Introduce SDIO runtime PM support:
1. Power to SDIO cards is kept low until one of its functions is bound
(i.e. a matching driver is successfully probed)
2. If the matching driver supports runtime PM, power to the card is
dropped soon after probe() returns. It is then up to the driver
to request power to its function, using runtime PM API (the get/put
variants). This is demonstrated with the wl1271 driver, in which
the power of the card power is coupled with the state of the wlan
interface (interface up -> power is up, interface down -> power is down)
3. If a matching driver does not support runtime PM, power to the card
is kept high during the whole lifetime of the driver
4. When the driver is removed, power to the card is immediately dropped
5. If there are multiple drivers for the same card (several SDIO functions),
power will be pulled high before the first driver probes, and dropped
down after the last driver is removed. In between, power will be
maintained accrording to the accumulated usage count of the complete
drivers group
6. SDIO suspend/resume semantics are unchanged. In addition, when the system
comes out of suspend, it is guaranteed that the power state of the
SDIO card will reflect its runtime PM usage count.
7. What was NOT changed:
- Interface: drivers can still assume that the card is powered
when probe/remove/suspend/resume are called
- Existing behavior: drivers that do not support runtime PM
are unchanged
Changes since v1:
- Interaction with system suspend/resume
- Better commentary
Dependencies:
- SDIO patches are against mmc-next, and have a runtime dependency on
commit "PM / Runtime: Lenient generic runtime pm callbacks"
(patch is in linux-next now)
- WLAN patches depend on recent wl1271 activity, and they are here
just to demonstrate the usage of the SDIO patchset (will be
resubmitted separately)
The full patchset, together with all its dependencies, is also available at:
git://wizery.com/pub/mmc.git runtime-pm-v2
Tests:
Besides the usual functional tests, the patchset was stress tested with
an overnight execution of (thousands of suspend-to-rams interacting with
the different possible runtime PM power states of the device/driver):
#!/bin/sh
mount -t debugfs none /sys/kernel/debug
echo core > /sys/power/pm_test
validate_module_up()
{
lsmod | grep wl1271_sdio
if [ "$?" -ne 0 ]; then echo "Module is not up"; exit; fi
}
validate_module_down()
{
lsmod | grep wl1271_sdio
if [ "$?" -eq 0 ]; then echo "Module is not down"; exit; fi
}
validate_card_is_powered()
{
cat /sys/kernel/debug/mmc2/ios | grep "power mode" | grep "on"
if [ "$?" -ne 0 ]; then echo "Power is not on"; exit; fi
cat /sys/kernel/debug/mmc2/ios | grep "clock" | grep "25000000"
if [ "$?" -ne 0 ]; then echo "Clock failure"; exit; fi
cat /sys/kernel/debug/mmc2/ios | grep "vdd" | grep "1.65 - 1.95"
if [ "$?" -ne 0 ]; then echo "Voltage failure"; exit; fi
cat /sys/kernel/debug/mmc2/ios | grep "bus width" | grep "4 bits"
if [ "$?" -ne 0 ]; then echo "Bus width failure"; exit; fi
}
validate_card_is_suspended()
{
cat /sys/kernel/debug/mmc2/ios | grep "power mode" | grep "off"
if [ "$?" -ne 0 ]; then echo "power is not off"; exit; fi
cat /sys/kernel/debug/mmc2/ios | grep "vdd" | grep "invalid"
if [ "$?" -ne 0 ]; then echo "Voltage not down ?"; exit; fi
}
while [ 1 ]
do
echo "beginning iteration $i"
validate_module_down
validate_card_is_suspended
echo mem > /sys/power/state
validate_card_is_suspended
insmod wl1271_sdio.ko
validate_module_up
validate_card_is_suspended
echo mem > /sys/power/state
validate_card_is_suspended
ifconfig wlan0 up
validate_card_is_powered
echo mem > /sys/power/state
validate_card_is_powered
ifconfig wlan0 down
validate_card_is_suspended
echo mem > /sys/power/state
validate_card_is_suspended
rmmod wl1271_sdio
let "i+=1"
done
Note: the ios values tested for are obviously specific to the
wl1271 device.
Ohad Ben-Cohen (11):
mmc: sdio: fully reconfigure oldcard on resume
mmc: propagate power save/restore ops return value
sdio: add power_restore support
mmc: add runtime PM handlers
sdio: use the generic runtime PM handlers
sdio: enable runtime PM for SDIO cards
sdio: enable runtime PM for SDIO functions
sdio: ensure mmc_sdio_detect is powered
sdio: support suspend/resume while runtime suspended
wl1271: sdio: enable runtime PM
wl1271: sdio: add suspend/resume support
drivers/mmc/core/bus.c | 37 +++++++++++++
drivers/mmc/core/core.c | 20 +++++--
drivers/mmc/core/core.h | 4 +-
drivers/mmc/core/mmc.c | 8 ++-
drivers/mmc/core/sd.c | 8 ++-
drivers/mmc/core/sdio.c | 54 +++++++++++++++---
drivers/mmc/core/sdio_bus.c | 85 ++++++++++++++++++++++++++++-
drivers/net/wireless/wl12xx/wl1271_sdio.c | 43 +++++++++++++--
include/linux/mmc/host.h | 4 +-
9 files changed, 232 insertions(+), 31 deletions(-)
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