From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 864FE3126CE for ; Tue, 23 Dec 2025 09:37:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766482660; cv=none; b=G6xFYED48hxN0g4fbY5XOXmygSJA4GvDBRR+O6dNregRmY/pgv0Xt4exc+7wpqpHre+f5yGq3hDHXa5nfuJ1ptXVPtaJlWRPjYzLh1h6VtgH3UbQ1ETQhGAKzhBWz0lX5hQCyq69yh+duU1KNZGQwmqt8QTL/zy+w6v57m4I8b4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766482660; c=relaxed/simple; bh=I4+sjLpsKmpKb4Ebaw6gs0Kx2q12xqzh2tUdl7nxWhM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZhtzRKpKvRiAkrMTy+Z5tzGOoHKLp9EFJIIaG+prUpuPxY43Wr0R1e8WdPM6kkmHYrO14XjS+ptD8+XIe9Cg0Ndj1JAxqMJkJEIi+2WV0DnfUM6zqVtcDBaDqXEzDkxuO8QzRG9LV36PGGIepUZNsW2rfddQdPXwnUVjKmUxllA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 3C6FE497; Tue, 23 Dec 2025 01:37:24 -0800 (PST) Received: from [10.57.78.114] (unknown [10.57.78.114]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AE9DD3F694; Tue, 23 Dec 2025 01:37:29 -0800 (PST) Message-ID: Date: Tue, 23 Dec 2025 09:37:27 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 4/4] coresight: tpda: add sysfs node to flush specific port Content-Language: en-GB To: Jie Gan , Mike Leach , James Clark , Alexander Shishkin , Tingwei Zhang Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Tao Zhang References: <20251222-add_sysfs_nodes_to_configure_tpda-v6-0-b27143d45c86@oss.qualcomm.com> <20251222-add_sysfs_nodes_to_configure_tpda-v6-4-b27143d45c86@oss.qualcomm.com> <9899b6c2-2bdf-41b8-9156-dcf1b611da39@arm.com> From: Suzuki K Poulose In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 23/12/2025 02:16, Jie Gan wrote: > > > On 12/22/2025 9:12 PM, Suzuki K Poulose wrote: >> On 22/12/2025 06:02, Jie Gan wrote: >>> From: Tao Zhang >>> >>> Setting bit i in the TPDA_FLUSH_CR register initiates a flush request >>> for port i, forcing the data to synchronize and be transmitted to the >>> sink device. >>> >>> Signed-off-by: Tao Zhang >>> Reviewed-by: James Clark >>> Co-developed-by: Jie Gan >>> Signed-off-by: Jie Gan >>> --- >>>   .../ABI/testing/sysfs-bus-coresight-devices-tpda   |  7 ++++ >>>   drivers/hwtracing/coresight/coresight-tpda.c       | 40 +++++++++++ >>> + ++++++++++ >>>   drivers/hwtracing/coresight/coresight-tpda.h       |  1 + >>>   3 files changed, 48 insertions(+) >>> >>> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices- >>> tpda b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda >>> index d359d90dca72..df8f03d4b573 100644 >>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda >>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda >>> @@ -51,3 +51,10 @@ Description: >>>           mode 0 - COUNT[11:0] value represents the approximate >>> number of bytes moved between two ASYNC packet requests >>>           mode 1 - the bits COUNT[11:7] are used as a power of 2. for >>> example, we could insert an async packet every 8K >>>                    data by writing a value 13 to the COUNT[11:7] field. >>> + >>> +What:        /sys/bus/coresight/devices//port_flush_req >>> +Date:        December 2025 >>> +KernelVersion:    6.19 >>> +Contact:    Jinlong Mao , Tao Zhang >>> , Jie Gan >>> +Description: >>> +        (RW) Configure the bit i to requests a flush operation of >>> port i on the TPDA. >> >> Does this have similar semantics as the "global_flush_req"  for "Read" ? > > Yes, global_flush_req triggers all ports at once, whereas this node > initiates a flush request for specific port(s). > > For reading, we can check whether the flush request has completed. Please document it as such. Suzuki > > Thanks, > Jie > >> i.e., the bit stays set until the request completes ? Otherwise, why >> isn't this Write only ? >> >> I don't see the point of "Reading" this value back. >> >> Suzuki >> >>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/ >>> hwtracing/coresight/coresight-tpda.c >>> index 7baa8a0965d3..f79fea4fbb2c 100644 >>> --- a/drivers/hwtracing/coresight/coresight-tpda.c >>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c >>> @@ -430,9 +430,49 @@ static ssize_t syncr_mode_store(struct device *dev, >>>   } >>>   static DEVICE_ATTR_RW(syncr_mode); >>> +static ssize_t port_flush_req_show(struct device *dev, >>> +                   struct device_attribute *attr, >>> +                   char *buf) >>> +{ >>> +    struct tpda_drvdata *drvdata = dev_get_drvdata(dev->parent); >>> +    unsigned long val; >>> + >>> +    if (!drvdata->csdev->refcnt) >>> +        return -EINVAL; >>> + >>> +    guard(spinlock)(&drvdata->spinlock); >>> +    val = readl_relaxed(drvdata->base + TPDA_FLUSH_CR); >>> + >>> +    return sysfs_emit(buf, "0x%lx\n", val); >>> +} >>> + >>> +static ssize_t port_flush_req_store(struct device *dev, >>> +                    struct device_attribute *attr, >>> +                    const char *buf, >>> +                    size_t size) >>> +{ >>> +    struct tpda_drvdata *drvdata = dev_get_drvdata(dev->parent); >>> +    u32 val; >>> + >>> +    if (kstrtou32(buf, 0, &val)) >>> +        return -EINVAL; >>> + >>> +    if (!drvdata->csdev->refcnt || !val) >>> +        return -EINVAL; >>> + >>> +    guard(spinlock)(&drvdata->spinlock); >>> +    CS_UNLOCK(drvdata->base); >>> +    writel_relaxed(val, drvdata->base + TPDA_FLUSH_CR); >>> +    CS_LOCK(drvdata->base); >>> + >>> +    return size; >>> +} >>> +static DEVICE_ATTR_RW(port_flush_req); >>> + >>>   static struct attribute *tpda_attrs[] = { >>>       &dev_attr_global_flush_req.attr, >>>       &dev_attr_syncr_mode.attr, >>> +    &dev_attr_port_flush_req.attr, >>>       tpda_trig_sysfs_rw(freq_ts_enable, FREQTS), >>>       tpda_trig_sysfs_rw(trig_freq_enable, FRIE), >>>       tpda_trig_sysfs_rw(trig_flag_ts_enable, FLRIE), >>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/ >>> hwtracing/coresight/coresight-tpda.h >>> index 1d2de50bb9f9..ef1ce2ce36a9 100644 >>> --- a/drivers/hwtracing/coresight/coresight-tpda.h >>> +++ b/drivers/hwtracing/coresight/coresight-tpda.h >>> @@ -10,6 +10,7 @@ >>>   #define TPDA_Pn_CR(n)        (0x004 + (n * 4)) >>>   #define TPDA_FPID_CR        (0x084) >>>   #define TPDA_SYNCR        (0x08C) >>> +#define TPDA_FLUSH_CR        (0x090) >>>   /* Cross trigger global (all ports) flush request bit */ >>>   #define TPDA_CR_FLREQ        BIT(0) >>> >> >