Introduce the sdio_claim_power/sdio_release_power API
(with correspoding mmc_claim_power/mmc_release_power)
that controls the power of the card. A reference count
scheme is employed, to allow SDIO function voting.
Signed-off-by: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
---
drivers/mmc/core/bus.c | 3 ++
drivers/mmc/core/core.c | 50 +++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/sdio.c | 5 ++++
drivers/mmc/core/sdio_io.c | 50 +++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/card.h | 2 +
include/linux/mmc/host.h | 2 +
include/linux/mmc/sdio_func.h | 3 ++
7 files changed, 115 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index 49d9dca..33151d5 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -17,6 +17,7 @@
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
+#include <asm/atomic.h>
#include "core.h"
#include "sdio_cis.h"
@@ -207,6 +208,8 @@ struct mmc_card *mmc_alloc_card(struct mmc_host *host, struct device_type *type)
card->host = host;
+ atomic_set(&card->power_claims, 0);
+
device_initialize(&card->dev);
card->dev.parent = mmc_classdev(host);
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 569e94d..ca5e3bf 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1334,6 +1334,56 @@ EXPORT_SYMBOL(mmc_resume_host);
#endif
+/**
+ * mmc_release_power - remove power from the card
+ * @host: mmc host
+ */
+int mmc_release_power(struct mmc_host *host)
+{
+ int err = 0;
+
+ mmc_bus_get(host);
+ if (host->bus_ops && !host->bus_dead) {
+ if (host->bus_ops->suspend)
+ err = host->bus_ops->suspend(host);
+ /* it's ok not to have a suspend handler */
+ err = err == -ENOSYS ? 0 : err;
+ }
+ mmc_bus_put(host);
+
+ if (!err)
+ mmc_power_off(host);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(mmc_release_power);
+
+/*
+ * mmc_claim_power - power up card
+ * @host: mmc host
+ */
+int mmc_claim_power(struct mmc_host *host)
+{
+ int err = 0;
+
+ mmc_bus_get(host);
+
+ mmc_power_up(host);
+ mmc_select_voltage(host, host->ocr);
+
+ BUG_ON(!host->bus_ops->resume);
+ err = host->bus_ops->resume(host);
+ if (err) {
+ printk(KERN_WARNING "%s: error %d during resume "
+ "(card was removed?)\n",
+ mmc_hostname(host), err);
+ }
+ mmc_bus_put(host);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(mmc_claim_power);
+
static int __init mmc_init(void)
{
int ret;
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 37739f5..79e6fa1 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -15,6 +15,7 @@
#include <linux/mmc/card.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/sdio_func.h>
+#include <asm/atomic.h>
#include "core.h"
#include "bus.h"
@@ -72,6 +73,10 @@ static int sdio_init_func(struct mmc_card *card, unsigned int fn)
card->sdio_func[fn - 1] = func;
+ /* For each SDIO function initialized, increase the power claim
+ * reference count of the card */
+ atomic_inc(&card->power_claims);
+
return 0;
fail:
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 0f687cd..28ebc16 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -17,6 +17,56 @@
#include "sdio_ops.h"
/**
+ * sdio_release_power - allow to release power of a certain SDIO function
+ * @func: SDIO function that is accessed
+ *
+ * Indicate to the core SDIO layer that we're not requiring that the
+ * function remain powered. If all functions for the card are in the
+ * same "no power" state, then the host controller can remove power from
+ * the card. Note: the function driver must preserve hardware states if
+ * necessary.
+ */
+int sdio_release_power(struct sdio_func *func)
+{
+ int ret = 0;
+ BUG_ON(!func);
+ BUG_ON(!func->card);
+
+ if (atomic_dec_and_test(&func->card->power_claims))
+ ret = mmc_release_power(func->card->host);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sdio_release_power);
+
+/*
+ * sdio_claim_power - request power for a certain SDIO function
+ * @func: SDIO function that is accessed
+ *
+ * Indicate to the core SDIO layer that we want power back for this
+ * SDIO function. The power may or may not actually have been removed
+ * since last call to sdio_release_power(), so the function driver must
+ * not assume any preserved state at the hardware level and re-perform
+ * all the necessary hardware config. This function returns 0 when
+ * power is actually restored, or some error code if this cannot be
+ * achieved. One error reason might be that the card is no longer
+ * available on the bus (was removed while powered down and card
+ * detection didn't trigger yet).
+ */
+int sdio_claim_power(struct sdio_func *func)
+{
+ int ret = 0;
+ BUG_ON(!func);
+ BUG_ON(!func->card);
+
+ if (atomic_inc_return(&func->card->power_claims) == 1)
+ ret = mmc_claim_power(func->card->host);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sdio_claim_power);
+
+/**
* sdio_claim_host - exclusively claim a bus for a certain SDIO function
* @func: SDIO function that will be accessed
*
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index d02d2c6..4073b43 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -11,6 +11,7 @@
#define LINUX_MMC_CARD_H
#include <linux/mmc/core.h>
+#include <asm/atomic.h>
struct mmc_cid {
unsigned int manfid;
@@ -120,6 +121,7 @@ struct mmc_card {
struct sdio_func_tuple *tuples; /* unknown common tuples */
struct dentry *debugfs_root;
+ atomic_t power_claims; /* ref count of power requests */
};
#define mmc_card_mmc(c) ((c)->type == MMC_TYPE_MMC)
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 80db597..3675d58 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -234,6 +234,8 @@ static inline void *mmc_priv(struct mmc_host *host)
extern int mmc_suspend_host(struct mmc_host *);
extern int mmc_resume_host(struct mmc_host *);
+extern int mmc_release_power(struct mmc_host *);
+extern int mmc_claim_power(struct mmc_host *);
extern void mmc_power_save_host(struct mmc_host *host);
extern void mmc_power_restore_host(struct mmc_host *host);
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index 31baaf8..e77b676 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -116,6 +116,9 @@ extern void sdio_unregister_driver(struct sdio_driver *);
/*
* SDIO I/O operations
*/
+int sdio_claim_power(struct sdio_func *func);
+int sdio_release_power(struct sdio_func *func);
+
extern void sdio_claim_host(struct sdio_func *func);
extern void sdio_release_host(struct sdio_func *func);
--
1.7.0.4
--
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