From patchwork Mon Dec 20 19:56:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 12696875 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7F75C433EF for ; Mon, 20 Dec 2021 19:59:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=O1r3s0BnKKTNnpJEbdegaa6VYH/Ks1+vRBJs+AqXNnw=; b=AUFbYCBwtA1k9D dLhcjNmmv0PrCN/pEaGEZrGlczLHnpN26tIhVOFcn2eonpGoZmu18sS1b1F19pR1zGk3rV1CeNgTm HQZxWOgFBCt77aD04ycYNhhVCedwnftiL6EzF+tHuT9ez+A9s9V8bHc8iMX+WuvLKW10/GAShydUq WcYXr3gxPYGF5ZoGgv6arkcfCcpKfw1O0VvymyKECDZ/DkvGKFVfCv08I+4aJZ/8E8c60ZyrbKk0q fYX7aT3KCUwTjaJ0wwC9WNDh5YMpnpqk3r49coDhPEl0hCfViKq2dC5HJlLGq+fvwXRm2ovLtGR7H 5UsAI6EOXEjP6aE8rkug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzOnM-004Alo-2Q; Mon, 20 Dec 2021 19:58:04 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzOmn-004AU1-Qy for linux-arm-kernel@lists.infradead.org; Mon, 20 Dec 2021 19:57:31 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 924821042; Mon, 20 Dec 2021 11:57:28 -0800 (PST) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E312F3F718; Mon, 20 Dec 2021 11:57:26 -0800 (PST) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, cristian.marussi@arm.com Subject: [PATCH v8 03/11] firmware: arm_scmi: Add sync_cmds_completed_on_ret transport flag Date: Mon, 20 Dec 2021 19:56:38 +0000 Message-Id: <20211220195646.44498-4-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211220195646.44498-1-cristian.marussi@arm.com> References: <20211220195646.44498-1-cristian.marussi@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211220_115730_005468_F5E50F57 X-CRM114-Status: GOOD ( 18.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Add a flag to let the transport signal to the core if its handling of sync command implies that, after .send_message has returned successfully, the requested command can be assumed to be fully and completely executed on SCMI platform side so that any possible response value is already immediately available to be retrieved by a .fetch_response: in other words the polling phase can be skipped in such a case and the response values accessed straight away. Note that all of the above applies only when polling mode of operation was selected by the core: if instead a completion IRQ was found to be available the normal response processing path based on completions will still be followed. Signed-off-by: Cristian Marussi --- v7 --> v8 - renaming to sync_cmds_completed_on_ret - removed poling_capable flag, using macros v5 --> v6 - added polling_capable helper flag v4 --> v5 - removed RFC tag - consider sync_cmds_atomic_replies flag when deciding if polling is to be supported and .poll_done() is not provided. - reviewed commit message --- drivers/firmware/arm_scmi/common.h | 8 ++++++ drivers/firmware/arm_scmi/driver.c | 40 ++++++++++++++++++++++-------- 2 files changed, 38 insertions(+), 10 deletions(-) diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 652e5d95ee65..24b1d1ac5f12 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -409,6 +409,13 @@ struct scmi_device *scmi_child_dev_find(struct device *parent, * @max_msg_size: Maximum size of data per message that can be handled. * @force_polling: Flag to force this whole transport to use SCMI core polling * mechanism instead of completion interrupts even if available. + * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures + * synchronous-command messages are atomically + * completed on .send_message: no need to poll + * actively waiting for a response. + * Used by core internally only when polling is + * selected as a waiting for reply method: i.e. + * if a completion irq was found use that anyway. */ struct scmi_desc { int (*transport_init)(void); @@ -418,6 +425,7 @@ struct scmi_desc { int max_msg; int max_msg_size; const bool force_polling; + const bool sync_cmds_completed_on_ret; }; #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index cb9fc12503f2..d4dd42ebc5e8 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -40,7 +40,14 @@ ((__c)->no_completion_irq || (__i)->desc->force_polling) \ #define IS_TRANSPORT_POLLING_CAPABLE(__i) \ - ((__i)->desc->ops->poll_done) +({ \ + bool __ret; \ + typeof(__i) i_ = __i; \ + \ + __ret = ((i_)->desc->ops->poll_done || \ + (i_)->desc->sync_cmds_completed_on_ret); \ + __ret; \ +}) #define IS_POLLING_ENABLED(__c, __i) \ ({ \ @@ -780,10 +787,28 @@ static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo, xfer->hdr.poll_completion); if (xfer->hdr.poll_completion) { - ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms); + /* + * Real polling is needed only if transport has NOT declared + * itself to support synchronous commands replies. + */ + if (!info->desc->sync_cmds_completed_on_ret) { + /* + * Poll on xfer using transport provided .poll_done(); + * assumes no completion interrupt was available. + */ + ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms); + + spin_until_cond(scmi_xfer_done_no_timeout(cinfo, + xfer, stop)); + if (ktime_after(ktime_get(), stop)) { + dev_err(dev, + "timed out in resp(caller: %pS) - polling\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } + } - spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop)); - if (ktime_before(ktime_get(), stop)) { + if (!ret) { unsigned long flags; /* @@ -796,11 +821,6 @@ static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo, xfer->state = SCMI_XFER_RESP_OK; } spin_unlock_irqrestore(&xfer->lock, flags); - } else { - dev_err(dev, - "timed out in resp(caller: %pS) - polling\n", - (void *)_RET_IP_); - ret = -ETIMEDOUT; } } else { /* And we wait for the response. */ @@ -835,7 +855,7 @@ static int do_xfer(const struct scmi_protocol_handle *ph, struct scmi_chan_info *cinfo; /* Check for polling request on custom command xfers at first */ - if (xfer->hdr.poll_completion && !info->desc->ops->poll_done) { + if (xfer->hdr.poll_completion && !IS_TRANSPORT_POLLING_CAPABLE(info)) { dev_warn_once(dev, "Polling mode is not supported by transport.\n"); return -EINVAL;