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Date: Thu, 29 Aug 2019 16:35:20 +0200
From: Boris Brezillon <boris.brezillon@...labora.com>
To: 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>,
Przemyslaw Gaj <pgaj@...ence.com>
Subject: Re: [PATCH 1/4] i3c: master: detach and free device if
pre_assign_dyn_addr() fails
On Thu, 29 Aug 2019 13:53:24 +0000
Vitor Soares <Vitor.Soares@...opsys.com> wrote:
> Hi Boris,
>
> From: Boris Brezillon <boris.brezillon@...labora.com>
> Date: Thu, Aug 29, 2019 at 11:41:15
>
> > +Przemek
> >
> > Please try to Cc active I3C contributors so they get a chance to
> > comment on your patches.
>
> I can do that next time.
>
> >
> > On Thu, 29 Aug 2019 12:19:32 +0200
> > Vitor Soares <Vitor.Soares@...opsys.com> wrote:
> >
> > > On pre_assing_dyn_addr() the devices that fail:
> > > i3c_master_setdasa_locked()
> > > i3c_master_reattach_i3c_dev()
> > > i3c_master_retrieve_dev_info()
> > >
> > > are kept in memory and master->bus.devs list. This makes the i3c devices
> > > without a dynamic address are sent on DEFSLVS CCC command. Fix this by
> > > detaching and freeing the devices that fail on pre_assign_dyn_addr().
> >
> > I don't think removing those entries is a good strategy, as one might
> > want to try to use a different dynamic address if the requested one
> > is not available.
>
> Do you mean same 'assigned-address' attribute in DT?
Yes, or say it's another device that got the address we want and this
device doesn't want to release the address (I'm assuming the !SA case).
>
> If so, it is checked here:
>
> static int i3c_master_bus_init(struct i3c_master_controller *master)
> ...
> list_for_each_entry(i3cboardinfo, &master->boardinfo.i3c, node) {
> struct i3c_device_info info = {
> .static_addr = i3cboardinfo->static_addr,
> };
>
> if (i3cboardinfo->init_dyn_addr) {
> status = i3c_bus_get_addr_slot_status(&master->bus,
> ^
> i3cboardinfo->init_dyn_addr);
> if (status != I3C_ADDR_SLOT_FREE) {
> ret = -EBUSY;
> goto err_detach_devs;
> }
> }
>
> i3cdev = i3c_master_alloc_i3c_dev(master, &info);
> if (IS_ERR(i3cdev)) {
> ret = PTR_ERR(i3cdev);
> goto err_detach_devs;
> }
>
> i3cdev->boardinfo = i3cboardinfo;
>
> ret = i3c_master_attach_i3c_dev(master, i3cdev);
> if (ret) {
> i3c_master_free_i3c_dev(i3cdev);
> goto err_detach_devs;
> }
> }
> ...
>
> and later if it fails i3c_master_pre_assign_dyn_addr(), the device can
> participate in Enter Dynamic Address Assignment process.
> I may need to check the boardinfo->init_dyn_addr status on
> i3c_master_add_i3c_dev_locked before i3c_master_setnewda_locked().
I need to double check but I thought we were already handling that case
properly.
>
> > Why not simply skipping entries that have ->dyn_addr
> > set to 0 when preparing a DEFSLVS frame
>
> I considered that solution too but if the device isn't enumerated why
> should it be attached and kept in memory?
Might be a device that supports HJ, and in that case we might want the
controller to reserve a slot in its device table for that device.
Anyway, it doesn't hurt to have it around as long as we don't pass the
device through DEFSLVS if it doesn't have a dynamic address. I really
prefer to keep the logic unchanged and fix it if it needs to be fixed.
> Anyway we have i3c_boardinfo
> with DT information.
>
> >
> > >
> > > Signed-off-by: Vitor Soares <vitor.soares@...opsys.com>
> > > ---
> > > drivers/i3c/master.c | 11 ++++++++---
> > > 1 file changed, 8 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > > index 5f4bd52..4d29e1f 100644
> > > --- a/drivers/i3c/master.c
> > > +++ b/drivers/i3c/master.c
> > > @@ -1438,7 +1438,7 @@ static void i3c_master_pre_assign_dyn_addr(struct i3c_dev_desc *dev)
> > > ret = i3c_master_setdasa_locked(master, dev->info.static_addr,
> > > dev->boardinfo->init_dyn_addr);
> > > if (ret)
> > > - return;
> > > + goto err_detach_dev;
> > >
> > > dev->info.dyn_addr = dev->boardinfo->init_dyn_addr;
> > > ret = i3c_master_reattach_i3c_dev(dev, 0);
> > > @@ -1453,6 +1453,10 @@ static void i3c_master_pre_assign_dyn_addr(struct i3c_dev_desc *dev)
> > >
> > > err_rstdaa:
> > > i3c_master_rstdaa_locked(master, dev->boardinfo->init_dyn_addr);
> > > +
> > > +err_detach_dev:
> > > + i3c_master_detach_i3c_dev(dev);
> > > + i3c_master_free_i3c_dev(dev);
> >
> > We certainly shouldn't detach/free the i3c_dev_desc from here. If it
> > has to be done somewhere (which I'd like to avoid), it should be done
> > in i3c_master_bus_init() (i3c_master_pre_assign_dyn_addr() should be
> > converted to return an int in that case).
>
> I can change it to return an error.
>
> >
> > > }
> > >
> > > static void
> > > @@ -1647,7 +1651,7 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> > > enum i3c_addr_slot_status status;
> > > struct i2c_dev_boardinfo *i2cboardinfo;
> > > struct i3c_dev_boardinfo *i3cboardinfo;
> > > - struct i3c_dev_desc *i3cdev;
> > > + struct i3c_dev_desc *i3cdev, *i3ctmp;
> > > struct i2c_dev_desc *i2cdev;
> > > int ret;
> > >
> > > @@ -1746,7 +1750,8 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> > > * Pre-assign dynamic address and retrieve device information if
> > > * needed.
> > > */
> > > - i3c_bus_for_each_i3cdev(&master->bus, i3cdev)
> > > + list_for_each_entry_safe(i3cdev, i3ctmp, &master->bus.devs.i3c,
> > > + common.node)
> > > i3c_master_pre_assign_dyn_addr(i3cdev);
> > >
> > > ret = i3c_master_do_daa(master);
>
> Thank for your feedback.
>
> Best regards,
> Vitor Soares
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