This adds a driver for hardware random number generator present on Qualcomm MSM SoC's. Signed-off-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx> --- drivers/char/hw_random/Kconfig | 12 +++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/msm-rng.c | 211 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 224 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..c4545d2da949 --- /dev/null +++ b/drivers/char/hw_random/msm-rng.c @@ -0,0 +1,211 @@ +/* + * 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 <linux/clk.h> +#include <linux/hw_random.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> + +/* 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_MASK 0x00000002 +#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; +}; + +static int msm_rng_enable(struct msm_rng *rng, int enable) +{ + 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; + + /* PRNG is not 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_MASK; + val |= PRNG_CONFIG_HW_ENABLE; + writel(val, rng->base + PRNG_CONFIG); + } else { + val = readl_relaxed(rng->base + PRNG_CONFIG); + val &= ~PRNG_CONFIG_MASK; + 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 = (struct msm_rng *)hwrng->priv; + 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) +{ + struct msm_rng *rng = (struct msm_rng *)hwrng->priv; + + return msm_rng_enable(rng, 1); +} + +static void msm_rng_cleanup(struct hwrng *hwrng) +{ + struct msm_rng *rng = (struct msm_rng *)hwrng->priv; + + msm_rng_enable(rng, 0); +} + +static struct hwrng msm_rng_ops = { + .name = KBUILD_MODNAME, + .init = msm_rng_init, + .cleanup = msm_rng_cleanup, + .read = msm_rng_read, +}; + +static int msm_rng_probe(struct platform_device *pdev) +{ + struct msm_rng *rng; + struct device_node *np; + struct resource res; + int ret; + + np = of_node_get(pdev->dev.of_node); + if (!np) + return -ENODEV; + + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); + if (!rng) { + ret = -ENOMEM; + goto err_exit; + } + + ret = of_address_to_resource(np, 0, &res); + if (ret) + goto err_exit; + + rng->base = devm_ioremap_resource(&pdev->dev, &res); + if (IS_ERR(rng->base)) { + ret = PTR_ERR(rng->base); + goto err_exit; + } + + rng->clk = devm_clk_get(&pdev->dev, "prng"); + if (IS_ERR(rng->clk)) { + ret = PTR_ERR(rng->clk); + goto err_exit; + } + + msm_rng_ops.priv = (unsigned long) rng; + ret = hwrng_register(&msm_rng_ops); + if (ret) + dev_err(&pdev->dev, "failed to register hwrng\n"); + +err_exit: + of_node_put(np); + return ret; +} + +static int msm_rng_remove(struct platform_device *pdev) +{ + hwrng_unregister(&msm_rng_ops); + return 0; +} + +static 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"); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html