| Message ID | 20211008153446.23188-3-arnaud.pouliquen@foss.st.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add rpmsg tty driver | expand |
On Fri, Oct 08, 2021 at 05:34:46PM +0200, Arnaud Pouliquen wrote: > This driver exposes a standard TTY interface on top of the rpmsg > framework through a rpmsg service. > > This driver supports multi-instances, offering a /dev/ttyRPMSGx entry > per rpmsg endpoint. > > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> > > --- > Update from V8 > => Update based on Greg Greg Kroah-Hartman comments: > - add module name in kconfig > - remove the tty_rpmsg.rst documentation file and add description in > rpmsg_tty.c. > - rpmsg_tty.c remove of useless check and logs. > - print err log instead of debug log on truncated RX buffer. > --- > drivers/tty/Kconfig | 12 ++ > drivers/tty/Makefile | 1 + > drivers/tty/rpmsg_tty.c | 275 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 288 insertions(+) > create mode 100644 drivers/tty/rpmsg_tty.c > > diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig > index 23cc988c68a4..cc30ff93e2e4 100644 > --- a/drivers/tty/Kconfig > +++ b/drivers/tty/Kconfig > @@ -368,6 +368,18 @@ config VCC > > source "drivers/tty/hvc/Kconfig" > > +config RPMSG_TTY > + tristate "RPMSG tty driver" > + depends on RPMSG > + help > + Say y here to export rpmsg endpoints as tty devices, usually found > + in /dev/ttyRPMSGx. > + This makes it possible for user-space programs to send and receive > + rpmsg messages as a standard tty protocol. > + > + To compile this driver as a module, choose M here: the module will be > + called rpmsg_tty. > + > endif # TTY > > source "drivers/tty/serdev/Kconfig" > diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile > index a2bd75fbaaa4..07aca5184a55 100644 > --- a/drivers/tty/Makefile > +++ b/drivers/tty/Makefile > @@ -26,5 +26,6 @@ obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o > obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o > obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o > obj-$(CONFIG_VCC) += vcc.o > +obj-$(CONFIG_RPMSG_TTY) += rpmsg_tty.o > > obj-y += ipwireless/ > diff --git a/drivers/tty/rpmsg_tty.c b/drivers/tty/rpmsg_tty.c > new file mode 100644 > index 000000000000..226a13f6ef94 > --- /dev/null > +++ b/drivers/tty/rpmsg_tty.c > @@ -0,0 +1,275 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2021 STMicroelectronics - All Rights Reserved > + * > + * The rpmsg tty driver implements serial communication on the RPMsg bus to makes > + * possible for user-space programs to send and receive rpmsg messages as a standard > + * tty protocol. > + * > + * The remote processor can instantiate a new tty by requesting a "rpmsg-tty" RPMsg service. > + * The "rpmsg-tty" service is directly used for data exchange. No flow control is implemented yet. > + */ > + > +#include <linux/module.h> > +#include <linux/rpmsg.h> > +#include <linux/slab.h> > +#include <linux/tty.h> > +#include <linux/tty_flip.h> > + > +#define MAX_TTY_RPMSG 32 > + > +static DEFINE_IDR(tty_idr); /* tty instance id */ > +static DEFINE_MUTEX(idr_lock); /* protects tty_idr */ > + > +static struct tty_driver *rpmsg_tty_driver; > + > +struct rpmsg_tty_port { > + struct tty_port port; /* TTY port data */ > + int id; /* TTY rpmsg index */ > + struct rpmsg_device *rpdev; /* rpmsg device */ > +}; > + > +static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src) > +{ > + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); > + int copied; > + > + if (!len) > + return -EINVAL; > + copied = tty_insert_flip_string(&cport->port, data, len); > + if (copied != len) > + dev_err(&rpdev->dev, "Trunc buffer: available space is %d\n", > + copied); > + tty_flip_buffer_push(&cport->port); > + > + return 0; > +} > + > +static int rpmsg_tty_install(struct tty_driver *driver, struct tty_struct *tty) > +{ > + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); > + > + tty->driver_data = cport; > + > + return tty_port_install(&cport->port, driver, tty); > +} > + > +static int rpmsg_tty_open(struct tty_struct *tty, struct file *filp) > +{ > + return tty_port_open(tty->port, tty, filp); > +} > + > +static void rpmsg_tty_close(struct tty_struct *tty, struct file *filp) > +{ > + return tty_port_close(tty->port, tty, filp); > +} > + > +static int rpmsg_tty_write(struct tty_struct *tty, const u8 *buf, int len) > +{ > + struct rpmsg_tty_port *cport = tty->driver_data; > + struct rpmsg_device *rpdev; > + int msg_max_size, msg_size; > + int ret; > + > + rpdev = cport->rpdev; > + > + msg_max_size = rpmsg_get_mtu(rpdev->ept); > + if (msg_max_size < 0) > + return msg_max_size; > + > + msg_size = min(len, msg_max_size); > + > + /* > + * Use rpmsg_trysend instead of rpmsg_send to send the message so the caller is not > + * hung until a rpmsg buffer is available. In such case rpmsg_trysend returns -ENOMEM. > + */ > + ret = rpmsg_trysend(rpdev->ept, (void *)buf, msg_size); > + if (ret) { > + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret); I'm with Greg on this one. Event if it's a dev_dbg() something like this could quickly fill the logs. Customers should learn to use ftrace. At the very least please use the ratelimited() version. Same comment applies to