diff options
Diffstat (limited to 'drivers/char/hw_random/omap3-rom-rng.c')
| -rw-r--r-- | drivers/char/hw_random/omap3-rom-rng.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c new file mode 100644 index 000000000..f06e4f951 --- /dev/null +++ b/drivers/char/hw_random/omap3-rom-rng.c @@ -0,0 +1,182 @@ +/* + * omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family + * + * Copyright (C) 2009 Nokia Corporation + * Author: Juha Yrjola <juha.yrjola@solidboot.com> + * + * Copyright (C) 2013 Pali Rohár <pali@kernel.org> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/random.h> +#include <linux/hw_random.h> +#include <linux/workqueue.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> + +#define RNG_RESET 0x01 +#define RNG_GEN_PRNG_HW_INIT 0x02 +#define RNG_GEN_HW 0x08 + +struct omap_rom_rng { + struct clk *clk; + struct device *dev; + struct hwrng ops; + u32 (*rom_rng_call)(u32 ptr, u32 count, u32 flag); +}; + +static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w) +{ + struct omap_rom_rng *ddata; + u32 ptr; + int r; + + ddata = (struct omap_rom_rng *)rng->priv; + + r = pm_runtime_get_sync(ddata->dev); + if (r < 0) { + pm_runtime_put_noidle(ddata->dev); + + return r; + } + + ptr = virt_to_phys(data); + r = ddata->rom_rng_call(ptr, 4, RNG_GEN_HW); + if (r != 0) + r = -EINVAL; + else + r = 4; + + pm_runtime_mark_last_busy(ddata->dev); + pm_runtime_put_autosuspend(ddata->dev); + + return r; +} + +static int __maybe_unused omap_rom_rng_runtime_suspend(struct device *dev) +{ + struct omap_rom_rng *ddata; + int r; + + ddata = dev_get_drvdata(dev); + + r = ddata->rom_rng_call(0, 0, RNG_RESET); + if (r != 0) + dev_err(dev, "reset failed: %d\n", r); + + clk_disable_unprepare(ddata->clk); + + return 0; +} + +static int __maybe_unused omap_rom_rng_runtime_resume(struct device *dev) +{ + struct omap_rom_rng *ddata; + int r; + + ddata = dev_get_drvdata(dev); + + r = clk_prepare_enable(ddata->clk); + if (r < 0) + return r; + + r = ddata->rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT); + if (r != 0) { + clk_disable_unprepare(ddata->clk); + dev_err(dev, "HW init failed: %d\n", r); + + return -EIO; + } + + return 0; +} + +static void omap_rom_rng_finish(void *data) +{ + struct omap_rom_rng *ddata = data; + + pm_runtime_dont_use_autosuspend(ddata->dev); + pm_runtime_disable(ddata->dev); +} + +static int omap3_rom_rng_probe(struct platform_device *pdev) +{ + struct omap_rom_rng *ddata; + int ret = 0; + + ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) + return -ENOMEM; + + ddata->dev = &pdev->dev; + ddata->ops.priv = (unsigned long)ddata; + ddata->ops.name = "omap3-rom"; + ddata->ops.read = of_device_get_match_data(&pdev->dev); + ddata->ops.quality = 900; + if (!ddata->ops.read) { + dev_err(&pdev->dev, "missing rom code handler\n"); + + return -ENODEV; + } + dev_set_drvdata(ddata->dev, ddata); + + ddata->rom_rng_call = pdev->dev.platform_data; + if (!ddata->rom_rng_call) { + dev_err(ddata->dev, "rom_rng_call is NULL\n"); + return -EINVAL; + } + + ddata->clk = devm_clk_get(ddata->dev, "ick"); + if (IS_ERR(ddata->clk)) { + dev_err(ddata->dev, "unable to get RNG clock\n"); + return PTR_ERR(ddata->clk); + } + + pm_runtime_enable(&pdev->dev); + pm_runtime_set_autosuspend_delay(&pdev->dev, 500); + pm_runtime_use_autosuspend(&pdev->dev); + + ret = devm_add_action_or_reset(ddata->dev, omap_rom_rng_finish, + ddata); + if (ret) + return ret; + + return devm_hwrng_register(ddata->dev, &ddata->ops); +} + +static const struct of_device_id omap_rom_rng_match[] = { + { .compatible = "nokia,n900-rom-rng", .data = omap3_rom_rng_read, }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, omap_rom_rng_match); + +static const struct dev_pm_ops omap_rom_rng_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(omap_rom_rng_runtime_suspend, + omap_rom_rng_runtime_resume) +}; + +static struct platform_driver omap3_rom_rng_driver = { + .driver = { + .name = "omap3-rom-rng", + .of_match_table = omap_rom_rng_match, + .pm = &omap_rom_rng_pm_ops, + }, + .probe = omap3_rom_rng_probe, +}; + +module_platform_driver(omap3_rom_rng_driver); + +MODULE_ALIAS("platform:omap3-rom-rng"); +MODULE_AUTHOR("Juha Yrjola"); +MODULE_AUTHOR("Pali Rohár <pali@kernel.org>"); +MODULE_LICENSE("GPL"); |