| Message ID | 1411874849-343-2-git-send-email-mitchelh@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Sep 27, 2014 at 08:27:28PM -0700, Mitchel Humpherys wrote: > From: Matt Wagantall <mattw@codeaurora.org> > > It is sometimes necessary to poll a memory-mapped register until its > value satisfies some condition. Introduce a family of convenience macros > that do this. Tight-loop and sleeping versions are provided with and > without timeouts. > > Cc: Thierry Reding <thierry.reding@gmail.com> > Cc: Will Deacon <will.deacon@arm.com> > Signed-off-by: Matt Wagantall <mattw@codeaurora.org> > Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> > --- > include/linux/iopoll.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 77 insertions(+) > create mode 100644 include/linux/iopoll.h It would be good to provide a changelog with each new version of the patch. As it is I now have v2 and v3 of this patch in my inbox and I have no idea what the differences are, so I'd need to download both and run them through interdiff to find out. Thierry
On Mon, Sep 29 2014 at 01:31:37 AM, Thierry Reding <thierry.reding@gmail.com> wrote: > On Sat, Sep 27, 2014 at 08:27:28PM -0700, Mitchel Humpherys wrote: >> From: Matt Wagantall <mattw@codeaurora.org> >> >> It is sometimes necessary to poll a memory-mapped register until its >> value satisfies some condition. Introduce a family of convenience macros >> that do this. Tight-loop and sleeping versions are provided with and >> without timeouts. >> >> Cc: Thierry Reding <thierry.reding@gmail.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Signed-off-by: Matt Wagantall <mattw@codeaurora.org> >> Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> >> --- >> include/linux/iopoll.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 77 insertions(+) >> create mode 100644 include/linux/iopoll.h > > It would be good to provide a changelog with each new version of the > patch. As it is I now have v2 and v3 of this patch in my inbox and I > have no idea what the differences are, so I'd need to download both > and run them through interdiff to find out. Yeah I put the changelog in the cover letter. There were no changes on this patch, though I admit that wasn't entirely clear now re-reading the cover letter text. I also didn't account for the fact that you probably aren't reading the whole series since I only Cc'd you on this patch, not the whole series. In any case, I probably shouldn't have re-sent the whole series after one minor modification to one patch in the series. -Mitch
On Mon, Sep 29, 2014 at 09:47:34AM -0700, Mitchel Humpherys wrote: > On Mon, Sep 29 2014 at 01:31:37 AM, Thierry Reding <thierry.reding@gmail.com> wrote: > > On Sat, Sep 27, 2014 at 08:27:28PM -0700, Mitchel Humpherys wrote: > >> From: Matt Wagantall <mattw@codeaurora.org> > >> > >> It is sometimes necessary to poll a memory-mapped register until its > >> value satisfies some condition. Introduce a family of convenience macros > >> that do this. Tight-loop and sleeping versions are provided with and > >> without timeouts. > >> > >> Cc: Thierry Reding <thierry.reding@gmail.com> > >> Cc: Will Deacon <will.deacon@arm.com> > >> Signed-off-by: Matt Wagantall <mattw@codeaurora.org> > >> Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> > >> --- > >> include/linux/iopoll.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 77 insertions(+) > >> create mode 100644 include/linux/iopoll.h > > > > It would be good to provide a changelog with each new version of the > > patch. As it is I now have v2 and v3 of this patch in my inbox and I > > have no idea what the differences are, so I'd need to download both > > and run them through interdiff to find out. > > Yeah I put the changelog in the cover letter. There were no changes on > this patch, though I admit that wasn't entirely clear now re-reading the > cover letter text. I also didn't account for the fact that you probably > aren't reading the whole series since I only Cc'd you on this patch, not > the whole series. In any case, I probably shouldn't have re-sent the > whole series after one minor modification to one patch in the series. No worries, thanks for clarifying. Thierry
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h new file mode 100644 index 0000000000..594b0d4f03 --- /dev/null +++ b/include/linux/iopoll.h @@ -0,0 +1,77 @@ +/* + * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#ifndef _LINUX_IOPOLL_H +#define _LINUX_IOPOLL_H + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/hrtimer.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/io.h> + +/** + * readl_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs + * @addr: Address to poll + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops) + * @timeout_us: Timeout in us, 0 means never timeout + * + * Returns 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @addr is stored in @val. Must not + * be called from atomic context if sleep_us or timeout_us are used. + */ +#define readl_poll_timeout(addr, val, cond, sleep_us, timeout_us) \ +({ \ + ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ + might_sleep_if(timeout_us); \ + for (;;) { \ + (val) = readl(addr); \ + if (cond) \ + break; \ + if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \ + (val) = readl(addr); \ + break; \ + } \ + if (sleep_us) \ + usleep_range(DIV_ROUND_UP(sleep_us, 4), sleep_us); \ + } \ + (cond) ? 0 : -ETIMEDOUT; \ +}) + +/** + * readl_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs + * @addr: Address to poll + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @max_reads: Maximum number of reads before giving up + * @time_between_us: Time to udelay() between successive reads + * + * Returns 0 on success and -ETIMEDOUT upon a timeout. + */ +#define readl_poll_timeout_atomic(addr, val, cond, max_reads, time_between_us) \ +({ \ + int count; \ + for (count = (max_reads); count > 0; count--) { \ + (val) = readl(addr); \ + if (cond) \ + break; \ + udelay(time_between_us); \ + } \ + (cond) ? 0 : -ETIMEDOUT; \ +}) + +#endif /* _LINUX_IOPOLL_H */