199 lines
5.2 KiB
Diff
199 lines
5.2 KiB
Diff
From f54ba59d355f59e4c01b5b9c7dbc2d27b47302d2 Mon Sep 17 00:00:00 2001
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From: Alison Wang <b18965@freescale.com>
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Date: Thu, 4 Aug 2011 09:59:41 +0800
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Subject: [PATCH 10/52] Add SRAM char device driver support for MCF5445x
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Created "/dev/sram" device file and implemented the sram mmap() operation to
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provide interface for userspace access.
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Signed-off-by: Alison Wang <b18965@freescale.com>
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---
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drivers/char/Kconfig | 11 ++++
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drivers/char/Makefile | 2 +
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drivers/char/sram.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++
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3 files changed, 164 insertions(+), 0 deletions(-)
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create mode 100644 drivers/char/sram.c
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--- a/drivers/char/Kconfig
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+++ b/drivers/char/Kconfig
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@@ -97,6 +97,17 @@ config DEVKMEM
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kind of kernel debugging operations.
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When in doubt, say "N".
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+config DEVSRAM
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+ tristate "/dev/sram virtual device support"
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+ depends on M5445X
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+ default m
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+ help
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+ Say Y here if you want to suppot the SRAM char device. When in
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+ doubt, say "N".
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+
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+ It implements mmap system call to provide interface for
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+ user space access.
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+
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config BFIN_JTAG_COMM
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tristate "Blackfin JTAG Communication"
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depends on BLACKFIN
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--- a/drivers/char/Makefile
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+++ b/drivers/char/Makefile
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@@ -87,3 +87,5 @@ obj-$(CONFIG_RAMOOPS) += ramoops.o
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obj-$(CONFIG_JS_RTC) += js-rtc.o
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js-rtc-y = rtc.o
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+
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+obj-$(CONFIG_DEVSRAM) += sram.o
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--- /dev/null
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+++ b/drivers/char/sram.c
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@@ -0,0 +1,151 @@
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+/*
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+ * linux/drivers/char/sram.c
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+ *
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+ * Copyright (C) 2009-2011 Freescale Semiconductor, Inc. All Rights Reserved.
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+ * Author: Lanttor.Guo@freescale.com
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+ *
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+ * SRAM char device driver, implements mmap() system call to provide
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+ * interface for user space access.
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version.
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+ */
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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/init.h>
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+#include <linux/kernel.h>
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+#include <linux/slab.h>
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+#include <linux/fs.h>
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+#include <linux/errno.h>
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+#include <linux/types.h>
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+#include <linux/mm.h>
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+#include <linux/kdev_t.h>
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+#include <asm/page.h>
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+#include <linux/cdev.h>
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+#include <linux/device.h>
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+
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+MODULE_LICENSE("GPL");
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+
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+static struct class *sram_class;
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+static int sram_major;
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+static int sram_minor;
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+static struct cdev sram_cdev;
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+
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+/*
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+ * Set up the cdev structure for sram.
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+ */
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+static void sram_setup_cdev(struct cdev *dev, int minor,
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+ const struct file_operations *fops)
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+{
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+ int err, devno = MKDEV(sram_major, minor);
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+
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+ cdev_init(dev, fops);
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+ dev->owner = THIS_MODULE;
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+ dev->ops = fops;
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+ err = cdev_add(dev, devno, 1);
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+ /* Fail gracefully if need be */
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+ if (err)
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+ printk(KERN_NOTICE "Error %d adding sram%d", err, minor);
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+}
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+
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+static int sram_open(struct inode *inode, struct file *filp)
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+{
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+ filp->f_mapping->backing_dev_info = &directly_mappable_cdev_bdi;
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+ return 0;
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+}
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+
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+static int sram_release(struct inode *inode, struct file *filp)
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+{
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+ return 0;
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+}
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+
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+void sram_vma_open(struct vm_area_struct *vma)
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+{
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+ printk(KERN_DEBUG "Sram VMA open, virt %lx, phys %lx\n",
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+ vma->vm_start,
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+ CONFIG_SRAM_BASE + (vma->vm_pgoff << PAGE_SHIFT));
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+}
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+
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+void sram_vma_close(struct vm_area_struct *vma)
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+{
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+ printk(KERN_DEBUG "Sram VMA close.\n");
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+}
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+
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+
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+static struct vm_operations_struct sram_remap_vm_ops = {
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+ .open = sram_vma_open,
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+ .close = sram_vma_close,
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+};
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+
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+static int sram_remap_mmap(struct file *filp, struct vm_area_struct *vma)
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+{
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+ size_t size = vma->vm_end - vma->vm_start;
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+
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+ if (PAGE_ALIGN(size) > CONFIG_SRAM_SIZE) {
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+ printk(KERN_ERR "required length exceed the size "
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+ "of physical sram (%x)\n", CONFIG_SRAM_SIZE);
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+ return -EAGAIN;
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+ }
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+
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+ if ((CONFIG_SRAM_BASE + (vma->vm_pgoff << PAGE_SHIFT) + size)
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+ > (CONFIG_SRAM_BASE + CONFIG_SRAM_SIZE)) {
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+ printk(KERN_ERR "required sram range exceed the size "
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+ "of phisical sram\n");
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+ return -EAGAIN;
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+ }
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+
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+ if (remap_pfn_range(vma, vma->vm_start,
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+ (CONFIG_SRAM_BASE >> PAGE_SHIFT) + vma->vm_pgoff,
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+ size,
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+ vma->vm_page_prot)) {
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+ printk(KERN_ERR "remap_pfn_range faile at %s()\n", __func__);
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+ return -EAGAIN;
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+ }
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+
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+ vma->vm_ops = &sram_remap_vm_ops;
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+ return 0;
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+}
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+
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+static const struct file_operations sram_ops = {
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+ .owner = THIS_MODULE,
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+ .open = sram_open,
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+ .release = sram_release,
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+ .mmap = sram_remap_mmap,
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+};
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+
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+static int __init sram_chrdev_init(void)
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+{
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+ int minor_devs = 1;
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+ int result;
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+ dev_t dev = 0;
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+ sram_minor = 0;
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+
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+ result = alloc_chrdev_region(&dev, sram_minor, minor_devs, "sram");
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+ sram_major = MAJOR(dev);
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+ if (result < 0) {
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+ printk(KERN_WARNING "sram: can't get major %d\n", sram_major);
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+ return result;
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+ }
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+
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+ sram_setup_cdev(&sram_cdev, 0, &sram_ops);
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+
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+ sram_class = class_create(THIS_MODULE, "sram");
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+ device_create(sram_class, NULL, MKDEV(sram_major, sram_minor),
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+ NULL, "sram");
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+
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+ return 0;
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+}
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+
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+static void sram_chrdev_cleanup(void)
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+{
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+ cdev_del(&sram_cdev);
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+ device_destroy(sram_class, MKDEV(sram_major, sram_minor));
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+ class_destroy(sram_class);
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+ unregister_chrdev_region(MKDEV(sram_major, 0), 1);
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+}
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+
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+module_init(sram_chrdev_init);
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+module_exit(sram_chrdev_cleanup);
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