rpmsg_tty_cb(). Otherwise: Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > + return ret; > + } > + > + return msg_size; > +} > + > +static unsigned int rpmsg_tty_write_room(struct tty_struct *tty) > +{ > + struct rpmsg_tty_port *cport = tty->driver_data; > + int size; > + > + size = rpmsg_get_mtu(cport->rpdev->ept); > + if (size < 0) > + return 0; > + > + return size; > +} > + > +static const struct tty_operations rpmsg_tty_ops = { > + .install = rpmsg_tty_install, > + .open = rpmsg_tty_open, > + .close = rpmsg_tty_close, > + .write = rpmsg_tty_write, > + .write_room = rpmsg_tty_write_room, > +}; > + > +static struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void) > +{ > + struct rpmsg_tty_port *cport; > + int err; > + > + cport = kzalloc(sizeof(*cport), GFP_KERNEL); > + if (!cport) > + return ERR_PTR(-ENOMEM); > + > + mutex_lock(&idr_lock); > + cport->id = idr_alloc(&tty_idr, cport, 0, MAX_TTY_RPMSG, GFP_KERNEL); > + mutex_unlock(&idr_lock); > + > + if (cport->id < 0) { > + err = cport->id; > + kfree(cport); > + return ERR_PTR(err); > + } > + > + return cport; > +} > + > +static void rpmsg_tty_release_cport(struct rpmsg_tty_port *cport) > +{ > + mutex_lock(&idr_lock); > + idr_remove(&tty_idr, cport->id); > + mutex_unlock(&idr_lock); > + > + kfree(cport); > +} > + > +static const struct tty_port_operations rpmsg_tty_port_ops = { }; > + > +static int rpmsg_tty_probe(struct rpmsg_device *rpdev) > +{ > + struct rpmsg_tty_port *cport; > + struct device *dev = &rpdev->dev; > + struct device *tty_dev; > + int ret; > + > + cport = rpmsg_tty_alloc_cport(); > + if (IS_ERR(cport)) { > + dev_err(dev, "Failed to alloc tty port\n"); > + return PTR_ERR(cport); > + } > + > + tty_port_init(&cport->port); > + cport->port.ops = &rpmsg_tty_port_ops; > + > + tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver, > + cport->id, dev); > + if (IS_ERR(tty_dev)) { > + dev_err(dev, "Failed to register tty port\n"); > + ret = PTR_ERR(tty_dev); > + goto err_destroy; > + } > + > + cport->rpdev = rpdev; > + > + dev_set_drvdata(dev, cport); > + > + dev_dbg(dev, "New channel: 0x%x -> 0x%x : ttyRPMSG%d\n", > + rpdev->src, rpdev->dst, cport->id); > + > + return 0; > + > +err_destroy: > + tty_port_destroy(&cport->port); > + rpmsg_tty_release_cport(cport); > + > + return ret; > +} > + > +static void rpmsg_tty_remove(struct rpmsg_device *rpdev) > +{ > + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); > + > + dev_dbg(&rpdev->dev, "Removing rpmsg tty device %d\n", cport->id); > + > + /* User hang up to release the tty */ > + if (tty_port_initialized(&cport->port)) > + tty_port_tty_hangup(&cport->port, false); > + > + tty_unregister_device(rpmsg_tty_driver, cport->id); > + > + tty_port_destroy(&cport->port); > + rpmsg_tty_release_cport(cport); > +} > + > +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = { > + { .name = "rpmsg-tty" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table); > + > +static struct rpmsg_driver rpmsg_tty_rpmsg_drv = { > + .drv.name = KBUILD_MODNAME, > + .id_table = rpmsg_driver_tty_id_table, > + .probe = rpmsg_tty_probe, > + .callback = rpmsg_tty_cb, > + .remove = rpmsg_tty_remove, > +}; > + > +static int __init rpmsg_tty_init(void) > +{ > + int err; > + > + rpmsg_tty_driver = tty_alloc_driver(MAX_TTY_RPMSG, TTY_DRIVER_REAL_RAW | > + TTY_DRIVER_DYNAMIC_DEV); > + if (IS_ERR(rpmsg_tty_driver)) > + return PTR_ERR(rpmsg_tty_driver); > + > + rpmsg_tty_driver->driver_name = "rpmsg_tty"; > + rpmsg_tty_driver->name = "ttyRPMSG"; > + rpmsg_tty_driver->major = 0; > + rpmsg_tty_driver->type = TTY_DRIVER_TYPE_CONSOLE; > + > + /* Disable unused mode by default */ > + rpmsg_tty_driver->init_termios = tty_std_termios; > + rpmsg_tty_driver->init_termios.c_lflag &= ~(ECHO | ICANON); > + rpmsg_tty_driver->init_termios.c_oflag &= ~(OPOST | ONLCR); > + > + tty_set_operations(rpmsg_tty_driver, &rpmsg_tty_ops); > + > + err = tty_register_driver(rpmsg_tty_driver); > + if (err < 0) { > + pr_err("Couldn't install rpmsg tty driver: err %d\n", err); > + goto error_put; > + } > + > + err = register_rpmsg_driver(&rpmsg_tty_rpmsg_drv); > + if (err < 0) { > + pr_err("Couldn't register rpmsg tty driver: err %d\n", err); > + goto error_unregister; > + } > + > + return 0; > + > +error_unregister: > + tty_unregister_driver(rpmsg_tty_driver); > + > +error_put: > + tty_driver_kref_put(rpmsg_tty_driver); > + > + return err; > +} > + > +static void __exit rpmsg_tty_exit(void) > +{ > + unregister_rpmsg_driver(&rpmsg_tty_rpmsg_drv); > + tty_unregister_driver(rpmsg_tty_driver); > + tty_driver_kref_put(rpmsg_tty_driver); > + idr_destroy(&tty_idr); > +} > + > +module_init(rpmsg_tty_init); > +module_exit(rpmsg_tty_exit); > + > +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>"); > +MODULE_DESCRIPTION("remote processor messaging tty driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.17.1 >
