102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Microchip PolarFire SoC (MPFS) hardware random driver
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*
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* Copyright (c) 2020-2022 Microchip Corporation. All rights reserved.
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*
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* Author: Conor Dooley <conor.dooley@microchip.com>
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*/
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#include <linux/module.h>
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#include <linux/hw_random.h>
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#include <linux/platform_device.h>
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#include <soc/microchip/mpfs.h>
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#define CMD_OPCODE 0x21
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#define CMD_DATA_SIZE 0U
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#define CMD_DATA NULL
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#define MBOX_OFFSET 0U
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#define RESP_OFFSET 0U
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#define RNG_RESP_BYTES 32U
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struct mpfs_rng {
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struct mpfs_sys_controller *sys_controller;
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struct hwrng rng;
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};
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static int mpfs_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct mpfs_rng *rng_priv = container_of(rng, struct mpfs_rng, rng);
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u32 response_msg[RNG_RESP_BYTES / sizeof(u32)];
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unsigned int count = 0, copy_size_bytes;
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int ret;
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struct mpfs_mss_response response = {
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.resp_status = 0U,
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.resp_msg = (u32 *)response_msg,
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.resp_size = RNG_RESP_BYTES
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};
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struct mpfs_mss_msg msg = {
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.cmd_opcode = CMD_OPCODE,
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.cmd_data_size = CMD_DATA_SIZE,
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.response = &response,
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.cmd_data = CMD_DATA,
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.mbox_offset = MBOX_OFFSET,
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.resp_offset = RESP_OFFSET
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};
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while (count < max) {
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ret = mpfs_blocking_transaction(rng_priv->sys_controller, &msg);
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if (ret)
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return ret;
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copy_size_bytes = max - count > RNG_RESP_BYTES ? RNG_RESP_BYTES : max - count;
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memcpy(buf + count, response_msg, copy_size_bytes);
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count += copy_size_bytes;
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if (!wait)
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break;
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}
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return count;
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}
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static int mpfs_rng_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct mpfs_rng *rng_priv;
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int ret;
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rng_priv = devm_kzalloc(dev, sizeof(*rng_priv), GFP_KERNEL);
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if (!rng_priv)
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return -ENOMEM;
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rng_priv->sys_controller = mpfs_sys_controller_get(&pdev->dev);
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if (IS_ERR(rng_priv->sys_controller))
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return dev_err_probe(dev, PTR_ERR(rng_priv->sys_controller),
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"Failed to register system controller hwrng sub device\n");
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rng_priv->rng.read = mpfs_rng_read;
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rng_priv->rng.name = pdev->name;
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ret = devm_hwrng_register(&pdev->dev, &rng_priv->rng);
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if (ret)
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return dev_err_probe(&pdev->dev, ret, "Failed to register MPFS hwrng\n");
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dev_info(&pdev->dev, "Registered MPFS hwrng\n");
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return 0;
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}
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static struct platform_driver mpfs_rng_driver = {
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.driver = {
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.name = "mpfs-rng",
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},
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.probe = mpfs_rng_probe,
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};
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module_platform_driver(mpfs_rng_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
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MODULE_DESCRIPTION("PolarFire SoC (MPFS) hardware random driver");
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