From mboxrd@z Thu Jan 1 00:00:00 1970 From: mitchelh@codeaurora.org (Mitchel Humpherys) Date: Wed, 29 Oct 2014 14:13:39 -0700 Subject: [PATCH v7 1/2] iopoll: Introduce memory-mapped IO polling macros In-Reply-To: <1414617220-21493-1-git-send-email-mitchelh@codeaurora.org> References: <1414617220-21493-1-git-send-email-mitchelh@codeaurora.org> Message-ID: <1414617220-21493-2-git-send-email-mitchelh@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Matt Wagantall 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-looping, sleeping, and timing out can all be accomplished using these macros. Cc: Thierry Reding Cc: Will Deacon Signed-off-by: Matt Wagantall Signed-off-by: Mitchel Humpherys --- Changes since v6: - No changes. Resending due to changes in the the next patch in the series. --- include/linux/iopoll.h | 213 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 include/linux/iopoll.h diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h new file mode 100644 index 0000000000..21dd41942b --- /dev/null +++ b/include/linux/iopoll.h @@ -0,0 +1,213 @@ +/* + * 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 +#include +#include +#include +#include +#include + +/** + * 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) + * @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. + * + * Generally you'll 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) + * @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. + * + * Generally you'll 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 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 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 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) + +#define ioread8_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(ioread8, addr, val, cond, delay_us, timeout_us) + +#define ioread8_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(ioread8, addr, val, cond, delay_us, timeout_us) + +#define ioread16_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(ioread16, addr, val, cond, delay_us, timeout_us) + +#define ioread16_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(ioread16, addr, val, cond, delay_us, timeout_us) + +#define ioread16be_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(ioread16be, addr, val, cond, delay_us, timeout_us) + +#define ioread16be_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(ioread16be, addr, val, cond, delay_us, timeout_us) + +#define ioread32_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(ioread32, addr, val, cond, delay_us, timeout_us) + +#define ioread32_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(ioread32, addr, val, cond, delay_us, timeout_us) + +#define ioread32b3_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(ioread32b3, addr, val, cond, delay_us, timeout_us) + +#define ioread32b3_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(ioread32b3, addr, val, cond, delay_us, timeout_us) + +#define inb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inb, addr, val, cond, delay_us, timeout_us) + +#define inb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inb, addr, val, cond, delay_us, timeout_us) + +#define inb_p_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inb_p, addr, val, cond, delay_us, timeout_us) + +#define inb_p_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inb_p, addr, val, cond, delay_us, timeout_us) + +#define inw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inw, addr, val, cond, delay_us, timeout_us) + +#define inw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inw, addr, val, cond, delay_us, timeout_us) + +#define inw_p_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inw_p, addr, val, cond, delay_us, timeout_us) + +#define inw_p_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inw_p, addr, val, cond, delay_us, timeout_us) + +#define inw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inw, addr, val, cond, delay_us, timeout_us) + +#define inw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inw, addr, val, cond, delay_us, timeout_us) + +#define inl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inl, addr, val, cond, delay_us, timeout_us) + +#define inl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inl, addr, val, cond, delay_us, timeout_us) + +#define inl_p_poll_timeout(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout(inl_p, addr, val, cond, delay_us, timeout_us) + +#define inl_p_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ + readx_poll_timeout_atomic(inl_p, addr, val, cond, delay_us, timeout_us) + + +#endif /* _LINUX_IOPOLL_H */ -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project