diff options
Diffstat (limited to 'drivers/char/hw_random/ks-sa-rng.c')
| -rw-r--r-- | drivers/char/hw_random/ks-sa-rng.c | 92 |
1 files changed, 55 insertions, 37 deletions
diff --git a/drivers/char/hw_random/ks-sa-rng.c b/drivers/char/hw_random/ks-sa-rng.c index 62c6696c1dbd..9e408144a10c 100644 --- a/drivers/char/hw_random/ks-sa-rng.c +++ b/drivers/char/hw_random/ks-sa-rng.c @@ -1,19 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Random Number Generator driver for the Keystone SOC * - * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com + * Copyright (C) 2016 Texas Instruments Incorporated - https://www.ti.com * * Authors: Sandeep Nair * Vitaly Andrianov - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * 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/hw_random.h> @@ -29,6 +21,7 @@ #include <linux/of.h> #include <linux/of_address.h> #include <linux/delay.h> +#include <linux/timekeeping.h> #define SA_CMD_STATUS_OFS 0x8 @@ -88,18 +81,39 @@ struct trng_regs { }; struct ks_sa_rng { - struct device *dev; struct hwrng rng; struct clk *clk; struct regmap *regmap_cfg; - struct trng_regs *reg_rng; + struct trng_regs __iomem *reg_rng; + u64 ready_ts; + unsigned int refill_delay_ns; }; +static unsigned int cycles_to_ns(unsigned long clk_rate, unsigned int cycles) +{ + return DIV_ROUND_UP_ULL((TRNG_DEF_CLK_DIV_CYCLES + 1) * 1000000000ull * + cycles, clk_rate); +} + +static unsigned int startup_delay_ns(unsigned long clk_rate) +{ + if (!TRNG_DEF_STARTUP_CYCLES) + return cycles_to_ns(clk_rate, BIT(24)); + return cycles_to_ns(clk_rate, 256 * TRNG_DEF_STARTUP_CYCLES); +} + +static unsigned int refill_delay_ns(unsigned long clk_rate) +{ + if (!TRNG_DEF_MAX_REFILL_CYCLES) + return cycles_to_ns(clk_rate, BIT(24)); + return cycles_to_ns(clk_rate, 256 * TRNG_DEF_MAX_REFILL_CYCLES); +} + static int ks_sa_rng_init(struct hwrng *rng) { u32 value; - struct device *dev = (struct device *)rng->priv; - struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev); + struct ks_sa_rng *ks_sa_rng = container_of(rng, struct ks_sa_rng, rng); + unsigned long clk_rate = clk_get_rate(ks_sa_rng->clk); /* Enable RNG module */ regmap_write_bits(ks_sa_rng->regmap_cfg, SA_CMD_STATUS_OFS, @@ -128,13 +142,16 @@ static int ks_sa_rng_init(struct hwrng *rng) value |= TRNG_CNTL_REG_TRNG_ENABLE; writel(value, &ks_sa_rng->reg_rng->control); + ks_sa_rng->refill_delay_ns = refill_delay_ns(clk_rate); + ks_sa_rng->ready_ts = ktime_get_ns() + + startup_delay_ns(clk_rate); + return 0; } static void ks_sa_rng_cleanup(struct hwrng *rng) { - struct device *dev = (struct device *)rng->priv; - struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev); + struct ks_sa_rng *ks_sa_rng = container_of(rng, struct ks_sa_rng, rng); /* Disable RNG */ writel(0, &ks_sa_rng->reg_rng->control); @@ -144,26 +161,34 @@ static void ks_sa_rng_cleanup(struct hwrng *rng) static int ks_sa_rng_data_read(struct hwrng *rng, u32 *data) { - struct device *dev = (struct device *)rng->priv; - struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev); + struct ks_sa_rng *ks_sa_rng = container_of(rng, struct ks_sa_rng, rng); /* Read random data */ data[0] = readl(&ks_sa_rng->reg_rng->output_l); data[1] = readl(&ks_sa_rng->reg_rng->output_h); writel(TRNG_INTACK_REG_READY, &ks_sa_rng->reg_rng->intack); + ks_sa_rng->ready_ts = ktime_get_ns() + ks_sa_rng->refill_delay_ns; return sizeof(u32) * 2; } static int ks_sa_rng_data_present(struct hwrng *rng, int wait) { - struct device *dev = (struct device *)rng->priv; - struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev); + struct ks_sa_rng *ks_sa_rng = container_of(rng, struct ks_sa_rng, rng); + u64 now = ktime_get_ns(); u32 ready; int j; + if (wait && now < ks_sa_rng->ready_ts) { + /* Max delay expected here is 81920000 ns */ + unsigned long min_delay = + DIV_ROUND_UP((u32)(ks_sa_rng->ready_ts - now), 1000); + + usleep_range(min_delay, min_delay + SA_RNG_DATA_RETRY_DELAY); + } + for (j = 0; j < SA_MAX_RNG_DATA_RETRIES; j++) { ready = readl(&ks_sa_rng->reg_rng->status); ready &= TRNG_STATUS_REG_READY; @@ -182,13 +207,11 @@ static int ks_sa_rng_probe(struct platform_device *pdev) struct ks_sa_rng *ks_sa_rng; struct device *dev = &pdev->dev; int ret; - struct resource *mem; ks_sa_rng = devm_kzalloc(dev, sizeof(*ks_sa_rng), GFP_KERNEL); if (!ks_sa_rng) return -ENOMEM; - ks_sa_rng->dev = dev; ks_sa_rng->rng = (struct hwrng) { .name = "ks_sa_hwrng", .init = ks_sa_rng_init, @@ -196,10 +219,8 @@ static int ks_sa_rng_probe(struct platform_device *pdev) .data_present = ks_sa_rng_data_present, .cleanup = ks_sa_rng_cleanup, }; - ks_sa_rng->rng.priv = (unsigned long)dev; - mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); - ks_sa_rng->reg_rng = devm_ioremap_resource(dev, mem); + ks_sa_rng->reg_rng = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(ks_sa_rng->reg_rng)) return PTR_ERR(ks_sa_rng->reg_rng); @@ -207,30 +228,27 @@ static int ks_sa_rng_probe(struct platform_device *pdev) syscon_regmap_lookup_by_phandle(dev->of_node, "ti,syscon-sa-cfg"); - if (IS_ERR(ks_sa_rng->regmap_cfg)) { - dev_err(dev, "syscon_node_to_regmap failed\n"); - return -EINVAL; - } + if (IS_ERR(ks_sa_rng->regmap_cfg)) + return dev_err_probe(dev, -EINVAL, "syscon_node_to_regmap failed\n"); + + ks_sa_rng->clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(ks_sa_rng->clk)) + return dev_err_probe(dev, PTR_ERR(ks_sa_rng->clk), "Failed to get clock\n"); pm_runtime_enable(dev); - ret = pm_runtime_get_sync(dev); + ret = pm_runtime_resume_and_get(dev); if (ret < 0) { - dev_err(dev, "Failed to enable SA power-domain\n"); pm_runtime_disable(dev); - return ret; + return dev_err_probe(dev, ret, "Failed to enable SA power-domain\n"); } - platform_set_drvdata(pdev, ks_sa_rng); - return devm_hwrng_register(&pdev->dev, &ks_sa_rng->rng); } -static int ks_sa_rng_remove(struct platform_device *pdev) +static void ks_sa_rng_remove(struct platform_device *pdev) { pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); - - return 0; } static const struct of_device_id ks_sa_rng_dt_match[] = { |