RE: [PATCH 1/4] i3c: master: detach and free device if pre_assign_dyn_addr() fails

Vitor Soares
2019-08-29T13:53:34Z

Hi Boris,

From: Boris Brezillon <boris.brezillon@collabora.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@synopsys.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?

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().

> 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? Anyway we have i3c_boardinfo
with DT information.

>
> >
> > Signed-off-by: Vitor Soares <vitor.soares@synopsys.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