sdio: introduce API for special power management features

This patch series provides the core changes needed to allow SDIO cards to remain powered and active while the host system is suspended, and let them wake up the host system when needed. This is used to implement wake-on-lan with SDIO wireless cards at the moment. Patches to add that support to the libertas driver will be posted separately. This patch: Some SDIO cards have the ability to keep on running autonomously when the host system is suspended, and wake it up when needed. This however requires that the host controller preserve power to the card, and configure itself appropriately for wake-up. There is however 4 layers of abstractions involved: the host controller driver, the MMC core code, the SDIO card management code, and the actual SDIO function driver. To make things simple and manageable, host drivers must advertise their PM capabilities with a feature bitmask, then function drivers can query and set those features from their suspend method. Then each layer in the suspend call chain is expected to act upon those bits accordingly. [akpm@linux-foundation.org: fix typo in comment] Signed-off-by: Nicolas Pitre <nico@marvell.com> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sdio: introduce API for special power management features
This patch series provides the core changes needed to allow SDIO cards to remain powered and active while the host system is suspended, and let them wake up the host system when needed. This is used to implement wake-on-lan with SDIO wireless cards at the moment. Patches to add that support to the libertas driver will be posted separately. This patch: Some SDIO cards have the ability to keep on running autonomously when the host system is suspended, and wake it up when needed. This however requires that the host controller preserve power to the card, and configure itself appropriately for wake-up. There is however 4 layers of abstractions involved: the host controller driver, the MMC core code, the SDIO card management code, and the actual SDIO function driver. To make things simple and manageable, host drivers must advertise their PM capabilities with a feature bitmask, then function drivers can query and set those features from their suspend method. Then each layer in the suspend call chain is expected to act upon those bits accordingly. [akpm@linux-foundation.org: fix typo in comment] Signed-off-by: Nicolas Pitre <nico@marvell.com> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicolas Pitre · Linus Torvalds
1 parent 9e506f35b1
Showing 5 changed files with 98 additions and 3 deletions Side-by-side Diff
drivers/mmc/core/core.c
drivers/mmc/core/sdio_io.c
include/linux/mmc/host.h
include/linux/mmc/pm.h
include/linux/mmc/sdio_func.h
@@ -1151,6 +1151,9 @@
 	cancel_delayed_work(&host->detect);
 	mmc_flush_scheduled_work();
  
+	/* clear pm flags now and let card drivers set them as needed */
+	host->pm_flags = 0;
+
 	mmc_bus_get(host);
 	if (host->bus_ops && !host->bus_dead) {
 		if (host->bus_ops->remove)
  
@@ -1273,12 +1276,13 @@
 			mmc_claim_host(host);
 			mmc_detach_bus(host);
 			mmc_release_host(host);
+			host->pm_flags = 0;
 			err = 0;
 		}
 	}
 	mmc_bus_put(host);
  
-	if (!err)
+	if (!err && !(host->pm_flags & MMC_PM_KEEP_POWER))
 		mmc_power_off(host);
  
 	return err;
@@ -1296,8 +1300,10 @@
  
 	mmc_bus_get(host);
 	if (host->bus_ops && !host->bus_dead) {
-		mmc_power_up(host);
-		mmc_select_voltage(host, host->ocr);
+		if (!(host->pm_flags & MMC_PM_KEEP_POWER)) {
+			mmc_power_up(host);
+			mmc_select_voltage(host, host->ocr);
+		}
 		BUG_ON(!host->bus_ops->resume);
 		err = host->bus_ops->resume(host);
 		if (err) {
@@ -640,4 +640,53 @@
 		*err_ret = ret;
 }
 EXPORT_SYMBOL_GPL(sdio_f0_writeb);
+
+/**
+ *	sdio_get_host_pm_caps - get host power management capabilities
+ *	@func: SDIO function attached to host
+ *
+ *	Returns a capability bitmask corresponding to power management
+ *	features supported by the host controller that the card function
+ *	might rely upon during a system suspend.  The host doesn't need
+ *	to be claimed, nor the function active, for this information to be
+ *	obtained.
+ */
+mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func)
+{
+	BUG_ON(!func);
+	BUG_ON(!func->card);
+
+	return func->card->host->pm_caps;
+}
+EXPORT_SYMBOL_GPL(sdio_get_host_pm_caps);
+
+/**
+ *	sdio_set_host_pm_flags - set wanted host power management capabilities
+ *	@func: SDIO function attached to host
+ *
+ *	Set a capability bitmask corresponding to wanted host controller
+ *	power management features for the upcoming suspend state.
+ *	This must be called, if needed, each time the suspend method of
+ *	the function driver is called, and must contain only bits that
+ *	were returned by sdio_get_host_pm_caps().
+ *	The host doesn't need to be claimed, nor the function active,
+ *	for this information to be set.
+ */
+int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags)
+{
+	struct mmc_host *host;
+
+	BUG_ON(!func);
+	BUG_ON(!func->card);
+
+	host = func->card->host;
+
+	if (flags & ~host->pm_caps)
+		return -EINVAL;
+
+	/* function suspend methods are serialized, hence no lock needed */
+	host->pm_flags |= flags;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sdio_set_host_pm_flags);
@@ -14,6 +14,7 @@
 #include <linux/sched.h>
  
