diff options
Diffstat (limited to 'drivers/platform/x86/intel_scu_ipcutil.c')
-rw-r--r-- | drivers/platform/x86/intel_scu_ipcutil.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel_scu_ipcutil.c b/drivers/platform/x86/intel_scu_ipcutil.c new file mode 100644 index 0000000000..b7c10c15a3 --- /dev/null +++ b/drivers/platform/x86/intel_scu_ipcutil.c @@ -0,0 +1,152 @@ +// 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; + +struct intel_scu_ipc_dev *scu; +static DEFINE_MUTEX(scu_lock); + +/* 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_dev_readv(scu, data->addr, data->data, count); + case INTE_SCU_IPC_REGISTER_WRITE: + return intel_scu_ipc_dev_writev(scu, data->addr, data->data, count); + case INTE_SCU_IPC_REGISTER_UPDATE: + return intel_scu_ipc_dev_update(scu, 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 int scu_ipc_open(struct inode *inode, struct file *file) +{ + int ret = 0; + + /* Only single open at the time */ + mutex_lock(&scu_lock); + if (scu) { + ret = -EBUSY; + goto unlock; + } + + scu = intel_scu_ipc_dev_get(); + if (!scu) + ret = -ENODEV; + +unlock: + mutex_unlock(&scu_lock); + return ret; +} + +static int scu_ipc_release(struct inode *inode, struct file *file) +{ + mutex_lock(&scu_lock); + intel_scu_ipc_dev_put(scu); + scu = NULL; + mutex_unlock(&scu_lock); + + return 0; +} + +static const struct file_operations scu_ipc_fops = { + .unlocked_ioctl = scu_ipc_ioctl, + .open = scu_ipc_open, + .release = scu_ipc_release, +}; + +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>"); |