On Wed, Mar 9, 2011 at 12:24 PM, Andrei Warkentin <andreiw@xxxxxxxxxxxx> wrote:
> On Tue, Mar 8, 2011 at 3:39 PM, Grant Grundler <grundler@xxxxxxxxxx> wrote:
>>
>> Save and restore SDHCI interrupt mask during suspend/resume.
>> Enables ARM Tegra2 board to suspend/resume.
>>
>> Signed-off-by: Venkat Rao <vrao@xxxxxxxxxxxx>
>> Reviewed-by: Olof Johansson <olofj@xxxxxxxxxxxx>
>> Reviewed-by: Grant Grundler <grundler@xxxxxxxxxxxx>
>> ---
>> Âdrivers/mmc/host/sdhci.c Â| Â Â5 +++++
>> Âinclude/linux/mmc/sdhci.h | Â Â2 ++
>> Â2 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 3c6358f..68d2e36 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1654,6 +1654,8 @@ int sdhci_suspend_host(struct sdhci_host *host, pm_message_t state)
>> Â Â Â Âif (mmc->card && (mmc->card->type != MMC_TYPE_SDIO))
>> Â Â Â Â Â Â Â Âret = mmc_suspend_host(host->mmc);
>>
>> + Â Â Â /* Save the original intmask to restore later */
>> + Â Â Â host->save_intmask = sdhci_readl(host, SDHCI_INT_ENABLE);
>> Â Â Â Âsdhci_mask_irqs(host, SDHCI_INT_ALL_MASK);
>>
>> Â Â Â Âif (host->vmmc)
>> @@ -1695,6 +1697,9 @@ int sdhci_resume_host(struct sdhci_host *host)
>>
>> Â Â Â Âsdhci_enable_card_detection(host);
>>
>> + Â Â Â /* Restore the original intmask */
>> + Â Â Â sdhci_unmask_irqs(host, host->save_intmask);
>> +
>> Â Â Â Âreturn ret;
>> Â}
>>
>> diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
>> index dfb2106..5b9f6db 100644
>> --- a/include/linux/mmc/sdhci.h
>> +++ b/include/linux/mmc/sdhci.h
>> @@ -141,6 +141,8 @@ struct sdhci_host {
>>
>> Â Â Â Âunsigned int caps; Â Â Â/* Alternative capabilities */
>>
>> + Â Â Â unsigned int save_intmask; Â Â/* Store original intmask */
>> +
>> Â Â Â Âunsigned long private[0] ____cacheline_aligned;
>> Â};
>> Â#endif /* __SDHCI_H */
>> --
>> 1.7.2.3
>>
>> --
>
> Hi Grant,
>
> Why is this necessary?
Hi Andrei,
Sorry - I didn't CC the original author of the patch...(now CC'd) and
hopefully he or Sandeep can explain.
> If I understand correctly, the sdhci resume
> sequence sets some base needed bits inside SDHCI_INT_ENABLE inside
> sdhci_clear_set_irqs. Only if you have some outstanding DMA, but
> surely all DMA must be completed prior to your suspending
> (mmc_queue_suspend ensures nothing is outstanding)?
That's a good question. Given this is a WIFI device, my initial
assumption is we could receive packets or state/event changes any
time. But the device might in fact be quiesced during the suspend
operation. I have to check what the brcm80211/brcmfmac driver is doing
in this case.
> I'm asking since we're on Tegra 2 and have suspend/resume working fine
> with eMMC.
We do too - but only if the brcmfmac driver isn't loaded.
I'll look up if there are any side effects of writing SDHCI_INT_ENABLE
as well. It's possible this is unique to having BRCM4329 connected to
the eMMC controller instead of a flash device.
thanks,
grant
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