 #include <linux/mmc/core.h>
+#include <linux/mmc/pm.h>
  
 struct mmc_ios {
 	unsigned int	clock;			/* clock rate */
@@ -152,6 +153,8 @@
 #define MMC_CAP_NONREMOVABLE	(1 << 8)	/* Nonremovable e.g. eMMC */
 #define MMC_CAP_WAIT_WHILE_BUSY	(1 << 9)	/* Waits while card is busy */
  
+	mmc_pm_flag_t		pm_caps;	/* supported pm features */
+
 	/* host specific block data */
 	unsigned int		max_seg_size;	/* see blk_queue_max_segment_size */
 	unsigned short		max_hw_segs;	/* see blk_queue_max_hw_segments */
@@ -196,6 +199,8 @@
 	unsigned int		sdio_irqs;
 	struct task_struct	*sdio_irq_thread;
 	atomic_t		sdio_irq_thread_abort;
+
+	mmc_pm_flag_t		pm_flags;	/* requested pm features */
  
 #ifdef CONFIG_LEDS_TRIGGERS
 	struct led_trigger	*led;		/* activity led */
+/*
+ * linux/include/linux/mmc/pm.h
+ *
+ * Author:	Nicolas Pitre
+ * Copyright:	(C) 2009 Marvell Technology Group Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef LINUX_MMC_PM_H
+#define LINUX_MMC_PM_H
+
+/*
+ * These flags are used to describe power management features that
+ * some cards (typically SDIO cards) might wish to benefit from when
+ * the host system is being suspended.  There are several layers of
+ * abstractions involved, from the host controller driver, to the MMC core
+ * code, to the SDIO core code, to finally get to the actual SDIO function
+ * driver.  This file is therefore used for common definitions shared across
+ * all those layers.
+ */
+
+typedef unsigned int mmc_pm_flag_t;
+
+#define MMC_PM_KEEP_POWER	(1 << 0)	/* preserve card power during suspend */
+#define MMC_PM_WAKE_SDIO_IRQ	(1 << 1)	/* wake up host system on SDIO IRQ assertion */
+
+#endif
@@ -15,6 +15,8 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
  
+#include <linux/mmc/pm.h>
+
 struct mmc_card;
 struct sdio_func;
  
@@ -152,6 +154,9 @@
 	unsigned int addr, int *err_ret);
 extern void sdio_f0_writeb(struct sdio_func *func, unsigned char b,
 	unsigned int addr, int *err_ret);
+
+extern mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func);
+extern int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags);
  