Hello Mathieu, On 10/12/21 8:07 PM, Mathieu Poirier wrote: > On Fri, Oct 08, 2021 at 05:34:46PM +0200, Arnaud Pouliquen wrote: >> This driver exposes a standard TTY interface on top of the rpmsg >> framework through a rpmsg service. >> >> This driver supports multi-instances, offering a /dev/ttyRPMSGx entry >> per rpmsg endpoint. >> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> >> >> --- >> Update from V8 >> => Update based on Greg Greg Kroah-Hartman comments: >> - add module name in kconfig >> - remove the tty_rpmsg.rst documentation file and add description in >> rpmsg_tty.c. >> - rpmsg_tty.c remove of useless check and logs. >> - print err log instead of debug log on truncated RX buffer. >> --- >> drivers/tty/Kconfig | 12 ++ >> drivers/tty/Makefile | 1 + >> drivers/tty/rpmsg_tty.c | 275 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 288 insertions(+) >> create mode 100644 drivers/tty/rpmsg_tty.c >> >> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig >> index 23cc988c68a4..cc30ff93e2e4 100644 >> --- a/drivers/tty/Kconfig >> +++ b/drivers/tty/Kconfig >> @@ -368,6 +368,18 @@ config VCC >> >> source "drivers/tty/hvc/Kconfig" >> >> +config RPMSG_TTY >> + tristate "RPMSG tty driver" >> + depends on RPMSG >> + help >> + Say y here to export rpmsg endpoints as tty devices, usually found >> + in /dev/ttyRPMSGx. >> + This makes it possible for user-space programs to send and receive >> + rpmsg messages as a standard tty protocol. >> + >> + To compile this driver as a module, choose M here: the module will be >> + called rpmsg_tty. >> + >> endif # TTY >> >> source "drivers/tty/serdev/Kconfig" >> diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile >> index a2bd75fbaaa4..07aca5184a55 100644 >> --- a/drivers/tty/Makefile >> +++ b/drivers/tty/Makefile >> @@ -26,5 +26,6 @@ obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o >> obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o >> obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o >> obj-$(CONFIG_VCC) += vcc.o >> +obj-$(CONFIG_RPMSG_TTY) += rpmsg_tty.o >> >> obj-y += ipwireless/ >> diff --git a/drivers/tty/rpmsg_tty.c b/drivers/tty/rpmsg_tty.c >> new file mode 100644 >> index 000000000000..226a13f6ef94 >> --- /dev/null >> +++ b/drivers/tty/rpmsg_tty.c >> @@ -0,0 +1,275 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (C) 2021 STMicroelectronics - All Rights Reserved >> + * >> + * The rpmsg tty driver implements serial communication on the RPMsg bus to makes >> + * possible for user-space programs to send and receive rpmsg messages as a standard >> + * tty protocol. >> + * >> + * The remote processor can instantiate a new tty by requesting a "rpmsg-tty" RPMsg service. >> + * The "rpmsg-tty" service is directly used for data exchange. No flow control is implemented yet. >> + */ >> + >> +#include <linux/module.h> >> +#include <linux/rpmsg.h> >> +#include <linux/slab.h> >> +#include <linux/tty.h> >> +#include <linux/tty_flip.h> >> + >> +#define MAX_TTY_RPMSG 32 >> + >> +static DEFINE_IDR(tty_idr); /* tty instance id */ >> +static DEFINE_MUTEX(idr_lock); /* protects tty_idr */ >> + >> +static struct tty_driver *rpmsg_tty_driver; >> + >> +struct rpmsg_tty_port { >> + struct tty_port port; /* TTY port data */ >> + int id; /* TTY rpmsg index */ >> + struct rpmsg_device *rpdev; /* rpmsg device */ >> +}; >> + >> +static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src) >> +{ >> + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); >> + int copied; >> + >> + if (!len) >> + return -EINVAL; >> + copied = tty_insert_flip_string(&cport->port, data, len); >> + if (copied != len) >> + dev_err(&rpdev->dev, "Trunc buffer: available space is %d\n", >> + copied); Here as the rpmsg callback return is not tested we need to log something because data is lost. I will add the ratelimited version to limit logs. >> + tty_flip_buffer_push(&cport->port); >> + >> + return 0; >> +} >> + >> +static int rpmsg_tty_install(struct tty_driver *driver, struct tty_struct *tty) >> +{ >> + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); >> + >> + tty->driver_data = cport; >> + >> + return tty_port_install(&cport->port, driver, tty); >> +} >> + >> +static int rpmsg_tty_open(struct tty_struct *tty, struct file *filp) >> +{ >> + return tty_port_open(tty->port, tty, filp); >> +} >> + >> +static void rpmsg_tty_close(struct tty_struct *tty, struct file *filp) >> +{ >> + return tty_port_close(tty->port, tty, filp); >> +} >> + >> +static int rpmsg_tty_write(struct tty_struct *tty, const u8 *buf, int len) >> +{ >> + struct rpmsg_tty_port *cport = tty->driver_data; >> + struct rpmsg_device *rpdev; >> + int msg_max_size, msg_size; >> + int ret; >> + >> + rpdev = cport->rpdev; >> + >> + msg_max_size = rpmsg_get_mtu(rpdev->ept); >> + if (msg_max_size < 0) >> + return msg_max_size; >> + >> + msg_size = min(len, msg_max_size); >> + >> + /* >> + * Use rpmsg_trysend instead of rpmsg_send to send the message so the caller is not >> + * hung until a rpmsg buffer is available. In such case rpmsg_trysend returns -ENOMEM. >> + */ >> + ret = rpmsg_trysend(rpdev->ept, (void *)buf, msg_size); >> + if (ret) { >> + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret); > > I'm with Greg on this one. Event if it's a dev_dbg() something like this could > quickly fill the logs. That's right,if the remote side is stalled and application doesn't propertly handle the error returned. > Customers should learn to use ftrace. At the very least > please use the ratelimited() version. Same comment applies to rpmsg_tty_cb(). I'm not yet an expert in ftrace, I don't see trace that would