From patchwork Tue Jan 2 14:42:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 123143 Delivered-To: patch@linaro.org Received: by 10.140.22.227 with SMTP id 90csp9044307qgn; Tue, 2 Jan 2018 06:46:10 -0800 (PST) X-Google-Smtp-Source: ACJfBot8Q+6socXLpLfCzXGn/R0QI69W9Hg+b9et3wMBrHik5TB1B0QNnYGzvtgtBuy8pO5I7P04 X-Received: by 10.84.252.137 with SMTP id y9mr44814506pll.153.1514904370141; Tue, 02 Jan 2018 06:46:10 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1514904370; cv=none; d=google.com; s=arc-20160816; b=BboBfxW12h5nVzJJQyMVN0lOoFHYIa5xg6o63p99xTa0gYdTW74jTO37dRV2X7pF+m qOD8jPSBm7ufYvVmhaZoBy1KUFeSvj/uu3M/Ta9zsZigoVv+60H6KAqRxOP3T5SG65eM sA2sf6YSp+EPCoW5eVgWdTp1e8byfoMi0qe4ezhNfptyE9hy2nfa+VX7fTg+fQmVkG2T OqnX8hayl63PTF65WMDaiOXx7Bm9q4XJQgJtGUm20E089jrnBb46JDXoluv/XbSKk+7+ xE+0IxIV2oBOVpCrlWKj5BhrFUlUUytx6rdoEf2Gvf5/qcYqixTP7ZjOaMsusgoyatep whjg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=8pHL7Asy7Btif+4vz6+WyQccvaTJBNiOJwUmKaQBziM=; b=yqtzeY16PHIrEK4OnXQ5jbSe7kkvZxzmcMaDB+LDGLY7uqzZ2KHQmz3tDP1P10rL5j nU7eqbBEW7brfrEU2OEc7HtKZRb066Qjm0nL9p8AqqSV9ij5CrzvJXjpT3BOrKgzOVkx 2NneAGgb0JzPuDtPa6MdMspRrkyVoMjqNuhvgqx5owmukUkkjsHe+tPewHCGED50PafW FQzmTGEIKiTLlESaqOHF81VmrGmL9Yjz2Qjz517OfTNVx2pp3EFQHnGycmKdK/64LHv7 wcFNo/ZWsD2YUuANIFFCSweXG6wcEMsIKLGXk69oHM8JME45fDL0e1lJLwAKli8mVgcD r+jQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id h12si31343405pls.547.2018.01.02.06.46.09; Tue, 02 Jan 2018 06:46:10 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752801AbeABOqG (ORCPT + 28 others); Tue, 2 Jan 2018 09:46:06 -0500 Received: from foss.arm.com ([217.140.101.70]:39778 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753199AbeABOnX (ORCPT ); Tue, 2 Jan 2018 09:43:23 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6A92A168F; Tue, 2 Jan 2018 06:43:23 -0800 (PST) Received: from e107155-lin.cambridge.arm.com (e107155-lin.cambridge.arm.com [10.1.210.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 57FD83F25C; Tue, 2 Jan 2018 06:43:21 -0800 (PST) From: Sudeep Holla To: ALKML , LKML , DTML Cc: Sudeep Holla , Roy Franz , Harb Abdulhamid , Nishanth Menon , Arnd Bergmann , Loc Ho , Alexey Klimov , Ryan Harkin , Jassi Brar Subject: [PATCH v5 11/20] firmware: arm_scmi: add support for polling based SCMI transfers Date: Tue, 2 Jan 2018 14:42:33 +0000 Message-Id: <1514904162-11201-12-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1514904162-11201-1-git-send-email-sudeep.holla@arm.com> References: <1514904162-11201-1-git-send-email-sudeep.holla@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It would be useful to have options to perform some SCMI transfers atomically by polling for the completion flag instead of interrupt driven. The SCMI specification has option to disable the interrupt and poll for the completion flag in the shared memory. This patch adds support for polling based SCMI transfers using that option. This might be used for uninterrupted/atomic DVFS operations from the scheduler context. Cc: Arnd Bergmann Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/driver.c | 49 +++++++++++++++++++++++++++++++------- 1 file changed, 41 insertions(+), 8 deletions(-) -- 2.7.4 diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 11c18ac9816f..0c9dda72f10c 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -26,9 +26,11 @@ */ #include +#include #include #include #include +#include #include #include #include @@ -363,6 +365,21 @@ void scmi_one_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer) up(&minfo->sem_xfer_count); } +static bool +scmi_xfer_poll_done(const struct scmi_info *info, struct scmi_xfer *xfer) +{ + struct scmi_shared_mem *mem = info->tx_payload; + u16 xfer_id = MSG_XTRACT_TOKEN(le32_to_cpu(mem->msg_header)); + + if (xfer->hdr.seq != xfer_id) + return false; + + return le32_to_cpu(mem->channel_status) & + (SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR | + SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE); +} + +#define SCMI_MAX_POLLING_TIMEOUT_NS (100 * NSEC_PER_USEC) /** * scmi_do_xfer() - Do one transfer * @@ -389,14 +406,30 @@ int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer) /* mbox_send_message returns non-negative value on success, so reset */ ret = 0; - /* And we wait for the response. */ - timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); - if (!wait_for_completion_timeout(&xfer->done, timeout)) { - dev_err(dev, "mbox timed out in resp(caller: %pF)\n", - (void *)_RET_IP_); - ret = -ETIMEDOUT; - } else if (xfer->hdr.status) { - ret = scmi_to_linux_errno(xfer->hdr.status); + if (xfer->hdr.poll_completion) { + ktime_t stop, cur; + + stop = ktime_add_ns(ktime_get(), SCMI_MAX_POLLING_TIMEOUT_NS); + do { + udelay(5); + cur = ktime_get(); + } while (!scmi_xfer_poll_done(info, xfer) && + ktime_before(cur, stop)); + + if (ktime_before(cur, stop)) + scmi_fetch_response(xfer, info->tx_payload); + else + ret = -ETIMEDOUT; + } else { + /* And we wait for the response. */ + timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); + if (!wait_for_completion_timeout(&xfer->done, timeout)) { + dev_err(dev, "mbox timed out in resp(caller: %pF)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } else if (xfer->hdr.status) { + ret = scmi_to_linux_errno(xfer->hdr.status); + } } /* * NOTE: we might prefer not to need the mailbox ticker to manage the