linux-kernel - RE: [PATCH 4/4] i3c: master: dw: reattach device on first available location of address table

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Date:   Thu, 29 Aug 2019 14:09:08 +0000
From:   Vitor Soares <Vitor.Soares@...opsys.com>
To:     Boris Brezillon <boris.brezillon@...labora.com>,
        Vitor Soares <Vitor.Soares@...opsys.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-i3c@...ts.infradead.org" <linux-i3c@...ts.infradead.org>,
        "bbrezillon@...nel.org" <bbrezillon@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "Joao.Pinto@...opsys.com" <Joao.Pinto@...opsys.com>
Subject: RE: [PATCH 4/4] i3c: master: dw: reattach device on first available
 location of address table

Hi Boris,

From: Boris Brezillon <boris.brezillon@...labora.com>
Date: Thu, Aug 29, 2019 at 12:15:19

> On Thu, 29 Aug 2019 12:19:35 +0200
> Vitor Soares <Vitor.Soares@...opsys.com> wrote:
> 
> > For today the reattach function only update the device address on the
> > controller.
> > 
> > Update the location to the first available too, will optimize the
> > enumeration process avoiding additional checks to keep the available
> > positions on address table consecutive.
> 
> Given the number of available slots I honestly don't think it makes a
> difference, but I also don't mind this change, so

The slots are HW dependent. The point is, I need to guarantee the 
available slot are consecutives.
If you have any suggestion I appreciate.

> 
> Reviewed-by: Boris Brezillon <boris.brezillon@...labora.com>
> 
> > 
> > Signed-off-by: Vitor Soares <vitor.soares@...opsys.com>
> > ---
> >  drivers/i3c/master/dw-i3c-master.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> > index 1d83c97..62261ac 100644
> > --- a/drivers/i3c/master/dw-i3c-master.c
> > +++ b/drivers/i3c/master/dw-i3c-master.c
> > @@ -898,6 +898,22 @@ static int dw_i3c_master_reattach_i3c_dev(struct i3c_dev_desc *dev,
> >  	struct dw_i3c_i2c_dev_data *data = i3c_dev_get_master_data(dev);
> >  	struct i3c_master_controller *m = i3c_dev_get_master(dev);
> >  	struct dw_i3c_master *master = to_dw_i3c_master(m);
> > +	int pos;
> > +
> > +	pos = dw_i3c_master_get_free_pos(master);
> > +
> > +	if (data->index > pos && pos > 0) {
> > +		writel(0,
> > +		       master->regs +
> > +		       DEV_ADDR_TABLE_LOC(master->datstartaddr, data->index));
> > +
> > +		master->addrs[data->index] = 0;
> > +		master->free_pos |= BIT(data->index);
> > +
> > +		data->index = pos;
> > +		master->addrs[pos] = dev->info.dyn_addr;
> > +		master->free_pos &= ~BIT(pos);
> > +	}
> >  
> >  	writel(DEV_ADDR_TABLE_DYNAMIC_ADDR(dev->info.dyn_addr),
> >  	       master->regs +

Best regards,
Vitor Soares