Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755200Ab3IZGbc (ORCPT ); Thu, 26 Sep 2013 02:31:32 -0400 Received: from ozlabs.org ([203.10.76.45]:47275 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751263Ab3IZGba (ORCPT ); Thu, 26 Sep 2013 02:31:30 -0400 From: Michael Ellerman To: Cc: Benjamin Herrenschmidt , Paul Mackerras , gleb@redhat.com, pbonzini@redhat.com, agraf@suse.de, mpm@selenic.com, herbert@gondor.hengli.com.au, , , , tytso@mit.edu Subject: [PATCH 2/3] hwrng: Add a driver for the hwrng found in power7+ systems Date: Thu, 26 Sep 2013 16:31:05 +1000 Message-Id: <1380177066-3835-2-git-send-email-michael@ellerman.id.au> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1380177066-3835-1-git-send-email-michael@ellerman.id.au> References: <1380177066-3835-1-git-send-email-michael@ellerman.id.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4475 Lines: 148 Add a driver for the hwrng found in power7+ systems, based on the existing code for the arch_get_random_long() hook. We only register a single instance of the driver, not one per device, because we use the existing per_cpu array of devices in the arch code. This means we always read from the "closest" device, avoiding inter-chip memory traffic. Signed-off-by: Guo Chao Signed-off-by: Michael Ellerman --- drivers/char/hw_random/Kconfig | 13 ++++++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/powernv-rng.c | 81 ++++++++++++++++++++++++++++++++++++ 3 files changed, 95 insertions(+) create mode 100644 drivers/char/hw_random/powernv-rng.c diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 0aa9d91..c206de2 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -290,6 +290,19 @@ config HW_RANDOM_PSERIES If unsure, say Y. +config HW_RANDOM_POWERNV + tristate "PowerNV Random Number Generator support" + depends on HW_RANDOM && PPC_POWERNV + default HW_RANDOM + ---help--- + This is the driver for Random Number Generator hardware found + in POWER7+ and above machines for PowerNV platform. + + To compile this driver as a module, choose M here: the + module will be called powernv-rng. + + If unsure, say Y. + config HW_RANDOM_EXYNOS tristate "EXYNOS HW random number generator support" depends on HW_RANDOM && HAS_IOMEM && HAVE_CLK diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index bed467c..d7d2435 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o +obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o diff --git a/drivers/char/hw_random/powernv-rng.c b/drivers/char/hw_random/powernv-rng.c new file mode 100644 index 0000000..e6965bf --- /dev/null +++ b/drivers/char/hw_random/powernv-rng.c @@ -0,0 +1,81 @@ +/* + * Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp. + * + * 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; either version + * 2 of the License, or (at your option) any later version. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + unsigned long *buf; + int i, len; + + /* We rely on rng_buffer_size() being >= sizeof(unsigned long) */ + len = max / sizeof(unsigned long); + + buf = (unsigned long *)data; + + for (i = 0; i < len; i++) + powernv_get_random_long(buf++); + + return len * sizeof(unsigned long); +} + +static struct hwrng powernv_hwrng = { + .name = "powernv-rng", + .read = powernv_rng_read, +}; + +static int powernv_rng_remove(struct platform_device *pdev) +{ + hwrng_unregister(&powernv_hwrng); + + return 0; +} + +static int powernv_rng_probe(struct platform_device *pdev) +{ + int rc; + + rc = hwrng_register(&powernv_hwrng); + if (rc) { + /* We only register one device, ignore any others */ + if (rc == -EEXIST) + rc = -ENODEV; + + return rc; + } + + pr_info("registered powernv hwrng.\n"); + + return 0; +} + +static struct of_device_id powernv_rng_match[] = { + { .compatible = "ibm,power-rng",}, + {}, +}; +MODULE_DEVICE_TABLE(of, powernv_rng_match); + +static struct platform_driver powernv_rng_driver = { + .driver = { + .name = "powernv_rng", + .of_match_table = powernv_rng_match, + }, + .probe = powernv_rng_probe, + .remove = powernv_rng_remove, +}; +module_platform_driver(powernv_rng_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Bare metal HWRNG driver for POWER7+ and above"); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/