crypto: hisilicon/trng - add support for HiSTB TRNG

HiSTB TRNG are found on some HiSilicon STB SoCs.

Signed-off-by: David Yang <mmyangfl@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/hisilicon/Kconfig b/drivers/crypto/hisilicon/Kconfig
index 4137a8b..e8690c2 100644 (file)
--- a/drivers/crypto/hisilicon/Kconfig
+++ b/drivers/crypto/hisilicon/Kconfig
@@ -82,3 +82,10 @@ config CRYPTO_DEV_HISI_TRNG
        select CRYPTO_RNG
        help
          Support for HiSilicon TRNG Driver.
+
+config CRYPTO_DEV_HISTB_TRNG
+       tristate "Support for HiSTB TRNG Driver"
+       depends on ARCH_HISI || COMPILE_TEST
+       select HW_RANDOM
+       help
+         Support for HiSTB TRNG Driver.

diff --git a/drivers/crypto/hisilicon/Makefile b/drivers/crypto/hisilicon/Makefile
index 8595a5a..fc51e0e 100644 (file)
--- a/drivers/crypto/hisilicon/Makefile
+++ b/drivers/crypto/hisilicon/Makefile
@@ -5,4 +5,4 @@ obj-$(CONFIG_CRYPTO_DEV_HISI_SEC2) += sec2/
 obj-$(CONFIG_CRYPTO_DEV_HISI_QM) += hisi_qm.o
 hisi_qm-objs = qm.o sgl.o debugfs.o
 obj-$(CONFIG_CRYPTO_DEV_HISI_ZIP) += zip/
-obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += trng/
+obj-y += trng/

diff --git a/drivers/crypto/hisilicon/trng/Makefile b/drivers/crypto/hisilicon/trng/Makefile
index d909079..cf20b05 100644 (file)
--- a/drivers/crypto/hisilicon/trng/Makefile
+++ b/drivers/crypto/hisilicon/trng/Makefile
@@ -1,2 +1,5 @@
 obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += hisi-trng-v2.o
 hisi-trng-v2-objs = trng.o
+
+obj-$(CONFIG_CRYPTO_DEV_HISTB_TRNG) += histb-trng.o
+histb-trng-objs += trng-stb.o

diff --git a/drivers/crypto/hisilicon/trng/trng-stb.c b/drivers/crypto/hisilicon/trng/trng-stb.c
new file mode 100644 (file)
index 0000000..29200a7
--- /dev/null
+++ b/drivers/crypto/hisilicon/trng/trng-stb.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+/*
+ * Device driver for True RNG in HiSTB SoCs
+ *
+ * Copyright (c) 2023 David Yang
+ */
+
+#include <crypto/internal/rng.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+
+#define HISTB_TRNG_CTRL                0x0
+#define  RNG_SOURCE                    GENMASK(1, 0)
+#define  DROP_ENABLE                   BIT(5)
+#define  POST_PROCESS_ENABLE           BIT(7)
+#define  POST_PROCESS_DEPTH            GENMASK(15, 8)
+#define HISTB_TRNG_NUMBER      0x4
+#define HISTB_TRNG_STAT                0x8
+#define  DATA_COUNT                    GENMASK(2, 0)   /* max 4 */
+
+struct histb_trng_priv {
+       struct hwrng rng;
+       void __iomem *base;
+};
+
+/*
+ * Observed:
+ * depth = 1 -> ~1ms
+ * depth = 255 -> ~16ms
+ */
+static int histb_trng_wait(void __iomem *base)
+{
+       u32 val;
+
+       return readl_relaxed_poll_timeout(base + HISTB_TRNG_STAT, val,
+                                         val & DATA_COUNT, 1000, 30 * 1000);
+}
+
+static void histb_trng_init(void __iomem *base, unsigned int depth)
+{
+       u32 val;
+
+       val = readl_relaxed(base + HISTB_TRNG_CTRL);
+
+       val &= ~RNG_SOURCE;
+       val |= 2;
+
+       val &= ~POST_PROCESS_DEPTH;
+       val |= min(depth, 0xffu) << 8;
+
+       val |= POST_PROCESS_ENABLE;
+       val |= DROP_ENABLE;
+
+       writel_relaxed(val, base + HISTB_TRNG_CTRL);
+}
+
+static int histb_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+       struct histb_trng_priv *priv = container_of(rng, typeof(*priv), rng);
+       void __iomem *base = priv->base;
+
+       for (int i = 0; i < max; i += sizeof(u32)) {
+               if (!(readl_relaxed(base + HISTB_TRNG_STAT) & DATA_COUNT)) {
+                       if (!wait)
+                               return i;
+                       if (histb_trng_wait(base)) {
+                               pr_err("failed to generate random number, generated %d\n",
+                                      i);
+                               return i ? i : -ETIMEDOUT;
+                       }
+               }
+               *(u32 *) (data + i) = readl_relaxed(base + HISTB_TRNG_NUMBER);
+       }
+
+       return max;
+}
+
+static unsigned int histb_trng_get_depth(void __iomem *base)
+{
+       return (readl_relaxed(base + HISTB_TRNG_CTRL) & POST_PROCESS_DEPTH) >> 8;
+}
+
+static ssize_t
+depth_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+       struct histb_trng_priv *priv = dev_get_drvdata(dev);
+       void __iomem *base = priv->base;
+
+       return sprintf(buf, "%d\n", histb_trng_get_depth(base));
+}
+
+static ssize_t
+depth_store(struct device *dev, struct device_attribute *attr,
+           const char *buf, size_t count)
+{
+       struct histb_trng_priv *priv = dev_get_drvdata(dev);
+       void __iomem *base = priv->base;
+       unsigned int depth;
+
+       if (kstrtouint(buf, 0, &depth))
+               return -ERANGE;
+
+       histb_trng_init(base, depth);
+       return count;
+}
+
+static DEVICE_ATTR_RW(depth);
+
+static struct attribute *histb_trng_attrs[] = {
+       &dev_attr_depth.attr,
+       NULL,
+};
+
+ATTRIBUTE_GROUPS(histb_trng);
+
+static int histb_trng_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct histb_trng_priv *priv;
+       void __iomem *base;
+       int ret;
+
+       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(base))
+               return -ENOMEM;
+
+       histb_trng_init(base, 144);
+       if (histb_trng_wait(base)) {
+               dev_err(dev, "cannot bring up device\n");
+               return -ENODEV;
+       }
+
+       priv->base = base;
+       priv->rng.name = pdev->name;
+       priv->rng.read = histb_trng_read;
+       ret = devm_hwrng_register(dev, &priv->rng);
+       if (ret) {
+               dev_err(dev, "failed to register hwrng: %d\n", ret);
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, priv);
+       dev_set_drvdata(dev, priv);
+       return 0;
+}
+
+static const struct of_device_id histb_trng_of_match[] = {
+       { .compatible = "hisilicon,histb-trng", },
+       { }
+};
+
+static struct platform_driver histb_trng_driver = {
+       .probe = histb_trng_probe,
+       .driver = {
+               .name = "histb-trng",
+               .of_match_table = histb_trng_of_match,
+               .dev_groups = histb_trng_groups,
+       },
+};
+
+module_platform_driver(histb_trng_driver);
+
+MODULE_DESCRIPTION("HiSTB True RNG");
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_AUTHOR("David Yang <mmyangfl@gmail.com>");