linux-kernel - Re: [PATCH v13 1/2] drivers/coresight: Add UltraSoc System Memory Buffer driver

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Date:   Mon, 21 Nov 2022 10:47:24 +0000
From:   Suzuki Kuruppassery Poulose <suzuki.poulose@....com>
To:     hejunhao <hejunhao3@...wei.com>, mathieu.poirier@...aro.org,
        mike.leach@...aro.org, leo.yan@...aro.org,
        jonathan.cameron@...wei.com, john.garry@...wei.com
Cc:     coresight@...ts.linaro.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org,
        lpieralisi@...nel.org, linuxarm@...wei.com, yangyicong@...wei.com,
        liuqi115@...wei.com, f.fangjian@...wei.com,
        prime.zeng@...ilicon.com
Subject: Re: [PATCH v13 1/2] drivers/coresight: Add UltraSoc System Memory
 Buffer driver

On 18/11/2022 12:45, hejunhao wrote:
> Hi Suzuki ,
> 
> 
> On 2022/11/15 19:06, Suzuki K Poulose wrote:
>> On 14/11/2022 09:03, Junhao He wrote:
>>> From: Qi Liu <liuqi115@...wei.com>
>>>

>>> +static void smb_init_hw(struct smb_drv_data *drvdata)
>>> +{
>>> +    /* First disable SMB and clear the status of SMB buffer */
>>> +    smb_reset_buffer_status(drvdata);
>>> +    smb_disable_hw(drvdata);
>>> +    smb_purge_data(drvdata);
>>> +
>>> +    writel(SMB_LB_CFG_LO_DEFAULT, drvdata->base + SMB_LB_CFG_LO_REG);
>>> +    writel(SMB_LB_CFG_HI_DEFAULT, drvdata->base + SMB_LB_CFG_HI_REG);
>>> +    writel(SMB_GLB_CFG_DEFAULT, drvdata->base + SMB_GLB_CFG_REG);
>>> +    writel(SMB_GLB_INT_CFG, drvdata->base + SMB_GLB_INT_REG);
>>> +    writel(SMB_LB_INT_CTRL_CFG, drvdata->base + SMB_LB_INT_CTRL_REG);
>>
>> Does this come with interrupt on overflow ? Do we not use this ?
>>
> When the buffer overflow, no interrupt will come.
> Interrupt will upgrade SMB_LB_INT_STS_REG register status if start trace.
> Thanks.
>> Rest looks fine to me.

What is the purpose of the "Interrupt" on the SMB ? It is not clear to
me.

Suzuki