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![Chris Metcalf](/assets/img/avatar_default.png)
The code was already configured that way, but the Kconfig file didn't support requesting it. A buglet caused a null pointer deref when unloading the module, but this commit also corrects that issue. Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
475 lines
12 KiB
C
475 lines
12 KiB
C
/*
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* Copyright 2011 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*
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* SPI Flash ROM driver
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*
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* This source code is derived from code provided in "Linux Device
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* Drivers, Third Edition", by Jonathan Corbet, Alessandro Rubini, and
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* Greg Kroah-Hartman, published by O'Reilly Media, Inc.
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/kernel.h> /* printk() */
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#include <linux/slab.h> /* kmalloc() */
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#include <linux/fs.h> /* everything... */
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#include <linux/errno.h> /* error codes */
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#include <linux/types.h> /* size_t */
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#include <linux/proc_fs.h>
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#include <linux/fcntl.h> /* O_ACCMODE */
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#include <linux/pagemap.h>
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#include <linux/hugetlb.h>
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#include <linux/uaccess.h>
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#include <linux/platform_device.h>
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#include <hv/hypervisor.h>
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#include <linux/ioctl.h>
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#include <linux/cdev.h>
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#include <linux/delay.h>
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#include <hv/drv_srom_intf.h>
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/*
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* Size of our hypervisor I/O requests. We break up large transfers
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* so that we don't spend large uninterrupted spans of time in the
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* hypervisor. Erasing an SROM sector takes a significant fraction of
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* a second, so if we allowed the user to, say, do one I/O to write the
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* entire ROM, we'd get soft lockup timeouts, or worse.
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*/
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#define SROM_CHUNK_SIZE ((size_t)4096)
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/*
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* When hypervisor is busy (e.g. erasing), poll the status periodically.
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*/
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/*
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* Interval to poll the state in msec
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*/
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#define SROM_WAIT_TRY_INTERVAL 20
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/*
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* Maximum times to poll the state
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*/
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#define SROM_MAX_WAIT_TRY_TIMES 1000
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struct srom_dev {
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int hv_devhdl; /* Handle for hypervisor device */
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u32 total_size; /* Size of this device */
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u32 sector_size; /* Size of a sector */
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u32 page_size; /* Size of a page */
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struct mutex lock; /* Allow only one accessor at a time */
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};
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static int srom_major; /* Dynamic major by default */
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module_param(srom_major, int, 0);
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MODULE_AUTHOR("Tilera Corporation");
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MODULE_LICENSE("GPL");
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static int srom_devs; /* Number of SROM partitions */
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static struct cdev srom_cdev;
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static struct platform_device *srom_parent;
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static struct class *srom_class;
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static struct srom_dev *srom_devices;
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/*
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* Handle calling the hypervisor and managing EAGAIN/EBUSY.
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*/
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static ssize_t _srom_read(int hv_devhdl, void *buf,
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loff_t off, size_t count)
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{
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int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
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for (;;) {
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retval = hv_dev_pread(hv_devhdl, 0, (HV_VirtAddr)buf,
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count, off);
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if (retval >= 0)
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return retval;
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if (retval == HV_EAGAIN)
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continue;
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if (retval == HV_EBUSY && --retries > 0) {
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msleep(SROM_WAIT_TRY_INTERVAL);
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continue;
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}
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pr_err("_srom_read: error %d\n", retval);
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return -EIO;
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}
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}
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static ssize_t _srom_write(int hv_devhdl, const void *buf,
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loff_t off, size_t count)
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{
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int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
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for (;;) {
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retval = hv_dev_pwrite(hv_devhdl, 0, (HV_VirtAddr)buf,
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count, off);
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if (retval >= 0)
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return retval;
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if (retval == HV_EAGAIN)
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continue;
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if (retval == HV_EBUSY && --retries > 0) {
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msleep(SROM_WAIT_TRY_INTERVAL);
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continue;
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}
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pr_err("_srom_write: error %d\n", retval);
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return -EIO;
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}
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}
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/**
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* srom_open() - Device open routine.
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* @inode: Inode for this device.
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* @filp: File for this specific open of the device.
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*
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* Returns zero, or an error code.
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*/
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static int srom_open(struct inode *inode, struct file *filp)
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{
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filp->private_data = &srom_devices[iminor(inode)];
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return 0;
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}
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/**
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* srom_release() - Device release routine.
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* @inode: Inode for this device.
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* @filp: File for this specific open of the device.
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*
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* Returns zero, or an error code.
