182 строки
4.0 KiB
C
182 строки
4.0 KiB
C
/*
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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 <juha.yrjola@solidboot.com>
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*
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* Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.com>
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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/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 <pali.rohar@gmail.com>");
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MODULE_LICENSE("GPL");
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