highligth this error (return value not traced), except adding trace_printk. If you have a solution, please could you point that out to me? The goal here is that a customers (who has an user spece application develloper profile) has the explicit information that something goes wrong. By default I would be in favour of using ratelimited version also here. > > Otherwise: > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > Thanks, Arnaud >> + return ret; >> + } >> + >> + return msg_size; >> +} >> + >> +static unsigned int rpmsg_tty_write_room(struct tty_struct *tty) >> +{ >> + struct rpmsg_tty_port *cport = tty->driver_data; >> + int size; >> + >> + size = rpmsg_get_mtu(cport->rpdev->ept); >> + if (size < 0) >> + return 0; >> + >> + return size; >> +} >> + >> +static const struct tty_operations rpmsg_tty_ops = { >> + .install = rpmsg_tty_install, >> + .open = rpmsg_tty_open, >> + .close = rpmsg_tty_close, >> + .write = rpmsg_tty_write, >> + .write_room = rpmsg_tty_write_room, >> +}; >> + >> +static struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void) >> +{ >> + struct rpmsg_tty_port *cport; >> + int err; >> + >> + cport = kzalloc(sizeof(*cport), GFP_KERNEL); >> + if (!cport) >> + return ERR_PTR(-ENOMEM); >> + >> + mutex_lock(&idr_lock); >> + cport->id = idr_alloc(&tty_idr, cport, 0, MAX_TTY_RPMSG, GFP_KERNEL); >> + mutex_unlock(&idr_lock); >> + >> + if (cport->id < 0) { >> + err = cport->id; >> + kfree(cport); >> + return ERR_PTR(err); >> + } >> + >> + return cport; >> +} >> + >> +static void rpmsg_tty_release_cport(struct rpmsg_tty_port *cport) >> +{ >> + mutex_lock(&idr_lock); >> + idr_remove(&tty_idr, cport->id); >> + mutex_unlock(&idr_lock); >> + >> + kfree(cport); >> +} >> + >> +static const struct tty_port_operations rpmsg_tty_port_ops = { }; >> + >> +static int rpmsg_tty_probe(struct rpmsg_device *rpdev) >> +{ >> + struct rpmsg_tty_port *cport; >> + struct device *dev = &rpdev->dev; >> + struct device *tty_dev; >> + int ret; >> + >> + cport = rpmsg_tty_alloc_cport(); >> + if (IS_ERR(cport)) { >> + dev_err(dev, "Failed to alloc tty port\n"); >> + return PTR_ERR(cport); >> + } >> + >> + tty_port_init(&cport->port); >> + cport->port.ops = &rpmsg_tty_port_ops; >> + >> + tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver, >> + cport->id, dev); >> + if (IS_ERR(tty_dev)) { >> + dev_err(dev, "Failed to register tty port\n"); >> + ret = PTR_ERR(tty_dev); >> + goto err_destroy; >> + } >> + >> + cport->rpdev = rpdev; >> + >> + dev_set_drvdata(dev, cport); >> + >> + dev_dbg(dev, "New channel: 0x%x -> 0x%x : ttyRPMSG%d\n", >> + rpdev->src, rpdev->dst, cport->id); >> + >> + return 0; >> + >> +err_destroy: >> + tty_port_destroy(&cport->port); >> + rpmsg_tty_release_cport(cport); >> + >> + return ret; >> +} >> + >> +static void rpmsg_tty_remove(struct rpmsg_device *rpdev) >> +{ >> + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); >> + >> + dev_dbg(&rpdev->dev, "Removing rpmsg tty device %d\n", cport->id); >> + >> + /* User hang up to release the tty */ >> + if (tty_port_initialized(&cport->port)) >> + tty_port_tty_hangup(&cport->port, false); >> + >> + tty_unregister_device(rpmsg_tty_driver, cport->id); >> + >> + tty_port_destroy(&cport->port); >> + rpmsg_tty_release_cport(cport); >> +} >> + >> +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = { >> + { .name = "rpmsg-tty" }, >> + { }, >> +}; >> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table); >> + >> +static struct rpmsg_driver rpmsg_tty_rpmsg_drv = { >> + .drv.name = KBUILD_MODNAME, >> + .id_table = rpmsg_driver_tty_id_table, >> + .probe = rpmsg_tty_probe, >> + .callback = rpmsg_tty_cb, >> + .remove = rpmsg_tty_remove, >> +}; >> + >> +static int __init rpmsg_tty_init(void) >> +{ >> + int err; >> + >> + rpmsg_tty_driver = tty_alloc_driver(MAX_TTY_RPMSG, TTY_DRIVER_REAL_RAW | >> + TTY_DRIVER_DYNAMIC_DEV); >> + if (IS_ERR(rpmsg_tty_driver)) >> + return PTR_ERR(rpmsg_tty_driver); >> + >> + rpmsg_tty_driver->driver_name = "rpmsg_tty"; >> + rpmsg_tty_driver->name = "ttyRPMSG"; >> + rpmsg_tty_driver->major = 0; >> + rpmsg_tty_driver->type = TTY_DRIVER_TYPE_CONSOLE; >> + >> + /* Disable unused mode by default */ >> + rpmsg_tty_driver->init_termios = tty_std_termios; >> + rpmsg_tty_driver->init_termios.c_lflag &= ~(ECHO | ICANON); >> + rpmsg_tty_driver->init_termios.c_oflag &= ~(OPOST | ONLCR); >> + >> + tty_set_operations(rpmsg_tty_driver, &rpmsg_tty_ops); >> + >> + err = tty_register_driver(rpmsg_tty_driver); >> + if (err < 0) { >> + pr_err("Couldn't install rpmsg tty driver: err %d\n", err); >> + goto error_put; >> + } >> + >> + err = register_rpmsg_driver(&rpmsg_tty_rpmsg_drv); >> + if (err < 0) { >> + pr_err("Couldn't register rpmsg tty driver: err %d\n", err); >> + goto error_unregister; >> + } >> + >> + return 0; >> + >> +error_unregister: >> + tty_unregister_driver(rpmsg_tty_driver); >> + >> +error_put: >> + tty_driver_kref_put(rpmsg_tty_driver); >> + >> + return err; >> +} >> + >> +static void __exit rpmsg_tty_exit(void) >> +{ >> + unregister_rpmsg_driver(&rpmsg_tty_rpmsg_drv); >> + tty_unregister_driver(rpmsg_tty_driver); >> + tty_driver_kref_put(rpmsg_tty_driver); >> + idr_destroy(&tty_idr); >> +} >> + >> +module_init(rpmsg_tty_init); >> +module_exit(rpmsg_tty_exit); >> + >> +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>"); >> +MODULE_DESCRIPTION("remote processor messaging tty driver"); >> +MODULE_LICENSE("GPL v2"); >> -- >> 2.17.1 >>
