* Re: MTD PM Resume
2005-06-04 1:24 ` Todd Poynor
@ 2005-07-02 0:51 ` Todd Poynor
0 siblings, 0 replies; 3+ messages in thread
From: Todd Poynor @ 2005-07-02 0:51 UTC (permalink / raw)
To: Todd Blumer, Aric Blumer; +Cc: linux-mtd
On Fri, Jun 03, 2005 at 06:24:34PM -0700, Todd Poynor wrote:
...
> If you initiated the suspend via a call to pm_suspend() or
> /sys/power/state then LDM suspend/resume driver methods will be called,
> and it looks like nothing in the mtd core will automatically register
> drivers or devices in LDM. There are existing examples of registering
> with LDM in some map drivers, registering a driver with the platform
> bus. Looks like boards that power cycle flash chips for certain sleep
> states need to also register a device, and add suspend/resume callbacks
> in the struct_driver that end up calling the chip driver suspend/resume
> methods (even if they don't use flash that powers up locked, since the
> mtd state machine needs to be reset to assume the flash chips are in
> ready state). Documentation/power/devices.txt has some more info on
> those interfaces.
>
> Or if anybody has a better way to handle this I'm all ears. A class
> device for generic mtd might do it, not sure.
>
> You just reminded me I need to figure out how to do this for a couple of
> boards, thanks. If there's no disagreement on the above being the
> correct approach I'll float a patch soon.
Here's an example of how it might be done via a board mapping driver,
for the PXA27x Mainstone board. I'm not sure if this is the ultimate in
mtd + ldm + pm integration, but it's something. Any comments appreciated.
Index: linux-2.6.12/arch/arm/mach-pxa/mainstone.c
===================================================================
--- linux-2.6.12.orig/arch/arm/mach-pxa/mainstone.c 2005-06-17 19:48:29.000000000 +0000
+++ linux-2.6.12/arch/arm/mach-pxa/mainstone.c 2005-07-02 00:33:23.000000000 +0000
@@ -189,6 +189,11 @@
.dev = { .platform_data = &mst_audio_ops },
};
+static struct platform_device mainstone_flash_device = {
+ .name = "mainstone-flash",
+ .id = -1,
+};
+
static void mainstone_backlight_power(int on)
{
if (on) {
@@ -304,6 +309,7 @@
platform_device_register(&smc91x_device);
platform_device_register(&mst_audio_device);
+ platform_device_register(&mainstone_flash_device);
/* reading Mainstone's "Virtual Configuration Register"
might be handy to select LCD type here */
Index: linux-2.6.12/drivers/mtd/maps/mainstone-flash.c
===================================================================
--- linux-2.6.12.orig/drivers/mtd/maps/mainstone-flash.c 2005-07-01 22:22:30.000000000 +0000
+++ linux-2.6.12/drivers/mtd/maps/mainstone-flash.c 2005-07-02 00:35:56.000000000 +0000
@@ -15,6 +15,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
@@ -69,7 +70,8 @@
static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
-static int __init init_mainstone(void)
+
+static int __init mainstone_flash_probe(struct device *_dev)
{
int SW7 = 0; /* FIXME: get from SCR (Mst doc section 3.2.1.1) */
int ret = 0, i;
@@ -147,10 +149,11 @@
add_mtd_device(mymtds[i]);
}
}
+
return 0;
}
-static void __exit cleanup_mainstone(void)
+static int mainstone_flash_remove(struct device *_dev)
{
int i;
for (i = 0; i < 2; i++) {
@@ -168,6 +171,59 @@
iounmap(mainstone_maps[i].cached);
kfree(parsed_parts[i]);
}
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int mainstone_flash_suspend(struct device *dev, u32 state, u32 level)
+{
+ int i;
+
+ if (level == SUSPEND_DISABLE) {
+ for (i = 0; i < 2; i++)
+ if (mymtds[i] && mymtds[i]->suspend)
+ mymtds[i]->suspend(mymtds[i]);
+ }
+
+ return 0;
+}
+
+static int mainstone_flash_resume(struct device *dev, u32 level)
+{
+ int i;
+
+ if (level == RESUME_ENABLE) {
+ for (i = 0; i < 2; i++)
+ if (mymtds[i] && mymtds[i]->resume)
+ mymtds[i]->resume(mymtds[i]);
+
+ }
+ return 0;
+}
+
+#endif
+
+static struct device_driver mainstone_flash_driver = {
+ .name = "mainstone-flash",
+ .bus = &platform_bus_type,
+ .probe = &mainstone_flash_probe,
+ .remove = &mainstone_flash_remove,
+#ifdef CONFIG_PM
+ .suspend = &mainstone_flash_suspend,
+ .resume = &mainstone_flash_resume,
+#endif
+};
+
+static int __init init_mainstone(void)
+{
+ return driver_register(&mainstone_flash_driver);
+}
+
+static void __exit cleanup_mainstone(void)
+{
+ driver_unregister(&mainstone_flash_driver);
}
module_init(init_mainstone);
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