From f95dabef4c70e27e5114f4802fe6234ff82ce406 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 25 Sep 2013 19:24:17 +1000 Subject: hwrng: Return errors to upper levels in pseries-rng.c We don't expect to get errors from the hypervisor when reading the rng, but if we do we should pass the error up to the hwrng driver. Otherwise the hwrng driver will continue calling us forever. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- drivers/char/hw_random/pseries-rng.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/hw_random/pseries-rng.c b/drivers/char/hw_random/pseries-rng.c index 5f1197929f0c..b761459a3436 100644 --- a/drivers/char/hw_random/pseries-rng.c +++ b/drivers/char/hw_random/pseries-rng.c @@ -17,6 +17,9 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include #include #include #include @@ -25,10 +28,15 @@ static int pseries_rng_data_read(struct hwrng *rng, u32 *data) { - if (plpar_hcall(H_RANDOM, (unsigned long *)data) != H_SUCCESS) { - printk(KERN_ERR "pseries rng hcall error\n"); - return 0; + int rc; + + rc = plpar_hcall(H_RANDOM, (unsigned long *)data); + if (rc != H_SUCCESS) { + pr_err_ratelimited("H_RANDOM call failed %d\n", rc); + return -EIO; } + + /* The hypervisor interface returns 64 bits */ return 8; } -- cgit v1.2.1 From 66548e40583b1470300341c6784fdc5176f7609f Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 11 Oct 2013 14:07:58 +1100 Subject: hwrng: Add a driver for the hwrng found in power7+ systems 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 Signed-off-by: Benjamin Herrenschmidt --- 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 (limited to 'drivers/char') diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 0aa9d91daef5..c206de2951f2 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 bed467c9300e..d7d2435ff7fa 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 000000000000..3f4f63204560 --- /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"); -- cgit v1.2.1