Good morning, On Thu, Oct 14, 2021 at 09:45:07AM +0200, Arnaud POULIQUEN wrote: > Hello Mathieu, > > On 10/12/21 8:07 PM, Mathieu Poirier wrote: > > On Fri, Oct 08, 2021 at 05:34:46PM +0200, Arnaud Pouliquen wrote: > >> This driver exposes a standard TTY interface on top of the rpmsg > >> framework through a rpmsg service. > >> > >> This driver supports multi-instances, offering a /dev/ttyRPMSGx entry > >> per rpmsg endpoint. > >> > >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> > >> > >> --- > >> Update from V8 > >> => Update based on Greg Greg Kroah-Hartman comments: > >> - add module name in kconfig > >> - remove the tty_rpmsg.rst documentation file and add description in > >> rpmsg_tty.c. > >> - rpmsg_tty.c remove of useless check and logs. > >> - print err log instead of debug log on truncated RX buffer. > >> --- > >> drivers/tty/Kconfig | 12 ++ > >> drivers/tty/Makefile | 1 + > >> drivers/tty/rpmsg_tty.c | 275 ++++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 288 insertions(+) > >> create mode 100644 drivers/tty/rpmsg_tty.c > >> > >> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig > >> index 23cc988c68a4..cc30ff93e2e4 100644 > >> --- a/drivers/tty/Kconfig > >> +++ b/drivers/tty/Kconfig > >> @@ -368,6 +368,18 @@ config VCC > >> > >> source "drivers/tty/hvc/Kconfig" > >> > >> +config RPMSG_TTY > >> + tristate "RPMSG tty driver" > >> + depends on RPMSG > >> + help > >> + Say y here to export rpmsg endpoints as tty devices, usually found > >> + in /dev/ttyRPMSGx. > >> + This makes it possible for user-space programs to send and receive > >> + rpmsg messages as a standard tty protocol. > >> + > >> + To compile this driver as a module, choose M here: the module will be > >> + called rpmsg_tty. > >> + > >> endif # TTY > >> > >> source "drivers/tty/serdev/Kconfig" > >> diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile > >> index a2bd75fbaaa4..07aca5184a55 100644 > >> --- a/drivers/tty/Makefile > >> +++ b/drivers/tty/Makefile > >> @@ -26,5 +26,6 @@ obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o > >> obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o > >> obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o > >> obj-$(CONFIG_VCC) += vcc.o > >> +obj-$(CONFIG_RPMSG_TTY) += rpmsg_tty.o > >> > >> obj-y += ipwireless/ > >> diff --git a/drivers/tty/rpmsg_tty.c b/drivers/tty/rpmsg_tty.c > >> new file mode 100644 > >> index 000000000000..226a13f6ef94 > >> --- /dev/null > >> +++ b/drivers/tty/rpmsg_tty.c > >> @@ -0,0 +1,275 @@ > >> +// SPDX-License-Identifier: GPL-2.0 > >> +/* > >> + * Copyright (C) 2021 STMicroelectronics - All Rights Reserved > >> + * > >> + * The rpmsg tty driver implements serial communication on the RPMsg bus to makes > >> + * possible for user-space programs to send and receive rpmsg messages as a standard > >> + * tty protocol. > >> + * > >> + * The remote processor can instantiate a new tty by requesting a "rpmsg-tty" RPMsg service. > >> + * The "rpmsg-tty" service is directly used for data exchange. No flow control is implemented yet. > >> + */ > >> + > >> +#include <linux/module.h> > >> +#include <linux/rpmsg.h> > >> +#include <linux/slab.h> > >> +#include <linux/tty.h> > >> +#include <linux/tty_flip.h> > >> + > >> +#define MAX_TTY_RPMSG 32 > >> + > >> +static DEFINE_IDR(tty_idr); /* tty instance id */ > >> +static DEFINE_MUTEX(idr_lock); /* protects tty_idr */ > >> + > >> +static struct tty_driver *rpmsg_tty_driver; > >> + > >> +struct rpmsg_tty_port { > >> + struct tty_port port; /* TTY port data */ > >> + int id; /* TTY rpmsg index */ > >> + struct rpmsg_device *rpdev; /* rpmsg device */ > >> +}; > >> + > >> +static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src) > >> +{ > >> + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); > >> + int copied; > >> + > >> + if (!len) > >> + return -EINVAL; > >> + copied = tty_insert_flip_string(&cport->port, data, len); > >> + if (copied != len) > >> + dev_err(&rpdev->dev, "Trunc buffer: available space is %d\n", > >> + copied); > > Here as the rpmsg callback return is not tested we need to log something because > data is lost. I will add the ratelimited version to limit logs. > > >> + tty_flip_buffer_push(&cport->port); > >> + > >> + return 0; > >> +} > >> + > >> +static int rpmsg_tty_install(struct tty_driver *driver, struct tty_struct *tty) > >> +{ > >> + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); > >> + > >> + tty->driver_data = cport; > >> + > >> + return tty_port_install(&cport->port, driver, tty); > >> +} > >> + > >> +static int rpmsg_tty_open(struct tty_struct *tty, struct file *filp) > >> +{ > >> + return tty_port_open(tty->port, tty, filp); > >> +} > >> + > >> +static void rpmsg_tty_close(struct tty_struct *tty, struct file *filp) > >> +{ > >> + return tty_port_close(tty->port, tty, filp); > >> +} > >> + > >> +static int rpmsg_tty_write(struct tty_struct *tty, const u8 *buf, int len) > >> +{ > >> + struct rpmsg_tty_port *cport = tty->driver_data; > >> + struct rpmsg_device *rpdev; > >> + int