/* * 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");