diff options
Diffstat (limited to 'drivers/crypto/amcc/crypto4xx_trng.c')
| -rw-r--r-- | drivers/crypto/amcc/crypto4xx_trng.c | 131 |
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"); |