Hi,
On Thursday, January 19, 2012, Guennadi Liakhovetski wrote:
> Using delayed clock gating to prevent too frequent gating of the clock
> is simple and efficient, but too inflexible.
I'd mention that you're working around the change made by commit
597dd9d79cfbbb1636d00a7fd0880355d9b20c41.
> We use PM QoS instead to
> let the runtime PM subsystem decide, which power states can be entered
> at any specific time, depending on the currently active governor.
Do I understand correctly that this is going to work, because
sh_mmcif_set_ios() uses pm_runtime_put() while powering off and
pm_runtime_get_sync() when powering on the device?
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
> drivers/mmc/host/sh_mmcif.c | 27 ++++++++++++++++++++++++---
> 1 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index 497e6f4..5a922be 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -55,6 +55,7 @@
> #include <linux/mmc/sh_mmcif.h>
> #include <linux/pagemap.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_qos.h>
> #include <linux/pm_runtime.h>
> #include <linux/spinlock.h>
> #include <linux/module.h>
> @@ -226,6 +227,7 @@ struct sh_mmcif_host {
> size_t blocksize;
> int sg_idx;
> int sg_blkidx;
The fields above are not present in the current mainline tree I have here.
> + struct dev_pm_qos_request pm_qos;
> bool power;
> bool card_present;
>
> @@ -977,10 +979,26 @@ static int sh_mmcif_get_cd(struct mmc_host *mmc)
> return p->get_cd(host->pd);
> }
>
> +static int sh_mmcif_enable(struct mmc_host *mmc)
> +{
> + struct sh_mmcif_host *host = mmc_priv(mmc);
> + dev_pm_qos_add_request(mmc->parent, &host->pm_qos, 100);
Why is the request added for the parent?
> + return 0;
> +}
> +
> +static int sh_mmcif_disable(struct mmc_host *mmc, int lazy)
> +{
> + struct sh_mmcif_host *host = mmc_priv(mmc);
> + dev_pm_qos_remove_request(&host->pm_qos);
> + return 0;
> +}
> +
> static struct mmc_host_ops sh_mmcif_ops = {
> .request = sh_mmcif_request,
> .set_ios = sh_mmcif_set_ios,
> .get_cd = sh_mmcif_get_cd,
> + .enable = sh_mmcif_enable,
> + .disable = sh_mmcif_disable,
> };
>
> static bool sh_mmcif_end_cmd(struct sh_mmcif_host *host)
> @@ -1061,7 +1079,6 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
> {
> struct sh_mmcif_host *host = dev_id;
> struct mmc_request *mrq = host->mrq;
> - struct mmc_data *data = mrq->data;
I'm not sure why this is necessary?
> cancel_delayed_work_sync(&host->timeout_work);
>
> @@ -1109,13 +1126,15 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
> case MMCIF_WAIT_FOR_READ_END:
> case MMCIF_WAIT_FOR_WRITE_END:
> if (host->sd_error)
> - data->error = sh_mmcif_error_manage(host);
> + mrq->data->error = sh_mmcif_error_manage(host);
> break;
> default:
> BUG();
> }
>
> if (host->wait_for != MMCIF_WAIT_FOR_STOP) {
> + struct mmc_data *data = mrq->data;
> +
> if (!mrq->cmd->error && data && !data->error)
> data->bytes_xfered =
> data->blocks * data->blksz;
> @@ -1303,12 +1322,14 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev)
> mmc->f_min = mmc->f_max / 512;
> if (pd->ocr)
> mmc->ocr_avail = pd->ocr;
> - mmc->caps = MMC_CAP_MMC_HIGHSPEED | pd->caps;
> + mmc->caps = MMC_CAP_MMC_HIGHSPEED | MMC_CAP_DISABLE | pd->caps;
> mmc->max_segs = 32;
> mmc->max_blk_size = 512;
> mmc->max_req_size = PAGE_CACHE_SIZE * mmc->max_segs;
> mmc->max_blk_count = mmc->max_req_size / mmc->max_blk_size;
> mmc->max_seg_size = mmc->max_req_size;
> + /* disable delayed clock gating, we use PM QoS for precise PM */
> + mmc->clkgate_delay = 0;
This isn't sufficient, because clkgate_delay may be changed by user space
at any time later.
> sh_mmcif_sync_reset(host);
> platform_set_drvdata(pdev, host);
>
Thanks,
Rafael
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