Messages in this thread | | | Date | Tue, 28 Feb 2023 07:58:48 +0100 | From | Jiri Slaby <> | Subject | Re: [PATCH 1/3] tty: n_gsm: add ioctl for DLC specific parameter configuration |
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On 28. 02. 23, 7:29, D. Starke wrote: > From: Daniel Starke <daniel.starke@siemens.com> > > Parameter negotiation has been introduced with > commit 92f1f0c3290d ("tty: n_gsm: add parameter negotiation support") > > However, means to set individual parameters per DLCI are not yet > implemented. Furthermore, it is currently not possible to keep a DLCI half > open until the user application sets the right parameters for it. This is > required to allow a user application to set its specific parameters before > the underlying link is established. Otherwise, the link is opened and > re-established right afterwards if the user application sets incompatible > parameters. This may be an unexpected behavior for the peer. > > Add parameter 'wait_config' to 'gsm_config' to support setups where the > DLCI specific user application sets its specific parameters after open() > and before the link gets fully established. Setting this to zero disables > the user application specific DLCI configuration option. > > Add the ioctls 'GSMIOC_GETCONF_DLCI' and 'GSMIOC_SETCONF_DLCI' for the > ldisc and virtual ttys. This gets/sets the DLCI specific parameters and may > trigger a reconnect of the DLCI if incompatible values have been set. Only > the parameters for the DLCI associated with the virtual tty can be set or > retrieved if called on these. > > Add remark within the documentation to introduce the new ioctls. > > Signed-off-by: Daniel Starke <daniel.starke@siemens.com> ... > @@ -2453,6 +2476,128 @@ static void gsm_kick_timer(struct timer_list *t) > pr_info("%s TX queue stalled\n", __func__); > } > > +/** > + * gsm_dlci_copy_config_values - copy DLCI configuration > + * @dlci: source DLCI > + * @dc: configuration structure to fill > + */ > +static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc) > +{ > + memset(dc, 0, sizeof(*dc)); > + dc->channel = (u32)dlci->addr; > + dc->adaption = (u32)dlci->adaption; > + dc->mtu = (u32)dlci->mtu; > + dc->priority = (u32)dlci->prio; > + if (dlci->ftype == UIH) > + dc->i = 1; > + else > + dc->i = 2; > + dc->k = (u32)dlci->k;
Why all those casts?
> +} > + > +/** > + * gsm_dlci_config - configure DLCI from configuration > + * @dlci: DLCI to configure > + * @dc: DLCI configuration > + * @open: open DLCI after configuration? > + */ > +static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open) > +{ > + struct gsm_mux *gsm; > + bool need_restart = false; > + bool need_open = false; > + unsigned int i; > + > + /* > + * Check that userspace doesn't put stuff in here to prevent breakages > + * in the future. > + */ > + for (i = 0; i < ARRAY_SIZE(dc->reserved); i++) > + if (dc->reserved[i]) > + return -EINVAL; > + > + if (!dlci) > + return -EINVAL; > + gsm = dlci->gsm; > + > + /* Stuff we don't support yet - I frame transport */ > + if (dc->adaption != 1 && dc->adaption != 2) > + return -EOPNOTSUPP; > + if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || (unsigned int)dc->mtu > gsm->mru) > + return -EINVAL; > + if (dc->priority >= 64) > + return -EINVAL; > + if (dc->i == 0 || dc->i > 2) /* UIH and UI only */ > + return -EINVAL; > + if (dc->k > 7) > + return -EINVAL; > + > + /* > + * See what is needed for reconfiguration > + */ > + /* Framing fields */ > + if ((int)dc->adaption != dlci->adaption) > + need_restart = true; > + if ((unsigned int)dc->mtu != dlci->mtu) > + need_restart = true; > + if ((u8)dc->i != dlci->ftype) > + need_restart = true; > + /* Requires care */ > + if ((u8)dc->priority != (u32)dlci->prio) > + need_restart = true;
And here.
> + > + if ((open && gsm->wait_config) || need_restart) > + need_open = true; > + if (dlci->state == DLCI_WAITING_CONFIG) { > + need_restart = false; > + need_open = true; > + } > + > + /* > + * Close down what is needed, restart and initiate the new > + * configuration. > + */ > + if (need_restart) { > + gsm_dlci_begin_close(dlci); > + wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED); > + if (signal_pending(current)) > + return -EINTR; > + } > + /* > + * Setup the new configuration values > + */ > + dlci->adaption = (int)dc->adaption; > + > + if (dlci->mtu)
dc->mtu?
> + dlci->mtu = (unsigned int)dc->mtu; > + else > + dlci->mtu = gsm->mtu; > + > + if (dc->priority) > + dlci->prio = (u8)dc->priority; > + else > + dlci->prio = roundup(dlci->addr + 1, 8) - 1; > + > + if (dc->i == 1) > + dlci->ftype = UIH; > + else if (dc->i == 2) > + dlci->ftype = UI; > + > + if (dc->k) > + dlci->k = (u8)dc->k; > + else > + dlci->k = gsm->k; > + > + if (need_open) { > + if (gsm->initiator) > + gsm_dlci_begin_open(dlci); > + else > + gsm_dlci_set_opening(dlci); > + } > + > + return 0; > +} > + > /* > * Allocate/Free DLCI channels > */
-- js suse labs
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