On Wed, Mar 9, 2011 at 12:24 PM, Andrei Warkentin <andr...@motorola.com> wrote:
> On Tue, Mar 8, 2011 at 3:39 PM, Grant Grundler <grund...@google.com> wrote:
>>
>> Save and restore SDHCI interrupt mask during suspend/resume.
>> Enables ARM Tegra2 board to suspend/resume.
>>
>> Signed-off-by: Venkat Rao <v...@broadcom.com>
>> Reviewed-by: Olof Johansson <ol...@chromium.org>
>> Reviewed-by: Grant Grundler <grund...@chromium.org>
>> ---
>> drivers/mmc/host/sdhci.c | 5 +++++
>> include/linux/mmc/sdhci.h | 2 ++
>> 2 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)
>> if (mmc->card && (mmc->card->type != MMC_TYPE_SDIO))
>> ret = mmc_suspend_host(host->mmc);
>>
>> + /* Save the original intmask to restore later */
>> + host->save_intmask = sdhci_readl(host, SDHCI_INT_ENABLE);
>> sdhci_mask_irqs(host, SDHCI_INT_ALL_MASK);
>>
>> if (host->vmmc)
>> @@ -1695,6 +1697,9 @@ int sdhci_resume_host(struct sdhci_host *host)
>>
>> sdhci_enable_card_detection(host);
>>
>> + /* Restore the original intmask */
>> + sdhci_unmask_irqs(host, host->save_intmask);
>> +
>> return ret;
>> }
>>
>> 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 {
>>
>> unsigned int caps; /* Alternative capabilities */
>>
>> + unsigned int save_intmask; /* Store original intmask */
>> +
>> unsigned long private[0] ____cacheline_aligned;
>> };
>> #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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