Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 216 insertions, 0 deletions

diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
new file mode 100644
index 000000000..19bde680a
--- /dev/null
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -0,0 +1,216 @@
+/**
+ * Copyright (c) 2010-2012 Broadcom. All rights reserved.
+ * Copyright (c) 2013 Lubomir Rintel
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License ("GPL")
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/hw_random.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/printk.h>
+#include <linux/clk.h>
+
+#define RNG_CTRL	0x0
+#define RNG_STATUS	0x4
+#define RNG_DATA	0x8
+#define RNG_INT_MASK	0x10
+
+/* enable rng */
+#define RNG_RBGEN	0x1
+
+/* the initial numbers generated are "less random" so will be discarded */
+#define RNG_WARMUP_COUNT 0x40000
+
+#define RNG_INT_OFF	0x1
+
+struct bcm2835_rng_priv {
+	struct hwrng rng;
+	void __iomem *base;
+	bool mask_interrupts;
+	struct clk *clk;
+};
+
+static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
+{
+	return container_of(rng, struct bcm2835_rng_priv, rng);
+}
+
+static inline u32 rng_readl(struct bcm2835_rng_priv *priv, u32 offset)
+{
+	/* MIPS chips strapped for BE will automagically configure the
+	 * peripheral registers for CPU-native byte order.
+	 */
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		return __raw_readl(priv->base + offset);
+	else
+		return readl(priv->base + offset);
+}
+
+static inline void rng_writel(struct bcm2835_rng_priv *priv, u32 val,
+			      u32 offset)
+{
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		__raw_writel(val, priv->base + offset);
+	else
+		writel(val, priv->base + offset);
+}
+
+static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
+			       bool wait)
+{
+	struct bcm2835_rng_priv *priv = to_rng_priv(rng);
+	u32 max_words = max / sizeof(u32);
+	u32 num_words, count;
+
+	while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) {
+		if (!wait)
+			return 0;
+		cpu_relax();
+	}
+
+	num_words = rng_readl(priv, RNG_STATUS) >> 24;
+	if (num_words > max_words)
+		num_words = max_words;
+
+	for (count = 0; count < num_words; count++)
+		((u32 *)buf)[count] = rng_readl(priv, RNG_DATA);
+
+	return num_words * sizeof(u32);
+}
+
+static int bcm2835_rng_init(struct hwrng *rng)
+{
+	struct bcm2835_rng_priv *priv = to_rng_priv(rng);
+	int ret = 0;
+	u32 val;
+
+	if (!IS_ERR(priv->clk)) {
+		ret = clk_prepare_enable(priv->clk);
+		if (ret)
+			return ret;
+	}
+
+	if (priv->mask_interrupts) {
+		/* mask the interrupt */
+		val = rng_readl(priv, RNG_INT_MASK);
+		val |= RNG_INT_OFF;
+		rng_writel(priv, val, RNG_INT_MASK);
+	}
+
+	/* set warm-up count & enable */
+	rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS);
+	rng_writel(priv, RNG_RBGEN, RNG_CTRL);
+
+	return ret;
+}
+
+static void bcm2835_rng_cleanup(struct hwrng *rng)
+{
+	struct bcm2835_rng_priv *priv = to_rng_priv(rng);
+
+	/* disable rng hardware */
+	rng_writel(priv, 0, RNG_CTRL);
+
+	if (!IS_ERR(priv->clk))
+		clk_disable_unprepare(priv->clk);
+}
+
+struct bcm2835_rng_of_data {
+	bool mask_interrupts;
+};
+
+static const struct bcm2835_rng_of_data nsp_rng_of_data = {
+	.mask_interrupts = true,
+};
+
+static const struct of_device_id bcm2835_rng_of_match[] = {
+	{ .compatible = "brcm,bcm2835-rng"},
+	{ .compatible = "brcm,bcm-nsp-rng", .data = &nsp_rng_of_data },
+	{ .compatible = "brcm,bcm5301x-rng", .data = &nsp_rng_of_data },
+	{ .compatible = "brcm,bcm6368-rng"},
+	{},
+};
+
+static int bcm2835_rng_probe(struct platform_device *pdev)
+{
+	const struct bcm2835_rng_of_data *of_data;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	const struct of_device_id *rng_id;
+	struct bcm2835_rng_priv *priv;
+	struct resource *r;
+	int err;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	/* map peripheral */
+	priv->base = devm_ioremap_resource(dev, r);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	/* Clock is optional on most platforms */
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	priv->rng.name = pdev->name;
+	priv->rng.init = bcm2835_rng_init;
+	priv->rng.read = bcm2835_rng_read;
+	priv->rng.cleanup = bcm2835_rng_cleanup;
+
+	if (dev_of_node(dev)) {
+		rng_id = of_match_node(bcm2835_rng_of_match, np);
+		if (!rng_id)
+			return -EINVAL;
+
+		/* Check for rng init function, execute it */
+		of_data = rng_id->data;
+		if (of_data)
+			priv->mask_interrupts = of_data->mask_interrupts;
+	}
+
+	/* register driver */
+	err = devm_hwrng_register(dev, &priv->rng);
+	if (err)
+		dev_err(dev, "hwrng registration failed\n");
+	else
+		dev_info(dev, "hwrng registered\n");
+
+	return err;
+}
+
+MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
+
+static struct platform_device_id bcm2835_rng_devtype[] = {
+	{ .name = "bcm2835-rng" },
+	{ .name = "bcm63xx-rng" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, bcm2835_rng_devtype);
+
+static struct platform_driver bcm2835_rng_driver = {
+	.driver = {
+		.name = "bcm2835-rng",
+		.of_match_table = bcm2835_rng_of_match,
+	},
+	.probe		= bcm2835_rng_probe,
+	.id_table	= bcm2835_rng_devtype,
+};
+module_platform_driver(bcm2835_rng_driver);
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
+MODULE_LICENSE("GPL v2");