From patchwork Fri Oct 11 15:16:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanimir Varbanov X-Patchwork-Id: 3024951 Return-Path: X-Original-To: patchwork-linux-arm-msm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8EFE39F3EF for ; Fri, 11 Oct 2013 15:19:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 32C182030D for ; Fri, 11 Oct 2013 15:19:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD1B7202C0 for ; Fri, 11 Oct 2013 15:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758247Ab3JKPTl (ORCPT ); Fri, 11 Oct 2013 11:19:41 -0400 Received: from ns.mm-sol.com ([212.124.72.66]:44237 "EHLO extserv.mm-sol.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756953Ab3JKPTk (ORCPT ); Fri, 11 Oct 2013 11:19:40 -0400 Received: from intsrv.int.mm-sol.com (unknown [172.18.0.3]) by extserv.mm-sol.com (Postfix) with ESMTP id 952A6C57A; Fri, 11 Oct 2013 18:19:38 +0300 (EEST) Received: from localhost (localhost [127.0.0.1]) by intsrv.int.mm-sol.com (Postfix) with ESMTP id 59DDED2E002; Fri, 11 Oct 2013 18:19:38 +0300 (EEST) X-Virus-Scanned: by amavisd-new-2.7.1 (20120429) Received: from intsrv.int.mm-sol.com ([127.0.0.1]) by localhost (mail.mm-sol.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Qudxsvgsi0L3; Fri, 11 Oct 2013 18:19:34 +0300 (EEST) Received: from localhost (mms734.int.mm-sol.com [172.20.2.166]) by intsrv.int.mm-sol.com (Postfix) with ESMTP id 5FDBFD2E001; Fri, 11 Oct 2013 18:19:34 +0300 (EEST) From: Stanimir Varbanov To: Rob Herring , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , Matt Mackall , Herbert Xu Cc: linux-kernel@vger.kernel.org, Rob Landley , devicetree@vger.kernel.org, linux-doc@vger.kernel.org, Greg Kroah-Hartman , linux-arm-msm@vger.kernel.org, Stanimir Varbanov Subject: [PATCH v2 2/2] hwrng: msm: Add PRNG support for MSM SoC's Date: Fri, 11 Oct 2013 18:16:41 +0300 Message-Id: <1381504601-23773-3-git-send-email-svarbanov@mm-sol.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1381504601-23773-1-git-send-email-svarbanov@mm-sol.com> References: <1381504601-23773-1-git-send-email-svarbanov@mm-sol.com> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This adds a driver for hardware random number generator present on Qualcomm MSM SoC's. Signed-off-by: Stanimir Varbanov --- drivers/char/hw_random/Kconfig | 12 +++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/msm-rng.c | 195 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 208 insertions(+) create mode 100644 drivers/char/hw_random/msm-rng.c diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 0aa9d91daef5..d902330cef43 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -314,3 +314,15 @@ config HW_RANDOM_TPM module will be called tpm-rng. If unsure, say Y. + +config HW_RANDOM_MSM + tristate "Qualcomm MSM Random Number Generator support" + depends on HW_RANDOM && ARCH_MSM && HAVE_CLK + ---help--- + This driver provides kernel-side support for the Random Number + Generator hardware found on Qualcomm MSM SoCs. + + To compile this driver as a module, choose M here. the + module will be called msm-rng. + + If unsure, say Y. diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index bed467c9300e..441a0a7705a2 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -27,3 +27,4 @@ obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o +obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o diff --git a/drivers/char/hw_random/msm-rng.c b/drivers/char/hw_random/msm-rng.c new file mode 100644 index 000000000000..e219e94d02c1 --- /dev/null +++ b/drivers/char/hw_random/msm-rng.c @@ -0,0 +1,195 @@ +/* + * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 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 + +/* Device specific register offsets */ +#define PRNG_DATA_OUT 0x0000 +#define PRNG_STATUS 0x0004 +#define PRNG_LFSR_CFG 0x0100 +#define PRNG_CONFIG 0x0104 + +/* Device specific register