--- /dev/null
+/*
+* Copyright (C) 2015 Broadcom Corporation
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License as
+* published by the Free Software Foundation version 2.
+*
+* This program is distributed "as is" WITHOUT ANY WARRANTY of any
+* kind, whether express or implied; without even the implied warranty
+* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*/
+/*
+ * DESCRIPTION: The Broadcom iProc RNG200 Driver
+ */
+
+#include <linux/hw_random.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+
+/* Registers */
+#define RNG_CTRL_OFFSET 0x00
+#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
+#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
+#define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000
+
+#define RNG_SOFT_RESET_OFFSET 0x04
+#define RNG_SOFT_RESET 0x00000001
+
+#define RBG_SOFT_RESET_OFFSET 0x08
+#define RBG_SOFT_RESET 0x00000001
+
+#define RNG_INT_STATUS_OFFSET 0x18
+#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
+#define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK 0x00020000
+#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
+#define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK 0x00000001
+
+#define RNG_FIFO_DATA_OFFSET 0x20
+
+#define RNG_FIFO_COUNT_OFFSET 0x24
+#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF
+
+struct iproc_rng200_dev {
+ struct hwrng rng;
+ void __iomem *base;
+};
+
+#define to_rng_priv(rng) container_of(rng, struct iproc_rng200_dev, rng)
+
+static void iproc_rng200_restart(void __iomem *rng_base)
+{
+ uint32_t val;
+
+ /* Disable RBG */
+ val = ioread32(rng_base + RNG_CTRL_OFFSET);
+ val &= ~RNG_CTRL_RNG_RBGEN_MASK;
+ val |= RNG_CTRL_RNG_RBGEN_DISABLE;
+ iowrite32(val, rng_base + RNG_CTRL_OFFSET);
+
+ /* Clear all interrupt status */
+ iowrite32(0xFFFFFFFFUL, rng_base + RNG_INT_STATUS_OFFSET);
+
+ /* Reset RNG and RBG */
+ val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
+ val |= RBG_SOFT_RESET;
+ iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);
+
+ val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
+ val |= RNG_SOFT_RESET;
+ iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);
+
+ val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
+ val &= ~RNG_SOFT_RESET;
+ iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);
+
+ val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
+ val &= ~RBG_SOFT_RESET;
+ iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);
+
+ /* Enable RBG */
+ val = ioread32(rng_base + RNG_CTRL_OFFSET);
+ val &= ~RNG_CTRL_RNG_RBGEN_MASK;
+ val |= RNG_CTRL_RNG_RBGEN_ENABLE;
+ iowrite32(val, rng_base + RNG_CTRL_OFFSET);
+}
+
+static int iproc_rng200_read(struct hwrng *rng, void *buf, size_t max,
+ bool wait)
+{
+ struct iproc_rng200_dev *priv = to_rng_priv(rng);
+ uint32_t num_remaining = max;
+ uint32_t status;
+
+ #define MAX_RESETS_PER_READ 1
+ uint32_t num_resets = 0;
+
+ #define MAX_IDLE_TIME (1 * HZ)
+ unsigned long idle_endtime = jiffies + MAX_IDLE_TIME;
+
+ while ((num_remaining > 0) && time_before(jiffies, idle_endtime)) {
+
+ /* Is RNG sane? If not, reset it. */
+ status = ioread32(priv->base + RNG_INT_STATUS_OFFSET);
+ if ((status & (RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK |
+ RNG_INT_STATUS_NIST_FAIL_IRQ_MASK)) != 0) {
+
+ if (num_resets >= MAX_RESETS_PER_READ)
+ return max - num_remaining;
+
+ iproc_rng200_restart(priv->base);
+ num_resets++;
+ }
+
+ /* Are there any random numbers available? */
+ if ((ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
+ RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) {
+
+ if (num_remaining >= sizeof(uint32_t)) {
+ /* Buffer has room to store entire word */
+ *(uint32_t *)buf = ioread32(priv->base +
+ RNG_FIFO_DATA_OFFSET);
+ buf += sizeof(uint32_t);
+ num_remaining -= sizeof(uint32_t);
+ } else {
+ /* Buffer can only store partial word */
+ uint32_t rnd_number = ioread32(priv->base +
+ RNG_FIFO_DATA_OFFSET);
+ memcpy(buf, &rnd_number, num_remaining);
+ buf += num_remaining;
+ num_remaining = 0;
+ }
+
+ /* Reset the IDLE timeout */
+ idle_endtime = jiffies + MAX_IDLE_TIME;
+ } else {
+ if (!wait)
+ /* Cannot wait, return immediately */
+ return max - num_remaining;
+
+ /* Can wait, give others chance to run */
+ usleep_range(min(num_remaining * 10, 500U), 500);
+ }
+ }
+
+ return max - num_remaining;
+}
+
+static int iproc_rng200_init(struct hwrng *rng)
+{
+ struct iproc_rng200_dev *priv = to_rng_priv(rng);
+ uint32_t val;
+
+ /* Setup RNG. */
+ val = ioread32(priv->base + RNG_CTRL_OFFSET);
+ val &= ~RNG_CTRL_RNG_RBGEN_MASK;
+ val |= RNG_CTRL_RNG_RBGEN_ENABLE;
+ iowrite32(val, priv->base + RNG_CTRL_OFFSET);
+
+ return 0;
+}
+
+static void iproc_rng200_cleanup(struct hwrng *rng)
+{
+ struct iproc_rng200_dev *priv = to_rng_priv(rng);
+ uint32_t val;
+
+ /* Disable RNG hardware */
+ val = ioread32(priv->base + RNG_CTRL_OFFSET);
+ val &= ~RNG_CTRL_RNG_RBGEN_MASK;
+ val |= RNG_CTRL_RNG_RBGEN_DISABLE;
+ iowrite32(val, priv->base + RNG_CTRL_OFFSET);
+}
+
+static int iproc_rng200_probe(struct platform_device *pdev)
+{
+ struct iproc_rng200_dev *priv;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ /* Map peripheral */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "failed to get rng resources\n");
+ return -EINVAL;
+ }
+
+ priv->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(priv->base)) {
+ dev_err(dev, "failed to remap rng regs\n");
+ return PTR_ERR(priv->base);
+ }
+
+ priv->rng.name = "iproc-rng200",
+ priv->rng.read = iproc_rng200_read,
+ priv->rng.init = iproc_rng200_init,
+ priv->rng.cleanup = iproc_rng200_cleanup,
+
+ /* Register driver */
+ ret = devm_hwrng_register(dev, &priv->rng);
+ if (ret) {
+ dev_err(dev, "hwrng registration failed\n");
+ return ret;
+ }
+
+ dev_info(dev, "hwrng registered\n");
+
+ return 0;
+}
+
+static const struct of_device_id iproc_rng200_of_match[] = {
+ { .compatible = "brcm,iproc-rng200", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, iproc_rng200_of_match);
+
+static struct platform_driver iproc_rng200_driver = {
+ .driver = {
+ .name = "iproc-rng200",
+ .of_match_table = iproc_rng200_of_match,
+ },
+ .probe = iproc_rng200_probe,
+};
+module_platform_driver(iproc_rng200_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("iProc RNG200 Random Number Generator driver");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff