diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/sbus/char/flash.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/sbus/char/flash.c b/drivers/sbus/char/flash.c new file mode 100644 index 000000000..3adfef210 --- /dev/null +++ b/drivers/sbus/char/flash.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* flash.c: Allow mmap access to the OBP Flash, for OBP updates. + * + * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/miscdevice.h> +#include <linux/fcntl.h> +#include <linux/poll.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/mm.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include <linux/uaccess.h> +#include <asm/io.h> +#include <asm/upa.h> + +static DEFINE_MUTEX(flash_mutex); +static DEFINE_SPINLOCK(flash_lock); +static struct { + unsigned long read_base; /* Physical read address */ + unsigned long write_base; /* Physical write address */ + unsigned long read_size; /* Size of read area */ + unsigned long write_size; /* Size of write area */ + unsigned long busy; /* In use? */ +} flash; + +static int +flash_mmap(struct file *file, struct vm_area_struct *vma) +{ + unsigned long addr; + unsigned long size; + + spin_lock(&flash_lock); + if (flash.read_base == flash.write_base) { + addr = flash.read_base; + size = flash.read_size; + } else { + if ((vma->vm_flags & VM_READ) && + (vma->vm_flags & VM_WRITE)) { + spin_unlock(&flash_lock); + return -EINVAL; + } + if (vma->vm_flags & VM_READ) { + addr = flash.read_base; + size = flash.read_size; + } else if (vma->vm_flags & VM_WRITE) { + addr = flash.write_base; + size = flash.write_size; + } else { + spin_unlock(&flash_lock); + return -ENXIO; + } + } + spin_unlock(&flash_lock); + + if ((vma->vm_pgoff << PAGE_SHIFT) > size) + return -ENXIO; + addr = vma->vm_pgoff + (addr >> PAGE_SHIFT); + + if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size) + size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)); + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot)) + return -EAGAIN; + + return 0; +} + +static long long +flash_llseek(struct file *file, long long offset, int origin) +{ + mutex_lock(&flash_mutex); + switch (origin) { + case 0: + file->f_pos = offset; + break; + case 1: + file->f_pos += offset; + if (file->f_pos > flash.read_size) + file->f_pos = flash.read_size; + break; + case 2: + file->f_pos = flash.read_size; + break; + default: + mutex_unlock(&flash_mutex); + return -EINVAL; + } + mutex_unlock(&flash_mutex); + return file->f_pos; +} + +static ssize_t +flash_read(struct file * file, char __user * buf, + size_t count, loff_t *ppos) +{ + loff_t p = *ppos; + int i; + + if (count > flash.read_size - p) + count = flash.read_size - p; + + for (i = 0; i < count; i++) { + u8 data = upa_readb(flash.read_base + p + i); + if (put_user(data, buf)) + return -EFAULT; + buf++; + } + + *ppos += count; + return count; +} + +static int +flash_open(struct inode *inode, struct file *file) +{ + mutex_lock(&flash_mutex); + if (test_and_set_bit(0, (void *)&flash.busy) != 0) { + mutex_unlock(&flash_mutex); + return -EBUSY; + } + + mutex_unlock(&flash_mutex); + return 0; +} + +static int +flash_release(struct inode *inode, struct file *file) +{ + spin_lock(&flash_lock); + flash.busy = 0; + spin_unlock(&flash_lock); + + return 0; +} + +static const struct file_operations flash_fops = { + /* no write to the Flash, use mmap + * and play flash dependent tricks. + */ + .owner = THIS_MODULE, + .llseek = flash_llseek, + .read = flash_read, + .mmap = flash_mmap, + .open = flash_open, + .release = flash_release, +}; + +static struct miscdevice flash_dev = { SBUS_FLASH_MINOR, "flash", &flash_fops }; + +static int flash_probe(struct platform_device *op) +{ + struct device_node *dp = op->dev.of_node; + struct device_node *parent; + + parent = dp->parent; + + if (!of_node_name_eq(parent, "sbus") && + !of_node_name_eq(parent, "sbi") && + !of_node_name_eq(parent, "ebus")) + return -ENODEV; + + flash.read_base = op->resource[0].start; + flash.read_size = resource_size(&op->resource[0]); + if (op->resource[1].flags) { + flash.write_base = op->resource[1].start; + flash.write_size = resource_size(&op->resource[1]); + } else { + flash.write_base = op->resource[0].start; + flash.write_size = resource_size(&op->resource[0]); + } + flash.busy = 0; + + printk(KERN_INFO "%pOF: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n", + op->dev.of_node, + flash.read_base, flash.read_size, + flash.write_base, flash.write_size); + + return misc_register(&flash_dev); +} + +static int flash_remove(struct platform_device *op) +{ + misc_deregister(&flash_dev); + + return 0; +} + +static const struct of_device_id flash_match[] = { + { + .name = "flashprom", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, flash_match); + +static struct platform_driver flash_driver = { + .driver = { + .name = "flash", + .of_match_table = flash_match, + }, + .probe = flash_probe, + .remove = flash_remove, +}; + +module_platform_driver(flash_driver); + +MODULE_LICENSE("GPL"); |