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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=exspM70xAUFqsS5uuEZMaA6Qso1vwe3UWsXOVI+vEOYSgkgxZsgmuUbtWjvSy1zzUX LkYfF1pAlwts8WiqC9zuxPWEnnz40Wcy+AbNYQPGqWoun9zrQ8yk3OhOX86WAI9/Ep7T AIhwIKuxxzhdBMlucEb4oMHTRs3XyyL/1M8xcY96tBsBLjg776yt1Y5DukrzQKKbDAHg UNCC1FGZcn03N2jIwa0RcXX0g5OrjL3NYo3QwUfaBLmBS2quHadaORVv30b6tccqsE5M TmGi0Es+sX005NOb4A9XlvG6nxJz3ElZUwrX2c13LuvK65O1vZuYpNLz4n1gkdUUZjf+ dfsg== X-Gm-Message-State: APjAAAVN4BeaeP19x1utkpH3IsLl99Q5aIefg9ILPZRg1NKfgM0d8amC x4+S86wzW0ydP/GoGqtEO1e/0ixaNadwc8I5HmPCDg== 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191127_070338_281747_E7AF85A1 X-CRM114-Status: GOOD ( 23.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Devicetree List , Herbert Xu , wsd_upstream@mediatek.com, Sean Wang , Linux Kernel Mailing List , Rob Herring , Crystal Guo , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Matt Mackall , Matthias Brugger , "moderated list:ARM/Mediatek SoC support" , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel