summaryrefslogtreecommitdiff
path: root/drivers/crypto/amcc/crypto4xx_trng.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/crypto/amcc/crypto4xx_trng.c')
-rw-r--r--drivers/crypto/amcc/crypto4xx_trng.c131
1 files changed, 131 insertions, 0 deletions
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");