projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 716a757c CD |
1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* | |
| 3 | * Microchip PolarFire SoC (MPFS) hardware random driver | |
| 4 | * | |
| 5 | * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved. | |
| 6 | * | |
| 7 | * Author: Conor Dooley <conor.dooley@microchip.com> | |
| 8 | */ | |
| 9 | ||
| 10 | #include <linux/module.h> | |
| 11 | #include <linux/hw_random.h> | |
| 12 | #include <linux/platform_device.h> | |
| 13 | #include <soc/microchip/mpfs.h> | |
| 14 | ||
| 15 | #define CMD_OPCODE 0x21 | |
| 16 | #define CMD_DATA_SIZE 0U | |
| 17 | #define CMD_DATA NULL | |
| 18 | #define MBOX_OFFSET 0U | |
| 19 | #define RESP_OFFSET 0U | |
| 20 | #define RNG_RESP_BYTES 32U | |
| 21 | ||
| 22 | struct mpfs_rng { | |
| 23 | struct mpfs_sys_controller *sys_controller; | |
| 24 | struct hwrng rng; | |
| 25 | }; | |
| 26 | ||
| 27 | static int mpfs_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) | |
| 28 | { | |
| 29 | struct mpfs_rng *rng_priv = container_of(rng, struct mpfs_rng, rng); | |
| 30 | u32 response_msg[RNG_RESP_BYTES / sizeof(u32)]; | |
| 31 | unsigned int count = 0, copy_size_bytes; | |
| 32 | int ret; | |
| 33 | ||
| 34 | struct mpfs_mss_response response = { | |
| 35 | .resp_status = 0U, | |
| 36 | .resp_msg = (u32 *)response_msg, | |
| 37 | .resp_size = RNG_RESP_BYTES | |
| 38 | }; | |
| 39 | struct mpfs_mss_msg msg = { | |
| 40 | .cmd_opcode = CMD_OPCODE, | |
| 41 | .cmd_data_size = CMD_DATA_SIZE, | |
| 42 | .response = &response, | |
| 43 | .cmd_data = CMD_DATA, | |
| 44 | .mbox_offset = MBOX_OFFSET, | |
| 45 | .resp_offset = RESP_OFFSET | |
| 46 | }; | |
| 47 | ||
| 48 | while (count < max) { | |
| 49 | ret = mpfs_blocking_transaction(rng_priv->sys_controller, &msg); | |
| 50 | if (ret) | |
| 51 | return ret; | |
| 52 | ||
| 53 | copy_size_bytes = max - count > RNG_RESP_BYTES ? RNG_RESP_BYTES : max - count; | |
| 54 | memcpy(buf + count, response_msg, copy_size_bytes); | |
| 55 | ||
| 56 | count += copy_size_bytes; | |
| 57 | if (!wait) | |
| 58 | break; | |
| 59 | } | |
| 60 | ||
| 61 | return count; | |
| 62 | } | |
| 63 | ||
| 64 | static int mpfs_rng_probe(struct platform_device *pdev) | |
| 65 | { | |
| 66 | struct device *dev = &pdev->dev; | |
| 67 | struct mpfs_rng *rng_priv; | |
| 68 | int ret; | |
| 69 | ||
| 70 | rng_priv = devm_kzalloc(dev, sizeof(*rng_priv), GFP_KERNEL); | |
| 71 | if (!rng_priv) | |
| 72 | return -ENOMEM; | |
| 73 | ||
| 74 | rng_priv->sys_controller = mpfs_sys_controller_get(&pdev->dev); | |
| 75 | if (IS_ERR(rng_priv->sys_controller)) | |
| 76 | return dev_err_probe(dev, PTR_ERR(rng_priv->sys_controller), | |
| 77 | "Failed to register system controller hwrng sub device\n"); | |
| 78 | ||
| 79 | rng_priv->rng.read = mpfs_rng_read; | |
| 80 | rng_priv->rng.name = pdev->name; | |
| 81 | rng_priv->rng.quality = 1024; | |
| 82 | ||
| 83 | platform_set_drvdata(pdev, rng_priv); | |
| 84 | ||
| 85 | ret = devm_hwrng_register(&pdev->dev, &rng_priv->rng); | |
| 86 | if (ret) | |
| 87 | return dev_err_probe(&pdev->dev, ret, "Failed to register MPFS hwrng\n"); | |
| 88 | ||
| 89 | dev_info(&pdev->dev, "Registered MPFS hwrng\n"); | |
| 90 | ||
| 91 | return 0; | |
| 92 | } | |
| 93 | ||
| 94 | static struct platform_driver mpfs_rng_driver = { | |
| 95 | .driver = { | |
| 96 | .name = "mpfs-rng", | |
| 97 | }, | |
| 98 | .probe = mpfs_rng_probe, | |
| 99 | }; | |
| 100 | module_platform_driver(mpfs_rng_driver); | |
| 101 | ||
| 102 | MODULE_LICENSE("GPL"); | |
| 103 | MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>"); | |
| 104 | MODULE_DESCRIPTION("PolarFire SoC (MPFS) hardware random driver"); |