On 2 May 2013 11:57, Asutosh Das <asutoshd@xxxxxxxxxxxxxx> wrote:
> On 5/2/2013 3:22 PM, Ulf Hansson wrote:
>>
>> On 2 May 2013 10:58, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>>
>>> On 16/04/13 13:00, 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. Obviously this value will likely
>>>> need to be configurable somehow since it needs to be trimmed depending
>>>> on the power save algorithm.
>>>
>>> Already is configurable in sysfs "power/autosuspend_delay_ms"
>>
>> Yes you are right - it is already configurable from sysfs point of view.
>>
>> What I had in mind was the default values, it could very well be
>> depending on what power save operation that is to be scheduled. For
>> example the aggressive power gating could likely use a longer timeout
>> than when about to schedule idle BKOPS. Anyway, I think it is fair to
>> leave this to a future patch to handle.
>>
>>> Another issue is that re-initialization consumes power - possibly more
>>> than
>>> is being saved by powering off. I wonder if the default value of 3
>>> seconds
>>> is realistic. Do you have any numbers to compare idle power consumption
>>> with the power consumed by re-initialization?
>>
>> This is very card specific data.
>>
>> - I have not done a measurement for the power consumed during a
>> re-init, but only the time it takes to do the re-init. Typically we
>> are talking about hundreds of ms.
>>
>> - I have done measurements for a handful of pretty new SD-cards and
>> for some eMMCs (preventing them from putting them to "sleep"). uSD:
>> ~100-400 uA, eMMC: ~10-150 uA - in both cases I expect the card to not
>> do any internal house keeping operations, since then we would likely
>> be talking about tens of mA instead.
>>
>> The above numbers should also be possible to be fetched from vendors
>> data sheets.
>>
>> Maybe some in the mmc code aurora team can elaborate more, since they
>> have been using this feature for a while now in end user products I
>> believe. Would be interesting to know what timeout they have chosen
>> here.
>
> Currently, we have a default idle-timeout of 10 seconds. However, we haven't
> pulled in and tested Ulf's patch series yet.
That sounds reasonable!
Although, I suggest we stick with the 3 s timeout in this patchset,
since it's to be considered as the generic default timeout. Then we
can send a new patch which possibly consider what power save
operations that are to be scheduled before changing timeout. Is that a
way forward for you?
>>
>>
>> Kind regards
>> Ulf Hansson
>>
>>>> For SD-combo cards, we are still leaving the enablement of runtime PM
>>>> to the SDIO init sequence since it depends on the capabilities of the
>>>> SDIO func driver.
>>>>
>>>> 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 want the
>>>> host suspend sequence to be unaware of any runtime power save operations
>>>> done for the card in this phase. Thus it can just handle the suspend as
>>>> the card is fully powered from a runtime perspective.
>>>>
>>>> Finally, this patch prepares 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>
>>>> Cc: Maya Erez <merez@xxxxxxxxxxxxxx>
>>>> Cc: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
>>>> Cc: Arnd Bergmann <arnd@xxxxxxxx>
>>>> Cc: Kevin Liu <kliu5@xxxxxxxxxxx>
>>>> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>>>> Cc: Daniel Drake <dsd@xxxxxxxxxx>
>>>> Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
>>>> ---
>>>> drivers/mmc/card/block.c | 32 ++++++++++++++++++++++++++------
>>>> drivers/mmc/core/core.c | 23 +++++++++++++++++++++++
>>>> drivers/mmc/core/debugfs.c | 8 ++++----
>>>> drivers/mmc/core/mmc.c | 4 ++--
>>>> drivers/mmc/core/sd.c | 4 ++--
