From patchwork Fri Apr 24 16:46:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 189441 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90C40C54FCB for ; Fri, 24 Apr 2020 16:47:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DF0A2075A for ; Fri, 24 Apr 2020 16:47:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QsUZIst0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728119AbgDXQrT (ORCPT ); Fri, 24 Apr 2020 12:47:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726793AbgDXQrT (ORCPT ); Fri, 24 Apr 2020 12:47:19 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E96AC09B047 for ; Fri, 24 Apr 2020 09:47:19 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id g6so4868998pgs.9 for ; Fri, 24 Apr 2020 09:47:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8LMkNBqXB+CeQceWfD+1N1s9IOWokLMqWssX/DZezGQ=; b=QsUZIst0n7NitTwTbPskwHB/A9M3npMfgM+TRceAN2YLnBjo7TiuFLgIDIAlNhloZQ Hhw57EsdqXMyumDsh1p+qtH9Zn5ICKQGQ58SLXj71jnWAYQwMA/6Pufm5DvprHi4Cef4 rH4sHfsgJYbQ0P7x2TuhVvmMmpEyWPlY6KftQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8LMkNBqXB+CeQceWfD+1N1s9IOWokLMqWssX/DZezGQ=; b=Q161pK9PaqwacDpdTdKr+4EhcvSU+v95iBdXc60eD64+SjLQ5zABn1TGB5I4NyUIsY vuL6MfuSNGGEIq3Fm4F5UD9tvm4pmpsk4tH+rEHQdWvA6K/ezE5Ct9zjNgH1R4xLgMl2 HwmcUEcYcY/BggzPr80J19+E9fKSfoxcAjTLd/fJ8gkk7Qc5McbyDj79M3p60cb0FLKj qFzJkoKYnLU7uyxUFOhXfNe6sHajvU9YSZsd1jwUWMQ2rkpVEFyM7GXCbi4rOyHtgwUJ 8k3m1iAygbI6lavP7vV99Hs0TGSRJxlQ0JCBr55kqznHcJ6QQ1gCDIY5SzvdY7ol2WU4 2ZYQ== X-Gm-Message-State: AGi0PuYKeFvfyGbKoskBaLcCoVyjN+2QKJ0l6UIqDOtRvzsqhkqFAFYQ rKDTYpc3GehzHT6Ec/K1cDV3Rw== X-Google-Smtp-Source: APiQypJWdVuaFCmqhM/KqVMwq1a10HxnD754ZLgp0ghuRAORQk+vl0gQ1jCPIlxmNdNeTKvaSlm4aw== X-Received: by 2002:a63:f30a:: with SMTP id l10mr10233893pgh.372.1587746838702; Fri, 24 Apr 2020 09:47:18 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id r28sm6319205pfg.186.2020.04.24.09.47.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2020 09:47:17 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , rafael.j.wysocki@intel.com, Andy Gross , Bjorn Andersson Cc: evgreen@chromium.org, mka@chromium.org, mkshah@codeaurora.org, swboyd@chromium.org, Douglas Anderson , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 1/5] soc: qcom: rpmh-rsc: Correctly ignore CPU_CLUSTER_PM notifications Date: Fri, 24 Apr 2020 09:46:53 -0700 Message-Id: <20200424094610.v5.1.Ic7096b3b9b7828cdd41cd5469a6dee5eb6abf549@changeid> X-Mailer: git-send-email 2.26.2.303.gf8c07b1a785-goog MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Our switch statement doesn't have entries for CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED, and CPU_CLUSTER_PM_EXIT and doesn't have a default. This means that we'll try to do a flush in those cases but we won't necessarily be the last CPU down. That's not so ideal since our (lack of) locking assumes we're on the last CPU. Luckily this isn't as big a problem as you'd think since (at least on the SoC I tested) we don't get these notifications except on full system suspend. ...and on full system suspend we get them on the last CPU down. That means that the worst problem we hit is flushing twice. Still, it's good to make it correct. Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches") Reported-by: Stephen Boyd Signed-off-by: Douglas Anderson Reviewed-by: Maulik Shah Reviewed-by: Stephen Boyd --- Changes in v5: - Corrently => Correctly Changes in v4: - ("...Corrently ignore CPU_CLUSTER_PM notifications") split out for v4. Changes in v3: None Changes in v2: None drivers/soc/qcom/rpmh-rsc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c index a9e15699f55f..3571a99fc839 100644 --- a/drivers/soc/qcom/rpmh-rsc.c +++ b/drivers/soc/qcom/rpmh-rsc.c @@ -806,6 +806,8 @@ static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb, case CPU_PM_EXIT: cpumask_clear_cpu(smp_processor_id(), &drv->cpus_entered_pm); goto exit; + default: + return NOTIFY_DONE; } ret = rpmh_rsc_ctrlr_is_busy(drv); From patchwork Fri Apr 24 16:46:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 189440 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DF14C55186 for ; Fri, 24 Apr 2020 16:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F4B120728 for ; Fri, 24 Apr 2020 16:47:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="anMh/gpG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728664AbgDXQr1 (ORCPT ); Fri, 24 Apr 2020 12:47:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728575AbgDXQrZ (ORCPT ); Fri, 24 Apr 2020 12:47:25 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A1D2C09B047 for ; Fri, 24 Apr 2020 09:47:24 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id o10so4875978pgb.6 for ; Fri, 24 Apr 2020 09:47:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=DlbMzsVP92mS9LVkheQwBLWwhs/wCWhGqHUKlJRd3Zk=; b=anMh/gpGlng+/GdOk/KtuufXhSHvjb3Xg5RwpWu7kDoaxfwXo9Xy56LEKeO0T1L9IS vyvNhjwKfOJMnUIZ+Z43SmvH4ZCdSWdGrrn8X8JxOmgNmwgq1w2yvT3MuxUb+R+ww7d/ CnKwgyJAKfLMnwRkrQw3WdnqRLShJktUFlZ9E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=DlbMzsVP92mS9LVkheQwBLWwhs/wCWhGqHUKlJRd3Zk=; b=FbAA6MAOQ3aeUbapE3tpIvHHHDb8QqxE8Nfdbpp0MYqOGfRnrn7iRzBopPu7bGO4lO QfpLnWDMTnepv4DQnm7DxgTRgX+R8ESbY45HY1D0FXs1usvT2PCk7aF1t9iXcyfrq7iO BnvSt67b6tvgLM1SjcJm+vJSGh3iBrON22SPS8poH1YhgrFEIbPmvvaKsgVLLeNh3YqC 6rHgV3Q58pC1D314KyeY+Qm2DH0ZKVT1PEtjTwFR87iHYlIy2OklHTSp4bUBZHIkaZ2w ETqMWP/NFyyw0+W878u0UI/P7RAtUykPBE79IKscA+SJCRRfxEcNAxZvnK7n8NSoIc+x SiMg== X-Gm-Message-State: AGi0Pubi4mBQtdhaSbChnY397+8Idf1JwNNj53/w4TOOrq9PhKdPhuEB iz0wl9aV+uXzVM1e7pe7Ox4p4Q== X-Google-Smtp-Source: APiQypJUUh7XgEeHmPzFV4AOAw9Zj6I2wSwm0lMRTnEKKVKtUnmkIn5IDTPw2TroFmgey8viuUmaAw== X-Received: by 2002:aa7:850f:: with SMTP id v15mr10264519pfn.204.1587746843519; Fri, 24 Apr 2020 09:47:23 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id r28sm6319205pfg.186.2020.04.24.09.47.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2020 09:47:22 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , rafael.j.wysocki@intel.com, Andy Gross , Bjorn Andersson Cc: evgreen@chromium.org, mka@chromium.org, mkshah@codeaurora.org, swboyd@chromium.org, Douglas Anderson , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 4/5] soc: qcom: rpmh-rsc: Simplify locking by eliminating the per-TCS lock Date: Fri, 24 Apr 2020 09:46:56 -0700 Message-Id: <20200424094610.v5.4.Ib8dccfdb10bf6b1fb1d600ca1c21d9c0db1ef746@changeid> X-Mailer: git-send-email 2.26.2.303.gf8c07b1a785-goog In-Reply-To: <20200424094610.v5.1.Ic7096b3b9b7828cdd41cd5469a6dee5eb6abf549@changeid> References: <20200424094610.v5.1.Ic7096b3b9b7828cdd41cd5469a6dee5eb6abf549@changeid> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The rpmh-rsc code had both a driver-level lock (sometimes referred to in comments as drv->lock) and a lock per-TCS. The idea was supposed to be that there would be times where you could get by with just locking a TCS lock and therefor other RPMH users wouldn't be blocked. The above didn't work out so well. Looking at tcs_write() the bigger drv->lock was held for most of the function anyway. Only the __tcs_buffer_write() and __tcs_set_trigger() calls were called without holding the drv->lock. It actually turns out that in tcs_write() we don't need to hold the drv->lock for those function calls anyway even if the per-TCS lock isn't there anymore. From the newly added comments in the code, this is because: - We marked "tcs_in_use" under lock. - Once "tcs_in_use" has been marked nobody else could be writing to these registers until the interrupt goes off. - The interrupt can't go off until we trigger w/ the last line of __tcs_set_trigger(). Thus, from a tcs_write() point of view, the per-TCS lock was useless. Looking at rpmh_rsc_write_ctrl_data(), only the per-TCS lock was held. It turns out, though, that this function already needs to be called with the equivalent of the drv->lock held anyway (we either need to hold drv->lock as we will in a future patch or we need to know no other CPUs could be running as happens today). Specifically rpmh_rsc_write_ctrl_data() might be writing to a TCS that has been borrowed for writing an active transation but it never checks this. Let's eliminate this extra overhead and avoid possible AB BA locking headaches. Suggested-by: Maulik Shah Signed-off-by: Douglas Anderson --- Changes in v5: - without it the => without holding the - Copy why tcs_write() could release drv->lock early to commit msg. - goto err => goto unlock - Verbosify comment, saying trigger meant end of __tcs_set_trigger(). Changes in v4: None Changes in v3: - ("soc: qcom: rpmh-rsc: Simplify locking...") new for v3. Changes in v2: None drivers/soc/qcom/rpmh-internal.h | 13 ++------ drivers/soc/qcom/rpmh-rsc.c | 55 +++++++++++++++----------------- 2 files changed, 28 insertions(+), 40 deletions(-) diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h index dba8510c0669..1f2857b3f38e 100644 --- a/drivers/soc/qcom/rpmh-internal.h +++ b/drivers/soc/qcom/rpmh-internal.h @@ -28,7 +28,6 @@ struct rsc_drv; * @offset: Start of the TCS group relative to the TCSes in the RSC. * @num_tcs: Number of TCSes in this type. * @ncpt: Number of commands in each TCS. - * @lock: Lock for synchronizing this TCS writes. * @req: Requests that are sent from the TCS; only used for ACTIVE_ONLY * transfers (could be on a wake/sleep TCS if we are borrowing for * an ACTIVE_ONLY transfer). @@ -48,7 +47,6 @@ struct tcs_group { u32 offset; int num_tcs; int ncpt; - spinlock_t lock; const struct tcs_request *req[MAX_TCS_PER_TYPE]; DECLARE_BITMAP(slots, MAX_TCS_SLOTS); }; @@ -103,14 +101,9 @@ struct rpmh_ctrlr { * @tcs_in_use: S/W state of the TCS; only set for ACTIVE_ONLY * transfers, but might show a sleep/wake TCS in use if * it was borrowed for an active_only transfer. You - * must hold both the lock in this struct and the - * tcs_lock for the TCS in order to mark a TCS as - * in-use, but you only need the lock in this structure - * (aka the drv->lock) to mark one freed. - * @lock: Synchronize state of the controller. If you will be - * grabbing this lock and a tcs_lock at the same time, - * grab the tcs_lock first so we always have a - * consistent lock ordering. + * must hold the lock in this struct (AKA drv->lock) in + * order to update this. + * @lock: Synchronize state of the controller. * @pm_lock: Synchronize during PM notifications. * Used when solver mode is not present. * @client: Handle to the DRV's client. diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c index e540e49fd61c..8ed39464d9d8 100644 --- a/drivers/soc/qcom/rpmh-rsc.c +++ b/drivers/soc/qcom/rpmh-rsc.c @@ -179,11 +179,7 @@ static void write_tcs_reg_sync(struct rsc_drv *drv, int reg, int tcs_id, * * Returns true if nobody has claimed this TCS (by setting tcs_in_use). * - * Context: Must be called with the drv->lock held or the tcs_lock for the TCS - * being tested. If only the tcs_lock is held then it is possible that - * this function will return that a tcs is still busy when it has been - * recently been freed but it will never return free when a TCS is - * actually in use. + * Context: Must be called with the drv->lock held. * * Return: true if the given TCS is free. */ @@ -242,8 +238,6 @@ void rpmh_rsc_invalidate(struct rsc_drv *drv) * This is normally pretty straightforward except if we are trying to send * an ACTIVE_ONLY message but don't have any active_only TCSes. * - * Called without drv->lock held and with no tcs_lock locks held. - * * Return: A pointer to a tcs_group or an ERR_PTR. */ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv, @@ -581,24 +575,19 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg) if (IS_ERR(tcs)) return PTR_ERR(tcs); - spin_lock_irqsave(&tcs->lock, flags); - spin_lock(&drv->lock); + spin_lock_irqsave(&drv->lock, flags); /* * The h/w does not like if we send a request to the same address, * when one is already in-flight or being processed. */ ret = check_for_req_inflight(drv, tcs, msg); - if (ret) { - spin_unlock(&drv->lock); - goto done_write; - } + if (ret) + goto unlock; - tcs_id = find_free_tcs(tcs); - if (tcs_id < 0) { - ret = tcs_id; - spin_unlock(&drv->lock); - goto done_write; - } + ret = find_free_tcs(tcs); + if (ret < 0) + goto unlock; + tcs_id = ret; tcs->req[tcs_id - tcs->offset] = msg; set_bit(tcs_id, drv->tcs_in_use); @@ -612,13 +601,22 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg) write_tcs_reg_sync(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, tcs_id, 0); enable_tcs_irq(drv, tcs_id, true); } - spin_unlock(&drv->lock); + spin_unlock_irqrestore(&drv->lock, flags); + /* + * These two can be done after the lock is released because: + * - We marked "tcs_in_use" under lock. + * - Once "tcs_in_use" has been marked nobody else could be writing + * to these registers until the interrupt goes off. + * - The interrupt can't go off until we trigger w/ the last line + * of __tcs_set_trigger() below. + */ __tcs_buffer_write(drv, tcs_id, 0, msg); __tcs_set_trigger(drv, tcs_id, true); -done_write: - spin_unlock_irqrestore(&tcs->lock, flags); + return 0; +unlock: + spin_unlock_irqrestore(&drv->lock, flags); return ret; } @@ -673,8 +671,6 @@ int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg) * Only for use on sleep/wake TCSes since those are the only ones we maintain * tcs->slots for. * - * Must be called with the tcs_lock for the group held. - * * Return: -ENOMEM if there was no room, else 0. */ static int find_slots(struct tcs_group *tcs, const struct tcs_request *msg, @@ -709,25 +705,25 @@ static int find_slots(struct tcs_group *tcs, const struct tcs_request *msg, * This should only be called for for sleep/wake state, never active-only * state. * + * The caller must ensure that no other RPMH actions are happening and the + * controller is idle when this function is called since it runs lockless. + * * Return: 0 if no error; else -error. */ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg) { struct tcs_group *tcs; int tcs_id = 0, cmd_id = 0; - unsigned long flags; int ret; tcs = get_tcs_for_msg(drv, msg); if (IS_ERR(tcs)) return PTR_ERR(tcs); - spin_lock_irqsave(&tcs->lock, flags); /* find the TCS id and the command in the TCS to write to */ ret = find_slots(tcs, msg, &tcs_id, &cmd_id); if (!ret) __tcs_buffer_write(drv, tcs_id, cmd_id, msg); - spin_unlock_irqrestore(&tcs->lock, flags); return ret; } @@ -756,8 +752,8 @@ static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv) * should be checked for not busy, because we used wake TCSes for * active requests in this case. * - * Since this is called from the last cpu, need not take drv or tcs - * lock before checking tcs_is_free(). + * Since this is called from the last cpu, need not take drv->lock + * before checking tcs_is_free(). */ if (!tcs->num_tcs) tcs = &drv->tcs[WAKE_TCS]; @@ -885,7 +881,6 @@ static int rpmh_probe_tcs_config(struct platform_device *pdev, tcs->type = tcs_cfg[i].type; tcs->num_tcs = tcs_cfg[i].n; tcs->ncpt = ncpt; - spin_lock_init(&tcs->lock); if (!tcs->num_tcs || tcs->type == CONTROL_TCS) continue;