From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB630C43215 for ; Wed, 27 Nov 2019 15:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A01420665 for ; Wed, 27 Nov 2019 15:03:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="dzr5XA0L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726655AbfK0PDk (ORCPT ); Wed, 27 Nov 2019 10:03:40 -0500 Received: from mail-wr1-f66.google.com ([209.85.221.66]:37316 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726926AbfK0PDj (ORCPT ); Wed, 27 Nov 2019 10:03:39 -0500 Received: by mail-wr1-f66.google.com with SMTP id g7so6375672wrw.4 for ; Wed, 27 Nov 2019 07:03:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TPSdYWPsxVaZZs7XMbf85yoh9+QLbbbAn0Y9s5Tq39Q=; b=dzr5XA0LFhxUEA80Hf1lH8eKQRxhAaPKRfQiWhNn8VfXmjd1dKLvUcRAjfxqg15rXo J/kLBjqWfKAj8mI8unG/clL1JPoxxNDp3NjZ+IfZlSZh9Pzv255gzi6juBMbZg4wl6za WMODD+imnxnqCL7Hw+GbNSTbuvaiW1jt8f0hiLtMnQXlBa1eT9Q+ZQBBw2oRHYGtWSOn WXA6jRvj2WeRX8kLUlQ4Amb9K0l+VuYdBsCDRgHm39fdFdmcc56MneivQbubnfKZf/6Z ZwaxVz51Prja2DpSAF81nSIPyfl4T1I6vLIqtaZ8AMxxA/a2OUmbxTru94LfV9P6Iyow 1sbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TPSdYWPsxVaZZs7XMbf85yoh9+QLbbbAn0Y9s5Tq39Q=; b=hV9Gxp7nyiaEvzSAftKsrd8Z7E6W3mO9To4EfF7OkSetDA/PINXRzk7SeWxNP4FHQ5 RF0Y55YE6wB0GZF8YgbjJjtdQnKQ8clemMzPCUVPyNVdHQtU7dYRghhdQLthLKwehXXN eNDu2iaKWiMjuA3tzbFrH9FaSFbYPkwYOsgvp3Botd9cEqL4D0GrQMkf67PyhBMttG55 N9ANRdgmK3Cc45U5krLPbf+Ul72v1kE2qwN71bm8Bz75uhvxLXQ9GtT6QN8+uKTRv1DZ 5rOjhTEMIKLdBrYQlMUUCSPTpR3WddT0fQ0h0lhIRZe7RuVy5k6t8gjwErp4hmtvaD/3 dOMw== X-Gm-Message-State: APjAAAVC7j9XyywFCre6GWPhMRC65pz8WLd03ncqUq10GIgZe4rps68j 56tsBXDQBzVdAdm6welUeKEjjC8vjvgBf5l8HaC+EQ== X-Google-Smtp-Source: APXvYqxIKLa2LPH2JUMg8rKd9cLtzDfM0oUfFtHHu1JmdjPCxQB1qigIXkCD7VJIQ76ZLrSxC6WbuHL3ePcRzmrpqUY= X-Received: by 2002:a5d:6652:: with SMTP id f18mr1250887wrw.246.1574867015749; Wed, 27 Nov 2019 07:03:35 -0800 (PST) MIME-Version: 1.0 References: <1574864578-467-1-git-send-email-neal.liu@mediatek.com> <1574864578-467-4-git-send-email-neal.liu@mediatek.com> In-Reply-To: <1574864578-467-4-git-send-email-neal.liu@mediatek.com> From: Ard Biesheuvel Date: Wed, 27 Nov 2019 16:03:24 +0100 Message-ID: Subject: Re: [PATCH v5 3/3] hwrng: add mtk-sec-rng driver To: Neal Liu Cc: Matt Mackall , Herbert Xu , Rob Herring , Mark Rutland , Matthias Brugger , Sean Wang , Crystal Guo , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Devicetree List , linux-arm-kernel , "moderated list:ARM/Mediatek SoC support" , Linux Kernel Mailing List , wsd_upstream@mediatek.com Content-Type: text/plain; charset="UTF-8" Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, 27 Nov 2019 at 15:23, Neal Liu wrote: > > For MediaTek SoCs on ARMv8 with TrustZone enabled, peripherals like > entropy sources is not accessible from normal world (linux) and > rather accessible from secure world (ATF/TEE) only. This driver aims > to provide a generic interface to ATF rng service. > > Signed-off-by: Neal Liu > --- > drivers/char/hw_random/Kconfig | 16 ++++++ > drivers/char/hw_random/Makefile | 1 + > drivers/char/hw_random/mtk-sec-rng.c | 103 ++++++++++++++++++++++++++++++++++ > 3 files changed, 120 insertions(+) > create mode 100644 drivers/char/hw_random/mtk-sec-rng.c > > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig > index 25a7d8f..f08c852 100644 > --- a/drivers/char/hw_random/Kconfig > +++ b/drivers/char/hw_random/Kconfig > @@ -398,6 +398,22 @@ config HW_RANDOM_MTK > > If unsure, say Y. > > +config HW_RANDOM_MTK_SEC > + tristate "MediaTek Security Random Number Generator support" > + depends on HW_RANDOM > + depends on ARCH_MEDIATEK || COMPILE_TEST > + default HW_RANDOM > + help > + This driver provides kernel-side support for the Random Number > + Generator hardware found on MediaTek SoCs. The difference with > + mtk-rng is the Random Number Generator hardware is secure > + access only. > + > + To compile this driver as a module, choose M here. the > + module will be called mtk-sec-rng. > + > + If unsure, say Y. > + > config HW_RANDOM_S390 > tristate "S390 True Random Number Generator support" > depends on S390 > diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile > index 7c9ef4a..bee5412 100644 > --- a/drivers/char/hw_random/Makefile > +++ b/drivers/char/hw_random/Makefile > @@ -36,6 +36,7 @@ obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o > obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o > obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o > obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o > +obj-$(CONFIG_HW_RANDOM_MTK_SEC) += mtk-sec-rng.o > obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o > obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o > obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o > diff --git a/drivers/char/hw_random/mtk-sec-rng.c b/drivers/char/hw_random/mtk-sec-rng.c > new file mode 100644 > index 0000000..69ddeca > --- /dev/null > +++ b/drivers/char/hw_random/mtk-sec-rng.c > @@ -0,0 +1,103 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 MediaTek Inc. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define MTK_SEC_RNG_MAGIC 0x74726e67 > +#define SMC_RET_NUM 4 > +#define MTK_SEC_RND_SIZE (sizeof(u32) * SMC_RET_NUM) > + > +static void mtk_sec_get_rnd(uint32_t *val) > +{ > + struct arm_smccc_res res; > + > + arm_smccc_smc(MTK_SIP_KERNEL_GET_RND, > + MTK_SEC_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res); > + Can this call never fail? How does the firmware signal that something is wrong with the underlying hardware? > + val[0] = res.a0; > + val[1] = res.a1; > + val[2] = res.a2; > + val[3] = res.a3; > +} > + > +static int mtk_sec_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > +{ > + u32 val[4] = {0}; > + int retval = 0; > + int i; > + > + while (max >= MTK_SEC_RND_SIZE) { > + mtk_sec_get_rnd(val); > + > + for (i = 0; i < SMC_RET_NUM; i++) { > + *(u32 *)buf = val[i]; > + buf += sizeof(u32); > + } > + > + retval += MTK_SEC_RND_SIZE; > + max -= MTK_SEC_RND_SIZE; > + } > + > + return retval; > +} > + > +static struct hwrng mtk_sec_rng = { > + .name = "mtk_sec_rng", > + .read = mtk_sec_rng_read, > + .quality = 900, > +}; > + > +static int mtk_sec_rng_probe(void) > +{ > + int ret; > + > + ret = hwrng_register(&mtk_sec_rng); > + if (ret) { > + pr_err("Failed to register rng device: %d\n", ret); > + return ret; > + } > + > + return 0; > +} > + > +static int __init mtk_sec_rng_driver_init(void) > +{ > + struct device_node *fw_np; > + struct device_node *np; > + const char *method; > + > + fw_np = of_find_node_by_name(NULL, "firmware"); > + if (!fw_np) > + return -ENODEV; > + > + np = of_find_compatible_node(fw_np, NULL, "mediatek,mtk-sec-rng"); > + if (!np) > + return -ENODEV; > + > + if (of_property_read_string(np, "method", &method)) > + return -ENXIO; > + > + if (strncmp("smc", method, strlen("smc"))) > + return -EINVAL; > + > + return mtk_sec_rng_probe(); > +} > + > +static void __exit mtk_sec_rng_driver_exit(void) > +{ > + hwrng_unregister(&mtk_sec_rng); > +} > + > +module_init(mtk_sec_rng_driver_init); > +module_exit(mtk_sec_rng_driver_exit); > + > +MODULE_DESCRIPTION("MediaTek Security Random Number Generator Driver"); > +MODULE_AUTHOR("Neal Liu "); > +MODULE_LICENSE("GPL"); > -- > 1.7.9.5