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Thu, 28 Nov 2019 07:13:00 -0800 Received: from MTKMBS02N2.mediatek.inc (172.21.101.101) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 28 Nov 2019 07:03:06 -0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 28 Nov 2019 23:02:41 +0800 Received: from [172.21.77.33] (172.21.77.33) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Thu, 28 Nov 2019 23:02:47 +0800 Message-ID: <1574953375.6465.8.camel@mtkswgap22> Subject: Re: [PATCH v5 3/3] hwrng: add mtk-sec-rng driver From: Neal Liu To: Ard Biesheuvel Date: Thu, 28 Nov 2019 23:02:55 +0800 In-Reply-To: References: <1574864578-467-1-git-send-email-neal.liu@mediatek.com> <1574864578-467-4-git-send-email-neal.liu@mediatek.com> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: BF5CA6FDD2FC2CB9BAB461AD12AAAA406649CF42595E3D02608CD659FD0140C62000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191128_071310_003097_93B66DFD X-CRM114-Status: GOOD ( 25.64 ) X-BeenThere: linux-mediatek@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 , Sean Wang , "moderated list:ARM/Mediatek SoC support" , Linux Kernel Mailing List , Rob Herring , Neal Liu , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Matt Mackall , Matthias Brugger , Crystal Guo =?UTF-8?Q?=28=E9=83=AD=E6=99=B6=29?= , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Wed, 2019-11-27 at 23:03 +0800, Ard Biesheuvel wrote: > 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? > The smc call is supported in both ARMv7 & ARMv8 architectures.But yes, it should check hardware status before assigning it. We would like to check that if hardware is something wrong, all return value will be zero. ex: if (!res.a0 && !res.a1 && !res.a2 && !res.a3) return false; > > + val[0] = res.a0; > > + val[1] = res.a1; > > + val[2] = res.a2; > > + val[3] = res.a3; return true; > > +} > > + > > +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-mediatek mailing list > Linux-mediatek@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-mediatek _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek