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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | // SPDX-License-Identifier: GPL-2.0 /* * Microchip PolarFire SoC (MPFS) hardware random driver * * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved. * * Author: Conor Dooley <conor.dooley@microchip.com> */ #include <linux/module.h> #include <linux/hw_random.h> #include <linux/platform_device.h> #include <soc/microchip/mpfs.h> #define CMD_OPCODE 0x21 #define CMD_DATA_SIZE 0U #define CMD_DATA NULL #define MBOX_OFFSET 0U #define RESP_OFFSET 0U #define RNG_RESP_BYTES 32U struct mpfs_rng { struct mpfs_sys_controller *sys_controller; struct hwrng rng; }; static int mpfs_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct mpfs_rng *rng_priv = container_of(rng, struct mpfs_rng, rng); u32 response_msg[RNG_RESP_BYTES / sizeof(u32)]; unsigned int count = 0, copy_size_bytes; int ret; struct mpfs_mss_response response = { .resp_status = 0U, .resp_msg = (u32 *)response_msg, .resp_size = RNG_RESP_BYTES }; struct mpfs_mss_msg msg = { .cmd_opcode = CMD_OPCODE, .cmd_data_size = CMD_DATA_SIZE, .response = &response, .cmd_data = CMD_DATA, .mbox_offset = MBOX_OFFSET, .resp_offset = RESP_OFFSET }; while (count < max) { ret = mpfs_blocking_transaction(rng_priv->sys_controller, &msg); if (ret) return ret; copy_size_bytes = max - count > RNG_RESP_BYTES ? RNG_RESP_BYTES : max - count; memcpy(buf + count, response_msg, copy_size_bytes); count += copy_size_bytes; if (!wait) break; } return count; } static int mpfs_rng_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct mpfs_rng *rng_priv; int ret; rng_priv = devm_kzalloc(dev, sizeof(*rng_priv), GFP_KERNEL); if (!rng_priv) return -ENOMEM; rng_priv->sys_controller = mpfs_sys_controller_get(&pdev->dev); if (IS_ERR(rng_priv->sys_controller)) return dev_err_probe(dev, PTR_ERR(rng_priv->sys_controller), "Failed to register system controller hwrng sub device\n"); rng_priv->rng.read = mpfs_rng_read; rng_priv->rng.name = pdev->name; platform_set_drvdata(pdev, rng_priv); ret = devm_hwrng_register(&pdev->dev, &rng_priv->rng); if (ret) return dev_err_probe(&pdev->dev, ret, "Failed to register MPFS hwrng\n"); dev_info(&pdev->dev, "Registered MPFS hwrng\n"); return 0; } static struct platform_driver mpfs_rng_driver = { .driver = { .name = "mpfs-rng", }, .probe = mpfs_rng_probe, }; module_platform_driver(mpfs_rng_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>"); MODULE_DESCRIPTION("PolarFire SoC (MPFS) hardware random driver"); |