+#define STARFIVE_STAT_LAST_RESEED(x)   ((x) << 16)
+#define STARFIVE_STAT_SRVC_RQST                BIT(27)
+#define STARFIVE_STAT_RAND_GENERATING  BIT(30)
+#define STARFIVE_STAT_RAND_SEEDING     BIT(31)
+#define STARFIVE_STAT_RUNNING          (STARFIVE_STAT_RAND_GENERATING | \
+                                        STARFIVE_STAT_RAND_SEEDING)
+
+/* MODE */
+#define STARFIVE_MODE_R256             BIT(3)
+
+/* SMODE */
+#define STARFIVE_SMODE_NONCE_MODE      BIT(2)
+#define STARFIVE_SMODE_MISSION_MODE    BIT(8)
+#define STARFIVE_SMODE_MAX_REJECTS(x)  ((x) << 16)
+
+/* IE */
+#define STARFIVE_IE_RAND_RDY_EN                BIT(0)
+#define STARFIVE_IE_SEED_DONE_EN       BIT(1)
+#define STARFIVE_IE_LFSR_LOCKUP_EN     BIT(4)
+#define STARFIVE_IE_GLBL_EN            BIT(31)
+
+#define STARFIVE_IE_ALL                        (STARFIVE_IE_GLBL_EN | \
+                                        STARFIVE_IE_RAND_RDY_EN | \
+                                        STARFIVE_IE_SEED_DONE_EN | \
+                                        STARFIVE_IE_LFSR_LOCKUP_EN)
+
+/* ISTAT */
+#define STARFIVE_ISTAT_RAND_RDY                BIT(0)
+#define STARFIVE_ISTAT_SEED_DONE       BIT(1)
+#define STARFIVE_ISTAT_LFSR_LOCKUP     BIT(4)
+
+#define STARFIVE_RAND_LEN              sizeof(u32)
+
+enum mode {
+       PRNG_128BIT,
+       PRNG_256BIT,
+};
+
+struct starfive_trng_plat {
+       void *base;
+       struct clk *hclk;
+       struct clk *ahb;
+       struct reset_ctl *rst;
+       u32 mode;
+};
+
+static inline int starfive_trng_wait_idle(struct starfive_trng_plat *trng)
+{
+       u32 stat;
+
+       return readl_relaxed_poll_timeout(trng->base + STARFIVE_STAT, stat,
+                                         !(stat & STARFIVE_STAT_RUNNING),
+                                         100000);
+}
+
+static inline void starfive_trng_irq_mask_clear(struct starfive_trng_plat 
*trng)
+{
+       /* clear register: ISTAT */
+       u32 data = readl(trng->base + STARFIVE_ISTAT);
+
+       writel(data, trng->base + STARFIVE_ISTAT);
+}
+
+static int starfive_trng_cmd(struct starfive_trng_plat *trng, u32 cmd)
+{
+       u32 stat, flg;
+       int ret;
+
+       switch (cmd) {
+       case STARFIVE_CTRL_GENE_RANDNUM:
+               writel(cmd, trng->base + STARFIVE_CTRL);
+               flg = STARFIVE_ISTAT_RAND_RDY;
+               break;
+       case STARFIVE_CTRL_EXEC_RANDRESEED:
+               writel(cmd, trng->base + STARFIVE_CTRL);
+               flg = STARFIVE_ISTAT_SEED_DONE;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       ret = readl_relaxed_poll_timeout(trng->base + STARFIVE_ISTAT, stat,
+                                        (stat & flg), 1000);
+       writel(flg, trng->base + STARFIVE_ISTAT);
+
+       return ret;
+}
+
+static int starfive_trng_read(struct udevice *dev, void *data, size_t len)
+{
+       struct starfive_trng_plat *trng = dev_get_plat(dev);
+       u8 *buffer = data;
+       int iter_mask;
+
+       if (trng->mode == PRNG_256BIT)
+               iter_mask = 7;
+       else
+               iter_mask = 3;
+
+       for (int i = 0; len; ++i, i &= iter_mask) {
+               u32 val;
+               size_t step;
+               int ret;
+
+               ret = starfive_trng_cmd(trng, STARFIVE_CTRL_GENE_RANDNUM);
+               if (ret)
+                       return ret;
+
+               val = readl(trng->base + STARFIVE_RAND0 +
+                           (i * STARFIVE_RAND_LEN));
+               step = min_t(size_t, len, STARFIVE_RAND_LEN);
+               memcpy(buffer, &val, step);
+               buffer += step;
+               len -= step;
+       }
+
+       return 0;
+}
+
+static int starfive_trng_init(struct starfive_trng_plat *trng)
+{
+       u32 mode, intr = 0;
+
+       /* setup Auto Request/Age register */
+       writel(0, trng->base + STARFIVE_AUTO_AGE);
+       writel(0, trng->base + STARFIVE_AUTO_RQSTS);
+
+       /* clear register: ISTAT */
+       starfive_trng_irq_mask_clear(trng);
+
+       intr |= STARFIVE_IE_ALL;
+       writel(intr, trng->base + STARFIVE_IE);
+
+       mode = readl(trng->base + STARFIVE_MODE);
+
+       switch (trng->mode) {
+       case PRNG_128BIT:
+               mode &= ~STARFIVE_MODE_R256;
+               break;
+       case PRNG_256BIT:
+               mode |= STARFIVE_MODE_R256;
+               break;
+       default:
+               mode |= STARFIVE_MODE_R256;
+               break;
+       }
+
+       writel(mode, trng->base + STARFIVE_MODE);
+
+       return starfive_trng_cmd(trng, STARFIVE_CTRL_EXEC_RANDRESEED);
+}
+
+static int starfive_trng_probe(struct udevice *dev)
+{
+       struct starfive_trng_plat *pdata = dev_get_plat(dev);
+       int err;
+
+       err = clk_enable(pdata->hclk);
+       if (err)
+               return err;
+
+       err = clk_enable(pdata->ahb);
+       if (err)
+               return err;
+
+       err = reset_deassert(pdata->rst);
+       if (err)
+               return err;
+
+       pdata->mode = PRNG_256BIT;
+
+       return starfive_trng_init(pdata);
+}
+
+static int starfive_trng_of_to_plat(struct udevice *dev)
+{
+       struct starfive_trng_plat *pdata = dev_get_plat(dev);
+
+       pdata->base = (void *)dev_read_addr(dev);
+       if (!pdata->base)
+               return -ENODEV;
+
+       pdata->hclk = devm_clk_get(dev, "hclk");
+       if (IS_ERR(pdata->hclk))
+               return -ENODEV;
+
+       pdata->ahb = devm_clk_get(dev, "ahb");
+       if (IS_ERR(pdata->ahb))
+               return -ENODEV;
+
+       pdata->rst = devm_reset_control_get(dev, NULL);
+       if (IS_ERR(pdata->rst))
+               return -ENODEV;
+
+       return 0;
+}
+
+static const struct dm_rng_ops starfive_trng_ops = {
+       .read = starfive_trng_read,
+};
+
+static const struct udevice_id starfive_trng_match[] = {
+       {
+               .compatible = "starfive,jh7110-trng",
+       },
+       {},
+};
+
+U_BOOT_DRIVER(starfive_trng) = {
+       .name = "jh7110-trng",
+       .id = UCLASS_RNG,
+       .of_match = starfive_trng_match,
+       .probe = starfive_trng_probe,
+       .ops = &starfive_trng_ops,
+       .plat_auto = sizeof(struct starfive_trng_plat),
+       .of_to_plat = starfive_trng_of_to_plat,
+};
-- 
2.39.2

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