diff options
Diffstat (limited to 'drivers/char/hw_random/imx-rngc.c')
| -rw-r--r-- | drivers/char/hw_random/imx-rngc.c | 229 |
1 files changed, 136 insertions, 93 deletions
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c index 14730be54edf..241664a9b5d9 100644 --- a/drivers/char/hw_random/imx-rngc.c +++ b/drivers/char/hw_random/imx-rngc.c @@ -1,15 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * RNG driver for Freescale RNGC * * Copyright (C) 2008-2012 Freescale Semiconductor, Inc. * Copyright (C) 2017 Martin Kaiser <martin@kaiser.cx> - * - * The code contained herein is licensed under the GNU General Public - * License. You may obtain a copy of the GNU General Public License - * Version 2 or later at the following locations: - * - * http://www.opensource.org/licenses/gpl-license.html - * http://www.gnu.org/copyleft/gpl.html */ #include <linux/module.h> @@ -19,35 +13,49 @@ #include <linux/clk.h> #include <linux/err.h> #include <linux/platform_device.h> +#include <linux/pm.h> +#include <linux/pm_runtime.h> #include <linux/interrupt.h> #include <linux/hw_random.h> #include <linux/completion.h> #include <linux/io.h> +#include <linux/bitfield.h> +#define RNGC_VER_ID 0x0000 #define RNGC_COMMAND 0x0004 #define RNGC_CONTROL 0x0008 #define RNGC_STATUS 0x000C #define RNGC_ERROR 0x0010 #define RNGC_FIFO 0x0014 -#define RNGC_CMD_CLR_ERR 0x00000020 -#define RNGC_CMD_CLR_INT 0x00000010 -#define RNGC_CMD_SEED 0x00000002 -#define RNGC_CMD_SELF_TEST 0x00000001 +/* the fields in the ver id register */ +#define RNG_TYPE GENMASK(31, 28) +#define RNGC_VER_MAJ_SHIFT 8 -#define RNGC_CTRL_MASK_ERROR 0x00000040 -#define RNGC_CTRL_MASK_DONE 0x00000020 +/* the rng_type field */ +#define RNGC_TYPE_RNGB 0x1 +#define RNGC_TYPE_RNGC 0x2 -#define RNGC_STATUS_ERROR 0x00010000 -#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00 -#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8 -#define RNGC_STATUS_SEED_DONE 0x00000020 -#define RNGC_STATUS_ST_DONE 0x00000010 -#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008 +#define RNGC_CMD_CLR_ERR BIT(5) +#define RNGC_CMD_CLR_INT BIT(4) +#define RNGC_CMD_SEED BIT(1) +#define RNGC_CMD_SELF_TEST BIT(0) -#define RNGC_TIMEOUT 3000 /* 3 sec */ +#define RNGC_CTRL_MASK_ERROR BIT(6) +#define RNGC_CTRL_MASK_DONE BIT(5) +#define RNGC_CTRL_AUTO_SEED BIT(4) +#define RNGC_STATUS_ERROR BIT(16) +#define RNGC_STATUS_FIFO_LEVEL_MASK GENMASK(11, 8) +#define RNGC_STATUS_SEED_DONE BIT(5) +#define RNGC_STATUS_ST_DONE BIT(4) + +#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008 + +#define RNGC_SELFTEST_TIMEOUT 2500 /* us */ +#define RNGC_SEED_TIMEOUT 200 /* ms */ +#define RNGC_PM_TIMEOUT 500 /* ms */ static bool self_test = true; module_param(self_test, bool, 0); @@ -105,24 +113,24 @@ static int imx_rngc_self_test(struct imx_rngc *rngc) cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND); - ret = wait_for_completion_timeout(&rngc->rng_op_done, RNGC_TIMEOUT); - if (!ret) { - imx_rngc_irq_mask_clear(rngc); + ret = wait_for_completion_timeout(&rngc->rng_op_done, + usecs_to_jiffies(RNGC_SELFTEST_TIMEOUT)); + imx_rngc_irq_mask_clear(rngc); + if (!ret) return -ETIMEDOUT; - } - if (rngc->err_reg != 0) - return -EIO; - - return 0; + return rngc->err_reg ? -EIO : 0; } static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) { struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); unsigned int status; - unsigned int level; - int retval = 0; + int err, retval = 0; + + err = pm_runtime_resume_and_get(rngc->dev); + if (err) + return err; while (max >= sizeof(u32)) { status = readl(rngc->base + RNGC_STATUS); @@ -131,11 +139,7 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) if (status & RNGC_STATUS_ERROR) break; - /* how many random numbers are in FIFO? [0-16] */ - level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >> - RNGC_STATUS_FIFO_LEVEL_SHIFT; - - if (level) { + if (status & RNGC_STATUS_FIFO_LEVEL_MASK) { /* retrieve a random number from FIFO */ *(u32 *)data = readl(rngc->base + RNGC_FIFO); @@ -144,6 +148,8 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) max -= sizeof(u32); } } + pm_runtime_mark_last_busy(rngc->dev); + pm_runtime_put(rngc->dev); return retval ? retval : -EIO; } @@ -171,71 +177,107 @@ static irqreturn_t imx_rngc_irq(int irq, void *priv) static int imx_rngc_init(struct hwrng *rng) { struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); - u32 cmd; - int ret; + u32 cmd, ctrl; + int ret, err; + + err = pm_runtime_resume_and_get(rngc->dev); + if (err) + return err; /* clear error */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND); + imx_rngc_irq_unmask(rngc); + /* create seed, repeat while there is some statistical error */ do { - imx_rngc_irq_unmask(rngc); - /* seed creation */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND); ret = wait_for_completion_timeout(&rngc->rng_op_done, - RNGC_TIMEOUT); - + msecs_to_jiffies(RNGC_SEED_TIMEOUT)); if (!ret) { - imx_rngc_irq_mask_clear(rngc); - return -ETIMEDOUT; + err = -ETIMEDOUT; + goto out; } } while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR); - return rngc->err_reg ? -EIO : 0; + if (rngc->err_reg) { + err = -EIO; + goto out; + } + + /* + * enable automatic seeding, the rngc creates a new seed automatically + * after serving 2^20 random 160-bit words + */ + ctrl = readl(rngc->base + RNGC_CONTROL); + ctrl |= RNGC_CTRL_AUTO_SEED; + writel(ctrl, rngc->base + RNGC_CONTROL); + +out: + /* + * if initialisation was successful, we keep the interrupt + * unmasked until imx_rngc_cleanup is called + * we mask the interrupt ourselves if we return an error + */ + if (err) + imx_rngc_irq_mask_clear(rngc); + + pm_runtime_put(rngc->dev); + return err; +} + +static void imx_rngc_cleanup(struct hwrng *rng) +{ + struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); + int err; + + err = pm_runtime_resume_and_get(rngc->dev); + if (!err) { + imx_rngc_irq_mask_clear(rngc); + pm_runtime_put(rngc->dev); + } } -static int imx_rngc_probe(struct platform_device *pdev) +static int __init imx_rngc_probe(struct platform_device *pdev) { struct imx_rngc *rngc; - struct resource *res; int ret; int irq; + u32 ver_id; + u8 rng_type; rngc = devm_kzalloc(&pdev->dev, sizeof(*rngc), GFP_KERNEL); if (!rngc) return -ENOMEM; - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - rngc->base = devm_ioremap_resource(&pdev->dev, res); + rngc->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rngc->base)) return PTR_ERR(rngc->base); rngc->clk = devm_clk_get(&pdev->dev, NULL); - if (IS_ERR(rngc->clk)) { - dev_err(&pdev->dev, "Can not get rng_clk\n"); - return PTR_ERR(rngc->clk); - } + if (IS_ERR(rngc->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(rngc->clk), "Cannot get rng_clk\n"); irq = platform_get_irq(pdev, 0); - if (irq <= 0) { - dev_err(&pdev->dev, "Couldn't get irq %d\n", irq); + if (irq < 0) return irq; - } - ret = clk_prepare_enable(rngc->clk); - if (ret) - return ret; + clk_prepare_enable(rngc->clk); - ret = devm_request_irq(&pdev->dev, - irq, imx_rngc_irq, 0, pdev->name, (void *)rngc); - if (ret) { - dev_err(rngc->dev, "Can't get interrupt working.