Fixed MTP to work with TWRP

drivers/sbus/char/flash.c

@@ -0,0 +1,219 @@
+/* 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 <asm/uaccess.h>
+#include <asm/pgtable.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;
+
+#define FLASH_MINOR	152
+
+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 = { 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 (strcmp(parent->name, "sbus") &&
+	    strcmp(parent->name, "sbi") &&
+	    strcmp(parent->name, "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 "%s: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
+	       op->dev.of_node->full_name,
+	       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",
+		.owner = THIS_MODULE,
+		.of_match_table = flash_match,
+	},
+	.probe		= flash_probe,
+	.remove		= flash_remove,
+};
+
+module_platform_driver(flash_driver);
+
+MODULE_LICENSE("GPL");