masks and config values */ +#define PRNG_LFSR_CFG_MASK 0x0000ffff +#define PRNG_LFSR_CFG_CLOCKS 0x0000dddd +#define PRNG_CONFIG_HW_ENABLE BIT(1) +#define PRNG_STATUS_DATA_AVAIL BIT(0) + +#define MAX_HW_FIFO_DEPTH 16 +#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4) +#define WORD_SZ 4 + +struct msm_rng { + void __iomem *base; + struct clk *clk; + struct hwrng hwrng; +}; + +#define to_msm_rng(p) container_of(p, struct msm_rng, hwrng) + +static int msm_rng_enable(struct hwrng *hwrng, int enable) +{ + struct msm_rng *rng = to_msm_rng(hwrng); + u32 val; + int ret; + + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + if (enable) { + /* Enable PRNG only if it is not already enabled */ + val = readl_relaxed(rng->base + PRNG_CONFIG); + if (val & PRNG_CONFIG_HW_ENABLE) + goto already_enabled; + + val = readl_relaxed(rng->base + PRNG_LFSR_CFG); + val &= ~PRNG_LFSR_CFG_MASK; + val |= PRNG_LFSR_CFG_CLOCKS; + writel(val, rng->base + PRNG_LFSR_CFG); + + val = readl_relaxed(rng->base + PRNG_CONFIG); + val |= PRNG_CONFIG_HW_ENABLE; + writel(val, rng->base + PRNG_CONFIG); + } else { + val = readl_relaxed(rng->base + PRNG_CONFIG); + val &= ~PRNG_CONFIG_HW_ENABLE; + writel(val, rng->base + PRNG_CONFIG); + } + +already_enabled: + clk_disable_unprepare(rng->clk); + return 0; +} + +static int msm_rng_read(struct hwrng *hwrng, void *data, size_t max, bool wait) +{ + struct msm_rng *rng = to_msm_rng(hwrng); + size_t currsize = 0; + u32 *retdata = data; + size_t maxsize; + int ret; + u32 val; + + /* calculate max size bytes to transfer back to caller */ + maxsize = min_t(size_t, MAX_HW_FIFO_SIZE, max); + + /* no room for word data */ + if (maxsize < WORD_SZ) + return 0; + + ret = clk_prepare_enable(rng->clk); + if (ret) + return ret; + + /* read random data from hardware */ + do { + val = readl_relaxed(rng->base + PRNG_STATUS); + if (!(val & PRNG_STATUS_DATA_AVAIL)) + break; + + val = readl_relaxed(rng->base + PRNG_DATA_OUT); + if (!val) + break; + + *retdata++ = val; + currsize += WORD_SZ; + + /* make sure we stay on 32bit boundary */ + if ((maxsize - currsize) < WORD_SZ) + break; + } while (currsize < maxsize); + + clk_disable_unprepare(rng->clk); + + return currsize; +} + +static int msm_rng_init(struct hwrng *hwrng) +{ + return msm_rng_enable(hwrng, 1); +} + +static void msm_rng_cleanup(struct hwrng *hwrng) +{ + msm_rng_enable(hwrng, 0); +} + +static int msm_rng_probe(struct platform_device *pdev) +{ + struct resource *res; + struct msm_rng *rng; + int ret; + + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); + if (!rng) + return -ENOMEM; + + platform_set_drvdata(pdev, rng); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rng->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rng->base)) + return PTR_ERR(rng->base); + + rng->clk = devm_clk_get(&pdev->dev, "prng"); + if (IS_ERR(rng->clk)) + return PTR_ERR(rng->clk); + + rng->hwrng.name = KBUILD_MODNAME, + rng->hwrng.init = msm_rng_init, + rng->hwrng.cleanup = msm_rng_cleanup, + rng->hwrng.read = msm_rng_read, + + ret = hwrng_register(&rng->hwrng); + if (ret) { + dev_err(&pdev->dev, "failed to register hwrng\n"); + return ret; + } + + return 0; +} + +static int msm_rng_remove(struct platform_device *pdev) +{ + struct msm_rng *rng = platform_get_drvdata(pdev); + + hwrng_unregister(&rng->hwrng); + return 0; +} + +static const struct of_device_id msm_rng_of_match[] = { + { .compatible = "qcom,prng", }, + {} +}; +MODULE_DEVICE_TABLE(of, msm_rng_of_match); + +static struct platform_driver msm_rng_driver = { + .probe = msm_rng_probe, + .remove = msm_rng_remove, + .driver = { + .name = KBUILD_MODNAME, + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(msm_rng_of_match), + } +}; +module_platform_driver(msm_rng_driver); + +MODULE_AUTHOR("The Linux Foundation"); +MODULE_DESCRIPTION("Qualcomm MSM random number generator driver"); +MODULE_LICENSE("GPL v2");