From: Boris Brezillon <boris.brezillon@collabora.com>
To: "Przemysław Gaj" <pgaj@cadence.com>
Cc: linux-i3c@lists.infradead.org, vitor.soares@synopsys.com,
rafalc@cadence.com, bbrezillon@kernel.org
Subject: Re: [PATCH v4 2/6] i3c: master: pre-reserve boardinfo->init_dyn_addr when available
Date: Tue, 10 Dec 2019 14:29:43 +0100 [thread overview]
Message-ID: <20191210142943.3804da04@collabora.com> (raw)
In-Reply-To: <20191210101502.8401-3-pgaj@cadence.com>
On Tue, 10 Dec 2019 11:14:58 +0100
Przemysław Gaj <pgaj@cadence.com> wrote:
> It may be the case that SETDASA fails for some reason. Reserve
> ->init_dyn_addr when it's defined to prevent assigning this address
> to another slave device. This way when device shows up we don't
> have to re-assign addresses.
>
> Signed-off-by: Przemysław Gaj <pgaj@cadence.com>
> ---
> drivers/i3c/master.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 5c06c41e6660..fab6e0609fca 100755
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -1263,7 +1263,8 @@ static void i3c_master_put_i3c_addrs(struct i3c_dev_desc *dev)
> I3C_ADDR_SLOT_FREE);
>
> if (dev->boardinfo && dev->boardinfo->init_dyn_addr)
> - i3c_bus_set_addr_slot_status(&master->bus, dev->info.dyn_addr,
> + i3c_bus_set_addr_slot_status(&master->bus,
> + dev->boardinfo->init_dyn_addr,
> I3C_ADDR_SLOT_FREE);
Should be fixed in a separate patch, or at least mentioned in the
commit message.
> }
>
> @@ -1675,6 +1676,11 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> ret = -EBUSY;
> goto err_detach_devs;
> }
> +
> + /* Reserve the slot. */
> + i3c_bus_set_addr_slot_status(&master->bus,
> + i3cboardinfo->init_dyn_addr,
> + I3C_ADDR_SLOT_I3C_DEV);
Looks like the "reserve/release init_dyn_addr slot" logic is
asymmetric. I wonder if that's not a problem. Can't we end up in a
situation where the ->init_dyn_addr is released (when SETDASA() fails)
and then re-used without being reserved (when the device is later
discovered through a regular DAA)?
So maybe I was wrong and we should indeed reserve the address in the
i3c_master_get_i3c_addrs() path.
> }
>
> i3cdev = i3c_master_alloc_i3c_dev(master, &info);
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next prev parent reply other threads:[~2019-12-10 13:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 10:14 [PATCH v4 0/6] I3C device addresing adjustments Przemysław Gaj
2019-12-10 10:14 ` [PATCH v4 1/6] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked() Przemysław Gaj
2019-12-10 10:14 ` [PATCH v4 2/6] i3c: master: pre-reserve boardinfo->init_dyn_addr when available Przemysław Gaj
2019-12-10 13:29 ` Boris Brezillon [this message]
2019-12-10 15:24 ` Vitor Soares
2019-12-11 8:51 ` Przemysław Gaj
2019-12-10 10:14 ` [PATCH v4 3/6] i3c: master: make sure the PID is set before registering the device Przemysław Gaj
2019-12-10 10:15 ` [PATCH v4 4/6] dt-bindings: i3c: Make 'assigned-address' valid if static address == 0 Przemysław Gaj
2019-12-10 10:15 ` [PATCH v4 5/6] dt-bindings: i3c: add a note for no guarantee of 'assigned-address' use Przemysław Gaj
2019-12-10 10:15 ` [PATCH v4 6/6] i3c: master: dw: reattach device on first available location of address table Przemysław Gaj
2019-12-10 14:40 ` Vitor Soares
2019-12-10 14:43 ` Przemysław Gaj
2019-12-10 14:52 ` Boris Brezillon
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