Hi Chris
On Tue, 23 Apr 2013, Guennadi Liakhovetski wrote:
> With MMC clock gating enabled the MMC core currently calls MMC host driver's
> .set_ios() method with .power_mode == MMC_POWER_ON and the clock value set
> either to 0 or to the target rate. The tmio MMC driver then wrongly
> translates the latter calls to card slot power-on requests, even when the
> slot already was on. This patch fixes the driver to avoid needlessly
> incrementing power-supplying regulator's use count.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@xxxxxxxxx>
Can we get this one into 3.10?
Thanks
Guennadi
> ---
>
> v2: Also make runtime PM handling safer and more resistant to possible
> MMC core changes. V1 worked fine too, but theoretically if the core
> decided to issue a sequence like
>
> .set_ios(ios->power_mode == MMC_POWER_ON, ios->clock != 0);
> .set_ios(ios->power_mode == MMC_POWER_ON, ios->clock == 0);
> .set_ios(ios->power_mode == MMC_POWER_OFF, ios->clock == 0);
>
> we would end up calling pm_runtime_put() twice in a row, which is wrong.
> V2 only toggles the controller runtime PM status only when entering or
> leaving the TMIO_MMC_ON_RUN state.
>
> drivers/mmc/host/tmio_mmc.h | 20 ++++++++++++++++++--
> drivers/mmc/host/tmio_mmc_pio.c | 27 +++++++++++++++++----------
> 2 files changed, 35 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
> index d857f5c..3cc589a 100644
> --- a/drivers/mmc/host/tmio_mmc.h
> +++ b/drivers/mmc/host/tmio_mmc.h
> @@ -40,6 +40,22 @@
>
> struct tmio_mmc_data;
>
> +/*
> + * We differentiate between the following 3 power states:
> + * 1. card slot powered off, controller stopped. This is used, when either there
> + * is no card in the slot, or the card really has to be powered down.
> + * 2. card slot powered on, controller stopped. This is used, when a card is in
> + * the slot, but no activity is currently taking place. This is a power-
> + * saving mode with card-state preserved. This state can be entered, e.g.
> + * when MMC clock-gating is used.
> + * 3. card slot powered on, controller running. This is the actual active state.
> + */
> +enum tmio_mmc_power {
> + TMIO_MMC_OFF_STOP, /* card power off, controller stopped */
> + TMIO_MMC_ON_STOP, /* card power on, controller stopped */
> + TMIO_MMC_ON_RUN, /* card power on, controller running */
> +};
> +
> struct tmio_mmc_host {
> void __iomem *ctl;
> unsigned long bus_shift;
> @@ -48,8 +64,8 @@ struct tmio_mmc_host {
> struct mmc_data *data;
> struct mmc_host *mmc;
>
> - /* Controller power state */
> - bool power;
> + /* Controller and card power state */
> + enum tmio_mmc_power power;
>
> /* Callbacks for clock / power control */
> void (*set_pwr)(struct platform_device *host, int state);
> diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
> index f508ecb..1d5ef64 100644
> --- a/drivers/mmc/host/tmio_mmc_pio.c
> +++ b/drivers/mmc/host/tmio_mmc_pio.c
> @@ -859,32 +859,39 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> * is kept positive, so no suspending actually takes place.
> */
> if (ios->power_mode == MMC_POWER_ON && ios->clock) {
> - if (!host->power) {
> + if (host->power != TMIO_MMC_ON_RUN) {
> tmio_mmc_clk_update(mmc);
> pm_runtime_get_sync(dev);
> }
> tmio_mmc_set_clock(host, ios->clock);
> - if (!host->power) {
> + if (host->power == TMIO_MMC_OFF_STOP)
> /* power up SD card and the bus */
> tmio_mmc_power_on(host, ios->vdd);
> - host->power = true;
> - }
> + host->power = TMIO_MMC_ON_RUN;
> /* start bus clock */
> tmio_mmc_clk_start(host);
> } else if (ios->power_mode != MMC_POWER_UP) {
> - if (host->power) {
> - struct tmio_mmc_data *pdata = host->pdata;
> - if (ios->power_mode == MMC_POWER_OFF)
> + struct tmio_mmc_data *pdata = host->pdata;
> + unsigned int old_power = host->power;
> +
> + if (old_power != TMIO_MMC_OFF_STOP) {
> + if (ios->power_mode == MMC_POWER_OFF) {
> tmio_mmc_power_off(host);
> + host->power = TMIO_MMC_OFF_STOP;
> + } else {
> + host->power = TMIO_MMC_ON_STOP;
> + }
> + }
> +
> + if (old_power == TMIO_MMC_ON_RUN) {
> tmio_mmc_clk_stop(host);
> - host->power = false;
> pm_runtime_put(dev);
> if (pdata->clk_disable)
> pdata->clk_disable(host->pdev);
> }
> }
>
> - if (host->power) {
> + if (host->power != TMIO_MMC_OFF_STOP) {
> switch (ios->bus_width) {
> case MMC_BUS_WIDTH_1:
> sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
> @@ -1025,7 +1032,7 @@ int tmio_mmc_host_probe(struct tmio_mmc_host **host,
> mmc->caps & MMC_CAP_NONREMOVABLE ||
> mmc->slot.cd_irq >= 0);
>
> - _host->power = false;
> + _host->power = TMIO_MMC_OFF_STOP;
> pm_runtime_enable(&pdev->dev);
> ret = pm_runtime_resume(&pdev->dev);
> if (ret < 0)
> --
> 1.7.2.5
>
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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