msg_max_size, msg_size; > >> + int ret; > >> + > >> + rpdev = cport->rpdev; > >> + > >> + msg_max_size = rpmsg_get_mtu(rpdev->ept); > >> + if (msg_max_size < 0) > >> + return msg_max_size; > >> + > >> + msg_size = min(len, msg_max_size); > >> + > >> + /* > >> + * Use rpmsg_trysend instead of rpmsg_send to send the message so the caller is not > >> + * hung until a rpmsg buffer is available. In such case rpmsg_trysend returns -ENOMEM. > >> + */ > >> + ret = rpmsg_trysend(rpdev->ept, (void *)buf, msg_size); > >> + if (ret) { > >> + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret); > > > > I'm with Greg on this one. Event if it's a dev_dbg() something like this could > > quickly fill the logs. > That's right,if the remote side is stalled and application doesn't propertly > handle the error returned. > > > Customers should learn to use ftrace. At the very least > > please use the ratelimited() version. Same comment applies to rpmsg_tty_cb(). > > I'm not yet an expert in ftrace, I don't see trace that would highligth this > error (return value not traced), except adding trace_printk. If you have a > solution, please could you point that out to me? > The goal here is that a customers (who has an user spece application develloper > profile) has the explicit information that something goes wrong. Typically trance_printk() are removed after debugging and spinning off your own events file under include/trace/events/ seems overkill to me. > > By default I would be in favour of using ratelimited version also here. Yes, ratelimited should do just fine. > > > > > Otherwise: > > > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > > > > Thanks, > Arnaud > > >> + return ret; > >> + } > >> + > >> + return msg_size; > >> +} > >> + > >> +static unsigned int rpmsg_tty_write_room(struct tty_struct *tty) > >> +{ > >> + struct rpmsg_tty_port *cport = tty->driver_data; > >> + int size; > >> + > >> + size = rpmsg_get_mtu(cport->rpdev->ept); > >> + if (size < 0) > >> + return 0; > >> + > >> + return size; > >> +} > >> + > >> +static const struct tty_operations rpmsg_tty_ops = { > >> + .install = rpmsg_tty_install, > >> + .open = rpmsg_tty_open, > >> + .close = rpmsg_tty_close, > >> + .write = rpmsg_tty_write, > >> + .write_room = rpmsg_tty_write_room, > >> +}; > >> + > >> +static struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void) > >> +{ > >> + struct rpmsg_tty_port *cport; > >> + int err; > >> + > >> + cport = kzalloc(sizeof(*cport), GFP_KERNEL); > >> + if (!cport) > >> + return ERR_PTR(-ENOMEM); > >> + > >> + mutex_lock(&idr_lock); > >> + cport->id = idr_alloc(&tty_idr, cport, 0, MAX_TTY_RPMSG, GFP_KERNEL); > >> + mutex_unlock(&idr_lock); > >> + > >> + if (cport->id < 0) { > >> + err = cport->id; > >> + kfree(cport); > >> + return ERR_PTR(err); > >> + } > >> + > >> + return cport; > >> +} > >> + > >> +static void rpmsg_tty_release_cport(struct rpmsg_tty_port *cport) > >> +{ > >> + mutex_lock(&idr_lock); > >> + idr_remove(&tty_idr, cport->id); > >> + mutex_unlock(&idr_lock); > >> + > >> + kfree(cport); > >> +} > >> + > >> +static const struct tty_port_operations rpmsg_tty_port_ops = { }; > >> + > >> +static int rpmsg_tty_probe(struct rpmsg_device *rpdev) > >> +{ > >> + struct rpmsg_tty_port *cport; > >> + struct device *dev = &rpdev->dev; > >> + struct device *tty_dev; > >> + int ret; > >> + > >> + cport = rpmsg_tty_alloc_cport(); > >> + if (IS_ERR(cport)) { > >> + dev_err(dev, "Failed to alloc tty port\n"); > >> + return PTR_ERR(cport); > >> + } > >> + > >> + tty_port_init(&cport->port); > >> + cport->port.ops = &rpmsg_tty_port_ops; > >> + > >> + tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver, > >> + cport->id, dev); > >> + if (IS_ERR(tty_dev)) { > >> + dev_err(dev, "Failed to register tty port\n"); > >> + ret = PTR_ERR(tty_dev); > >> + goto err_destroy; > >> + } > >> + > >> + cport->rpdev = rpdev; > >> + > >> + dev_set_drvdata(dev, cport); > >> + > >> + dev_dbg(dev, "New channel: 0x%x -> 0x%x : ttyRPMSG%d\n", > >> + rpdev->src, rpdev->dst, cport->id); > >> + > >> + return 0; > >> + > >> +err_destroy: > >> + tty_port_destroy(&cport->port); > >> + rpmsg_tty_release_cport(cport); > >> + > >> + return ret; > >> +} > >> + > >> +static void rpmsg_tty_remove(struct rpmsg_device *rpdev) > >> +{ > >> + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); > >> + > >> + dev_dbg(&rpdev->dev, "Removing rpmsg tty device %d\n", cport->id); > >> + > >> + /* User hang up to release the tty */ > >> + if (tty_port_initialized(&cport->port)) > >> + tty_port_tty_hangup(&cport->port, false); > >> + > >> + tty_unregister_device(rpmsg_tty_driver, cport->id); > >> + > >> + tty_port_destroy(&cport->port); > >> + rpmsg_tty_release_cport(cport); > >> +} > >> + > >> +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = { > >> + { .name = "rpmsg-tty" }, > >> + { }, > >> +}; > >> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table); > >> + > >> +static struct rpmsg_driver rpmsg_tty_rpmsg_drv = { > >> + .drv.name = KBUILD_MODNAME, > >> + .id_table = rpmsg_driver_tty_id_table, > >> + .probe = rpmsg_tty_probe, > >> + .callback = rpmsg_tty_cb, > >> + .remove = rpmsg_tty_remove, > >> +}; > >> + > >> +static int __init rpmsg_tty_init(void) > >> +{ > >> + int