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*/
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static int srom_release(struct inode *inode, struct file *filp)
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{
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struct srom_dev *srom = filp->private_data;
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char dummy;
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/* Make sure we've flushed anything written to the ROM. */
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mutex_lock(&srom->lock);
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if (srom->hv_devhdl >= 0)
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_srom_write(srom->hv_devhdl, &dummy, SROM_FLUSH_OFF, 1);
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mutex_unlock(&srom->lock);
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filp->private_data = NULL;
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return 0;
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}
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/**
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* srom_read() - Read data from the device.
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* @filp: File for this specific open of the device.
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* @buf: User's data buffer.
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* @count: Number of bytes requested.
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* @f_pos: File position.
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*
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* Returns number of bytes read, or an error code.
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*/
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static ssize_t srom_read(struct file *filp, char __user *buf,
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size_t count, loff_t *f_pos)
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{
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int retval = 0;
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void *kernbuf;
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struct srom_dev *srom = filp->private_data;
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kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
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if (!kernbuf)
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return -ENOMEM;
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if (mutex_lock_interruptible(&srom->lock)) {
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retval = -ERESTARTSYS;
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kfree(kernbuf);
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return retval;
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}
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while (count) {
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int hv_retval;
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int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
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hv_retval = _srom_read(srom->hv_devhdl, kernbuf,
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*f_pos, bytes_this_pass);
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if (hv_retval <= 0) {
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if (retval == 0)
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retval = hv_retval;
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break;
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}
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if (copy_to_user(buf, kernbuf, hv_retval) != 0) {
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retval = -EFAULT;
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break;
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}
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retval += hv_retval;
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*f_pos += hv_retval;
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buf += hv_retval;
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count -= hv_retval;
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}
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mutex_unlock(&srom->lock);
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kfree(kernbuf);
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return retval;
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}
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/**
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* srom_write() - Write data to the device.
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* @filp: File for this specific open of the device.
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* @buf: User's data buffer.
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* @count: Number of bytes requested.
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* @f_pos: File position.
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*
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* Returns number of bytes written, or an error code.
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*/
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static ssize_t srom_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *f_pos)
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{
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int retval = 0;
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void *kernbuf;
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struct srom_dev *srom = filp->private_data;
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kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
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if (!kernbuf)
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return -ENOMEM;
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if (mutex_lock_interruptible(&srom->lock)) {
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retval = -ERESTARTSYS;
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kfree(kernbuf);
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return retval;
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}
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while (count) {
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int hv_retval;
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int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
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if (copy_from_user(kernbuf, buf, bytes_this_pass) != 0) {
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retval = -EFAULT;
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break;
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}
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hv_retval = _srom_write(srom->hv_devhdl, kernbuf,
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*f_pos, bytes_this_pass);
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if (hv_retval <= 0) {
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if (retval == 0)
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retval = hv_retval;
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break;
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}
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retval += hv_retval;
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*f_pos += hv_retval;
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buf += hv_retval;
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count -= hv_retval;
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}
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mutex_unlock(&srom->lock);
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kfree(kernbuf);
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return retval;
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}
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/* Provide our own implementation so we can use srom->total_size. */
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loff_t srom_llseek(struct file *file, loff_t offset, int origin)
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{
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struct srom_dev *srom = file->private_data;
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return fixed_size_llseek(file, offset, origin, srom->total_size);
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}
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static ssize_t total_size_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct srom_dev *srom = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", srom->total_size);
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}
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static DEVICE_ATTR_RO(total_size);
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static ssize_t sector_size_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct srom_dev *srom = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", srom->sector_size);
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}
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static DEVICE_ATTR_RO(sector_size);
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static ssize_t page_size_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct srom_dev *srom = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", srom->page_size);
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}
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static DEVICE_ATTR_RO(page_size);
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static struct attribute *srom_dev_attrs[] = {
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&dev_attr_total_size.attr,
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&dev_attr_sector_size.attr,
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&dev_attr_page_size.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(srom_dev);
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static char *srom_devnode(struct device *dev, umode_t *mode)
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{
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if (mode)
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*mode = 0644;
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return kasprintf(GFP_KERNEL, "srom/%s", dev_name(dev));
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}
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/*
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* The fops
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*/
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static const struct file_operations srom_fops = {
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.owner = THIS_MODULE,
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.llseek = srom_llseek,
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.read = srom_read,
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.write = srom_write,
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.open = srom_open,
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.release = srom_release,
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};
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/**
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* srom_setup_minor() - Initialize per-minor information.
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* @srom: Per-device SROM state.
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* @devhdl: Partition device handle.
