x86: Use syscore_ops instead of sysdev classes and sysdevs

Some subsystems in the x86 tree need to carry out suspend/resume and
shutdown operations with one CPU on-line and interrupts disabled and
they define sysdev classes and sysdevs or sysdev drivers for this
purpose.  This leads to unnecessarily complicated code and excessive
memory usage, so switch them to using struct syscore_ops objects for
this purpose instead.

Generally, there are three categories of subsystems that use
sysdevs for implementing PM operations: (1) subsystems whose
suspend/resume callbacks ignore their arguments entirely (the
majority), (2) subsystems whose suspend/resume callbacks use their
struct sys_device argument, but don't really need to do that,
because they can be implemented differently in an arguably simpler
way (io_apic.c), and (3) subsystems whose suspend/resume callbacks
use their struct sys_device argument, but the value of that argument
is always the same and could be ignored (microcode_core.c).  In all
of these cases the subsystems in question may be readily converted to
using struct syscore_ops objects for power management and shutdown.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 23 deletions

diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
index d9ca749c123b..65b8f5c2eebf 100644
--- a/arch/x86/kernel/i8259.c
+++ b/arch/x86/kernel/i8259.c
@@ -8,7 +8,7 @@
 #include <linux/random.h>
 #include <linux/init.h>
 #include <linux/kernel_stat.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/bitops.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
@@ -245,20 +245,19 @@ static void save_ELCR(char *trigger)
         trigger[1] = inb(0x4d1) & 0xDE;
 }
 
-static int i8259A_resume(struct sys_device *dev)
+static void i8259A_resume(void)
 {
         init_8259A(i8259A_auto_eoi);
         restore_ELCR(irq_trigger);
-        return 0;
 }
 
-static int i8259A_suspend(struct sys_device *dev, pm_message_t state)
+static int i8259A_suspend(void)
 {
         save_ELCR(irq_trigger);
         return 0;
 }
 
-static int i8259A_shutdown(struct sys_device *dev)
+static void i8259A_shutdown(void)
 {
         /* Put the i8259A into a quiescent state that
          * the kernel initialization code can get it
@@ -266,21 +265,14 @@ static int i8259A_shutdown(struct sys_device *dev)
          */
         outb(0xff, PIC_MASTER_IMR);     /* mask all of 8259A-1 */
         outb(0xff, PIC_SLAVE_IMR);      /* mask all of 8259A-1 */
-        return 0;
 }
 
-static struct sysdev_class i8259_sysdev_class = {
-        .name = "i8259",
+static struct syscore_ops i8259_syscore_ops = {
         .suspend = i8259A_suspend,
         .resume = i8259A_resume,
         .shutdown = i8259A_shutdown,
 };
 
-static struct sys_device device_i8259A = {
-        .id     = 0,
-        .cls    = &i8259_sysdev_class,
-};
-
 static void mask_8259A(void)
 {
         unsigned long flags;
@@ -399,17 +391,12 @@ struct legacy_pic default_legacy_pic = {
 
 struct legacy_pic *legacy_pic = &default_legacy_pic;
 
-static int __init i8259A_init_sysfs(void)
+static int __init i8259A_init_ops(void)
 {
-        int error;
-
-        if (legacy_pic != &default_legacy_pic)
-                return 0;
+        if (legacy_pic == &default_legacy_pic)
+                register_syscore_ops(&i8259_syscore_ops);
 
-        error = sysdev_class_register(&i8259_sysdev_class);
-        if (!error)
-                error = sysdev_register(&device_i8259A);
-        return error;
+        return 0;
 }
 
-device_initcall(i8259A_init_sysfs);
+device_initcall(i8259A_init_ops);