--- /dev/null
+From patchwork Sat Nov 12 14:10:58 2022
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 7bit
+X-Patchwork-Submitter: Aurelien Jarno <aurelien@aurel32.net>
+X-Patchwork-Id: 13041222
+Return-Path:
+ <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org>
+X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
+ aws-us-west-2-korg-lkml-1.web.codeaurora.org
+From: Aurelien Jarno <aurelien@aurel32.net>
+To: Olivia Mackall <olivia@selenic.com>,
+ Herbert Xu <herbert@gondor.apana.org.au>,
+ Rob Herring <robh+dt@kernel.org>,
+ Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
+ Heiko Stuebner <heiko@sntech.de>,
+ Philipp Zabel <p.zabel@pengutronix.de>,
+ Lin Jinhan <troy.lin@rock-chips.com>
+Cc: linux-crypto@vger.kernel.org (open list:HARDWARE RANDOM NUMBER GENERATOR
+ CORE),
+ devicetree@vger.kernel.org (open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE
+ BINDINGS),
+ linux-arm-kernel@lists.infradead.org (moderated list:ARM/Rockchip SoC
+ support),
+ linux-rockchip@lists.infradead.org (open list:ARM/Rockchip SoC support),
+ linux-kernel@vger.kernel.org (open list),
+ Aurelien Jarno <aurelien@aurel32.net>
+Subject: [PATCH v1 2/3] hwrng: add Rockchip SoC hwrng driver
+Date: Sat, 12 Nov 2022 15:10:58 +0100
+Message-Id: <20221112141059.3802506-3-aurelien@aurel32.net>
+In-Reply-To: <20221112141059.3802506-1-aurelien@aurel32.net>
+References: <20221112141059.3802506-1-aurelien@aurel32.net>
+MIME-Version: 1.0
+List-Id: <linux-arm-kernel.lists.infradead.org>
+
+Rockchip SoCs used to have a random number generator as part of their
+crypto device, and support for it has to be added to the corresponding
+driver. However newer Rockchip SoCs like the RK356x have an independent
+True Random Number Generator device. This patch adds a driver for it,
+greatly inspired from the downstream driver.
+
+The TRNG device does not seem to have a signal conditionner and the FIPS
+140-2 test returns a lot of failures. They can be reduced by increasing
+RK_RNG_SAMPLE_CNT, in a tradeoff between quality and speed. This value
+has been adjusted to get ~90% of successes and the quality value has
+been set accordingly.
+
+Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
+---
+ drivers/char/hw_random/Kconfig | 14 ++
+ drivers/char/hw_random/Makefile | 1 +
+ drivers/char/hw_random/rockchip-rng.c | 251 ++++++++++++++++++++++++++
+ 3 files changed, 266 insertions(+)
+ create mode 100644 drivers/char/hw_random/rockchip-rng.c
+
+--- a/drivers/char/hw_random/Kconfig
++++ b/drivers/char/hw_random/Kconfig
+@@ -549,6 +549,20 @@ config HW_RANDOM_CN10K
+ To compile this driver as a module, choose M here.
+ The module will be called cn10k_rng. If unsure, say Y.
+
++config HW_RANDOM_ROCKCHIP
++ tristate "Rockchip True Random Number Generator"
++ depends on HW_RANDOM && (ARCH_ROCKCHIP || COMPILE_TEST)
++ depends on HAS_IOMEM
++ default HW_RANDOM
++ help
++ This driver provides kernel-side support for the True Random Number
++ Generator hardware found on some Rockchip SoC like RK3566 or RK3568.
++
++ To compile this driver as a module, choose M here: the
++ module will be called rockchip-rng.
++
++ If unsure, say Y.
++
+ endif # HW_RANDOM
+
+ config UML_RANDOM
+--- a/drivers/char/hw_random/Makefile
++++ b/drivers/char/hw_random/Makefile
+@@ -47,3 +47,4 @@ obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphe
+ obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o
+ obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o
+ obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o
++obj-$(CONFIG_HW_RANDOM_ROCKCHIP) += rockchip-rng.o
+--- /dev/null
++++ b/drivers/char/hw_random/rockchip-rng.c
+@@ -0,0 +1,251 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * rockchip-rng.c True Random Number Generator driver for Rockchip SoCs
++ *
++ * Copyright (c) 2018, Fuzhou Rockchip Electronics Co., Ltd.
