From 4ca589661d964840d0d5de4b3baabbef78f453e3 Mon Sep 17 00:00:00 2001 From: Daniel Starke Date: Wed, 15 Mar 2023 11:53:52 +0100 Subject: tty: n_gsm: add ioctl for DLC specific parameter configuration 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. Link: https://lore.kernel.org/oe-kbuild-all/202302281856.S9Lz4gHB-lkp@intel.com/ Reported-by: kernel test robot Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20230315105354.6234-1-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- Documentation/driver-api/tty/n_gsm.rst | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation/driver-api') diff --git a/Documentation/driver-api/tty/n_gsm.rst b/Documentation/driver-api/tty/n_gsm.rst index 9447b8a3b8e2..c2624546fb8f 100644 --- a/Documentation/driver-api/tty/n_gsm.rst +++ b/Documentation/driver-api/tty/n_gsm.rst @@ -29,6 +29,8 @@ Config Initiator #. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl. +#. Configure DLCs using ``GSMIOC_GETCONF_DLCI``/``GSMIOC_SETCONF_DLCI`` ioctl for non-defaults. + #. Obtain base gsmtty number for the used serial port. Major parts of the initialization program @@ -120,6 +122,8 @@ Config Requester #. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl. +#. Configure DLCs using ``GSMIOC_GETCONF_DLCI``/``GSMIOC_SETCONF_DLCI`` ioctl for non-defaults. + #. Obtain base gsmtty number for the used serial port:: #include -- cgit v1.2.3 From afe3154ba87e798de87ab65c72d6e3f6cd32d9d1 Mon Sep 17 00:00:00 2001 From: Daniel Starke Date: Wed, 15 Mar 2023 11:53:54 +0100 Subject: tty: n_gsm: add ioctl for DLC config via ldisc handle The application which initializes the n_gsm ldisc may like to set individual default parameters for each DLCI or take over of the application specific DLCI configuration completely. This is currently not possible. It is either possible to set common default parameters for all DLCIs or let the user application set its DLCI specific configuration parameters. Add support of GSMIOC_GETCONF_DLCI and GSMIOC_SETCONF_DLCI for the n_gsm ldisc handle to support DLCI specific parameter configuration upfront. Add a code example for this use case to the n_gsm documentation. Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20230315105354.6234-3-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- Documentation/driver-api/tty/n_gsm.rst | 16 ++++++++++++++++ drivers/tty/n_gsm.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) (limited to 'Documentation/driver-api') diff --git a/Documentation/driver-api/tty/n_gsm.rst b/Documentation/driver-api/tty/n_gsm.rst index c2624546fb8f..120317ec990f 100644 --- a/Documentation/driver-api/tty/n_gsm.rst +++ b/Documentation/driver-api/tty/n_gsm.rst @@ -47,6 +47,7 @@ Config Initiator int ldisc = N_GSM0710; struct gsm_config c; struct gsm_config_ext ce; + struct gsm_dlci_config dc; struct termios configuration; uint32_t first; @@ -83,6 +84,13 @@ Config Initiator c.mtu = 127; /* set the new configuration */ ioctl(fd, GSMIOC_SETCONF, &c); + /* get DLC 1 configuration */ + dc.channel = 1; + ioctl(fd, GSMIOC_GETCONF_DLCI, &dc); + /* the first user channel gets a higher priority */ + dc.priority = 1; + /* set the new DLC 1 specific configuration */ + ioctl(fd, GSMIOC_SETCONF_DLCI, &dc); /* get first gsmtty device node */ ioctl(fd, GSMIOC_GETFIRST, &first); printf("first muxed line: /dev/gsmtty%i\n", first); @@ -136,6 +144,7 @@ Config Requester int ldisc = N_GSM0710; struct gsm_config c; struct gsm_config_ext ce; + struct gsm_dlci_config dc; struct termios configuration; uint32_t first; @@ -165,6 +174,13 @@ Config Requester c.mtu = 127; /* set the new configuration */ ioctl(fd, GSMIOC_SETCONF, &c); + /* get DLC 1 configuration */ + dc.channel = 1; + ioctl(fd, GSMIOC_GETCONF_DLCI, &dc); + /* the first user channel gets a higher priority */ + dc.priority = 1; + /* set the new DLC 1 specific configuration */ + ioctl(fd, GSMIOC_SETCONF_DLCI, &dc); /* get first gsmtty device node */ ioctl(fd, GSMIOC_GETFIRST, &first); printf("first muxed line: /dev/gsmtty%i\n", first); diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 5bbedfc36fd1..b7e1369a035c 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3716,7 +3716,9 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, { struct gsm_config c; struct gsm_config_ext ce; + struct gsm_dlci_config dc; struct gsm_mux *gsm = tty->disc_data; + struct gsm_dlci *dlci; unsigned int base; switch (cmd) { @@ -3741,6 +3743,33 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, if (copy_from_user(&ce, (void __user *)arg, sizeof(ce))) return -EFAULT; return gsm_config_ext(gsm, &ce); + case GSMIOC_GETCONF_DLCI: + if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) + return -EFAULT; + if (dc.channel == 0 || dc.channel >= NUM_DLCI) + return -EINVAL; + dlci = gsm->dlci[dc.channel]; + if (!dlci) { + dlci = gsm_dlci_alloc(gsm, dc.channel); + if (!dlci) + return -ENOMEM; + } + gsm_dlci_copy_config_values(dlci, &dc); + if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) + return -EFAULT; + return 0; + case GSMIOC_SETCONF_DLCI: + if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) + return -EFAULT; + if (dc.channel == 0 || dc.channel >= NUM_DLCI) + return -EINVAL; + dlci = gsm->dlci[dc.channel]; + if (!dlci) { + dlci = gsm_dlci_alloc(gsm, dc.channel); + if (!dlci) + return -ENOMEM; + } + return gsm_dlci_config(dlci, &dc, 0); default: return n_tty_ioctl_helper(tty, cmd, arg); } -- cgit v1.2.3