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>
---
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
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