From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 13 Mar 2024 12:05:51 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rkMQh-004I1z-1L for lore@lore.pengutronix.de; Wed, 13 Mar 2024 12:05:51 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rkMQg-0000pe-Hn for lore@pengutronix.de; Wed, 13 Mar 2024 12:05:51 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VZQQCn8lvK3i7hCEbIgqLh8LzTVMTnt1SkOG6dxQMss=; b=FTAACU/Pyhxcg5e/Kt1H6MhpY4 Bhy+tS9MWcrNC7LDExyvcvUwZpBDCDGpF8443uMNIpf/s0iEYHi8+l029e9szxZjAqiuRxuxFfjda N3xV7/9crvHBd9Nng/lpLOYypukouLG9jQNJJ1yHZ5Dpq9c/oVinAn3GzRHzkM3WpuAkZ+XB+Zrdx 3PMcammDLVBIcawUPs5dnprWsyHh1fEhI2Hn1xGO8YEpzkBcrjurG62DhAZB2qJ//5LmVc89bTP2q N6hNoSOQAsL/JADMdOkNM1fwnKxkcgKJI/YYmHM5oX/Hab+G1BBsB1XU1KOiqHbJgQLY456SQNzlE CRRmLcZA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rkMPy-00000009oJN-0qJk; Wed, 13 Mar 2024 11:05:06 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rkMOX-00000009nDA-2U3Z for barebox@lists.infradead.org; Wed, 13 Mar 2024 11:03:39 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rkMOW-0007Av-5b; Wed, 13 Mar 2024 12:03:36 +0100 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rkMOV-00662P-PC; Wed, 13 Mar 2024 12:03:35 +0100 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1rkMHg-004FrF-0y; Wed, 13 Mar 2024 11:56:32 +0100 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 13 Mar 2024 11:56:30 +0100 Message-Id: <20240313105631.686778-12-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240313105631.686778-1-a.fatoum@pengutronix.de> References: <20240313105631.686778-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240313_040337_751349_4CAC45CB X-CRM114-Status: GOOD ( 27.25 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.6 required=4.0 tests=AWL,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 11/12] hw_random: add timeriomem_rng driver X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) To enable proper hardening with stack protector, add support for the RNGs with the interface of a single memory mapped 32-bit register. This can possibly come in handy for the web demo. Signed-off-by: Ahmad Fatoum --- drivers/hw_random/Kconfig | 7 ++ drivers/hw_random/Makefile | 1 + drivers/hw_random/timeriomem-rng.c | 145 +++++++++++++++++++++++++++++ 3 files changed, 153 insertions(+) create mode 100644 drivers/hw_random/timeriomem-rng.c diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig index 58df6a75443c..bd1ac89ad37d 100644 --- a/drivers/hw_random/Kconfig +++ b/drivers/hw_random/Kconfig @@ -8,6 +8,13 @@ menuconfig HWRNG if HWRNG +config HW_RANDOM_TIMERIOMEM + tristate "Timer IOMEM HW Random Number Generator support" + help + This driver provides barebox support for a generic Random + Number Generator used by reading a 'dumb' iomem address that + is to be read no faster than, for example, once a second. + config HWRNG_MXC_RNGC tristate "Freescale i.MX RNGC Random Number Generator" depends on ARCH_IMX25 || ARCH_IMX35 || ARCH_IMX53 || COMPILE_TEST diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile index 8658d4e52521..32b02fa211ac 100644 --- a/drivers/hw_random/Makefile +++ b/drivers/hw_random/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_HW_RANDOM_ATMEL) += atmel-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o obj-$(CONFIG_HW_RANDOM_ROCKCHIP) += rockchip-rng.o +obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o diff --git a/drivers/hw_random/timeriomem-rng.c b/drivers/hw_random/timeriomem-rng.c new file mode 100644 index 000000000000..8d4705830653 --- /dev/null +++ b/drivers/hw_random/timeriomem-rng.