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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A507C433F5 for ; Tue, 8 Mar 2022 07:56:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344707AbiCHH5A (ORCPT ); Tue, 8 Mar 2022 02:57:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344706AbiCHH4z (ORCPT ); Tue, 8 Mar 2022 02:56:55 -0500 Received: from isilmar-4.linta.de (isilmar-4.linta.de [136.243.71.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 257FB3E5DC; Mon, 7 Mar 2022 23:55:58 -0800 (PST) X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES X-isilmar-external: YES Received: from owl.dominikbrodowski.net (owl.brodo.linta [10.2.0.111]) by isilmar-4.linta.de (Postfix) with ESMTPSA id 4FA7B2013FA; Tue, 8 Mar 2022 07:55:55 +0000 (UTC) Received: by owl.dominikbrodowski.net (Postfix, from userid 1000) id DF9BF801EA; Tue, 8 Mar 2022 08:55:50 +0100 (CET) Date: Tue, 8 Mar 2022 08:55:50 +0100 From: Dominik Brodowski To: conor.dooley@microchip.com Cc: mpm@selenic.com, herbert@gondor.apana.org.au, lewis.hanly@microchip.com, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 1/2] hwrng: mpfs - add polarfire soc hwrng support Message-ID: References: <20220307154023.813158-1-conor.dooley@microchip.com> <20220307154023.813158-2-conor.dooley@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220307154023.813158-2-conor.dooley@microchip.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Mon, Mar 07, 2022 at 03:40:23PM +0000 schrieb conor.dooley@microchip.com: > From: Conor Dooley > > Add a driver to access the hardware random number generator on the > Polarfire SoC. The hwrng can only be accessed via the system controller, > so use the mailbox interface the system controller exposes to access the > hwrng. > > Signed-off-by: Conor Dooley > --- > drivers/char/hw_random/Kconfig | 13 ++++ > drivers/char/hw_random/Makefile | 1 + > drivers/char/hw_random/mpfs-rng.c | 103 ++++++++++++++++++++++++++++++ > 3 files changed, 117 insertions(+) > create mode 100644 drivers/char/hw_random/mpfs-rng.c > > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig > index 9704963f9d50..69f1fd538589 100644 > --- a/drivers/char/hw_random/Kconfig > +++ b/drivers/char/hw_random/Kconfig > @@ -385,6 +385,19 @@ config HW_RANDOM_PIC32 > > If unsure, say Y. > > +config HW_RANDOM_POLARFIRE_SOC > + tristate "Microchip PolarFire SoC Random Number Generator support" > + depends on HW_RANDOM && POLARFIRE_SOC_SYS_CTRL > + help > + This driver provides kernel-side support for the Random Number > + Generator hardware found on PolarFire SoC (MPFS). > + > + To compile this driver as a module, choose M here. The > + module will be called mfps_rng. > + > + If unsure, say N. > + > + > config HW_RANDOM_MESON > tristate "Amlogic Meson Random Number Generator support" > depends on HW_RANDOM > diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile > index 584d47ba32f7..3e948cf04476 100644 > --- a/drivers/char/hw_random/Makefile > +++ b/drivers/char/hw_random/Makefile > @@ -46,3 +46,4 @@ obj-$(CONFIG_HW_RANDOM_CCTRNG) += cctrng.o > obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphera-trng.o > obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o > obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o > +obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o > diff --git a/drivers/char/hw_random/mpfs-rng.c b/drivers/char/hw_random/mpfs-rng.c > new file mode 100644 > index 000000000000..a103c765d021 > --- /dev/null > +++ b/drivers/char/hw_random/mpfs-rng.c > @@ -0,0 +1,103 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Microchip PolarFire SoC (MPFS) hardware random driver > + * > + * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved. > + * > + * Author: Conor Dooley > + */ > + > +#include > +#include > +#include > +#include > + > +#define CMD_OPCODE 0x21 > +#define CMD_DATA_SIZE 0U > +#define CMD_DATA NULL > +#define MBOX_OFFSET 0U > +#define RESP_OFFSET 0U > +#define RNG_RESP_BYTES 32U > + > +struct mpfs_rng { > + struct mpfs_sys_controller *sys_controller; > + struct hwrng rng; > +}; > + > +static int mpfs_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > +{ > + struct mpfs_rng *rng_priv = container_of(rng, struct mpfs_rng, rng); > + u32 response_msg[RNG_RESP_BYTES / sizeof(u32)]; > + unsigned int count = 0, copy_size_bytes; > + int ret; > + > + struct mpfs_mss_response response = { > + .resp_status = 0U, > + .resp_msg = (u32 *)response_msg, > + .resp_size = RNG_RESP_BYTES > + }; > + struct mpfs_mss_msg msg = { > + .cmd_opcode = CMD_OPCODE, > + .cmd_data_size = CMD_DATA_SIZE, > + .response = &response, > + .cmd_data = CMD_DATA, > + .mbox_offset = MBOX_OFFSET, > + .resp_offset = RESP_OFFSET > + }; > + > + while (count < max) { > + ret = mpfs_blocking_transaction(rng_priv->sys_controller, &msg); > + if (ret) > + return ret; > + > + copy_size_bytes = max - count > RNG_RESP_BYTES ? RNG_RESP_BYTES : max - count; > + memcpy(buf + count, response_msg, copy_size_bytes); > + > + count += copy_size_bytes; > + if (!wait) > + break; > + } > + > + return count; > +} > + > +static int mpfs_rng_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct mpfs_rng *rng_priv; > + int ret; > + > + rng_priv = devm_kzalloc(dev, sizeof(*rng_priv), GFP_KERNEL); > + if (!rng_priv) > + return -ENOMEM; > + > + rng_priv->sys_controller = mpfs_sys_controller_get(&pdev->dev); > + if (IS_ERR(rng_priv->sys_controller)) > + return dev_err_probe(dev, PTR_ERR(rng_priv->sys_controller), > + "Failed to register system controller hwrng sub device\n"); > + > + rng_priv->rng.read = mpfs_rng_read; > + rng_priv->rng.name = pdev->name; Is there also some quality estimation, or should this hwrng only be trusted if it passes validation by userspace? Thanks, Dominik