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

[Suzuki K Poulose]

On 22/11/2022 13:23, hejunhao wrote:
> On 2022/11/21 18:47, Suzuki Kuruppassery Poulose wrote:
> > 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@xxxxxxxxxx>
> >
> > > > > +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.
> The SMB_LB_INT_CTRL_REG register control the validity of both real-time
> events and interrupts. When logical buffer status changes causes to 
> issue an
> interrupt at the same time as it issues a real-time event.
> Real-time events are used in SMB driver, which needs to get the buffer 
> status.
> Interrupts are used in debugger mode and cannot be registered in kernel.
>   ..._BUF_NOTE_MASK control which events flags or interrupts are valid.

Please add this to a comment in the code above the register write.

Thanks
Suzuki

> Thanks.
>
> Best regards,
> Junhao.
>
> > Suzuki
> >
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