From patchwork Tue Apr 11 18:08:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 9675913 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CFE6460382 for ; Tue, 11 Apr 2017 18:09:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C8E4626B41 for ; Tue, 11 Apr 2017 18:09:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BBD9128548; Tue, 11 Apr 2017 18:09:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 20E1828545 for ; Tue, 11 Apr 2017 18:09:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753214AbdDKSJH (ORCPT ); Tue, 11 Apr 2017 14:09:07 -0400 Received: from mail.kernel.org ([198.145.29.136]:50374 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752580AbdDKSJC (ORCPT ); Tue, 11 Apr 2017 14:09:02 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E132520173; Tue, 11 Apr 2017 18:08:59 +0000 (UTC) Received: from localhost.localdomain (pub082136089155.dh-hfc.datazug.ch [82.136.89.155]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C98252017E; Tue, 11 Apr 2017 18:08:53 +0000 (UTC) From: Krzysztof Kozlowski To: James Hogan , Matt Mackall , Herbert Xu , Kukjin Kim , Krzysztof Kozlowski , Javier Martinez Canillas , "David S. Miller" , Dave Airlie , David Airlie , Bernie Thompson , Bartlomiej Zolnierkiewicz , Greg Kroah-Hartman , PrasannaKumar Muralidharan , linux-kernel@vger.kernel.org, linux-metag@vger.kernel.org, linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, =?UTF-8?q?Stephan=20M=C3=BCller?= Subject: [PATCH v5 2/2] crypto: hw_random - Add new Exynos RNG driver Date: Tue, 11 Apr 2017 20:08:35 +0200 Message-Id: <20170411180835.8928-3-krzk@kernel.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170411180835.8928-1-krzk@kernel.org> References: <20170411180835.8928-1-krzk@kernel.org> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Replace existing hw_ranndom/exynos-rng driver with a new, reworked one. This is a driver for pseudo random number generator block which on Exynos4 chipsets must be seeded with some value. On newer Exynos5420 chipsets it might seed itself from true random number generator block but this is not implemented yet. New driver is a complete rework to use the crypto ALGAPI instead of hw_random API. Rationale for the change: 1. hw_random interface is for true RNG devices. 2. The old driver was seeding itself with jiffies which is not a reliable source for randomness. 3. Device generates five random 32-bit numbers in each pass but old driver was returning only one 32-bit number thus its performance was reduced. Compatibility with DeviceTree bindings is preserved. New driver does not use runtime power management but manually enables and disables the clock when needed. This is preferred approach because using runtime PM just to toggle clock is huge overhead. Another difference is reseeding itself with generated random data periodically and during resuming from system suspend (previously driver was re-seeding itself again with jiffies). Signed-off-by: Krzysztof Kozlowski Reviewed-by: Stephan Müller Reviewed-by: PrasannaKumar Muralidharan Reviewed-by: Bartlomiej Zolnierkiewicz --- MAINTAINERS | 8 + drivers/char/hw_random/Kconfig | 14 -- drivers/char/hw_random/Makefile | 1 - drivers/char/hw_random/exynos-rng.c | 231 --------------------- drivers/crypto/Kconfig | 15 ++ drivers/crypto/Makefile | 1 + drivers/crypto/exynos-rng.c | 389 ++++++++++++++++++++++++++++++++++++ 7 files changed, 413 insertions(+), 246 deletions(-) delete mode 100644 drivers/char/hw_random/exynos-rng.c create mode 100644 drivers/crypto/exynos-rng.c diff --git a/MAINTAINERS b/MAINTAINERS index affecc6d59f4..371fda859d43 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10977,6 +10977,14 @@ L: alsa-devel@alsa-project.org (moderated for non-subscribers) S: Supported F: sound/soc/samsung/ +SAMSUNG EXYNOS PSEUDO RANDOM NUMBER GENERATOR (RNG) DRIVER +M: Krzysztof Kozlowski +L: linux-crypto@vger.kernel.org +L: linux-samsung-soc@vger.kernel.org +S: Maintained +F: drivers/crypto/exynos-rng.c +F: Documentation/devicetree/bindings/rng/samsung,exynos-rng4.txt + SAMSUNG FRAMEBUFFER DRIVER M: Jingoo Han L: linux-fbdev@vger.kernel.org diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 0cafe08919c9..bdae802e7154 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -294,20 +294,6 @@ config HW_RANDOM_POWERNV If unsure, say Y. -config HW_RANDOM_EXYNOS - tristate "EXYNOS HW random number generator support" - depends on ARCH_EXYNOS || COMPILE_TEST - depends on HAS_IOMEM - default HW_RANDOM - ---help--- - This driver provides kernel-side support for the Random Number - Generator hardware found on EXYNOS SOCs. - - To compile this driver as a module, choose M here: the - module will be called exynos-rng. - - If unsure, say Y. - config HW_RANDOM_TPM tristate "TPM HW Random Number Generator support" depends on TCG_TPM diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index 5f52b1e4e7be..6f1eecc2045c 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -24,7 +24,6 @@ obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o -obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o diff --git a/drivers/char/hw_random/exynos-rng.c b/drivers/char/hw_random/exynos-rng.c deleted file mode 100644 index 23d358553b21..000000000000 --- a/drivers/char/hw_random/exynos-rng.c +++ /dev/null @@ -1,231 +0,0 @@ -/* - * exynos-rng.c - Random Number Generator driver for the exynos - * - * Copyright (C) 2012 Samsung Electronics - * Jonghwa Lee - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - */ - -#include -#include -#include -#include -#include -#include -#include -#include - -#define EXYNOS_PRNG_STATUS_OFFSET 0x10 -#define EXYNOS_PRNG_SEED_OFFSET 0x140 -#define EXYNOS_PRNG_OUT1_OFFSET 0x160 -#define SEED_SETTING_DONE BIT(1) -#define PRNG_START 0x18 -#define PRNG_DONE BIT(5) -#define EXYNOS_AUTOSUSPEND_DELAY 100 - -struct exynos_rng { - struct device *dev; - struct hwrng rng; - void __iomem *mem; - struct clk *clk; -}; - -static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset) -{ - return readl_relaxed(rng->mem + offset); -} - -static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset) -{ - writel_relaxed(val, rng->mem + offset); -} - -static int exynos_rng_configure(struct exynos_rng *exynos_rng) -{ - int i; - int ret = 0; - - for (i = 0 ; i < 5 ; i++) - exynos_rng_writel(exynos_rng, jiffies, - EXYNOS_PRNG_SEED_OFFSET + 4*i); - - if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET) - & SEED_SETTING_DONE)) - ret = -EIO; - - return ret; -} - -static int exynos_init(struct hwrng *rng) -{ - struct exynos_rng *exynos_rng = container_of(rng, - struct exynos_rng, rng); - int ret = 0; - - pm_runtime_get_sync(exynos_rng->dev); - ret = exynos_rng_configure(exynos_rng); - pm_runtime_mark_last_busy(exynos_rng->dev); - pm_runtime_put_autosuspend(exynos_rng->dev); - - return ret; -} - -static int exynos_read(struct hwrng *rng, void *buf, - size_t max, bool wait) -{ - struct exynos_rng *exynos_rng = container_of(rng, - struct exynos_rng, rng); - u32 *data = buf; - int retry = 100; - int ret = 4; - - pm_runtime_get_sync(exynos_rng->dev); - - exynos_rng_writel(exynos_rng, PRNG_START, 0); - - while (!(exynos_rng_readl(exynos_rng, - EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE) && --retry) - cpu_relax(); - if (!retry) { - ret = -ETIMEDOUT; - goto out; - } - - exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET); - - *data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET); - -out: - pm_runtime_mark_last_busy(exynos_rng->dev); - pm_runtime_put_sync_autosuspend(exynos_rng->dev); - - return ret; -} - -static int exynos_rng_probe(struct platform_device *pdev) -{ - struct exynos_rng *exynos_rng; - struct resource *res; - int ret; - - exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng), - GFP_KERNEL); - if (!exynos_rng) - return -ENOMEM; - - exynos_rng->dev = &pdev->dev; - exynos_rng->rng.name = "exynos"; - exynos_rng->rng.init = exynos_init; - exynos_rng->rng.read = exynos_read; - exynos_rng->clk = devm_clk_get(&pdev->dev, "secss"); - if (IS_ERR(exynos_rng->clk)) { - dev_err(&pdev->dev, "Couldn't get clock.\n"); - return -ENOENT; - } - - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res); - if (IS_ERR(exynos_rng->mem)) - return PTR_ERR(exynos_rng->mem); - - platform_set_drvdata(pdev, exynos_rng); - - pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY); - pm_runtime_use_autosuspend(&pdev->dev); - pm_runtime_enable(&pdev->dev); - - ret = devm_hwrng_register(&pdev->dev, &exynos_rng->rng); - if (ret) { - pm_runtime_dont_use_autosuspend(&pdev->dev); - pm_runtime_disable(&pdev->dev); - } - - return ret; -} - -static int exynos_rng_remove(struct platform_device *pdev) -{ - pm_runtime_dont_use_autosuspend(&pdev->dev); - pm_runtime_disable(&pdev->dev); - - return 0; -} - -static int __maybe_unused exynos_rng_runtime_suspend(struct device *dev) -{ - struct platform_device *pdev = to_platform_device(dev); - struct exynos_rng *exynos_rng = platform_get_drvdata(pdev); - - clk_disable_unprepare(exynos_rng->clk); - - return 0; -} - -static int __maybe_unused exynos_rng_runtime_resume(struct device *dev) -{ - struct platform_device *pdev = to_platform_device(dev); - struct exynos_rng *exynos_rng = platform_get_drvdata(pdev); - - return clk_prepare_enable(exynos_rng->clk); -} - -static int __maybe_unused exynos_rng_suspend(struct device *dev) -{ - return pm_runtime_force_suspend(dev); -} - -static int __maybe_unused exynos_rng_resume(struct device *dev) -{ - struct platform_device *pdev = to_platform_device(dev); - struct exynos_rng *exynos_rng = platform_get_drvdata(pdev); - int ret; - - ret = pm_runtime_force_resume(dev); - if (ret) - return ret; - - return exynos_rng_configure(exynos_rng); -} - -static const struct dev_pm_ops exynos_rng_pm_ops = { - SET_SYSTEM_SLEEP_PM_OPS(exynos_rng_suspend, exynos_rng_resume) - SET_RUNTIME_PM_OPS(exynos_rng_runtime_suspend, - exynos_rng_runtime_resume, NULL) -}; - -static const struct of_device_id exynos_rng_dt_match[] = { - { - .compatible = "samsung,exynos4-rng", - }, - { }, -}; -MODULE_DEVICE_TABLE(of, exynos_rng_dt_match); - -static struct platform_driver exynos_rng_driver = { - .driver = { - .name = "exynos-rng", - .pm = &exynos_rng_pm_ops, - .of_match_table = exynos_rng_dt_match, - }, - .probe = exynos_rng_probe, - .remove = exynos_rng_remove, -}; - -module_platform_driver(exynos_rng_driver); - -MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver"); -MODULE_AUTHOR("Jonghwa Lee "); -MODULE_LICENSE("GPL"); diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 1a60626937e4..7d1fdf6a751c 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -388,6 +388,21 @@ config CRYPTO_DEV_MXC_SCC This option enables support for the Security Controller (SCC) found in Freescale i.MX25 chips. +config CRYPTO_DEV_EXYNOS_RNG + tristate "EXYNOS HW pseudo random number generator support" + depends on ARCH_EXYNOS || COMPILE_TEST + depends on HAS_IOMEM + select CRYPTO_RNG + ---help--- + This driver provides kernel-side support through the + cryptographic API for the pseudo random number generator hardware + found on Exynos SoCs. + + To compile this driver as a module, choose M here: the + module will be called exynos-rng. + + If unsure, say Y. + config CRYPTO_DEV_S5P tristate "Support for Samsung S5PV210/Exynos crypto accelerator" depends on ARCH_S5PV210 || ARCH_EXYNOS || COMPILE_TEST diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile index 41ca339e89d3..9603f1862b30 100644 --- a/drivers/crypto/Makefile +++ b/drivers/crypto/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_CRYPTO_DEV_CAVIUM_ZIP) += cavium/ obj-$(CONFIG_CRYPTO_DEV_CCP) += ccp/ obj-$(CONFIG_CRYPTO_DEV_CHELSIO) += chelsio/ obj-$(CONFIG_CRYPTO_DEV_CPT) += cavium/cpt/ +obj-$(CONFIG_CRYPTO_DEV_EXYNOS_RNG) += exynos-rng.o obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM) += caam/ obj-$(CONFIG_CRYPTO_DEV_GEODE) += geode-aes.o obj-$(CONFIG_CRYPTO_DEV_HIFN_795X) += hifn_795x.o diff --git a/drivers/crypto/exynos-rng.c b/drivers/crypto/exynos-rng.c new file mode 100644 index 000000000000..451620b475a0 --- /dev/null +++ b/drivers/crypto/exynos-rng.c @@ -0,0 +1,389 @@ +/* + * exynos-rng.c - Random Number Generator driver for the Exynos + * + * Copyright (c) 2017 Krzysztof Kozlowski + * + * Loosely based on old driver from drivers/char/hw_random/exynos-rng.c: + * Copyright (C) 2012 Samsung Electronics + * Jonghwa Lee + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include + +#include + +#define EXYNOS_RNG_CONTROL 0x0 +#define EXYNOS_RNG_STATUS 0x10 +#define EXYNOS_RNG_SEED_BASE 0x140 +#define EXYNOS_RNG_SEED(n) (EXYNOS_RNG_SEED_BASE + (n * 0x4)) +#define EXYNOS_RNG_OUT_BASE 0x160 +#define EXYNOS_RNG_OUT(n) (EXYNOS_RNG_OUT_BASE + (n * 0x4)) + +/* EXYNOS_RNG_CONTROL bit fields */ +#define EXYNOS_RNG_CONTROL_START 0x18 +/* EXYNOS_RNG_STATUS bit fields */ +#define EXYNOS_RNG_STATUS_SEED_SETTING_DONE BIT(1) +#define EXYNOS_RNG_STATUS_RNG_DONE BIT(5) + +/* Five seed and output registers, each 4 bytes */ +#define EXYNOS_RNG_SEED_REGS 5 +#define EXYNOS_RNG_SEED_SIZE (EXYNOS_RNG_SEED_REGS * 4) + +/* + * Driver re-seeds itself with generated random numbers to increase + * the randomness. + * + * Time for next re-seed in ms. + */ +#define EXYNOS_RNG_RESEED_TIME 100 +/* + * In polling mode, do not wait infinitely for the engine to finish the work. + */ +#define EXYNOS_RNG_WAIT_RETRIES 100 + +/* Context for crypto */ +struct exynos_rng_ctx { + struct exynos_rng_dev *rng; +}; + +/* Device associated memory */ +struct exynos_rng_dev { + struct device *dev; + void __iomem *mem; + struct clk *clk; + /* Generated numbers stored for seeding during resume */ + u8 seed_save[EXYNOS_RNG_SEED_SIZE]; + unsigned int seed_save_len; + /* Time of last seeding in jiffies */ + unsigned long last_seeding; +}; + +static struct exynos_rng_dev *exynos_rng_dev; + +static u32 exynos_rng_readl(struct exynos_rng_dev *rng, u32 offset) +{ + return readl_relaxed(rng->mem + offset); +} + +static void exynos_rng_writel(struct exynos_rng_dev *rng, u32 val, u32 offset) +{ + writel_relaxed(val, rng->mem + offset); +} + +static int exynos_rng_set_seed(struct exynos_rng_dev *rng, + const u8 *seed, unsigned int slen) +{ + u32 val; + int i; + + /* Round seed length because loop iterates over full register size */ + slen = ALIGN_DOWN(slen, 4); + + if (slen < EXYNOS_RNG_SEED_SIZE) + return -EINVAL; + + for (i = 0; i < slen ; i += 4) { + unsigned int seed_reg = (i / 4) % EXYNOS_RNG_SEED_REGS; + + val = seed[i] << 24; + val |= seed[i + 1] << 16; + val |= seed[i + 2] << 8; + val |= seed[i + 3] << 0; + + exynos_rng_writel(rng, val, EXYNOS_RNG_SEED(seed_reg)); + } + + val = exynos_rng_readl(rng, EXYNOS_RNG_STATUS); + if (!(val & EXYNOS_RNG_STATUS_SEED_SETTING_DONE)) { + dev_warn(rng->dev, "Seed setting not finished\n"); + return -EIO; + } + + rng->last_seeding = jiffies; + + return 0; +} + +/* + * Read from output registers and put the data under 'dst' array, + * up to dlen bytes. + * + * Returns number of bytes actually stored in 'dst' (dlen + * or EXYNOS_RNG_SEED_SIZE). + */ +static unsigned int exynos_rng_copy_random(struct exynos_rng_dev *rng, + u8 *dst, unsigned int dlen) +{ + unsigned int cnt = 0; + int i, j; + u32 val; + + for (j = 0; j < EXYNOS_RNG_SEED_REGS; j++) { + val = exynos_rng_readl(rng, EXYNOS_RNG_OUT(j)); + + for (i = 0; i < 4; i++) { + dst[cnt] = val & 0xff; + val >>= 8; + if (++cnt >= dlen) + return cnt; + } + } + + return cnt; +} + +/* + * Start the engine and poll for finish. Then read from output registers + * filling the 'dst' buffer up to 'dlen' bytes or up to size of generated + * random data (EXYNOS_RNG_SEED_SIZE). + * + * On success: return 0 and store number of read bytes under 'read' address. + * On error: return -ERRNO. + */ +static int exynos_rng_get_random(struct exynos_rng_dev *rng, + u8 *dst, unsigned int dlen, + unsigned int *read) +{ + int retry = EXYNOS_RNG_WAIT_RETRIES; + + exynos_rng_writel(rng, EXYNOS_RNG_CONTROL_START, + EXYNOS_RNG_CONTROL); + + while (!(exynos_rng_readl(rng, + EXYNOS_RNG_STATUS) & EXYNOS_RNG_STATUS_RNG_DONE) && --retry) + cpu_relax(); + + if (!retry) + return -ETIMEDOUT; + + /* Clear status bit */ + exynos_rng_writel(rng, EXYNOS_RNG_STATUS_RNG_DONE, + EXYNOS_RNG_STATUS); + *read = exynos_rng_copy_random(rng, dst, dlen); + + return 0; +} + +/* Re-seed itself from time to time */ +static void exynos_rng_reseed(struct exynos_rng_dev *rng) +{ + unsigned long next_seeding = rng->last_seeding + \ + msecs_to_jiffies(EXYNOS_RNG_RESEED_TIME); + unsigned long now = jiffies; + unsigned int read = 0; + u8 seed[EXYNOS_RNG_SEED_SIZE]; + + if (time_before(now, next_seeding)) + return; + + if (exynos_rng_get_random(rng, seed, sizeof(seed), &read)) + return; + + exynos_rng_set_seed(rng, seed, read); +} + +static int exynos_rng_generate(struct crypto_rng *tfm, + const u8 *src, unsigned int slen, + u8 *dst, unsigned int dlen) +{ + struct exynos_rng_ctx *ctx = crypto_rng_ctx(tfm); + struct exynos_rng_dev *rng = ctx->rng; + unsigned int read = 0; + int ret; + + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + do { + ret = exynos_rng_get_random(rng, dst, dlen, &read); + if (ret) + break; + + dlen -= read; + dst += read; + + exynos_rng_reseed(rng); + } while (dlen > 0); + + clk_disable_unprepare(rng->clk); + + return ret; +} + +static int exynos_rng_seed(struct crypto_rng *tfm, const u8 *seed, + unsigned int slen) +{ + struct exynos_rng_ctx *ctx = crypto_rng_ctx(tfm); + struct