\n"); - goto err; + ver_id = readl(rngc->base + RNGC_VER_ID); + rng_type = FIELD_GET(RNG_TYPE, ver_id); + /* + * This driver supports only RNGC and RNGB. (There's a different + * driver for RNGA.) + */ + if (rng_type != RNGC_TYPE_RNGC && rng_type != RNGC_TYPE_RNGB) { + clk_disable_unprepare(rngc->clk); + return -ENODEV; } init_completion(&rngc->rng_op_done); @@ -243,47 +285,46 @@ static int imx_rngc_probe(struct platform_device *pdev) rngc->rng.name = pdev->name; rngc->rng.init = imx_rngc_init; rngc->rng.read = imx_rngc_read; + rngc->rng.cleanup = imx_rngc_cleanup; + rngc->rng.quality = 19; rngc->dev = &pdev->dev; platform_set_drvdata(pdev, rngc); imx_rngc_irq_mask_clear(rngc); + ret = devm_request_irq(&pdev->dev, + irq, imx_rngc_irq, 0, pdev->name, (void *)rngc); + if (ret) { + clk_disable_unprepare(rngc->clk); + return dev_err_probe(&pdev->dev, ret, "Can't get interrupt working.\n"); + } + if (self_test) { ret = imx_rngc_self_test(rngc); if (ret) { - dev_err(rngc->dev, "FSL RNGC self test failed.\n"); - goto err; + clk_disable_unprepare(rngc->clk); + return dev_err_probe(&pdev->dev, ret, "self test failed\n"); } } - ret = hwrng_register(&rngc->rng); - if (ret) { - dev_err(&pdev->dev, "FSL RNGC registering failed (%d)\n", ret); - goto err; - } - - dev_info(&pdev->dev, "Freescale RNGC registered.\n"); - return 0; - -err: - clk_disable_unprepare(rngc->clk); + pm_runtime_set_autosuspend_delay(&pdev->dev, RNGC_PM_TIMEOUT); + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + devm_pm_runtime_enable(&pdev->dev); - return ret; -} - -static int __exit imx_rngc_remove(struct platform_device *pdev) -{ - struct imx_rngc *rngc = platform_get_drvdata(pdev); - - hwrng_unregister(&rngc->rng); - - clk_disable_unprepare(rngc->clk); + ret = devm_hwrng_register(&pdev->dev, &rngc->rng); + if (ret) + return dev_err_probe(&pdev->dev, ret, "hwrng registration failed\n"); + dev_info(&pdev->dev, + "Freescale RNG%c registered (HW revision %d.%02d)\n", + rng_type == RNGC_TYPE_RNGB ? 'B' : 'C', + (ver_id >> RNGC_VER_MAJ_SHIFT) & 0xff, ver_id & 0xff); return 0; } -static int __maybe_unused imx_rngc_suspend(struct device *dev) +static int imx_rngc_suspend(struct device *dev) { struct imx_rngc *rngc = dev_get_drvdata(dev); @@ -292,7 +333,7 @@ static int __maybe_unused imx_rngc_suspend(struct device *dev) return 0; } -static int __maybe_unused imx_rngc_resume(struct device *dev) +static int imx_rngc_resume(struct device *dev) { struct imx_rngc *rngc = dev_get_drvdata(dev); @@ -301,21 +342,23 @@ static int __maybe_unused imx_rngc_resume(struct device *dev) return 0; } -static SIMPLE_DEV_PM_OPS(imx_rngc_pm_ops, imx_rngc_suspend, imx_rngc_resume); +static const struct dev_pm_ops imx_rngc_pm_ops = { + SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) + RUNTIME_PM_OPS(imx_rngc_suspend, imx_rngc_resume, NULL) +}; static const struct of_device_id imx_rngc_dt_ids[] = { - { .compatible = "fsl,imx25-rngb", .data = NULL, }, + { .compatible = "fsl,imx25-rngb" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, imx_rngc_dt_ids); static struct platform_driver imx_rngc_driver = { .driver = { - .name = "imx_rngc", - .pm = &imx_rngc_pm_ops, + .name = KBUILD_MODNAME, + .pm = pm_ptr(&imx_rngc_pm_ops), .of_match_table = imx_rngc_dt_ids, }, - .remove = __exit_p(imx_rngc_remove), }; module_platform_driver_probe(imx_rngc_driver, imx_rngc_probe); |