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Mon, 16 Dec 2024 12:48:06 +0000 (GMT) Received: from nasanex01c.na.qualcomm.com (nasanex01c.na.qualcomm.com [10.45.79.139]) by NASANPPMTA02.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 4BGCm6FV026100 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 16 Dec 2024 12:48:06 GMT Received: from [10.216.16.207] (10.80.80.8) by nasanex01c.na.qualcomm.com (10.45.79.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Mon, 16 Dec 2024 04:47:57 -0800 Message-ID: <5e83f946-e157-4ec0-8ebf-14dbbdb93e34@quicinc.com> Date: Mon, 16 Dec 2024 18:17:53 +0530 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 4/4] i2c: i2c-qcom-geni: Enable i2c controller sharing between two subsystems To: Konrad Dybcio , , , , , , , , , , , , , , , , , , CC: References: <20241129144357.2008465-1-quic_msavaliy@quicinc.com> <20241129144357.2008465-5-quic_msavaliy@quicinc.com> <57815272-bc07-4c5e-8ae6-8bf8eaaca78f@quicinc.com> Content-Language: en-US From: Mukesh Kumar Savaliya In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01c.na.qualcomm.com (10.45.79.139) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: hjhOGOKRTxUkFq7LD5rE0G6VcfpCfb-Y X-Proofpoint-ORIG-GUID: hjhOGOKRTxUkFq7LD5rE0G6VcfpCfb-Y X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 phishscore=0 mlxlogscore=999 priorityscore=1501 malwarescore=0 suspectscore=0 spamscore=0 clxscore=1015 adultscore=0 mlxscore=0 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2412160108 On 12/16/2024 5:40 PM, Konrad Dybcio wrote: > On 15.12.2024 9:59 AM, Mukesh Kumar Savaliya wrote: >> Hi Konrad, >> >> On 12/13/2024 6:35 PM, Konrad Dybcio wrote: >>> On 29.11.2024 3:43 PM, Mukesh Kumar Savaliya wrote: >>>> Add support to share I2C controller in multiprocessor system in a mutually >>>> exclusive way. Use "qcom,shared-se" flag in a particular i2c instance node >>>> if the usecase requires i2c controller to be shared. >>>> >>>> Sharing of I2C SE(Serial engine) is possible only for GSI mode as client >>>> from each processor can queue transfers over its own GPII Channel. For >>>> non GSI mode, we should force disable this feature even if set by user >>>> from DT by mistake. >>>> >>>> I2C driver just need to mark first_msg and last_msg flag to help indicate >>>> GPI driver to take lock and unlock TRE there by protecting from concurrent >>>> access from other EE or Subsystem. >>>> >>>> gpi_create_i2c_tre() function at gpi.c will take care of adding Lock and >>>> Unlock TRE for the respective transfer operations. >>>> >>>> Since the GPIOs are also shared between two SS, do not unconfigure them >>>> during runtime suspend. This will allow other SS to continue to transfer >>>> the data without any disturbance over the IO lines. >>>> >>>> For example, Assume an I2C EEPROM device connected with an I2C controller. >>>> Each client from ADSP and APPS processor can perform i2c transactions >>>> without any disturbance from each other. >>>> >>>> Signed-off-by: Mukesh Kumar Savaliya >>>> --- >>>>   drivers/i2c/busses/i2c-qcom-geni.c | 22 +++++++++++++++++++--- >>>>   1 file changed, 19 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c >>>> index 7a22e1f46e60..ccf9933e2dad 100644 >>>> --- a/drivers/i2c/busses/i2c-qcom-geni.c >>>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c >>>> @@ -1,5 +1,6 @@ >>>>   // SPDX-License-Identifier: GPL-2.0 >>>>   // Copyright (c) 2017-2018, The Linux Foundation. All rights reserved. >>>> +// Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved. >>>>     #include >>>>   #include >>>> @@ -617,6 +618,7 @@ static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], i >>>>       peripheral.clk_div = itr->clk_div; >>>>       peripheral.set_config = 1; >>>>       peripheral.multi_msg = false; >>>> +    peripheral.shared_se = gi2c->se.shared_geni_se; >>>>         for (i = 0; i < num; i++) { >>>>           gi2c->cur = &msgs[i]; >>>> @@ -627,6 +629,8 @@ static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], i >>>>           if (i < num - 1) >>>>               peripheral.stretch = 1; >>>>   +        peripheral.first_msg = (i == 0); >>>> +        peripheral.last_msg = (i == num - 1); >>>>           peripheral.addr = msgs[i].addr; >>>>             ret =  geni_i2c_gpi(gi2c, &msgs[i], &config, >>>> @@ -815,6 +819,11 @@ static int geni_i2c_probe(struct platform_device *pdev) >>>>           gi2c->clk_freq_out = KHZ(100); >>>>       } >>>>   +    if (of_property_read_bool(pdev->dev.of_node, "qcom,shared-se")) { >>>> +        gi2c->se.shared_geni_se = true; >>>> +        dev_dbg(&pdev->dev, "I2C is shared between subsystems\n"); >>>> +    } >>>> + >>>>       if (has_acpi_companion(dev)) >>>>           ACPI_COMPANION_SET(&gi2c->adap.dev, ACPI_COMPANION(dev)); >>>>   @@ -887,8 +896,10 @@ static int geni_i2c_probe(struct platform_device *pdev) >>>>       else >>>>           fifo_disable = readl_relaxed(gi2c->se.base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE; >>>>   -    if (fifo_disable) { >>>> -        /* FIFO is disabled, so we can only use GPI DMA */ >>>> +    if (fifo_disable || gi2c->se.shared_geni_se) { >>>> +        /* FIFO is disabled, so we can only use GPI DMA. >>>> +         * SE can be shared in GSI mode between subsystems, each SS owns a GPII. >>>> +         **/ >>> >>> I don't think this change makes things clearer, I would drop it >> Shall i revert back to previous change ? What's your suggestion ? > > Yes, drop changing this comment. Sure, Thanks for confirming ! > > Konrad