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*/
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static int srom_setup_minor(struct srom_dev *srom, int devhdl)
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{
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srom->hv_devhdl = devhdl;
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mutex_init(&srom->lock);
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if (_srom_read(devhdl, &srom->total_size,
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SROM_TOTAL_SIZE_OFF, sizeof(srom->total_size)) < 0)
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return -EIO;
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if (_srom_read(devhdl, &srom->sector_size,
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SROM_SECTOR_SIZE_OFF, sizeof(srom->sector_size)) < 0)
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return -EIO;
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if (_srom_read(devhdl, &srom->page_size,
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SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
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return -EIO;
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return 0;
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}
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/** srom_init() - Initialize the driver's module. */
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static int srom_init(void)
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{
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int result, i;
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dev_t dev = MKDEV(srom_major, 0);
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/*
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* Start with a plausible number of partitions; the krealloc() call
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* below will yield about log(srom_devs) additional allocations.
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*/
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srom_devices = kmalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
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/* Discover the number of srom partitions. */
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for (i = 0; ; i++) {
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int devhdl;
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char buf[20];
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struct srom_dev *new_srom_devices =
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krealloc(srom_devices, (i+1) * sizeof(struct srom_dev),
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GFP_KERNEL);
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if (!new_srom_devices) {
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result = -ENOMEM;
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goto fail_mem;
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}
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srom_devices = new_srom_devices;
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sprintf(buf, "srom/0/%d", i);
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devhdl = hv_dev_open((HV_VirtAddr)buf, 0);
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if (devhdl < 0) {
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if (devhdl != HV_ENODEV)
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pr_notice("srom/%d: hv_dev_open failed: %d.\n",
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i, devhdl);
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break;
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}
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result = srom_setup_minor(&srom_devices[i], devhdl);
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if (result != 0)
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goto fail_mem;
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}
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srom_devs = i;
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/* Bail out early if we have no partitions at all. */
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if (srom_devs == 0) {
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result = -ENODEV;
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goto fail_mem;
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}
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/* Register our major, and accept a dynamic number. */
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if (srom_major)
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result = register_chrdev_region(dev, srom_devs, "srom");
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else {
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result = alloc_chrdev_region(&dev, 0, srom_devs, "srom");
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srom_major = MAJOR(dev);
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}
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if (result < 0)
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goto fail_mem;
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/* Register a character device. */
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cdev_init(&srom_cdev, &srom_fops);
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srom_cdev.owner = THIS_MODULE;
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srom_cdev.ops = &srom_fops;
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result = cdev_add(&srom_cdev, dev, srom_devs);
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if (result < 0)
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goto fail_chrdev;
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/* Create a parent device */
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srom_parent = platform_device_register_simple("srom", -1, NULL, 0);
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if (IS_ERR(srom_parent)) {
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result = PTR_ERR(srom_parent);
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goto fail_pdev;
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}
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/* Create a sysfs class. */
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srom_class = class_create(THIS_MODULE, "srom");
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if (IS_ERR(srom_class)) {
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result = PTR_ERR(srom_class);
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goto fail_cdev;
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}
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srom_class->dev_groups = srom_dev_groups;
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srom_class->devnode = srom_devnode;
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/* Create per-partition devices */
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for (i = 0; i < srom_devs; i++) {
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struct device *dev =
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device_create(srom_class, &srom_parent->dev,
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MKDEV(srom_major, i), srom_devices + i,
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"%d", i);
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result = PTR_ERR_OR_ZERO(dev);
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if (result < 0)
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goto fail_class;
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}
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return 0;
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fail_class:
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for (i = 0; i < srom_devs; i++)
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device_destroy(srom_class, MKDEV(srom_major, i));
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class_destroy(srom_class);
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fail_cdev:
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platform_device_unregister(srom_parent);
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fail_pdev:
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cdev_del(&srom_cdev);
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fail_chrdev:
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unregister_chrdev_region(dev, srom_devs);
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fail_mem:
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kfree(srom_devices);
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return result;
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}
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/** srom_cleanup() - Clean up the driver's module. */
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static void srom_cleanup(void)
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{
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int i;
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for (i = 0; i < srom_devs; i++)
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device_destroy(srom_class, MKDEV(srom_major, i));
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class_destroy(srom_class);
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cdev_del(&srom_cdev);
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platform_device_unregister(srom_parent);
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unregister_chrdev_region(MKDEV(srom_major, 0), srom_devs);
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kfree(srom_devices);
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}
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module_init(srom_init);
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module_exit(srom_cleanup);
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