[v10] iopoll: Introduce memory-mapped IO polling macros

Message ID	1418687243-16395-1-git-send-email-mitchelh@codeaurora.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> sender: mitchelh@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id C467E140B3A; Mon, 15 Dec 2014 23:47:29 +0000 (UTC) From: Mitchel Humpherys <mitchelh@codeaurora.org> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, Thierry Reding <thierry.reding@gmail.com>, Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>, Andrew Morton <akpm@linux-foundation.org>, Robert Elliott <elliott@hp.com> Subject: [PATCH v10] iopoll: Introduce memory-mapped IO polling macros Date: Mon, 15 Dec 2014 15:47:23 -0800 Message-Id: <1418687243-16395-1-git-send-email-mitchelh@codeaurora.org> Cc: Mitchel Humpherys <mitchelh@codeaurora.org>, Matt Wagantall <mattw@codeaurora.org> Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h new file mode 100644 index 000000000000..08fd52cdb5a0 --- /dev/null +++ b/include/linux/iopoll.h @@ -0,0 +1,144 @@ +/* + * 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> + +/** + * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs + * @op: accessor function (takes @addr as its only argument) + * @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). Should be less than ~20ms since usleep_range + * is used (see Documentation/timers/timers-howto.txt). + * @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. + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + */ +#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ +({ \ + ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ + might_sleep_if(sleep_us); \ + for (;;) { \ + (val) = op(addr); \ + if (cond) \ + break; \ + if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \ + (val) = op(addr); \ + break; \ + } \ + if (sleep_us) \ + usleep_range((sleep_us >> 2) + 1, sleep_us); \ + } \ + (cond) ? 0 : -ETIMEDOUT; \ +}) + +/** + * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs + * @op: accessor function (takes @addr as its only argument) + * @addr: Address to poll + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @delay_us: Time to udelay between reads in us (0 tight-loops). Should + * be less than ~10us since udelay is used (see + * Documentation/timers/timers-howto.txt). + * @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. + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + */ +#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ +({ \ + ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ + for (;;) { \ + (val) = op(addr); \ + if (cond) \ + break; \ + if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \ + (val) = op(addr); \ + break; \ + } \ + if (delay_us) \ + udelay(delay_us); \ + } \ + (cond) ? 0 : -ETIMEDOUT; \ +}) + + +#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) + +#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) + +#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) + +#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) + +#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) + +#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) + +#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) + +#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) + +#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) + +#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) + +#endif /* _LINUX_IOPOLL_H */

[v10] iopoll: Introduce memory-mapped IO polling macros

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