++ * Copyright (c) 2022, Aurelien Jarno
++ * Authors:
++ * Lin Jinhan <troy.lin@rock-chips.com>
++ * Aurelien Jarno <aurelien@aurel32.net>
++ */
++#include <linux/clk.h>
++#include <linux/hw_random.h>
++#include <linux/io.h>
++#include <linux/iopoll.h>
++#include <linux/kernel.h>
++#include <linux/module.h>
++#include <linux/of_platform.h>
++#include <linux/pm_runtime.h>
++#include <linux/reset.h>
++#include <linux/slab.h>
++
++#define RK_RNG_AUTOSUSPEND_DELAY 100
++#define RK_RNG_MAX_BYTE 32
++#define RK_RNG_POLL_PERIOD_US 100
++#define RK_RNG_POLL_TIMEOUT_US 10000
++
++/*
++ * TRNG collects osc ring output bit every RK_RNG_SAMPLE_CNT time. The value is
++ * a tradeoff between speed and quality and has been adjusted to get a quality
++ * of ~900 (~90% of FIPS 140-2 successes).
++ */
++#define RK_RNG_SAMPLE_CNT 1000
++
++/* TRNG registers from RK3568 TRM-Part2, section 5.4.1 */
++#define TRNG_RST_CTL 0x0004
++#define TRNG_RNG_CTL 0x0400
++#define TRNG_RNG_CTL_LEN_64_BIT (0x00 << 4)
++#define TRNG_RNG_CTL_LEN_128_BIT (0x01 << 4)
++#define TRNG_RNG_CTL_LEN_192_BIT (0x02 << 4)
++#define TRNG_RNG_CTL_LEN_256_BIT (0x03 << 4)
++#define TRNG_RNG_CTL_OSC_RING_SPEED_0 (0x00 << 2)
++#define TRNG_RNG_CTL_OSC_RING_SPEED_1 (0x01 << 2)
++#define TRNG_RNG_CTL_OSC_RING_SPEED_2 (0x02 << 2)
++#define TRNG_RNG_CTL_OSC_RING_SPEED_3 (0x03 << 2)
++#define TRNG_RNG_CTL_ENABLE BIT(1)
++#define TRNG_RNG_CTL_START BIT(0)
++#define TRNG_RNG_SAMPLE_CNT 0x0404
++#define TRNG_RNG_DOUT_0 0x0410
++#define TRNG_RNG_DOUT_1 0x0414
++#define TRNG_RNG_DOUT_2 0x0418
++#define TRNG_RNG_DOUT_3 0x041c
++#define TRNG_RNG_DOUT_4 0x0420
++#define TRNG_RNG_DOUT_5 0x0424
++#define TRNG_RNG_DOUT_6 0x0428
++#define TRNG_RNG_DOUT_7 0x042c
++
++struct rk_rng {
++ struct hwrng rng;
++ void __iomem *base;
++ struct reset_control *rst;
++ int clk_num;
++ struct clk_bulk_data *clk_bulks;
++};
++
++/* The mask determine the bits that are updated */
++static void rk_rng_write_ctl(struct rk_rng *rng, u32 val, u32 mask)
++{
++ writel_relaxed((mask << 16) | val, rng->base + TRNG_RNG_CTL);
++}
++
++static int rk_rng_init(struct hwrng *rng)
++{
++ struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
++ u32 reg;
++ int ret;
++
++ /* start clocks */
++ ret = clk_bulk_prepare_enable(rk_rng->clk_num, rk_rng->clk_bulks);
++ if (ret < 0) {
++ dev_err((struct device *) rk_rng->rng.priv,
++ "Failed to enable clks %d\n", ret);
++ return ret;
++ }
++
++ /* set the sample period */
++ writel(RK_RNG_SAMPLE_CNT, rk_rng->base + TRNG_RNG_SAMPLE_CNT);
++
++ /* set osc ring speed and enable it */
++ reg = TRNG_RNG_CTL_LEN_256_BIT |
++ TRNG_RNG_CTL_OSC_RING_SPEED_0 |
++ TRNG_RNG_CTL_ENABLE;
++ rk_rng_write_ctl(rk_rng, reg, 0xffff);
++
++ return 0;
++}
++
++static void rk_rng_cleanup(struct hwrng *rng)
++{
++ struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
++ u32 reg;
++
++ /* stop TRNG */
++ reg = 0;
++ rk_rng_write_ctl(rk_rng, reg, 0xffff);
++
++ /* stop clocks */
++ clk_bulk_disable_unprepare(rk_rng->clk_num, rk_rng->clk_bulks);
++}
++
++static int rk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
++{
++ struct rk_rng *rk_rng = container_of(rng, struct rk_rng, rng);
++ u32 reg;
++ int ret = 0;
++ int i;
++
++ pm_runtime_get_sync((struct device *) rk_rng->rng.priv);
++
++ /* Start collecting random data */
++ reg = TRNG_RNG_CTL_START;
++ rk_rng_write_ctl(rk_rng, reg, reg);
++
++ ret = readl_poll_timeout(rk_rng->base + TRNG_RNG_CTL, reg,