err; > >> + > >> + rpmsg_tty_driver = tty_alloc_driver(MAX_TTY_RPMSG, TTY_DRIVER_REAL_RAW | > >> + TTY_DRIVER_DYNAMIC_DEV); > >> + if (IS_ERR(rpmsg_tty_driver)) > >> + return PTR_ERR(rpmsg_tty_driver); > >> + > >> + rpmsg_tty_driver->driver_name = "rpmsg_tty"; > >> + rpmsg_tty_driver->name = "ttyRPMSG"; > >> + rpmsg_tty_driver->major = 0; > >> + rpmsg_tty_driver->type = TTY_DRIVER_TYPE_CONSOLE; > >> + > >> + /* Disable unused mode by default */ > >> + rpmsg_tty_driver->init_termios = tty_std_termios; > >> + rpmsg_tty_driver->init_termios.c_lflag &= ~(ECHO | ICANON); > >> + rpmsg_tty_driver->init_termios.c_oflag &= ~(OPOST | ONLCR); > >> + > >> + tty_set_operations(rpmsg_tty_driver, &rpmsg_tty_ops); > >> + > >> + err = tty_register_driver(rpmsg_tty_driver); > >> + if (err < 0) { > >> + pr_err("Couldn't install rpmsg tty driver: err %d\n", err); > >> + goto error_put; > >> + } > >> + > >> + err = register_rpmsg_driver(&rpmsg_tty_rpmsg_drv); > >> + if (err < 0) { > >> + pr_err("Couldn't register rpmsg tty driver: err %d\n", err); > >> + goto error_unregister; > >> + } > >> + > >> + return 0; > >> + > >> +error_unregister: > >> + tty_unregister_driver(rpmsg_tty_driver); > >> + > >> +error_put: > >> + tty_driver_kref_put(rpmsg_tty_driver); > >> + > >> + return err; > >> +} > >> + > >> +static void __exit rpmsg_tty_exit(void) > >> +{ > >> + unregister_rpmsg_driver(&rpmsg_tty_rpmsg_drv); > >> + tty_unregister_driver(rpmsg_tty_driver); > >> + tty_driver_kref_put(rpmsg_tty_driver); > >> + idr_destroy(&tty_idr); > >> +} > >> + > >> +module_init(rpmsg_tty_init); > >> +module_exit(rpmsg_tty_exit); > >> + > >> +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>"); > >> +MODULE_DESCRIPTION("remote processor messaging tty driver"); > >> +MODULE_LICENSE("GPL v2"); > >> -- > >> 2.17.1 > >>
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 23cc988c68a4..cc30ff93e2e4 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -368,6 +368,18 @@ config VCC source "drivers/tty/hvc/Kconfig" +config RPMSG_TTY + tristate "RPMSG tty driver" + depends on RPMSG + help + Say y here to export rpmsg endpoints as tty devices, usually found + in /dev/ttyRPMSGx. + This makes it possible for user-space programs to send and receive + rpmsg messages as a standard tty protocol. + + To compile this driver as a module, choose M here: the module will be + called rpmsg_tty. + endif # TTY source "drivers/tty/serdev/Kconfig" diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index a2bd75fbaaa4..07aca5184a55 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -26,5 +26,6 @@ obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o obj-$(CONFIG_VCC) += vcc.o +obj-$(CONFIG_RPMSG_TTY) += rpmsg_tty.o obj-y += ipwireless/ diff --git a/drivers/tty/rpmsg_tty.c b/drivers/tty/rpmsg_tty.c new file mode 100644 index 000000000000..226a13f6ef94 --- /dev/null +++ b/drivers/tty/rpmsg_tty.c @@ -0,0 +1,275 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 STMicroelectronics - All Rights Reserved + * + * The rpmsg tty driver implements serial communication on the RPMsg bus to makes + * possible for user-space programs to send and receive rpmsg messages as a standard + * tty protocol. + * + * The remote processor can instantiate a new tty by requesting a "rpmsg-tty" RPMsg service. + * The "rpmsg-tty" service is directly used for data exchange. No flow control is implemented yet. + */ + +#include <linux/module.h> +#include <linux/rpmsg.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> + +#define MAX_TTY_RPMSG 32 + +static DEFINE_IDR(tty_idr); /* tty instance id */ +static DEFINE_MUTEX(idr_lock); /* protects tty_idr */ + +static struct tty_driver *rpmsg_tty_driver; + +struct rpmsg_tty_port { + struct tty_port port; /* TTY port data */ + int id; /* TTY rpmsg index */ + struct rpmsg_device *rpdev; /* rpmsg device */ +}; + +static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src) +{ + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); + int copied; + + if (!len) + return -EINVAL; + copied = tty_insert_flip_string(&cport->port, data, len); + if (copied != len) + dev_err(&rpdev->dev, "Trunc buffer: available space is %d\n", + copied); + tty_flip_buffer_push(&cport->port); + + return 0; +} + +static int rpmsg_tty_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); + + tty->driver_data = cport; + + return tty_port_install(&cport->port, driver, tty); +} + +static int rpmsg_tty_open(struct tty_struct *tty, struct file *filp) +{ + return tty_port_open(tty->port, tty, filp); +} + +static void rpmsg_tty_close(struct tty_struct *tty, struct file *filp) +{ + return tty_port_close(tty->port, tty, filp); +} + +static int rpmsg_tty_write(struct tty_struct *tty, const u8 *buf, int len) +{ + struct rpmsg_tty_port *cport = tty->driver_data; + struct rpmsg_device *rpdev; + int msg_max_size, msg_size; + int ret; + + rpdev = cport->rpdev; + + msg_max_size = rpmsg_get_mtu(rpdev->ept); + if (msg_max_size < 0) + return msg_max_size; + + msg_size = min(len, msg_max_size); + + /* + * Use rpmsg_trysend instead of rpmsg_send to send the message so the caller is not + * hung until a rpmsg buffer is available. In such case rpmsg_trysend returns -ENOMEM. + */ + ret = rpmsg_trysend(rpdev->ept, (void *)buf, msg_size); + if (ret) { + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret); + return ret; + } + + return msg_size; +} + +static unsigned int rpmsg_tty_write_room(struct tty_struct *tty) +{ + struct rpmsg_tty_port *cport = tty->driver_data; + int size; + + size = rpmsg_get_mtu(cport->rpdev->ept); + if (size < 0) + return 0; + + return size; +} + +static const struct tty_operations rpmsg_tty_ops = { + .install = rpmsg_tty_install, + .open = rpmsg_tty_open, + .close = rpmsg_tty_close, + .write = rpmsg_tty_write, + .write_room = rpmsg_tty_write_room, +}; + +static struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void) +{ + struct rpmsg_tty_port *cport; + int err; + + cport = kzalloc(sizeof(*cport), GFP_KERNEL); + if (!cport) + return ERR_PTR(-ENOMEM); + + mutex_lock(&idr_lock); + cport->id = idr_alloc(&tty_idr, cport, 0, MAX_TTY_RPMSG, GFP_KERNEL); + mutex_unlock(&idr_lock); + + if (cport->id < 0) { + err = cport->id; + kfree(cport); + return ERR_PTR(err); + } + + return cport; +} + +static void rpmsg_tty_release_cport(struct rpmsg_tty_port *cport) +{ + mutex_lock(&idr_lock); + idr_remove(&tty_idr, cport->id); + mutex_unlock(&idr_lock); + + kfree(cport); +} + +static const struct tty_port_operations rpmsg_tty_port_ops = { }; + +static int rpmsg_tty_probe(struct rpmsg_device *rpdev) +{ + struct rpmsg_tty_port *cport; + struct device *dev = &rpdev->dev; + struct device *tty_dev; + int ret; + + cport = rpmsg_tty_alloc_cport(); + if (IS_ERR(cport)) { + dev_err(dev, "Failed to alloc tty port\n"); + return PTR_ERR(cport); + } + + tty_port_init(&cport->port); + cport->port.ops = &rpmsg_tty_port_ops; + + tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver, + cport->id, dev); + if (IS_ERR(tty_dev)) { + dev_err(dev, "Failed to register tty port\n"); + ret = PTR_ERR(tty_dev); + goto err_destroy; + } + + cport->rpdev = rpdev; + + dev_set_drvdata(dev, cport); + + dev_dbg(dev, "New channel: 0x%x -> 0x%x : ttyRPMSG%d\n", + rpdev->src, rpdev->dst, cport->id); + + return 0; + +err_destroy: + tty_port_destroy(&cport->port); + rpmsg_tty_release_cport(cport); + + return ret; +} + +static void rpmsg_tty_remove(struct rpmsg_device *rpdev) +{ + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); + + dev_dbg(&rpdev->dev, "Removing rpmsg tty device %d\n", cport->id); + + /* User hang up to release the tty */ + if (tty_port_initialized(&cport->port)) + tty_port_tty_hangup(&cport->port, false); + + tty_unregister_device(rpmsg_tty_driver, cport->id); + + tty_port_destroy(&cport->port); + rpmsg_tty_release_cport(cport); +} + +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = { + { .name = "rpmsg-tty" }, + { }, +}; +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table); + +static struct rpmsg_driver rpmsg_tty_rpmsg_drv = { + .drv.name = KBUILD_MODNAME, + .id_table = rpmsg_driver_tty_id_table, + .probe = rpmsg_tty_probe, + .callback = rpmsg_tty_cb, + .remove = rpmsg_tty_remove, +}; + +static int __init rpmsg_tty_init(void) +{ + int err; + + rpmsg_tty_driver = tty_alloc_driver(MAX_TTY_RPMSG, TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV); + if (IS_ERR(rpmsg_tty_driver)) + return PTR_ERR(rpmsg_tty_driver); + + rpmsg_tty_driver->driver_name = "rpmsg_tty"; + rpmsg_tty_driver->name = "ttyRPMSG"; + rpmsg_tty_driver->major = 0; + rpmsg_tty_driver->type = TTY_DRIVER_TYPE_CONSOLE; + + /* Disable unused mode by default */ + rpmsg_tty_driver->init_termios = tty_std_termios; + rpmsg_tty_driver->init_termios.c_lflag &= ~(ECHO | ICANON); + rpmsg_tty_driver->init_termios.c_oflag &= ~(OPOST | ONLCR); + + tty_set_operations(rpmsg_tty_driver, &rpmsg_tty_ops); + + err = tty_register_driver(rpmsg_tty_driver); + if (err < 0) { + pr_err("Couldn't install rpmsg tty driver: err %d\n", err); + goto error_put; + } + + err = register_rpmsg_driver(&rpmsg_tty_rpmsg_drv); + if (err < 0) { + pr_err("Couldn't register rpmsg tty driver: err %d\n", err); + goto error_unregister; + } + + return 0; + +error_unregister: + tty_unregister_driver(rpmsg_tty_driver); + +error_put: + tty_driver_kref_put(rpmsg_tty_driver); + + return err; +} + +static void __exit rpmsg_tty_exit(void) +{ + unregister_rpmsg_driver(&rpmsg_tty_rpmsg_drv); + tty_unregister_driver(rpmsg_tty_driver); + tty_driver_kref_put(rpmsg_tty_driver); + idr_destroy(&tty_idr); +} + +module_init(rpmsg_tty_init); +module_exit(rpmsg_tty_exit); + +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>"); +MODULE_DESCRIPTION("remote processor messaging tty driver"); +MODULE_LICENSE("GPL v2");
This driver exposes a standard TTY interface on top of the rpmsg framework through a rpmsg service. This driver supports multi-instances, offering a /dev/ttyRPMSGx entry per rpmsg endpoint. Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> --- Update from V8 => Update based on Greg Greg Kroah-Hartman comments: - add module name in kconfig - remove the tty_rpmsg.rst documentation file and add description in rpmsg_tty.c. - rpmsg_tty.c remove of useless check and logs. - print err log instead of debug log on truncated RX buffer. --- drivers/tty/Kconfig | 12 ++ drivers/tty/Makefile | 1 + drivers/tty/rpmsg_tty.c | 275 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 288 insertions(+) create mode 100644 drivers/tty/rpmsg_tty.c