[PATCH 2.6.7-rc3] Add's class support to msr.c

From: Hanna Linder
Date: Wed Jun 09 2004 - 18:28:18 EST



This patch enables class support in arch/i386/kernel/msr.c. Very simliar
to cpuid (with the fixes Zwane/Greg made, thanks).

[root@w-hlinder2 root]# tree /sys/class/msr
/sys/class/msr
|-- msr0
| `-- dev
`-- msr1
`-- dev

2 directories, 2 files

Please consider for testing/inclusion.

Signed-off-by Hanna Linder <hannal@xxxxxxxxxx>

Thanks.

Hanna Linder
IBM Linux Technology Center
-----------
diff -Nrup linux-2.6.7-rc3/arch/i386/kernel/msr.c linux-2.6.7-rc3p/arch/i386/kernel/msr.c
--- linux-2.6.7-rc3/arch/i386/kernel/msr.c 2004-06-08 16:49:29.000000000 -0700
+++ linux-2.6.7-rc3p/arch/i386/kernel/msr.c 2004-06-09 15:26:31.000000000 -0700
@@ -35,12 +35,17 @@
#include <linux/smp_lock.h>
#include <linux/major.h>
#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>

#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/system.h>

+static struct class_simple *msr_class;
+
/* Note: "err" is handled in a funny way below. Otherwise one version
of gcc or another breaks. */

@@ -255,20 +260,82 @@ static struct file_operations msr_fops =
.open = msr_open,
};

+static int msr_class_simple_device_add(int i)
+{
+ int err = 0;
+ struct class_device *class_err;
+
+ class_err = class_simple_device_add(msr_class, MKDEV(MSR_MAJOR, i), NULL, "msr%d",i);
+ if (IS_ERR(class_err))
+ err = PTR_ERR(class_err);
+ return err;
+}
+
+static int __devinit msr_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+
+ switch (action) {
+ case CPU_ONLINE:
+ msr_class_simple_device_add(cpu);
+ break;
+ case CPU_DEAD:
+ class_simple_device_remove(MKDEV(MSR_MAJOR, cpu));
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block msr_class_cpu_notifier =
+{
+ .notifier_call = msr_class_cpu_callback,
+};
+
int __init msr_init(void)
{
+ int i, err = 0;
+ i = 0;
+
if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
printk(KERN_ERR "msr: unable to get major %d for msr\n",
MSR_MAJOR);
- return -EBUSY;
+ err = -EBUSY;
+ goto out;
+ }
+ msr_class = class_simple_create(THIS_MODULE, "msr");
+ if (IS_ERR(msr_class)) {
+ err = PTR_ERR(msr_class);
+ goto out_chrdev;
+ }
+ for_each_online_cpu(i) {
+ err = msr_class_simple_device_add(i);
+ if (err != 0)
+ goto out_class;
}
+ register_cpu_notifier(&msr_class_cpu_notifier);

- return 0;
+ err = 0;
+ goto out;
+
+ out_class:
+ i = 0;
+ for_each_online_cpu(i)
+ class_simple_device_remove(MKDEV(MSR_MAJOR, i));
+ class_simple_destroy(msr_class);
+ out_chrdev:
+ unregister_chrdev(MSR_MAJOR, "cpu/msr");
+ out:
+ return err;
}

void __exit msr_exit(void)
{
+ int cpu = 0;
+ for_each_online_cpu(cpu)
+ class_simple_device_remove(MKDEV(MSR_MAJOR, cpu));
+ class_simple_destroy(msr_class);
unregister_chrdev(MSR_MAJOR, "cpu/msr");
+ unregister_cpu_notifier(&msr_class_cpu_notifier);
}

module_init(msr_init);

-
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