From 5343e674f32fb82b7a80a24b5a84eee62d3fe624 Mon Sep 17 00:00:00 2001
From: Christian Lamparter <chunkeey@googlemail.com>
Date: Mon, 18 Apr 2016 12:57:41 +0200
Subject: crypto4xx: integrate ppc4xx-rng into crypto4xx

This patch integrates the ppc4xx-rng driver into the existing
crypto4xx. This is because the true random number generator
is controlled and part of the security core.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 drivers/crypto/amcc/crypto4xx_trng.c | 131 +++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 drivers/crypto/amcc/crypto4xx_trng.c

(limited to 'drivers/crypto/amcc/crypto4xx_trng.c')

diff --git a/drivers/crypto/amcc/crypto4xx_trng.c b/drivers/crypto/amcc/crypto4xx_trng.c
new file mode 100644
index 000000000000..677ca17fd223
--- /dev/null
+++ b/drivers/crypto/amcc/crypto4xx_trng.c
@@ -0,0 +1,131 @@
+/*
+ * Generic PowerPC 44x RNG driver
+ *
+ * Copyright 2011 IBM 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 of the License.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+#include "crypto4xx_core.h"
+#include "crypto4xx_trng.h"
+#include "crypto4xx_reg_def.h"
+
+#define PPC4XX_TRNG_CTRL	0x0008
+#define PPC4XX_TRNG_CTRL_DALM	0x20
+#define PPC4XX_TRNG_STAT	0x0004
+#define PPC4XX_TRNG_STAT_B	0x1
+#define PPC4XX_TRNG_DATA	0x0000
+
+static int ppc4xx_trng_data_present(struct hwrng *rng, int wait)
+{
+	struct crypto4xx_device *dev = (void *)rng->priv;
+	int busy, i, present = 0;
+
+	for (i = 0; i < 20; i++) {
+		busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) &
+			PPC4XX_TRNG_STAT_B);
+		if (!busy || !wait) {
+			present = 1;
+			break;
+		}
+		udelay(10);
+	}
+	return present;
+}
+
+static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data)
+{
+	struct crypto4xx_device *dev = (void *)rng->priv;
+	*data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA);
+	return 4;
+}
+
+static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable)
+{
+	u32 device_ctrl;
+
+	device_ctrl = readl(dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
+	if (enable)
+		device_ctrl |= PPC4XX_TRNG_EN;
+	else
+		device_ctrl &= ~PPC4XX_TRNG_EN;
+	writel(device_ctrl, dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
+}
+
+static const struct of_device_id ppc4xx_trng_match[] = {
+	{ .compatible = "ppc4xx-rng", },
+	{ .compatible = "amcc,ppc460ex-rng", },
+	{ .compatible = "amcc,ppc440epx-rng", },
+	{},
+};
+
+void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev)
+{
+	struct crypto4xx_device *dev = core_dev->dev;
+	struct device_node *trng = NULL;
+	struct hwrng *rng = NULL;
+	int err;
+
+	/* Find the TRNG device node and map it */
+	trng = of_find_matching_node(NULL, ppc4xx_trng_match);
+	if (!trng || !of_device_is_available(trng))
+		return;
+
+	dev->trng_base = of_iomap(trng, 0);
+	of_node_put(trng);
+	if (!dev->trng_base)
+		goto err_out;
+
+	rng = kzalloc(sizeof(*rng), GFP_KERNEL);
+	if (!rng)
+		goto err_out;
+
+	rng->name = MODULE_NAME;
+	rng->data_present = ppc4xx_trng_data_present;
+	rng->data_read = ppc4xx_trng_data_read;
+	rng->priv = (unsigned long) dev;
+	core_dev->trng = rng;
+	ppc4xx_trng_enable(dev, true);
+	out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
+	err = devm_hwrng_register(core_dev->device, core_dev->trng);
+	if (err) {
+		ppc4xx_trng_enable(dev, false);
+		dev_err(core_dev->device, "failed to register hwrng (%d).\n",
+			err);
+		goto err_out;
+	}
+	return;
+
+err_out:
+	of_node_put(trng);
+	iounmap(dev->trng_base);
+	kfree(rng);
+	dev->trng_base = NULL;
+	core_dev->trng = NULL;
+}
+
+void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev)
+{
+	if (core_dev && core_dev->trng) {
+		struct crypto4xx_device *dev = core_dev->dev;
+
+		devm_hwrng_unregister(core_dev->device, core_dev->trng);
+		ppc4xx_trng_enable(dev, false);
+		iounmap(dev->trng_base);
+		kfree(core_dev->trng);
+	}
+}
+
+MODULE_ALIAS("ppc4xx_rng");
-- 
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