>>>> include/linux/mmc/core.h | 3 +++
>>>> 6 files changed, 60 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>>> index e12a03c..360a41a 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>
>>>> @@ -222,7 +223,7 @@ static ssize_t power_ro_lock_store(struct device
>>>> *dev,
>>>> md = mmc_blk_get(dev_to_disk(dev));
>>>> card = md->queue.card;
>>>>
>>>> - mmc_claim_host(card->host);
>>>> + mmc_get_card(card);
>>>>
>>>> ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,
>>>> card->ext_csd.boot_ro_lock |
>>>> @@ -233,7 +234,7 @@ static ssize_t power_ro_lock_store(struct device
>>>> *dev,
>>>> else
>>>> card->ext_csd.boot_ro_lock |=
>>>> EXT_CSD_BOOT_WP_B_PWR_WP_EN;
>>>>
>>>> - mmc_release_host(card->host);
>>>> + mmc_put_card(card);
>>>>
>>>> if (!ret) {
>>>> pr_info("%s: Locking boot partition ro until next power
>>>> on\n",
>>>> @@ -492,7 +493,7 @@ static int mmc_blk_ioctl_cmd(struct block_device
>>>> *bdev,
>>>>
>>>> mrq.cmd = &cmd;
>>>>
>>>> - mmc_claim_host(card->host);
>>>> + mmc_get_card(card);
>>>>
>>>> err = mmc_blk_part_switch(card, md);
>>>> if (err)
>>>> @@ -559,7 +560,7 @@ static int mmc_blk_ioctl_cmd(struct block_device
>>>> *bdev,
>>>> }
>>>>
>>>> cmd_rel_host:
>>>> - mmc_release_host(card->host);
>>>> + mmc_put_card(card);
>>>>
>>>> cmd_done:
>>>> mmc_blk_put(md);
>>>> @@ -1896,7 +1897,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq,
>>>> struct request *req)
>>>>
>>>> if (req && !mq->mqrq_prev->req)
>>>> /* claim host only for the first request */
>>>> - mmc_claim_host(card->host);
>>>> + mmc_get_card(card);
>>>>
>>>> ret = mmc_blk_part_switch(card, md);
>>>> if (ret) {
>>>> @@ -1940,7 +1941,7 @@ out:
>>>> * In case sepecial request, there is no reentry to
>>>> * the 'mmc_blk_issue_rq' with 'mqrq_prev->req'.
>>>> */
>>>> - mmc_release_host(card->host);
>>>> + mmc_put_card(card);
>>>> return ret;
>>>> }
>>>>
>>>> @@ -2337,6 +2338,19 @@ static int mmc_blk_probe(struct mmc_card *card)
>>>> if (mmc_add_disk(part_md))
>>>> goto out;
>>>> }
>>>> +
>>>> + pm_runtime_set_autosuspend_delay(&card->dev, 3000);
>>>> + pm_runtime_use_autosuspend(&card->dev);
>>>> +
>>>> + /*
>>>> + * Don't enable runtime PM for SD-combo cards here. Leave that
>>>> + * decision to be taken during the SDIO init sequence instead.
>>>> + */
>>>> + if (card->type != MMC_TYPE_SD_COMBO) {
>>>> + pm_runtime_set_active(&card->dev);
>>>> + pm_runtime_enable(&card->dev);
>>>> + }
>>>> +
>>>> return 0;
>>>>
>>>> out:
>>>> @@ -2350,9 +2364,13 @@ 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);
>>>> + if (card->type != MMC_TYPE_SD_COMBO)
>>>> + pm_runtime_disable(&card->dev);
>>>> + pm_runtime_put_noidle(&card->dev);
>>>> mmc_blk_remove_req(md);
>>>> mmc_set_drvdata(card, NULL);
>>>> }
>>>> @@ -2364,6 +2382,7 @@ 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);
>>>> @@ -2387,6 +2406,7 @@ 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;
>>>> }
>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>> index b16b64a..602db00 100644
>>>> --- a/drivers/mmc/core/core.c
>>>> +++ b/drivers/mmc/core/core.c
>>>> @@ -952,6 +952,29 @@ void mmc_release_host(struct mmc_host *host)
>>>> EXPORT_SYMBOL(mmc_release_host);
>>>>
>>>> /*
>>>> + * This is a helper function, which fetches a runtime pm reference for
>>>> the
>>>> + * card device and also claims the host.
>>>> + */
>>>> +void mmc_get_card(struct mmc_card *card)
>>>> +{
>>>> + pm_runtime_get_sync(&card->dev);
>>>> + mmc_claim_host(card->host);
>>>> +}
>>>> +EXPORT_SYMBOL(mmc_get_card);
>>>> +
>>>> +/*
>>>> + * This is a helper function, which releases the host and drops the
>>>> runtime
>>>> + * pm reference for the card device.
