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Mon, 23 Aug 2021 23:58:46 -0700 Envelope-to: wsa@kernel.org, linux-i2c@vger.kernel.org, marex@denx.de Received: from [172.30.17.109] (port=44168) by smtp.xilinx.com with esmtp (Exim 4.90) (envelope-from ) id 1mIQOU-00047f-DL; Mon, 23 Aug 2021 23:58:46 -0700 Subject: Re: [PATCH v2 0/6] i2c: xiic: Fix broken locking To: Marek Vasut , , Raviteja Narayanam CC: Michal Simek , Shubhrajyoti Datta , Wolfram Sang References: <20210823214145.295104-1-marex@denx.de> From: Michal Simek Message-ID: Date: Tue, 24 Aug 2021 08:58:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210823214145.295104-1-marex@denx.de> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 09e16ca1-9c43-4cdf-dc11-08d966cc9eed X-MS-TrafficTypeDiagnostic: PH0PR02MB8731: X-Microsoft-Antispam-PRVS: X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply X-MS-Oob-TLC-OOBClassifiers: OLM:9508; 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X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Aug 2021 06:58:47.4586 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 09e16ca1-9c43-4cdf-dc11-08d966cc9eed X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.62.198];Helo=[xsj-pvapexch02.xlnx.xilinx.com] X-MS-Exchange-CrossTenant-AuthSource: SN1NAM02FT0029.eop-nam02.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR02MB8731 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org +ravi On 8/23/21 11:41 PM, Marek Vasut wrote: > Booting ZynqMP with XIIC I2C driver shows multitude of race conditions > in the XIIC driver. This is because locking is completely missing from > the driver, and there are odd corner cases where the hardware behaves > strangely. > > Most of these races could be triggered easily when booting on SMP > machines, like the ZynqMP which has up to 4 cores. It is sufficient > for the interrupt handler to run on another core than xiic_start_xfer > and the driver fails completely. > > This does not add support for long transfers, this only fixes the > driver to be usable at all instead of being completely broken. > > The V2 fixes a few remaining details which cropped up in deployment > over the last year or so, so I believe the result should be reasonably > well tested. > > Marek Vasut (6): > i2c: xiic: Fix broken locking on tx_msg > i2c: xiic: Drop broken interrupt handler > i2c: xiic: Defer xiic_wakeup() and __xiic_start_xfer() in > xiic_process() > i2c: xiic: Switch from waitqueue to completion > i2c: xiic: Only ever transfer single message > i2c: xiic: Fix RX IRQ busy check > > drivers/i2c/busses/i2c-xiic.c | 161 +++++++++++++++------------------- > 1 file changed, 69 insertions(+), 92 deletions(-) > > Cc: Michal Simek > Cc: Shubhrajyoti Datta > Cc: Wolfram Sang >