| Message ID | 20230831141324.2841525-1-Frank.Li@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3,1/1] i3c: master: svc: fix probe failure when no i3c device exist | expand |
Hi Frank, Frank.Li@nxp.com wrote on Thu, 31 Aug 2023 10:13:24 -0400: > I3C masters are expected to support hot-join. This means at initialization > time we might not yet discover any device and this should not be treated > as a fatal error. > > During the DAA procedure which happens at probe time, if no device has > joined, all CCC will be NACKed (from a bus perspective). This leads to an > early return with an error code which fails the probe of the master. > > Let's avoid this by just telling the core through an I3C_ERROR_M2 > return command code that no device was discovered, which is a valid > situation. This way the master will no longer bail out and fail to probe > for a wrong reason. > > Cc: stable@vger.kernel.org > Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver") > Signed-off-by: Frank Li <Frank.Li@nxp.com> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com> Thanks, Miquèl
On Thu, 31 Aug 2023 10:13:24 -0400, Frank Li wrote: > I3C masters are expected to support hot-join. This means at initialization > time we might not yet discover any device and this should not be treated > as a fatal error. > > During the DAA procedure which happens at probe time, if no device has > joined, all CCC will be NACKed (from a bus perspective). This leads to an > early return with an error code which fails the probe of the master. > > [...] Applied, thanks! [1/1] i3c: master: svc: fix probe failure when no i3c device exist commit: 6e13d6528be2f7e801af63c8153b87293f25d736 Best regards,
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c index 770b40e28015e..cf932ee056ef9 100644 --- a/drivers/i3c/master/svc-i3c-master.c +++ b/drivers/i3c/master/svc-i3c-master.c @@ -789,6 +789,10 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master, */ break; } else if (SVC_I3C_MSTATUS_NACKED(reg)) { + /* No I3C devices attached */ + if (dev_nb == 0) + break; + /* * A slave device nacked the address, this is * allowed only once, DAA will be stopped and @@ -1263,11 +1267,17 @@ static int svc_i3c_master_send_ccc_cmd(struct i3c_master_controller *m, { struct svc_i3c_master *master = to_svc_i3c_master(m); bool broadcast = cmd->id < 0x80; + int ret; if (broadcast) - return svc_i3c_master_send_bdcast_ccc_cmd(master, cmd); + ret = svc_i3c_master_send_bdcast_ccc_cmd(master, cmd); else - return svc_i3c_master_send_direct_ccc_cmd(master, cmd); + ret = svc_i3c_master_send_direct_ccc_cmd(master, cmd); + + if (ret) + cmd->err = I3C_ERROR_M2; + + return ret; } static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,
I3C masters are expected to support hot-join. This means at initialization time we might not yet discover any device and this should not be treated as a fatal error. During the DAA procedure which happens at probe time, if no device has joined, all CCC will be NACKed (from a bus perspective). This leads to an early return with an error code which fails the probe of the master. Let's avoid this by just telling the core through an I3C_ERROR_M2 return command code that no device was discovered, which is a valid situation. This way the master will no longer bail out and fail to probe for a wrong reason. Cc: stable@vger.kernel.org Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver") Signed-off-by: Frank Li <Frank.Li@nxp.com> --- Notes: Change from v3 to v3 - No code change - Remove patch i3c: master: fixes i3c bus driver probe failure if no i3c device attached - After test, only need this patch to fix probe failure because i3c_master_rstdaa_locked() already correct handle error code. Change from v1 to v2: - rewrite commit message - cc stable - add empty line in daa() drivers/i3c/master/svc-i3c-master.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)