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![Chuhong Yuan](/assets/img/avatar_default.png)
Use devm_hwrng_register to get rid of manual unregistration. Signed-off-by: Chuhong Yuan <hslester96@gmail.com> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
170 lines
4 KiB
C
170 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Microchip / Atmel SHA204A (I2C) driver.
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*
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* Copyright (c) 2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include "atmel-i2c.h"
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static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data,
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void *areq, int status)
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{
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struct atmel_i2c_client_priv *i2c_priv = work_data->ctx;
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struct hwrng *rng = areq;
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if (status)
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dev_warn_ratelimited(&i2c_priv->client->dev,
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"i2c transaction failed (%d)\n",
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status);
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rng->priv = (unsigned long)work_data;
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atomic_dec(&i2c_priv->tfm_count);
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}
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static int atmel_sha204a_rng_read_nonblocking(struct hwrng *rng, void *data,
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size_t max)
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{
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struct atmel_i2c_client_priv *i2c_priv;
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struct atmel_i2c_work_data *work_data;
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i2c_priv = container_of(rng, struct atmel_i2c_client_priv, hwrng);
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/* keep maximum 1 asynchronous read in flight at any time */
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if (!atomic_add_unless(&i2c_priv->tfm_count, 1, 1))
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return 0;
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if (rng->priv) {
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work_data = (struct atmel_i2c_work_data *)rng->priv;
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max = min(sizeof(work_data->cmd.data), max);
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memcpy(data, &work_data->cmd.data, max);
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rng->priv = 0;
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} else {
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work_data = kmalloc(sizeof(*work_data), GFP_ATOMIC);
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if (!work_data)
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return -ENOMEM;
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work_data->ctx = i2c_priv;
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work_data->client = i2c_priv->client;
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max = 0;
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}
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atmel_i2c_init_random_cmd(&work_data->cmd);
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atmel_i2c_enqueue(work_data, atmel_sha204a_rng_done, rng);
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return max;
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}
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static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max,
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bool wait)
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{
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struct atmel_i2c_client_priv *i2c_priv;
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struct atmel_i2c_cmd cmd;
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int ret;
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if (!wait)
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return atmel_sha204a_rng_read_nonblocking(rng, data, max);
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i2c_priv = container_of(rng, struct atmel_i2c_client_priv, hwrng);
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atmel_i2c_init_random_cmd(&cmd);
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ret = atmel_i2c_send_receive(i2c_priv->client, &cmd);
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if (ret)
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return ret;
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max = min(sizeof(cmd.data), max);
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memcpy(data, cmd.data, max);
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return max;
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}
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static int atmel_sha204a_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct atmel_i2c_client_priv *i2c_priv;
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int ret;
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ret = atmel_i2c_probe(client, id);
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if (ret)
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return ret;
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i2c_priv = i2c_get_clientdata(client);
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memset(&i2c_priv->hwrng, 0, sizeof(i2c_priv->hwrng));
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i2c_priv->hwrng.name = dev_name(&client->dev);
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i2c_priv->hwrng.read = atmel_sha204a_rng_read;
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i2c_priv->hwrng.quality = 1024;
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ret = devm_hwrng_register(&client->dev, &i2c_priv->hwrng);
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if (ret)
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dev_warn(&client->dev, "failed to register RNG (%d)\n", ret);
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return ret;
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}
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static int atmel_sha204a_remove(struct i2c_client *client)
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{
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struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
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if (atomic_read(&i2c_priv->tfm_count)) {
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dev_err(&client->dev, "Device is busy\n");
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return -EBUSY;
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}
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if (i2c_priv->hwrng.priv)
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kfree((void *)i2c_priv->hwrng.priv);
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return 0;
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}
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static const struct of_device_id atmel_sha204a_dt_ids[] = {
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{ .compatible = "atmel,atsha204a", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, atmel_sha204a_dt_ids);
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static const struct i2c_device_id atmel_sha204a_id[] = {
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{ "atsha204a", 0 },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(i2c, atmel_sha204a_id);
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static struct i2c_driver atmel_sha204a_driver = {
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.probe = atmel_sha204a_probe,
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.remove = atmel_sha204a_remove,
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.id_table = atmel_sha204a_id,
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.driver.name = "atmel-sha204a",
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.driver.of_match_table = of_match_ptr(atmel_sha204a_dt_ids),
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};
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static int __init atmel_sha204a_init(void)
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{
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return i2c_add_driver(&atmel_sha204a_driver);
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}
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static void __exit atmel_sha204a_exit(void)
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{
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flush_scheduled_work();
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i2c_del_driver(&atmel_sha204a_driver);
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}
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module_init(atmel_sha204a_init);
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module_exit(atmel_sha204a_exit);
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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