[v4,0/5] spi: spi-geni-qcom: Fixes / perf improvements
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Message ID 20200618150626.237027-1-dianders@chromium.org
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Doug Anderson June 18, 2020, 3:06 p.m. UTC
This patch series is a new version of the previous patch posted:
  [PATCH v2] spi: spi-geni-qcom: Speculative fix of "nobody cared" about interrupt
  https://lore.kernel.org/r/20200317133653.v2.1.I752ebdcfd5e8bf0de06d66e767b8974932b3620e@changeid

At this point I've done enough tracing to know that there was a real
race in the old code (not just weakly ordered memory problems) and
that should be fixed with the locking patches.

While looking at this driver, I also noticed we weren't properly
noting error interrupts and also weren't actually using our FIFO
effectively, so I fixed those.

The last patch in the series addresses review feedback about dislike
for the "cur_mcmd" state variable.  It also could possibly make
"abort" work ever-so-slightly more reliably.

Changes in v4:
- Drop 'controller' in comment.
- Use Stephen's diagram to explain the race better.

Changes in v3:
- ("spi: spi-geni-qcom: No need for irqsave variant...") new for v3
- Split out some lock cleanup to previous patch.
- Don't need to read IRQ status register inside spinlock.
- Don't check for state CMD_NONE; later patch is removing state var.
- Don't hold the lock for all of setup_fifo_xfer().
- Comment about why it's safe to Ack interrupts at the end.
- Subject/desc changed since race is definitely there.
- ("spi: spi-geni-qcom: Check for error IRQs") new in v3.
- ("spi: spi-geni-qcom: Actually use our FIFO") new in v3.
- ("spi: spi-geni-qcom: Don't keep a local state variable") new in v3.

Changes in v2:
- Detect true spurious interrupt.
- Still return IRQ_NONE for state machine mismatch, but print warn.

Douglas Anderson (5):
  spi: spi-geni-qcom: No need for irqsave variant of spinlock calls
  spi: spi-geni-qcom: Mo' betta locking
  spi: spi-geni-qcom: Check for error IRQs
  spi: spi-geni-qcom: Actually use our FIFO
  spi: spi-geni-qcom: Don't keep a local state variable

 drivers/spi/spi-geni-qcom.c | 120 ++++++++++++++++++++++++------------
 1 file changed, 81 insertions(+), 39 deletions(-)

Comments

Mark Brown June 19, 2020, 1:28 p.m. UTC | #1
On Thu, 18 Jun 2020 08:06:21 -0700, Douglas Anderson wrote:
> This patch series is a new version of the previous patch posted:
>   [PATCH v2] spi: spi-geni-qcom: Speculative fix of "nobody cared" about interrupt
>   https://lore.kernel.org/r/20200317133653.v2.1.I752ebdcfd5e8bf0de06d66e767b8974932b3620e@changeid
> 
> At this point I've done enough tracing to know that there was a real
> race in the old code (not just weakly ordered memory problems) and
> that should be fixed with the locking patches.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/4] spi: spi-geni-qcom: Mo' betta locking
      commit: 2ee471a1e28ec79fbfcdc8900ed0ed74132b0efe
[2/4] spi: spi-geni-qcom: Check for error IRQs
      commit: e191a082d764e80a36c198da61fbf2851ebf425a
[3/4] spi: spi-geni-qcom: Actually use our FIFO
      commit: 902481a78ee4173926dc59f060526dee21aeb7a8
[4/4] spi: spi-geni-qcom: Don't keep a local state variable
      commit: 7ba9bdcb91f694b0eaf486a825afd9c2d99532b7

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark
Mark Brown June 22, 2020, 2:59 p.m. UTC | #2
On Thu, 18 Jun 2020 08:06:21 -0700, Douglas Anderson wrote:
> This patch series is a new version of the previous patch posted:
>   [PATCH v2] spi: spi-geni-qcom: Speculative fix of "nobody cared" about interrupt
>   https://lore.kernel.org/r/20200317133653.v2.1.I752ebdcfd5e8bf0de06d66e767b8974932b3620e@changeid
> 
> At this point I've done enough tracing to know that there was a real
> race in the old code (not just weakly ordered memory problems) and
> that should be fixed with the locking patches.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/2] spi: spi-geni-qcom: Simplify setup_fifo_xfer()
      commit: 0d574c6b59c6ac0ae5b581a2ffb813d446a50a3d
[2/2] spi: spi-geni-qcom: Don't set {tx,rx}_rem_bytes unnecessarily
      (no commit info)

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark