Hi. Jaehoon.
I have questions.
1. Would you explain why we need on/off function of this CMD23 at runtime ?
2. While frequently reading/writing, Have you tested by being
enabling/disbling CMD23 using this function ?
3. Why is irq disable needed when calling mmc_change_operation_mode ?
If are we just using spin_lock ?
4. When do we use host->pre_defined_op value after setting it ?
Thanks.
2012/2/6 Jaehoon Chung <jh80.chung@xxxxxxxxxxx>:
> This patch is support the sysfs for operation mode.
>
> There are two operation modes(open-ended/pre-defined).
> Now, operation mode is selected only one at the compile time.
>
> But using this patch, we can change the operation mode with node at runtime.
>
> * pre-defined mode
> echo 1 > /sys/class/mmc_host/mmc0/pre_defined_op
> * open-ended mode
> echo 0 > /sys/class/mmc_host/mmc0/pre_defined_op
>
> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
> Changelog V4:
> - Add the explanation in Documentation/mmc/mmc-dev-attrs.txt
> Changelog V3:
> - Add the mmc_change_operation_mode()
> Changelog v2:
> - Add the check point in mmc_cmd23_store()
> (If host controller didn't support CMD23, need not to change the ops-mode.)
>
> Documentation/mmc/mmc-dev-attrs.txt | 16 ++++++++++++++
> drivers/mmc/card/block.c | 19 +++++++++++++++++
> drivers/mmc/core/host.c | 39 +++++++++++++++++++++++++++++++++++
> include/linux/mmc/card.h | 1 +
> include/linux/mmc/host.h | 3 ++
> 5 files changed, 78 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/mmc/mmc-dev-attrs.txt b/Documentation/mmc/mmc-dev-attrs.txt
> index 22ae844..e7ba3b6 100644
> --- a/Documentation/mmc/mmc-dev-attrs.txt
> +++ b/Documentation/mmc/mmc-dev-attrs.txt
> @@ -74,3 +74,19 @@ This attribute appears only if CONFIG_MMC_CLKGATE is enabled.
> clkgate_delay Tune the clock gating delay with desired value in milliseconds.
>
> echo <desired delay> > /sys/class/mmc_host/mmcX/clkgate_delay
> +
> +SD and MMC Operation Mode Attribute
> +==========================================
> +
> +SD and MMC can support the two operation mode.
> +(Pre-defined(CMD23)/Open-ended operation mode)
> +
> +This attribute can change the operation mode at runtime if card is supported the CMD23.
> +
> + pre_defined_op Support the pre-defined mode if set 1.
> +
> +1) Open-ended mode
> +echo 0 > /sys/class/mmc_host/mmcX/pre_defined_op
> +
> +2) Pre-defined mode
> +echo 1 > /sys/class/mmc_host/mmcX/pre_defined_op
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index a7c75d8..2c1981c 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1766,6 +1766,25 @@ static const struct mmc_fixup blk_fixups[] =
> END_FIXUP
> };
>
> +void mmc_change_operation_mode(struct mmc_card *card, int val)
> +{
> + struct mmc_blk_data *md = mmc_get_drvdata(card);
> +
> + if (mmc_host_cmd23(card->host)) {
> + if (mmc_card_mmc(card) ||
> + (mmc_card_sd(card) &&
> + card->scr.cmds & SD_SCR_CMD23_SUPPORT)) {
> + if (val) {
> + md->flags |= MMC_BLK_CMD23;
> + card->host->pre_defined_op = val;
> + } else {
> + md->flags &= ~MMC_BLK_CMD23;
> + card->host->pre_defined_op = val;
> + }
> + }
> + }
> +}
> +
> static int mmc_blk_probe(struct mmc_card *card)
> {
> struct mmc_blk_data *md, *part_md;
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 30055f2..7dab0dc 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -293,6 +293,41 @@ static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
>
> #endif
>
> +static ssize_t mmc_cmd23_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct mmc_host *host = cls_dev_to_mmc_host(dev);
> + return snprintf(buf, PAGE_SIZE, "%d\n", host->pre_defined_op);
> +}
> +
> +static ssize_t mmc_cmd23_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t count)
> +{
> + struct mmc_host *host = cls_dev_to_mmc_host(dev);
> + int value;
> + unsigned long flags;
> +
> + if (kstrtoint(buf, 0, &value))
> + return -EINVAL;
> +
> + spin_lock_irqsave(&host->lock, flags);
> + mmc_change_operation_mode(host->card, value);
> + spin_unlock_irqrestore(&host->lock, flags);
> + return count;
> +}
> +
> +static inline void mmc_host_cmd23_sysfs_init(struct mmc_host *host)
> +{
> + host->pre_defined_attr.show = mmc_cmd23_show;
> + host->pre_defined_attr.store = mmc_cmd23_store;
> + sysfs_attr_init(&host->pre_defined_attr.attr);
> + host->pre_defined_attr.attr.name = "pre_defined_op";
> + host->pre_defined_attr.attr.mode = S_IRUGO | S_IWUSR;
> + if (device_create_file(&host->class_dev, &host->pre_defined_attr))
> + pr_err("%s: Failed to create pre_defined_op sysfs entry\n",
> + mmc_hostname(host));
> +}
> +
> /**
> * mmc_alloc_host - initialise the per-host structure.
> * @extra: sizeof private data structure
> @@ -381,6 +416,10 @@ int mmc_add_host(struct mmc_host *host)
> #endif
> mmc_host_clk_sysfs_init(host);
>
> + if (host->caps & MMC_CAP_CMD23)
> + host->pre_defined_op = 1;
> + mmc_host_cmd23_sysfs_init(host);
> +
> mmc_start_host(host);
> register_pm_notifier(&host->pm_notify);
>
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 1a1ca71..b36d408 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -489,5 +489,6 @@ extern void mmc_unregister_driver(struct mmc_driver *);
>
> extern void mmc_fixup_device(struct mmc_card *card,
> const struct mmc_fixup *table);
> +extern void mmc_change_operation_mode(struct mmc_card *card, int val);
>
> #endif /* LINUX_MMC_CARD_H */
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 20d7c82..59a30bf 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -259,6 +259,9 @@ struct mmc_host {
> MMC_CAP2_HS200_1_2V_SDR)
> #define MMC_CAP2_BROKEN_VOLTAGE (1 << 7) /* Use the broken voltage */
>
> + struct device_attribute pre_defined_attr;
> + int pre_defined_op; /* CMD23 should be use or not */
> +
> mmc_pm_flag_t pm_caps; /* supported pm features */
> unsigned int power_notify_type;
> #define MMC_HOST_PW_NOTIFY_NONE 0
> --
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