From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECBE0C677F1 for ; Mon, 16 Jan 2023 16:02:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232238AbjAPQCf (ORCPT ); Mon, 16 Jan 2023 11:02:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232072AbjAPQBz (ORCPT ); Mon, 16 Jan 2023 11:01:55 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 164272386D; Mon, 16 Jan 2023 08:01:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B5B9DB81061; Mon, 16 Jan 2023 16:01:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF783C433F0; Mon, 16 Jan 2023 16:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673884906; bh=y0ykQ5LxFyBMrgAOQxypx7vnPabzGGYUIb99kre3vn0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=RZrpQpaLuDnKOcBDICQF/OAAYXnQ43KVfMZ7t1c7g4/ozCliZf8WnDSxoesPwBMeQ b1u/BOlnUqWiov9JRjEAgH74CZ3QPMYBJqZFwG4N7w90eCOYqCXL0R2c2c/5LbtEgZ 5t9JAzBkogX9B5qnVSnLzYSBiTYUV+G7L0EI5UhTNkYVgHNGr4GIA0uNajhpbo/hZI bKEiE01cZjbG10SXTHWSs6Cd+0EV7+tx8i1y+P+6gaWgpSytcYtHko3ZcrLQ7sTGbn xxv8+o/7BZEQc76RkwitlAp1o5GFWoshQ3sPysrqSszHiWg0Onpl6sYLBdsnsDj87U OZxEEHwPOvo+Q== Message-ID: Date: Mon, 16 Jan 2023 18:01:40 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH net-next v2] net: ethernet: ti: am65-cpsw/cpts: Fix CPTS release action Content-Language: en-US To: Siddharth Vadapalli , Leon Romanovsky Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux@armlinux.org.uk, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, srk@ti.com References: <20230116044517.310461-1-s-vadapalli@ti.com> From: Roger Quadros In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Siddharth, On 16/01/2023 09:43, Siddharth Vadapalli wrote: > > > On 16/01/23 13:00, Leon Romanovsky wrote: >> On Mon, Jan 16, 2023 at 10:15:17AM +0530, Siddharth Vadapalli wrote: >>> The am65_cpts_release() function is registered as a devm_action in the >>> am65_cpts_create() function in am65-cpts driver. When the am65-cpsw driver >>> invokes am65_cpts_create(), am65_cpts_release() is added in the set of devm >>> actions associated with the am65-cpsw driver's device. >>> >>> In the event of probe failure or probe deferral, the platform_drv_probe() >>> function invokes dev_pm_domain_detach() which powers off the CPSW and the >>> CPSW's CPTS hardware, both of which share the same power domain. Since the >>> am65_cpts_disable() function invoked by the am65_cpts_release() function >>> attempts to reset the CPTS hardware by writing to its registers, the CPTS >>> hardware is assumed to be powered on at this point. However, the hardware >>> is powered off before the devm actions are executed. >>> >>> Fix this by getting rid of the devm action for am65_cpts_release() and >>> invoking it directly on the cleanup and exit paths. >>> >>> Fixes: f6bd59526ca5 ("net: ethernet: ti: introduce am654 common platform time sync driver") >>> Signed-off-by: Siddharth Vadapalli >>> Reviewed-by: Roger Quadros >>> --- >>> Changes from v1: >>> 1. Fix the build issue when "CONFIG_TI_K3_AM65_CPTS" is not set. This >>> error was reported by kernel test robot at: >>> https://lore.kernel.org/r/202301142105.lt733Lt3-lkp@intel.com/ >>> 2. Collect Reviewed-by tag from Roger Quadros. >>> >>> v1: >>> https://lore.kernel.org/r/20230113104816.132815-1-s-vadapalli@ti.com/ >>> >>> drivers/net/ethernet/ti/am65-cpsw-nuss.c | 8 ++++++++ >>> drivers/net/ethernet/ti/am65-cpts.c | 15 +++++---------- >>> drivers/net/ethernet/ti/am65-cpts.h | 5 +++++ >>> 3 files changed, 18 insertions(+), 10 deletions(-) >>> >>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c >>> index 5cac98284184..00f25d8a026b 100644 >>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c >>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c >>> @@ -1913,6 +1913,12 @@ static int am65_cpsw_am654_get_efuse_macid(struct device_node *of_node, >>> return 0; >>> } >>> >>> +static void am65_cpsw_cpts_cleanup(struct am65_cpsw_common *common) >>> +{ >>> + if (IS_ENABLED(CONFIG_TI_K3_AM65_CPTS) && common->cpts) >> >> Why do you have IS_ENABLED(CONFIG_TI_K3_AM65_CPTS), if >> am65_cpts_release() defined as empty when CONFIG_TI_K3_AM65_CPTS not set? >> >> How is it possible to have common->cpts == NULL? > > Thank you for reviewing the patch. I realize now that checking > CONFIG_TI_K3_AM65_CPTS is unnecessary. > > common->cpts remains NULL in the following cases: > 1. am65_cpsw_init_cpts() returns 0 since CONFIG_TI_K3_AM65_CPTS is not enabled. > 2. am65_cpsw_init_cpts() returns -ENOENT since the cpts node is not defined. > 3. The call to am65_cpts_create() fails within the am65_cpsw_init_cpts() > function with a return value of 0 when cpts is disabled. In this case common->cpts is not NULL and is set to error pointer. Probe will continue normally. Is it OK to call any of the cpts APIs with invalid handle? Also am65_cpts_release() will be called with invalid handle. > 4. The call to am65_cpts_create() within the am65_cpsw_init_cpts() function > fails with an error. In this case common->cpts is not NULL and will invoke am65_cpts_release() with invalid handle. > > Of the above cases, the am65_cpsw_cpts_cleanup() function would have to handle > cases 1 and 3, since the probe might fail at a later point, following which the > probe cleanup path will invoke the am65_cpts_cpts_cleanup() function. This > function then checks for common->cpts not being NULL, so that it can invoke the > am65_cpts_release() function with this pointer. > >> >> And why do you need special am65_cpsw_cpts_cleanup() which does nothing >> except call to am65_cpts_release()? It will be more intuitive change >> the latter to be exported function. > > The am65_cpts_release() function expects the cpts pointer to be valid. Thus, I > had added the am65_cpsw_cpts_cleanup() function to conditionally invoke the > am65_cpts_release() function whenever the cpts pointer is valid. Based on your > suggestion, I believe that you want me to check for the cpts pointer being valid > within the am65_cpts_release() function instead, so that the > am65_cpsw_cpts_cleanup() function doesn't have to be added. Please let me know > if this is what you meant. > > Regards, > Siddharth. cheers, -roger