>>>> + */
>>>> +void mmc_put_card(struct mmc_card *card)
>>>> +{
>>>> + mmc_release_host(card->host);
>>>> + pm_runtime_mark_last_busy(&card->dev);
>>>> + pm_runtime_put_autosuspend(&card->dev);
>>>> +}
>>>> +EXPORT_SYMBOL(mmc_put_card);
>>>> +
>>>> +/*
>>>> * Internal function that does the actual ios call to the host driver,
>>>> * optionally printing some debug output.
>>>> */
>>>> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>>>> index 35c2f85..54829c0 100644
>>>> --- a/drivers/mmc/core/debugfs.c
>>>> +++ b/drivers/mmc/core/debugfs.c
>>>> @@ -258,13 +258,13 @@ static int mmc_dbg_card_status_get(void *data, u64
>>>> *val)
>>>> u32 status;
>>>> int ret;
>>>>
>>>> - mmc_claim_host(card->host);
>>>> + mmc_get_card(card);
>>>>
>>>> ret = mmc_send_status(data, &status);
>>>> if (!ret)
>>>> *val = status;
>>>>
>>>> - mmc_release_host(card->host);
>>>> + mmc_put_card(card);
>>>>
>>>> return ret;
>>>> }
>>>> @@ -291,9 +291,9 @@ static int mmc_ext_csd_open(struct inode *inode,
>>>> struct file *filp)
>>>> goto out_free;
>>>> }
>>>>
>>>> - mmc_claim_host(card->host);
>>>> + mmc_get_card(card);
>>>> err = mmc_send_ext_csd(card, ext_csd);
>>>> - mmc_release_host(card->host);
>>>> + mmc_put_card(card);
>>>> if (err)
>>>> goto out_free;
>>>>
>>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>>> index 66a530e..bf19058 100644
>>>> --- a/drivers/mmc/core/mmc.c
>>>> +++ b/drivers/mmc/core/mmc.c
>>>> @@ -1380,14 +1380,14 @@ static void mmc_detect(struct mmc_host *host)
>>>> BUG_ON(!host);
>>>> BUG_ON(!host->card);
>>>>
>>>> - mmc_claim_host(host);
>>>> + mmc_get_card(host->card);
>>>>
>>>> /*
>>>> * Just check if our card has been removed.
>>>> */
>>>> err = _mmc_detect_card_removed(host);
>>>>
>>>> - mmc_release_host(host);
>>>> + mmc_put_card(host->card);
>>>>
>>>> if (err) {
>>>> mmc_remove(host);
>>>> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
>>>> index 9e645e1..30387d6 100644
>>>> --- a/drivers/mmc/core/sd.c
>>>> +++ b/drivers/mmc/core/sd.c
>>>> @@ -1037,14 +1037,14 @@ static void mmc_sd_detect(struct mmc_host *host)
>>>> BUG_ON(!host);
>>>> BUG_ON(!host->card);
>>>>
>>>> - mmc_claim_host(host);
>>>> + mmc_get_card(host->card);
>>>>
>>>> /*
>>>> * Just check if our card has been removed.
>>>> */
>>>> err = _mmc_detect_card_removed(host);
>>>>
>>>> - mmc_release_host(host);
>>>> + mmc_put_card(host->card);
>>>>
>>>> if (err) {
>>>> mmc_sd_remove(host);
>>>> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
>>>> index 39613b9..49fb132 100644
>>>> --- a/include/linux/mmc/core.h
>>>> +++ b/include/linux/mmc/core.h
>>>> @@ -188,6 +188,9 @@ extern int __mmc_claim_host(struct mmc_host *host,
>>>> atomic_t *abort);
>>>> extern void mmc_release_host(struct mmc_host *host);
>>>> extern int mmc_try_claim_host(struct mmc_host *host);
>>>>
>>>> +extern void mmc_get_card(struct mmc_card *card);
>>>> +extern void mmc_put_card(struct mmc_card *card);
>>>> +
>>>> extern int mmc_flush_cache(struct mmc_card *);
>>>>
>>>> extern int mmc_detect_card_removed(struct mmc_host *host);
>>>>
>> --
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>
>
>
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>
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