sdhci: Move real work out of an atomic context
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- v1 Latest8 patches 9 repliesIn review
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/8 | sdhci: Turn timeout timer into delayed workdrivers/ drivers/ | +10 | 0 replies | |
| 2/8 | sdhci: Use work structs instead of taskletsdrivers/ drivers/ | +23 | 0 replies | |
| 3/8 | sdhci: Clear interrupt status register just oncedrivers/ | +6 | 0 replies | |
| 4/8 | sdhci: Use threaded IRQ handlerdrivers/ | +28 | 0 replies | |
| 5/8 | sdhci: Turn host->lock into a mutexdrivers/ drivers/ | +24 | 0 replies | |
| 6/8 | sdhci: Get rid of card detect workdrivers/ drivers/ | +2 | 0 replies | |
| 7/8 | sdhci: Get rid of mdelay()s where it is safe and makes sensedrivers/ drivers/ | +4 | 0 replies | |
| 8/8 | sdhci: Use jiffies instead of a timeout counterdrivers/ | +5 | 0 replies |
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Cover letter [PATCH 0/8] sdhci: Move real work out of an atomic context
Hi all,
Currently the sdhci driver does everything in the atomic context. And what is worse, PIO transfers are made from the IRQ handler.
This causes huge latencies (up to 120 ms). On some P2020 SOCs, DMA and card detection is broken, which means that kernel polls for the card via PIO transfers every second. Needless to say that this is quite bad.
So, this patch set reworks sdhci code to avoid atomic context, almost completely. We only do two device memory operations in the atomic context, and all the rest is threaded.
I noticed no throughput drop neither with PIO transfers nor with DMA (tested on MPC8569E CPU), while latencies should be greatly improved.
Thanks,
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Anton Vorontsov email: [email protected] irc://irc.freenode.net/bd2