crypto: ingenic - Add hardware RNG for Ingenic JZ4780 and X1000

Add JZ4780 SoC and X1000 SoC random number generator driver,
based on PrasannaKumar Muralidharan's JZ4780 RNG driver.

Tested-by: 周正 (Zhou Zheng) <sernia.zhou@foxmail.com>
Tested-by: Mathieu Malaterre <malat@debian.org>
Suggested-by: Jeffrey Walton <noloader@gmail.com>
Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 98f95a0..f976a49 100644 (file)
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -267,6 +267,21 @@ config HW_RANDOM_IMX_RNGC
 
          If unsure, say Y.
 
+config HW_RANDOM_INGENIC_RNG
+       tristate "Ingenic Random Number Generator support"
+       depends on HW_RANDOM
+       depends on MACH_JZ4780 || MACH_X1000
+       default HW_RANDOM
+       help
+         This driver provides kernel-side support for the Random Number Generator
+         hardware found in ingenic JZ4780 and X1000 SoC. MIPS Creator CI20 uses
+         JZ4780 SoC, YSH & ATIL CU1000-Neo uses X1000 SoC.
+
+         To compile this driver as a module, choose M here: the
+         module will be called ingenic-rng.
+
+         If unsure, say Y.
+
 config HW_RANDOM_NOMADIK
        tristate "ST-Ericsson Nomadik Random Number Generator support"
        depends on ARCH_NOMADIK

diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 4ed9feb..26ae068 100644 (file)
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
 obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
 obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
 obj-$(CONFIG_HW_RANDOM_IMX_RNGC) += imx-rngc.o
+obj-$(CONFIG_HW_RANDOM_INGENIC_RNG) += ingenic-rng.o
 obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
 obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o

diff --git a/drivers/char/hw_random/ingenic-rng.c b/drivers/char/hw_random/ingenic-rng.c
new file mode 100644 (file)
index 0000000..d704cef
--- /dev/null
+++ b/drivers/char/hw_random/ingenic-rng.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Ingenic Random Number Generator driver
+ * Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
+ * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
+ */
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* RNG register offsets */
+#define RNG_REG_ERNG_OFFSET            0x0
+#define RNG_REG_RNG_OFFSET             0x4
+
+/* bits within the ERND register */
+#define ERNG_READY                             BIT(31)
+#define ERNG_ENABLE                            BIT(0)
+
+enum ingenic_rng_version {
+       ID_JZ4780,
+       ID_X1000,
+};
+
+/* Device associated memory */
+struct ingenic_rng {
+       enum ingenic_rng_version version;
+
+       void __iomem *base;
+       struct hwrng rng;
+};
+
+static int ingenic_rng_init(struct hwrng *rng)
+{
+       struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
+
+       writel(ERNG_ENABLE, priv->base + RNG_REG_ERNG_OFFSET);
+
+       return 0;
+}
+
+static void ingenic_rng_cleanup(struct hwrng *rng)
+{
+       struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
+
+       writel(0, priv->base + RNG_REG_ERNG_OFFSET);
+}
+
+static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+       struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
+       u32 *data = buf;
+       u32 status;
+       int ret;
+
+       if (priv->version >= ID_X1000) {
+               ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status,
+                                        status & ERNG_READY, 10, 1000);
+               if (ret == -ETIMEDOUT) {
+                       pr_err("%s: Wait for RNG data ready timeout\n", __func__);
+                       return ret;
+               }
+       } else {
+               /*
+                * A delay is required so that the current RNG data is not bit shifted
+                * version of previous RNG data which could happen if random data is
+                * read continuously from this device.
+                */
+               udelay(20);
+       }
+
+       *data = readl(priv->base + RNG_REG_RNG_OFFSET);
+
+       return 4;
+}
+
+static int ingenic_rng_probe(struct platform_device *pdev)
+{
+       struct ingenic_rng *priv;
+       int ret;
+
+       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(priv->base)) {
+               pr_err("%s: Failed to map RNG registers\n", __func__);
+               ret = PTR_ERR(priv->base);
+               goto err_free_rng;
+       }
+
+       priv->version = (enum ingenic_rng_version)of_device_get_match_data(&pdev->dev);
+
+       priv->rng.name = pdev->name;
+       priv->rng.init = ingenic_rng_init;
+       priv->rng.cleanup = ingenic_rng_cleanup;
+       priv->rng.read = ingenic_rng_read;
+
+       ret = hwrng_register(&priv->rng);
+       if (ret) {
+               dev_err(&pdev->dev, "Failed to register hwrng\n");
+               goto err_free_rng;
+       }
+
+       platform_set_drvdata(pdev, priv);
+
+       dev_info(&pdev->dev, "Ingenic RNG driver registered\n");
+       return 0;
+
+err_free_rng:
+       kfree(priv);
+       return ret;
+}
+
+static int ingenic_rng_remove(struct platform_device *pdev)
+{
+       struct ingenic_rng *priv = platform_get_drvdata(pdev);
+
+       hwrng_unregister(&priv->rng);
+
+       writel(0, priv->base + RNG_REG_ERNG_OFFSET);
+
+       return 0;
+}
+
+static const struct of_device_id ingenic_rng_of_match[] = {
+       { .compatible = "ingenic,jz4780-rng", .data = (void *) ID_JZ4780 },
+       { .compatible = "ingenic,x1000-rng", .data = (void *) ID_X1000 },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ingenic_rng_of_match);
+
+static struct platform_driver ingenic_rng_driver = {
+       .probe          = ingenic_rng_probe,
+       .remove         = ingenic_rng_remove,
+       .driver         = {
+               .name   = "ingenic-rng",
+               .of_match_table = ingenic_rng_of_match,
+       },
+};
+
+module_platform_driver(ingenic_rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>");
+MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
+MODULE_DESCRIPTION("Ingenic Random Number Generator driver");