exynos_rng_dev *rng = ctx->rng; + int ret; + + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + ret = exynos_rng_set_seed(ctx->rng, seed, slen); + + clk_disable_unprepare(rng->clk); + + return ret; +} + +static int exynos_rng_kcapi_init(struct crypto_tfm *tfm) +{ + struct exynos_rng_ctx *ctx = crypto_tfm_ctx(tfm); + + ctx->rng = exynos_rng_dev; + + return 0; +} + +static struct rng_alg exynos_rng_alg = { + .generate = exynos_rng_generate, + .seed = exynos_rng_seed, + .seedsize = EXYNOS_RNG_SEED_SIZE, + .base = { + .cra_name = "stdrng", + .cra_driver_name = "exynos_rng", + .cra_priority = 100, + .cra_ctxsize = sizeof(struct exynos_rng_ctx), + .cra_module = THIS_MODULE, + .cra_init = exynos_rng_kcapi_init, + } +}; + +static int exynos_rng_probe(struct platform_device *pdev) +{ + struct exynos_rng_dev *rng; + struct resource *res; + int ret; + + if (exynos_rng_dev) + return -EEXIST; + + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); + if (!rng) + return -ENOMEM; + + rng->dev = &pdev->dev; + rng->clk = devm_clk_get(&pdev->dev, "secss"); + if (IS_ERR(rng->clk)) { + dev_err(&pdev->dev, "Couldn't get clock.\n"); + return PTR_ERR(rng->clk); + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rng->mem = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rng->mem)) + return PTR_ERR(rng->mem); + + platform_set_drvdata(pdev, rng); + + exynos_rng_dev = rng; + + ret = crypto_register_rng(&exynos_rng_alg); + if (ret) { + dev_err(&pdev->dev, + "Couldn't register rng crypto alg: %d\n", ret); + exynos_rng_dev = NULL; + } + + return ret; +} + +static int exynos_rng_remove(struct platform_device *pdev) +{ + crypto_unregister_rng(&exynos_rng_alg); + + exynos_rng_dev = NULL; + + return 0; +} + +static int __maybe_unused exynos_rng_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct exynos_rng_dev *rng = platform_get_drvdata(pdev); + int ret; + + /* If we were never seeded then after resume it will be the same */ + if (!rng->last_seeding) + return 0; + + rng->seed_save_len = 0; + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + /* Get new random numbers and store them for seeding on resume. */ + exynos_rng_get_random(rng, rng->seed_save, sizeof(rng->seed_save), + &(rng->seed_save_len)); + dev_dbg(rng->dev, "Stored %u bytes for seeding on system resume\n", + rng->seed_save_len); + + clk_disable_unprepare(rng->clk); + + return 0; +} + +static int __maybe_unused exynos_rng_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct exynos_rng_dev *rng = platform_get_drvdata(pdev); + int ret; + + /* Never seeded so nothing to do */ + if (!rng->last_seeding) + return 0; + + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + ret = exynos_rng_set_seed(rng, rng->seed_save, rng->seed_save_len); + + clk_disable_unprepare(rng->clk); + + return ret; +} + +static SIMPLE_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_suspend, + exynos_rng_resume); + +static const struct of_device_id exynos_rng_dt_match[] = { + { + .compatible = "samsung,exynos4-rng", + }, + { }, +}; +MODULE_DEVICE_TABLE(of, exynos_rng_dt_match); + +static struct platform_driver exynos_rng_driver = { + .driver = { + .name = "exynos-rng", + .pm = &exynos_rng_pm_ops, + .of_match_table = exynos_rng_dt_match, + }, + .probe = exynos_rng_probe, + .remove = exynos_rng_remove, +}; + +module_platform_driver(exynos_rng_driver); + +MODULE_DESCRIPTION("Exynos H/W Random Number Generator driver"); +MODULE_AUTHOR("Krzysztof Kozlowski "); +MODULE_LICENSE("GPL");