 #endif
...	...	@@ -1151,6 +1151,9 @@
1151	1151	cancel_delayed_work(&host->detect);
1152	1152	mmc_flush_scheduled_work();
1153	1153
	1154	+ /* clear pm flags now and let card drivers set them as needed */
	1155	+ host->pm_flags = 0;
	1156	+
1154	1157	mmc_bus_get(host);
1155	1158	if (host->bus_ops && !host->bus_dead) {
1156	1159	if (host->bus_ops->remove)
1157	1160
...	...	@@ -1273,12 +1276,13 @@
1273	1276	mmc_claim_host(host);
1274	1277	mmc_detach_bus(host);
1275	1278	mmc_release_host(host);
	1279	+ host->pm_flags = 0;
1276	1280	err = 0;
1277	1281	}
1278	1282	}
1279	1283	mmc_bus_put(host);
1280	1284
1281		- if (!err)
	1285	+ if (!err && !(host->pm_flags & MMC_PM_KEEP_POWER))
1282	1286	mmc_power_off(host);
1283	1287
1284	1288	return err;
...	...	@@ -1296,8 +1300,10 @@
1296	1300
1297	1301	mmc_bus_get(host);
1298	1302	if (host->bus_ops && !host->bus_dead) {
1299		- mmc_power_up(host);
1300		- mmc_select_voltage(host, host->ocr);
	1303	+ if (!(host->pm_flags & MMC_PM_KEEP_POWER)) {
	1304	+ mmc_power_up(host);
	1305	+ mmc_select_voltage(host, host->ocr);
	1306	+ }
1301	1307	BUG_ON(!host->bus_ops->resume);
1302	1308	err = host->bus_ops->resume(host);
1303	1309	if (err) {
...	...	@@ -640,4 +640,53 @@
640	640	*err_ret = ret;
641	641	}
642	642	EXPORT_SYMBOL_GPL(sdio_f0_writeb);
	643	+
	644	+/**
	645	+ * sdio_get_host_pm_caps - get host power management capabilities
	646	+ * @func: SDIO function attached to host
	647	+ *
	648	+ * Returns a capability bitmask corresponding to power management
	649	+ * features supported by the host controller that the card function
	650	+ * might rely upon during a system suspend. The host doesn't need
	651	+ * to be claimed, nor the function active, for this information to be
	652	+ * obtained.
	653	+ */
	654	+mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func)
	655	+{
	656	+ BUG_ON(!func);
	657	+ BUG_ON(!func->card);
	658	+
	659	+ return func->card->host->pm_caps;
	660	+}
	661	+EXPORT_SYMBOL_GPL(sdio_get_host_pm_caps);
	662	+
	663	+/**
	664	+ * sdio_set_host_pm_flags - set wanted host power management capabilities
	665	+ * @func: SDIO function attached to host
	666	+ *
	667	+ * Set a capability bitmask corresponding to wanted host controller
	668	+ * power management features for the upcoming suspend state.
	669	+ * This must be called, if needed, each time the suspend method of
	670	+ * the function driver is called, and must contain only bits that
	671	+ * were returned by sdio_get_host_pm_caps().
	672	+ * The host doesn't need to be claimed, nor the function active,
	673	+ * for this information to be set.
	674	+ */
	675	+int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags)
	676	+{
	677	+ struct mmc_host *host;
	678	+
	679	+ BUG_ON(!func);
	680	+ BUG_ON(!func->card);
	681	+
	682	+ host = func->card->host;
	683	+
	684	+ if (flags & ~host->pm_caps)
	685	+ return -EINVAL;
	686	+
	687	+ /* function suspend methods are serialized, hence no lock needed */
	688	+ host->pm_flags \|= flags;
	689	+ return 0;
	690	+}
	691	+EXPORT_SYMBOL_GPL(sdio_set_host_pm_flags);
...	...	@@ -14,6 +14,7 @@
14	14	#include <linux/sched.h>
15	15
16	16	#include <linux/mmc/core.h>
	17	+#include <linux/mmc/pm.h>
17	18
18	19	struct mmc_ios {
19	20	unsigned int clock; /* clock rate */
...	...	@@ -152,6 +153,8 @@
152	153	#define MMC_CAP_NONREMOVABLE (1 << 8) /* Nonremovable e.g. eMMC */
153	154	#define MMC_CAP_WAIT_WHILE_BUSY (1 << 9) /* Waits while card is busy */
154	155
	156	+ mmc_pm_flag_t pm_caps; /* supported pm features */
	157	+
155	158	/* host specific block data */
156	159	unsigned int max_seg_size; /* see blk_queue_max_segment_size */
157	160	unsigned short max_hw_segs; /* see blk_queue_max_hw_segments */
...	...	@@ -196,6 +199,8 @@
196	199	unsigned int sdio_irqs;
197	200	struct task_struct *sdio_irq_thread;
198	201	atomic_t sdio_irq_thread_abort;
	202	+
	203	+ mmc_pm_flag_t pm_flags; /* requested pm features */
199	204
200	205	#ifdef CONFIG_LEDS_TRIGGERS
201	206	struct led_trigger led; / activity led */
	1	+/*
	2	+ * linux/include/linux/mmc/pm.h
	3	+ *
	4	+ * Author: Nicolas Pitre
	5	+ * Copyright: (C) 2009 Marvell Technology Group Ltd.
	6	+ *
	7	+ * This program is free software; you can redistribute it and/or modify
	8	+ * it under the terms of the GNU General Public License version 2 as
	9	+ * published by the Free Software Foundation.
	10	+ */
	11	+
	12	+#ifndef LINUX_MMC_PM_H
	13	+#define LINUX_MMC_PM_H
	14	+
	15	+/*
	16	+ * These flags are used to describe power management features that
	17	+ * some cards (typically SDIO cards) might wish to benefit from when
	18	+ * the host system is being suspended. There are several layers of
	19	+ * abstractions involved, from the host controller driver, to the MMC core
	20	+ * code, to the SDIO core code, to finally get to the actual SDIO function
	21	+ * driver. This file is therefore used for common definitions shared across
	22	+ * all those layers.
	23	+ */
	24	+
	25	+typedef unsigned int mmc_pm_flag_t;
	26	+
	27	+#define MMC_PM_KEEP_POWER (1 << 0) /* preserve card power during suspend */
	28	+#define MMC_PM_WAKE_SDIO_IRQ (1 << 1) /* wake up host system on SDIO IRQ assertion */
	29	+
	30	+#endif
...	...	@@ -15,6 +15,8 @@
15	15	#include <linux/device.h>
16	16	#include <linux/mod_devicetable.h>
17	17
	18	+#include <linux/mmc/pm.h>
	19	+
18	20	struct mmc_card;
19	21	struct sdio_func;
20	22
...	...	@@ -152,6 +154,9 @@
152	154	unsigned int addr, int *err_ret);
153	155	extern void sdio_f0_writeb(struct sdio_func *func, unsigned char b,
154	156	unsigned int addr, int *err_ret);
	157	+
	158	+extern mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func);
	159	+extern int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags);
155	160
156	161	#endif