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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Generic PowerPC 44x RNG driver4 *5 * Copyright 2011 IBM Corporation6 */7 8#include <linux/module.h>9#include <linux/kernel.h>10#include <linux/interrupt.h>11#include <linux/platform_device.h>12#include <linux/hw_random.h>13#include <linux/delay.h>14#include <linux/of_address.h>15#include <linux/of_platform.h>16#include <linux/io.h>17 18#include "crypto4xx_core.h"19#include "crypto4xx_trng.h"20#include "crypto4xx_reg_def.h"21 22#define PPC4XX_TRNG_CTRL 0x000823#define PPC4XX_TRNG_CTRL_DALM 0x2024#define PPC4XX_TRNG_STAT 0x000425#define PPC4XX_TRNG_STAT_B 0x126#define PPC4XX_TRNG_DATA 0x000027 28static int ppc4xx_trng_data_present(struct hwrng *rng, int wait)29{30 struct crypto4xx_device *dev = (void *)rng->priv;31 int busy, i, present = 0;32 33 for (i = 0; i < 20; i++) {34 busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) &35 PPC4XX_TRNG_STAT_B);36 if (!busy || !wait) {37 present = 1;38 break;39 }40 udelay(10);41 }42 return present;43}44 45static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data)46{47 struct crypto4xx_device *dev = (void *)rng->priv;48 *data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA);49 return 4;50}51 52static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable)53{54 u32 device_ctrl;55 56 device_ctrl = readl(dev->ce_base + CRYPTO4XX_DEVICE_CTRL);57 if (enable)58 device_ctrl |= PPC4XX_TRNG_EN;59 else60 device_ctrl &= ~PPC4XX_TRNG_EN;61 writel(device_ctrl, dev->ce_base + CRYPTO4XX_DEVICE_CTRL);62}63 64static const struct of_device_id ppc4xx_trng_match[] = {65 { .compatible = "ppc4xx-rng", },66 { .compatible = "amcc,ppc460ex-rng", },67 { .compatible = "amcc,ppc440epx-rng", },68 {},69};70 71void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev)72{73 struct crypto4xx_device *dev = core_dev->dev;74 struct device_node *trng = NULL;75 struct hwrng *rng = NULL;76 int err;77 78 /* Find the TRNG device node and map it */79 trng = of_find_matching_node(NULL, ppc4xx_trng_match);80 if (!trng || !of_device_is_available(trng)) {81 of_node_put(trng);82 return;83 }84 85 dev->trng_base = of_iomap(trng, 0);86 of_node_put(trng);87 if (!dev->trng_base)88 goto err_out;89 90 rng = kzalloc(sizeof(*rng), GFP_KERNEL);91 if (!rng)92 goto err_out;93 94 rng->name = KBUILD_MODNAME;95 rng->data_present = ppc4xx_trng_data_present;96 rng->data_read = ppc4xx_trng_data_read;97 rng->priv = (unsigned long) dev;98 core_dev->trng = rng;99 ppc4xx_trng_enable(dev, true);100 out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);101 err = devm_hwrng_register(core_dev->device, core_dev->trng);102 if (err) {103 ppc4xx_trng_enable(dev, false);104 dev_err(core_dev->device, "failed to register hwrng (%d).\n",105 err);106 goto err_out;107 }108 return;109 110err_out:111 iounmap(dev->trng_base);112 kfree(rng);113 dev->trng_base = NULL;114 core_dev->trng = NULL;115}116 117void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev)118{119 if (core_dev && core_dev->trng) {120 struct crypto4xx_device *dev = core_dev->dev;121 122 devm_hwrng_unregister(core_dev->device, core_dev->trng);123 ppc4xx_trng_enable(dev, false);124 iounmap(dev->trng_base);125 kfree(core_dev->trng);126 }127}128 129MODULE_ALIAS("ppc4xx_rng");130