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