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/char/hw_random/timeriomem-rng.c + * + * Copyright (C) 2009 Alexander Clouter + * + * Derived from drivers/char/hw_random/omap-rng.c + * Copyright 2005 (c) MontaVista Software, Inc. + * Author: Deepak Saxena + * + * Overview: + * This driver is useful for platforms that have an IO range that provides + * periodic random data from a single IO memory address. All the platform + * has to do is provide the address and 'wait time' that new data becomes + * available. + * + * TODO: add support for reading sizes other than 32bits and masking + */ + +#include +#include +#include +#include +#include +#include + +struct timeriomem_rng_private { + void __iomem *io_base; + + ktime_t period; + ktime_t next_read; + + struct hwrng rng_ops; +}; + +static int timeriomem_rng_read(struct hwrng *hwrng, void *data, + size_t max, bool wait) +{ + struct timeriomem_rng_private *priv = + container_of(hwrng, struct timeriomem_rng_private, rng_ops); + int retval = 0; + int period_us = ktime_to_us(priv->period); + ktime_t now = ktime_get(); + + /* + * There may not have been enough time for new data to be generated + * since the last request. If the caller doesn't want to wait, let them + * bail out. Otherwise, wait for the completion. If the new data has + * already been generated, the completion should already be available. + */ + if (ktime_before(now, priv->next_read)) { + if (!wait) + return 0; + + udelay(ktime_to_us(ktime_sub(priv->next_read, now))); + } + + do { + /* + * After the first read, all additional reads will need to wait + * for the RNG to generate new data. Since the period can have + * a wide range of values (1us to 1s have been observed), allow + * for 1% tolerance in the sleep time rather than a fixed value. + */ + if (retval > 0) + udelay(period_us); + + *(u32 *)data = readl(priv->io_base); + retval += sizeof(u32); + data += sizeof(u32); + max -= sizeof(u32); + } while (wait && max > sizeof(u32)); + + /* + * Block any new callers until the RNG has had time to generate new + * data. + */ + priv->next_read = ktime_add(ktime_get(), priv->period); + + return retval; +} + +static int timeriomem_rng_probe(struct device *dev) +{ + struct timeriomem_rng_private *priv; + struct resource *res; + int err = 0; + int period; + + /* Allocate memory for the device structure (and zero it) */ + priv = devm_kzalloc(dev, + sizeof(struct timeriomem_rng_private), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->io_base = dev_platform_get_and_ioremap_resource(dev, 0, &res); + if (IS_ERR(priv->io_base)) + return PTR_ERR(priv->io_base); + + if (res->start % 4 != 0 || resource_size(res) < 4) { + dev_err(dev, + "address must be at least four bytes wide and 32-bit aligned\n"); + return -EINVAL; + } + + if (of_property_read_u32(dev->of_node, "period", &period)) + return dev_err_probe(dev, -EINVAL, "missing period\n"); + + priv->period = ns_to_ktime(period * NSEC_PER_USEC); + + priv->rng_ops.name = dev_name(dev); + priv->rng_ops.read = timeriomem_rng_read; + + /* Assume random data is already available. */ + priv->next_read = ktime_get(); + + err = hwrng_register(dev, &priv->rng_ops); + if (err) { + dev_err(dev, "problem registering\n"); + return err; + } + + dev_info(dev, "32bits from 0x%p @ %dus\n", + priv->io_base, period); + + return 0; +} + +static const struct of_device_id timeriomem_rng_match[] = { + { .compatible = "timeriomem_rng" }, + {}, +}; +MODULE_DEVICE_TABLE(of, timeriomem_rng_match); + +static struct driver timeriomem_rng_driver = { + .name = "timeriomem_rng", + .of_match_table = timeriomem_rng_match, + .probe = timeriomem_rng_probe, +}; + +device_platform_driver(timeriomem_rng_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alexander Clouter "); +MODULE_DESCRIPTION("Timer IOMEM H/W RNG driver"); -- 2.39.2