Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 219 insertions, 0 deletions

diff --git a/drivers/char/hw_random/ba431-rng.c b/drivers/char/hw_random/ba431-rng.c
new file mode 100644
index 0000000000..9de7466e68
--- /dev/null
+++ b/drivers/char/hw_random/ba431-rng.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Silex Insight
+
+#include <linux/delay.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/workqueue.h>
+
+#define BA431_RESET_DELAY			1 /* usec */
+#define BA431_RESET_READ_STATUS_TIMEOUT		1000 /* usec */
+#define BA431_RESET_READ_STATUS_INTERVAL	10 /* usec */
+#define BA431_READ_RETRY_INTERVAL		1 /* usec */
+
+#define BA431_REG_CTRL				0x00
+#define BA431_REG_FIFO_LEVEL			0x04
+#define BA431_REG_STATUS			0x30
+#define BA431_REG_FIFODATA			0x80
+
+#define BA431_CTRL_ENABLE			BIT(0)
+#define BA431_CTRL_SOFTRESET			BIT(8)
+
+#define BA431_STATUS_STATE_MASK			(BIT(1) | BIT(2) | BIT(3))
+#define BA431_STATUS_STATE_OFFSET		1
+
+enum ba431_state {
+	BA431_STATE_RESET,
+	BA431_STATE_STARTUP,
+	BA431_STATE_FIFOFULLON,
+	BA431_STATE_FIFOFULLOFF,
+	BA431_STATE_RUNNING,
+	BA431_STATE_ERROR
+};
+
+struct ba431_trng {
+	struct device *dev;
+	void __iomem *base;
+	struct hwrng rng;
+	atomic_t reset_pending;
+	struct work_struct reset_work;
+};
+
+static inline u32 ba431_trng_read_reg(struct ba431_trng *ba431, u32 reg)
+{
+	return ioread32(ba431->base + reg);
+}
+
+static inline void ba431_trng_write_reg(struct ba431_trng *ba431, u32 reg,
+					u32 val)
+{
+	iowrite32(val, ba431->base + reg);
+}
+
+static inline enum ba431_state ba431_trng_get_state(struct ba431_trng *ba431)
+{
+	u32 status = ba431_trng_read_reg(ba431, BA431_REG_STATUS);
+
+	return (status & BA431_STATUS_STATE_MASK) >> BA431_STATUS_STATE_OFFSET;
+}
+
+static int ba431_trng_is_in_error(struct ba431_trng *ba431)
+{
+	enum ba431_state state = ba431_trng_get_state(ba431);
+
+	if ((state < BA431_STATE_STARTUP) ||
+	    (state >= BA431_STATE_ERROR))
+		return 1;
+
+	return 0;
+}
+
+static int ba431_trng_reset(struct ba431_trng *ba431)
+{
+	int ret;
+
+	/* Disable interrupts, random generation and enable the softreset */
+	ba431_trng_write_reg(ba431, BA431_REG_CTRL, BA431_CTRL_SOFTRESET);
+	udelay(BA431_RESET_DELAY);
+	ba431_trng_write_reg(ba431, BA431_REG_CTRL, BA431_CTRL_ENABLE);
+
+	/* Wait until the state changed */
+	if (readx_poll_timeout(ba431_trng_is_in_error, ba431, ret, !ret,
+			       BA431_RESET_READ_STATUS_INTERVAL,
+			       BA431_RESET_READ_STATUS_TIMEOUT)) {
+		dev_err(ba431->dev, "reset failed (state: %d)\n",
+			ba431_trng_get_state(ba431));
+		return -ETIMEDOUT;
+	}
+
+	dev_info(ba431->dev, "reset done\n");
+
+	return 0;
+}
+
+static void ba431_trng_reset_work(struct work_struct *work)
+{
+	struct ba431_trng *ba431 = container_of(work, struct ba431_trng,
+						reset_work);
+	ba431_trng_reset(ba431);
+	atomic_set(&ba431->reset_pending, 0);
+}
+
+static void ba431_trng_schedule_reset(struct ba431_trng *ba431)
+{
+	if (atomic_cmpxchg(&ba431->reset_pending, 0, 1))
+		return;
+
+	schedule_work(&ba431->reset_work);
+}
+
+static int ba431_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct ba431_trng *ba431 = container_of(rng, struct ba431_trng, rng);
+	u32 *data = buf;
+	unsigned int level, i;
+	int n = 0;
+
+	while (max > 0) {
+		level = ba431_trng_read_reg(ba431, BA431_REG_FIFO_LEVEL);
+		if (!level) {
+			if (ba431_trng_is_in_error(ba431)) {
+				ba431_trng_schedule_reset(ba431);
+				break;
+			}
+
+			if (!wait)
+				break;
+
+			udelay(BA431_READ_RETRY_INTERVAL);
+			continue;
+		}
+
+		i = level;
+		do {
+			data[n++] = ba431_trng_read_reg(ba431,
+							BA431_REG_FIFODATA);
+			max -= sizeof(*data);
+		} while (--i && (max > 0));
+
+		if (ba431_trng_is_in_error(ba431)) {
+			n -= (level - i);
+			ba431_trng_schedule_reset(ba431);
+			break;
+		}
+	}
+
+	n *= sizeof(data);
+	return (n || !wait) ? n : -EIO;
+}
+
+static void ba431_trng_cleanup(struct hwrng *rng)
+{
+	struct ba431_trng *ba431 = container_of(rng, struct ba431_trng, rng);
+
+	ba431_trng_write_reg(ba431, BA431_REG_CTRL, 0);
+	cancel_work_sync(&ba431->reset_work);
+}
+
+static int ba431_trng_init(struct hwrng *rng)
+{
+	struct ba431_trng *ba431 = container_of(rng, struct ba431_trng, rng);
+
+	return ba431_trng_reset(ba431);
+}
+
+static int ba431_trng_probe(struct platform_device *pdev)
+{
+	struct ba431_trng *ba431;
+	int ret;
+
+	ba431 = devm_kzalloc(&pdev->dev, sizeof(*ba431), GFP_KERNEL);
+	if (!ba431)
+		return -ENOMEM;
+
+	ba431->dev = &pdev->dev;
+
+	ba431->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ba431->base))
+		return PTR_ERR(ba431->base);
+
+	atomic_set(&ba431->reset_pending, 0);
+	INIT_WORK(&ba431->reset_work, ba431_trng_reset_work);
+	ba431->rng.name = pdev->name;
+	ba431->rng.init = ba431_trng_init;
+	ba431->rng.cleanup = ba431_trng_cleanup;
+	ba431->rng.read = ba431_trng_read;
+
+	ret = devm_hwrng_register(&pdev->dev, &ba431->rng);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "BA431 registration failed\n");
+
+	dev_info(&pdev->dev, "BA431 TRNG registered\n");
+
+	return 0;
+}
+
+static const struct of_device_id ba431_trng_dt_ids[] = {
+	{ .compatible = "silex-insight,ba431-rng" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ba431_trng_dt_ids);
+
+static struct platform_driver ba431_trng_driver = {
+	.driver = {
+		.name = "ba431-rng",
+		.of_match_table = ba431_trng_dt_ids,
+	},
+	.probe = ba431_trng_probe,
+};
+
+module_platform_driver(ba431_trng_driver);
+
+MODULE_AUTHOR("Olivier Sobrie <olivier@sobrie.be>");
+MODULE_DESCRIPTION("TRNG driver for Silex Insight BA431");
+MODULE_LICENSE("GPL");