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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | // SPDX-License-Identifier: GPL-2.0 /* * Driver for the Intel SCU IPC mechanism * * (C) Copyright 2008-2010 Intel Corporation * Author: Sreedhara DS (sreedhara.ds@intel.com) * * This driver provides IOCTL interfaces to call Intel SCU IPC driver API. */ #include <linux/errno.h> #include <linux/fcntl.h> #include <linux/fs.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/uaccess.h> #include <asm/intel_scu_ipc.h> static int major; /* IOCTL commands */ #define INTE_SCU_IPC_REGISTER_READ 0 #define INTE_SCU_IPC_REGISTER_WRITE 1 #define INTE_SCU_IPC_REGISTER_UPDATE 2 struct scu_ipc_data { u32 count; /* No. of registers */ u16 addr[5]; /* Register addresses */ u8 data[5]; /* Register data */ u8 mask; /* Valid for read-modify-write */ }; /** * scu_reg_access - implement register access ioctls * @cmd: command we are doing (read/write/update) * @data: kernel copy of ioctl data * * Allow the user to perform register accesses on the SCU via the * kernel interface */ static int scu_reg_access(u32 cmd, struct scu_ipc_data *data) { unsigned int count = data->count; if (count == 0 || count == 3 || count > 4) return -EINVAL; switch (cmd) { case INTE_SCU_IPC_REGISTER_READ: return intel_scu_ipc_readv(data->addr, data->data, count); case INTE_SCU_IPC_REGISTER_WRITE: return intel_scu_ipc_writev(data->addr, data->data, count); case INTE_SCU_IPC_REGISTER_UPDATE: return intel_scu_ipc_update_register(data->addr[0], data->data[0], data->mask); default: return -ENOTTY; } } /** * scu_ipc_ioctl - control ioctls for the SCU * @fp: file handle of the SCU device * @cmd: ioctl coce * @arg: pointer to user passed structure * * Support the I/O and firmware flashing interfaces of the SCU */ static long scu_ipc_ioctl(struct file *fp, unsigned int cmd, unsigned long arg) { int ret; struct scu_ipc_data data; void __user *argp = (void __user *)arg; if (!capable(CAP_SYS_RAWIO)) return -EPERM; if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data))) return -EFAULT; ret = scu_reg_access(cmd, &data); if (ret < 0) return ret; if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data))) return -EFAULT; return 0; } static const struct file_operations scu_ipc_fops = { .unlocked_ioctl = scu_ipc_ioctl, }; static int __init ipc_module_init(void) { major = register_chrdev(0, "intel_mid_scu", &scu_ipc_fops); if (major < 0) return major; return 0; } static void __exit ipc_module_exit(void) { unregister_chrdev(major, "intel_mid_scu"); } module_init(ipc_module_init); module_exit(ipc_module_exit); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Utility driver for intel scu ipc"); MODULE_AUTHOR("Sreedhara <sreedhara.ds@intel.com>"); |