// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Generic PowerPC 44x RNG driver
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*
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* Copyright 2011 IBM Corporation
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/hw_random.h>
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#include <linux/delay.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/io.h>
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#include "crypto4xx_core.h"
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#include "crypto4xx_trng.h"
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#include "crypto4xx_reg_def.h"
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#define PPC4XX_TRNG_CTRL 0x0008
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#define PPC4XX_TRNG_CTRL_DALM 0x20
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#define PPC4XX_TRNG_STAT 0x0004
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#define PPC4XX_TRNG_STAT_B 0x1
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#define PPC4XX_TRNG_DATA 0x0000
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static int ppc4xx_trng_data_present(struct hwrng *rng, int wait)
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{
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struct crypto4xx_device *dev = (void *)rng->priv;
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int busy, i, present = 0;
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for (i = 0; i < 20; i++) {
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busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) &
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PPC4XX_TRNG_STAT_B);
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if (!busy || !wait) {
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present = 1;
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break;
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}
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udelay(10);
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}
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return present;
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}
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static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data)
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{
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struct crypto4xx_device *dev = (void *)rng->priv;
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*data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA);
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return 4;
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}
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static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable)
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{
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u32 device_ctrl;
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device_ctrl = readl(dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
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if (enable)
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device_ctrl |= PPC4XX_TRNG_EN;
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else
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device_ctrl &= ~PPC4XX_TRNG_EN;
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writel(device_ctrl, dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
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}
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static const struct of_device_id ppc4xx_trng_match[] = {
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{ .compatible = "ppc4xx-rng", },
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{ .compatible = "amcc,ppc460ex-rng", },
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{ .compatible = "amcc,ppc440epx-rng", },
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{},
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};
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void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev)
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{
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struct crypto4xx_device *dev = core_dev->dev;
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struct device_node *trng = NULL;
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struct hwrng *rng = NULL;
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int err;
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/* Find the TRNG device node and map it */
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trng = of_find_matching_node(NULL, ppc4xx_trng_match);
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if (!trng || !of_device_is_available(trng)) {
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of_node_put(trng);
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return;
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}
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dev->trng_base = of_iomap(trng, 0);
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of_node_put(trng);
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if (!dev->trng_base)
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goto err_out;
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rng = kzalloc(sizeof(*rng), GFP_KERNEL);
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if (!rng)
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goto err_out;
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rng->name = KBUILD_MODNAME;
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rng->data_present = ppc4xx_trng_data_present;
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rng->data_read = ppc4xx_trng_data_read;
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rng->priv = (unsigned long) dev;
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core_dev->trng = rng;
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ppc4xx_trng_enable(dev, true);
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out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
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err = devm_hwrng_register(core_dev->device, core_dev->trng);
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if (err) {
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ppc4xx_trng_enable(dev, false);
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dev_err(core_dev->device, "failed to register hwrng (%d).\n",
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err);
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goto err_out;
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}
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return;
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err_out:
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iounmap(dev->trng_base);
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kfree(rng);
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dev->trng_base = NULL;
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core_dev->trng = NULL;
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}
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void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev)
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{
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if (core_dev && core_dev->trng) {
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struct crypto4xx_device *dev = core_dev->dev;
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devm_hwrng_unregister(core_dev->device, core_dev->trng);
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ppc4xx_trng_enable(dev, false);
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iounmap(dev->trng_base);
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kfree(core_dev->trng);
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}
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}
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MODULE_ALIAS("ppc4xx_rng");
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