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Add the character device interface into remoteproc framework. This interface can be used in order to boot/shutdown remote subsystems and provides a basic ioctl based interface to implement supplementary functionality. An ioctl call is implemented to enable the shutdown on release feature which will allow remote processors to be shutdown when the controlling userspace application crashes or hangs. Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org> Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org> Link: https://lore.kernel.org/r/1596044401-22083-2-git-send-email-sidgup@codeaurora.org [bjorn: s/int32_t/s32/ per checkpatch] Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
125 lines
2.9 KiB
C
125 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Character device interface driver for Remoteproc framework.
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*
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* Copyright (c) 2020, The Linux Foundation. All rights reserved.
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*/
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#include <linux/cdev.h>
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#include <linux/compat.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/remoteproc.h>
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#include <linux/uaccess.h>
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#include <uapi/linux/remoteproc_cdev.h>
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#include "remoteproc_internal.h"
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#define NUM_RPROC_DEVICES 64
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static dev_t rproc_major;
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static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_t len, loff_t *pos)
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{
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struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
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int ret = 0;
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char cmd[10];
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if (!len || len > sizeof(cmd))
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return -EINVAL;
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ret = copy_from_user(cmd, buf, len);
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if (ret)
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return -EFAULT;
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if (!strncmp(cmd, "start", len)) {
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if (rproc->state == RPROC_RUNNING)
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return -EBUSY;
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ret = rproc_boot(rproc);
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} else if (!strncmp(cmd, "stop", len)) {
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if (rproc->state != RPROC_RUNNING)
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return -EINVAL;
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rproc_shutdown(rproc);
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} else {
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dev_err(&rproc->dev, "Unrecognized option\n");
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ret = -EINVAL;
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}
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return ret ? ret : len;
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}
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static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
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{
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struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
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void __user *argp = (void __user *)arg;
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s32 param;
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switch (ioctl) {
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case RPROC_SET_SHUTDOWN_ON_RELEASE:
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if (copy_from_user(¶m, argp, sizeof(s32)))
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return -EFAULT;
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rproc->cdev_put_on_release = !!param;
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break;
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case RPROC_GET_SHUTDOWN_ON_RELEASE:
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param = (s32)rproc->cdev_put_on_release;
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if (copy_to_user(argp, ¶m, sizeof(s32)))
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return -EFAULT;
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break;
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default:
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dev_err(&rproc->dev, "Unsupported ioctl\n");
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return -EINVAL;
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}
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return 0;
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}
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static int rproc_cdev_release(struct inode *inode, struct file *filp)
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{
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struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
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if (rproc->cdev_put_on_release && rproc->state == RPROC_RUNNING)
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rproc_shutdown(rproc);
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return 0;
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}
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static const struct file_operations rproc_fops = {
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.write = rproc_cdev_write,
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.unlocked_ioctl = rproc_device_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.release = rproc_cdev_release,
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};
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int rproc_char_device_add(struct rproc *rproc)
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{
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int ret;
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cdev_init(&rproc->cdev, &rproc_fops);
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rproc->cdev.owner = THIS_MODULE;
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rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
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cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
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ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
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if (ret < 0)
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dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
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return ret;
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}
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void rproc_char_device_remove(struct rproc *rproc)
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{
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__unregister_chrdev(MAJOR(rproc->dev.devt), rproc->index, 1, "remoteproc");
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}
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void __init rproc_init_cdev(void)
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{
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int ret;
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ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
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if (ret < 0)
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pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
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}
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