105 lines
2.1 KiB
C
105 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 MediaTek Inc.
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*/
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#include <linux/module.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/of.h>
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#include <linux/arm-smccc.h>
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#include <linux/soc/mediatek/mtk_sip_svc.h>
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#define PFX KBUILD_MODNAME ": "
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#define MT67XX_RNG_MAGIC 0x74726e67
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#define SMC_RET_NUM 4
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struct mt67xx_rng_priv {
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struct hwrng rng;
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};
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static void __rng_sec_read(uint32_t *val)
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{
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struct arm_smccc_res res;
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arm_smccc_smc(MTK_SIP_KERNEL_GET_RND,
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MT67XX_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res);
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val[0] = res.a0;
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val[1] = res.a1;
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val[2] = res.a2;
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val[3] = res.a3;
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}
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static int mt67xx_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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int i, retval = 0;
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uint32_t val[4] = {0};
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size_t get_rnd_size = sizeof(u32) * SMC_RET_NUM;
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if (!buf) {
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pr_err("%s, buf is NULL\n", __func__);
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return -EFAULT;
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}
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while (max >= get_rnd_size) {
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__rng_sec_read(val);
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for (i = 0; i < SMC_RET_NUM; i++) {
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*(u32 *)buf = val[i];
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buf += sizeof(u32);
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}
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retval += get_rnd_size;
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max -= get_rnd_size;
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}
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return retval;
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}
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static int mt67xx_rng_probe(struct platform_device *pdev)
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{
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int ret;
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struct mt67xx_rng_priv *priv;
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pr_info(PFX "driver registered\n");
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->rng.name = KBUILD_MODNAME;
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priv->rng.read = mt67xx_rng_read;
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priv->rng.priv = (unsigned long)&pdev->dev;
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priv->rng.quality = 900;
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ret = devm_hwrng_register(&pdev->dev, &priv->rng);
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if (ret) {
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dev_err(&pdev->dev, "failed to register rng device: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static const struct of_device_id mt67xx_rng_match[] = {
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{ .compatible = "mediatek,mt67xx-rng", },
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{}
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};
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MODULE_DEVICE_TABLE(of, mt67xx_rng_match);
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static struct platform_driver mt67xx_rng_driver = {
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.probe = mt67xx_rng_probe,
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.driver = {
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.name = KBUILD_MODNAME,
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.owner = THIS_MODULE,
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.of_match_table = mt67xx_rng_match,
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},
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};
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module_platform_driver(mt67xx_rng_driver);
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MODULE_DESCRIPTION("Mediatek MT67XX Random Number Generator Driver");
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MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
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MODULE_LICENSE("GPL");
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