mmc: sdhci: Disable runtime pm when the sdio_irq is enabled

commit 923713b3 upstream.

SDIO cards may need clock to send the card interrupt to the host.

On a cherrytrail tablet with a RTL8723BS wifi chip, without this patch
pinging the tablet results in:

PING 192.168.1.14 (192.168.1.14) 56(84) bytes of data.
64 bytes from 192.168.1.14: icmp_seq=1 ttl=64 time=78.6 ms
64 bytes from 192.168.1.14: icmp_seq=2 ttl=64 time=1760 ms
64 bytes from 192.168.1.14: icmp_seq=3 ttl=64 time=753 ms
64 bytes from 192.168.1.14: icmp_seq=4 ttl=64 time=3.88 ms
64 bytes from 192.168.1.14: icmp_seq=5 ttl=64 time=795 ms
64 bytes from 192.168.1.14: icmp_seq=6 ttl=64 time=1841 ms
64 bytes from 192.168.1.14: icmp_seq=7 ttl=64 time=810 ms
64 bytes from 192.168.1.14: icmp_seq=8 ttl=64 time=1860 ms
64 bytes from 192.168.1.14: icmp_seq=9 ttl=64 time=812 ms
64 bytes from 192.168.1.14: icmp_seq=10 ttl=64 time=48.6 ms

Where as with this patch I get:

PING 192.168.1.14 (192.168.1.14) 56(84) bytes of data.
64 bytes from 192.168.1.14: icmp_seq=1 ttl=64 time=3.96 ms
64 bytes from 192.168.1.14: icmp_seq=2 ttl=64 time=1.97 ms
64 bytes from 192.168.1.14: icmp_seq=3 ttl=64 time=17.2 ms
64 bytes from 192.168.1.14: icmp_seq=4 ttl=64 time=2.46 ms
64 bytes from 192.168.1.14: icmp_seq=5 ttl=64 time=2.83 ms
64 bytes from 192.168.1.14: icmp_seq=6 ttl=64 time=1.40 ms
64 bytes from 192.168.1.14: icmp_seq=7 ttl=64 time=2.10 ms
64 bytes from 192.168.1.14: icmp_seq=8 ttl=64 time=1.40 ms
64 bytes from 192.168.1.14: icmp_seq=9 ttl=64 time=2.04 ms
64 bytes from 192.168.1.14: icmp_seq=10 ttl=64 time=1.40 ms

Cc: Dong Aisheng <b29396@freescale.com>
Cc: Ian W MORRISON <ianwmorrison@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/mmc/host/sdhci.c

@@ -1708,6 +1708,9 @@ static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
 
 	sdhci_runtime_pm_get(host);
 
+	if (enable)
+		pm_runtime_get_noresume(host->mmc->parent);
+
 	spin_lock_irqsave(&host->lock, flags);
 	if (enable)
 		host->flags |= SDHCI_SDIO_IRQ_ENABLED;
@@ -1717,6 +1720,9 @@ static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
 	sdhci_enable_sdio_irq_nolock(host, enable);
 	spin_unlock_irqrestore(&host->lock, flags);
 
+	if (!enable)
+		pm_runtime_put_noidle(host->mmc->parent);
+
 	sdhci_runtime_pm_put(host);
 }