Messages in this thread | | | Date | Thu, 25 Jul 2019 11:55:15 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCHv3 4/4] tty: n_gsm: add ioctl to map serial device to mux'ed tty |
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On Wed, Jul 10, 2019 at 09:26:56PM +0200, Martin Hundebøll wrote: > Guessing the first tty for a gsm0710 multiplexed serial device is not > currently possible, which makes it racy to use with multiple modems. > > Add a way to map the physical serial tty to its related mux devices > using an ioctl. > > Signed-off-by: Martin Hundebøll <martin@geanix.com> > --- > > Changes since v2: > * rename IOCTL from GSMIOC_GETBASE to GSMIOC_GETFIRST > * return first usable line instead of private control line > * return uint32_t instead of int > > Changes since v1: > * use put_user() instead of copy_to_user() > * add missing opening quote > > Documentation/serial/n_gsm.rst | 11 +++++++++-- > drivers/tty/n_gsm.c | 4 ++++ > include/uapi/linux/gsmmux.h | 2 ++ > 3 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/Documentation/serial/n_gsm.rst b/Documentation/serial/n_gsm.rst > index 0ba731ab00b2..286e7ff4d2d9 100644 > --- a/Documentation/serial/n_gsm.rst > +++ b/Documentation/serial/n_gsm.rst > @@ -18,10 +18,13 @@ How to use it > 2. switch the serial line to using the n_gsm line discipline by using > TIOCSETD ioctl, > 3. configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl, > +4. obtain base gsmtty number for the used serial port,
As this file is in .rst format, do we need the enumerated list anymore?
Just a meta-comment...
> > Major parts of the initialization program : > (a good starting point is util-linux-ng/sys-utils/ldattach.c):: > > + #include <stdio.h> > + #include <stdint.h> > #include <linux/gsmmux.h> > #include <linux/tty.h> > #define DEFAULT_SPEED B115200 > @@ -30,6 +33,7 @@ Major parts of the initialization program : > int ldisc = N_GSM0710; > struct gsm_config c; > struct termios configuration; > + uint32_t first; > > /* open the serial port connected to the modem */ > fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY); > @@ -58,19 +62,22 @@ Major parts of the initialization program : > c.mtu = 127; > /* set the new configuration */ > ioctl(fd, GSMIOC_SETCONF, &c); > + /* get first gsmtty device node */ > + ioctl(fd, GSMIOC_GETFIRST, &first); > + printf("first muxed line: /dev/gsmtty%i\n", first); > > /* and wait for ever to keep the line discipline enabled */ > daemon(0,0); > pause(); > > -4. use these devices as plain serial ports. > +5. use these devices as plain serial ports. > > for example, it's possible: > > - and to use gnokii to send / receive SMS on ttygsm1 > - to use ppp to establish a datalink on ttygsm2 > > -5. first close all virtual ports before closing the physical port. > +6. first close all virtual ports before closing the physical port. > > Note that after closing the physical port the modem is still in multiplexing > mode. This may prevent a successful re-opening of the port later. To avoid > diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c > index a60be591f1fc..dac98f3ead3d 100644 > --- a/drivers/tty/n_gsm.c > +++ b/drivers/tty/n_gsm.c > @@ -2613,6 +2613,7 @@ static int gsmld_ioctl(struct tty_struct *tty, struct file *file, > { > struct gsm_config c; > struct gsm_mux *gsm = tty->disc_data; > + unsigned int base; > > switch (cmd) { > case GSMIOC_GETCONF: > @@ -2624,6 +2625,9 @@ static int gsmld_ioctl(struct tty_struct *tty, struct file *file, > if (copy_from_user(&c, (void *)arg, sizeof(c))) > return -EFAULT; > return gsm_config(gsm, &c); > + case GSMIOC_GETFIRST: > + base = mux_num_to_base(gsm); > + return put_user(base + 1, (uint32_t __user *)arg);
> default: > return n_tty_ioctl_helper(tty, file, cmd, arg); > } > diff --git a/include/uapi/linux/gsmmux.h b/include/uapi/linux/gsmmux.h > index 101d3c469acb..e292869245dc 100644 > --- a/include/uapi/linux/gsmmux.h > +++ b/include/uapi/linux/gsmmux.h > @@ -37,5 +37,7 @@ struct gsm_netconfig { > #define GSMIOC_ENABLE_NET _IOW('G', 2, struct gsm_netconfig) > #define GSMIOC_DISABLE_NET _IO('G', 3) > > +/* get the base tty number for a configured gsmmux tty */ > +#define GSMIOC_GETFIRST _IOR('G', 4, uint32_t)
Variables that cross the boundry from user/kernel should use the correct type. That would be "__u32" here.
thanks.
greg k-h
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