++ !(reg & TRNG_RNG_CTL_START),
++ RK_RNG_POLL_PERIOD_US,
++ RK_RNG_POLL_TIMEOUT_US);
++ if (ret < 0)
++ goto out;
++
++ /* Read random data stored in big endian in the registers */
++ ret = min_t(size_t, max, RK_RNG_MAX_BYTE);
++ for (i = 0; i < ret; i += 4) {
++ reg = readl_relaxed(rk_rng->base + TRNG_RNG_DOUT_0 + i);
++ *(u32 *)(buf + i) = be32_to_cpu(reg);
++ }
++
++out:
++ pm_runtime_mark_last_busy((struct device *) rk_rng->rng.priv);
++ pm_runtime_put_sync_autosuspend((struct device *) rk_rng->rng.priv);
++
++ return ret;
++}
++
++static int rk_rng_probe(struct platform_device *pdev)
++{
++ struct device *dev = &pdev->dev;
++ struct rk_rng *rk_rng;
++ int ret;
++
++ rk_rng = devm_kzalloc(dev, sizeof(struct rk_rng), GFP_KERNEL);
++ if (!rk_rng)
++ return -ENOMEM;
++
++ rk_rng->base = devm_platform_ioremap_resource(pdev, 0);
++ if (IS_ERR(rk_rng->base))
++ return PTR_ERR(rk_rng->base);
++
++ rk_rng->clk_num = devm_clk_bulk_get_all(dev, &rk_rng->clk_bulks);
++ if (rk_rng->clk_num < 0)
++ return dev_err_probe(dev, rk_rng->clk_num,
++ "Failed to get clks property\n");
++
++ rk_rng->rst = devm_reset_control_array_get(&pdev->dev, false, false);
++ if (IS_ERR(rk_rng->rst))
++ return dev_err_probe(dev, PTR_ERR(rk_rng->rst),
++ "Failed to get reset property\n");
++
++ reset_control_assert(rk_rng->rst);
++ udelay(2);
++ reset_control_deassert(rk_rng->rst);
++
++ platform_set_drvdata(pdev, rk_rng);
++
++ rk_rng->rng.name = dev_driver_string(dev);
++#ifndef CONFIG_PM
++ rk_rng->rng.init = rk_rng_init;
++ rk_rng->rng.cleanup = rk_rng_cleanup;
++#endif
++ rk_rng->rng.read = rk_rng_read;
++ rk_rng->rng.priv = (unsigned long) dev;
++ rk_rng->rng.quality = 900;
++
++ pm_runtime_set_autosuspend_delay(dev, RK_RNG_AUTOSUSPEND_DELAY);
++ pm_runtime_use_autosuspend(dev);
++ pm_runtime_enable(dev);
++
++ ret = devm_hwrng_register(dev, &rk_rng->rng);
++ if (ret)
++ return dev_err_probe(&pdev->dev, ret, "Failed to register Rockchip hwrng\n");
++
++ dev_info(&pdev->dev, "Registered Rockchip hwrng\n");
++
++ return 0;
++}
++
++static int rk_rng_remove(struct platform_device *pdev)
++{
++ pm_runtime_disable(&pdev->dev);
++
++ return 0;
++}
++
++#ifdef CONFIG_PM
++static int rk_rng_runtime_suspend(struct device *dev)
++{
++ struct rk_rng *rk_rng = dev_get_drvdata(dev);
++
++ rk_rng_cleanup(&rk_rng->rng);
++
++ return 0;
++}
++
++static int rk_rng_runtime_resume(struct device *dev)
++{
++ struct rk_rng *rk_rng = dev_get_drvdata(dev);
++
++ return rk_rng_init(&rk_rng->rng);
++}
++#endif
++
++static const struct dev_pm_ops rk_rng_pm_ops = {
++ SET_RUNTIME_PM_OPS(rk_rng_runtime_suspend,
++ rk_rng_runtime_resume, NULL)
++ SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
++ pm_runtime_force_resume)
++};
++
++static const struct of_device_id rk_rng_dt_match[] = {
++ {
++ .compatible = "rockchip,rk3568-rng",
++ },
++ {},
++};
++
++MODULE_DEVICE_TABLE(of, rk_rng_dt_match);
++
++static struct platform_driver rk_rng_driver = {
++ .driver = {
++ .name = "rockchip-rng",
++ .pm = &rk_rng_pm_ops,
++ .of_match_table = rk_rng_dt_match,
++ },
++ .probe = rk_rng_probe,
++ .remove = rk_rng_remove,
++};
++
++module_platform_driver(rk_rng_driver);
++
++MODULE_DESCRIPTION("Rockchip True Random Number Generator driver");
++MODULE_AUTHOR("Lin Jinhan <troy.lin@rock-chips.com>, Aurelien Jarno <aurelien@aurel32.net>");
++MODULE_LICENSE("GPL v2");
projects / openwrt / staging / blocktrron.git / commitdiff