On 3/5/2013 7:09 AM, Ulf Hansson wrote:
On 4 March 2013 21:48, Asutosh Das <asutoshd@xxxxxxxxxxxxxx> wrote:
On 3/1/2013 6:17 PM, Ulf Hansson wrote:
From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Once the mmc blkdevice is being probed, runtime pm will be enabled.
By using runtime autosuspend, the power save operations can be done
when request inactivity occurs for a certain time. Right now the
selected timeout value is set to 3 s.
Moreover, when the blk device is being suspended, we make sure the device
will be runtime resumed. The reason for doing this is that we what the
host suspend sequence to be unaware of any runtime power save operations,
so it can just handle the suspend as the device is fully powerered from a
runtime perspective.
This patch is preparing to make it possible to move BKOPS handling into
the runtime callbacks for the mmc bus_ops. Thus IDLE BKOPS can be
accomplished.
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
drivers/mmc/card/block.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 5bab73b..89d1c39 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -34,6 +34,7 @@
#include <linux/delay.h>
#include <linux/capability.h>
#include <linux/compat.h>
+#include <linux/pm_runtime.h>
#include <linux/mmc/ioctl.h>
#include <linux/mmc/card.h>
@@ -222,6 +223,7 @@ static ssize_t power_ro_lock_store(struct device *dev,
md = mmc_blk_get(dev_to_disk(dev));
card = md->queue.card;
+ pm_runtime_get_sync(&card->dev);
mmc_claim_host(card->host);
ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,
@@ -234,6 +236,8 @@ static ssize_t power_ro_lock_store(struct device *dev,
card->ext_csd.boot_ro_lock |= EXT_CSD_BOOT_WP_B_PWR_WP_EN;
mmc_release_host(card->host);
+ pm_runtime_mark_last_busy(&card->dev);
+ pm_runtime_put_autosuspend(&card->dev);
if (!ret) {
pr_info("%s: Locking boot partition ro until next power
on\n",
@@ -492,6 +496,7 @@ static int mmc_blk_ioctl_cmd(struct block_device
*bdev,
mrq.cmd = &cmd;
+ pm_runtime_get_sync(&card->dev);
mmc_claim_host(card->host);
err = mmc_blk_part_switch(card, md);
@@ -560,6 +565,8 @@ static int mmc_blk_ioctl_cmd(struct block_device
*bdev,
cmd_rel_host:
mmc_release_host(card->host);
+ pm_runtime_mark_last_busy(&card->dev);
+ pm_runtime_put_autosuspend(&card->dev);
cmd_done:
mmc_blk_put(md);
@@ -1894,9 +1901,11 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq,
struct request *req)
struct mmc_host *host = card->host;
unsigned long flags;
- if (req && !mq->mqrq_prev->req)
+ if (req && !mq->mqrq_prev->req) {
+ pm_runtime_get_sync(&card->dev);
/* claim host only for the first request */
mmc_claim_host(card->host);
+ }
ret = mmc_blk_part_switch(card, md);
if (ret) {
@@ -1932,9 +1941,13 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq,
struct request *req)
}
out:
- if (!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST))
+ if (!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) {
/* release host only when there are no more requests */
mmc_release_host(card->host);
+ pm_runtime_mark_last_busy(&card->dev);
+ pm_runtime_put_autosuspend(&card->dev);
+ }
+
return ret;
}
@@ -2331,6 +2344,12 @@ static int mmc_blk_probe(struct mmc_card *card)
if (mmc_add_disk(part_md))
goto out;
}
+
+ pm_runtime_set_active(&card->dev);
+ pm_runtime_set_autosuspend_delay(&card->dev, 3000);
+ pm_runtime_use_autosuspend(&card->dev);
+ pm_runtime_enable(&card->dev);
+
return 0;
out:
@@ -2344,9 +2363,12 @@ static void mmc_blk_remove(struct mmc_card *card)
struct mmc_blk_data *md = mmc_get_drvdata(card);
mmc_blk_remove_parts(card, md);
+ pm_runtime_get_sync(&card->dev);
mmc_claim_host(card->host);
mmc_blk_part_switch(card, md);
mmc_release_host(card->host);
+ pm_runtime_disable(&card->dev);
+ pm_runtime_put_noidle(&card->dev);
mmc_blk_remove_req(md);
mmc_set_drvdata(card, NULL);
}
@@ -2358,6 +2380,7 @@ static int mmc_blk_suspend(struct mmc_card *card)
struct mmc_blk_data *md = mmc_get_drvdata(card);
if (md) {
+ pm_runtime_get_sync(&card->dev);
mmc_queue_suspend(&md->queue);
list_for_each_entry(part_md, &md->part, part) {
mmc_queue_suspend(&part_md->queue);
@@ -2381,6 +2404,7 @@ static int mmc_blk_resume(struct mmc_card *card)
list_for_each_entry(part_md, &md->part, part) {
mmc_queue_resume(&part_md->queue);
}
+ pm_runtime_put(&card->dev);
}
return 0;
}
Hi Asutosh,
Hi Ulf
Currently, I am implementing a patch that facilitates each device to manage
is runtime pm on its own.
I am using the parent-child relationship that is already established in the
mmc stack for this implementation. In this case,
mmc_card is a child of mmc_host which is in turn is the child of
platform-device.
The following contexts exist which would have to invoke get_sync and
put_sync on the mmc_card device:
1. mmcqd
2. bkops
3. mmc_rescan
The get_sync on card device would resume all the 3 devices starting from the
platform-device and the put-sync would suspend all the 3 devices starting
from the card-device.
pm_auto_suspend/pm_schedule_suspend may be used to trigger the suspend from
the above contexts.
I believe this would simplify the runtime pm functionality.
I can put up the patch for review in a couple of days.
Please let me know your opinion about this approach.
No, I don't think this is way of doing it. I will try to elaborate a
bit with the approach I took in my patchset and why.
First of all, the host platform device must be kept separate (no
parent/child and not the same bus) from the card device. There is many
reason to why, but within this context (runtime pm point of view), the
host must be able to handle it's runtime pm resources completely
separate from the blk device (card device) runtime resources. More
precisely and from a BKOPS point of view; while doing BKOPS the host
platform device must still be able to enter runtime power save states.
I realize that in your case, you are doing mmc_suspend|resume_host in
your host drivers runtime callbacks, which is kind of a very special
case, though worth to consider of course. There are two solutions to
enable the option for this functionality. In both cases a host caps
flag will be needed to enable this.
1.
In mmc bus_ops runtime callback, do a pm_runtime_get_sync("host plf
device"), and vice verse in the runtime resume callback. This will
prevent the host driver from entering runtime power save sate while
for example doing BKOPS, thus preventing your host driver from doing
mmc_suspend_host while BKOPS is running.
2.
Move mmc_suspend|resume_host from your host runtime callbacks, into
the bus_ops runtime callbacks. Typically, when no BKOPS is needed
mmc_suspend_host can be done.
What are you thoughts around this?
Kind regards
Ulf Hansson
--
Thanks
Asutosh
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
Hi Ulf,
Typically, when the pltfm device enters power-save during bkops, it can
only shut-off the clocks to the card (?), the power would still be on.
With clock-gating in place, this would be done anyhow.
I wanted to separate the functionality as detailed below:
Say we do aggressive power management: (invoke mmc_[suspend/resume]_host
in runtime pm as well), idle-timeout of 10 s (configurable though)
during suspend of mmc_card device:
- do all card related power management, like power-off notifications etc.
during suspend of mmc_host device:
- do all the host related power management, like power-off host,
shut-off clocks etc.
during suspend of pltfm device:
- do all the pltfm specific power management, like disable irqs,
configure wake-ups etc.
During system-suspend, it can be checked if the device is
runtime-suspended, if yes, return.
On resume, the above path would be retraced in the reverse order.
I think each bus can be responsible for suspending its devices during
system suspend.
>> First of all, the host platform device must be kept separate (no
parent/child and not the same bus) from the card device.
Can you please elaborate on this point a bit.
I guess you would be joining the IRC chat tomorrow, if yes, we can
discuss there itself.
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
