On Fri, Apr 5, 2019 at 8:33 PM Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> wrote: > > > > On 4/5/19 12:12 PM, xiang xiao wrote: > > On Fri, Apr 5, 2019 at 12:14 AM Arnaud Pouliquen > > <arnaud.pouliquen@xxxxxx> wrote: > >> > >> Hello Xiang, > >> > >> > >> On 4/3/19 2:47 PM, xiang xiao wrote: > >>> On Thu, Mar 21, 2019 at 11:48 PM Fabien Dessenne <fabien.dessenne@xxxxxx> wrote: > >>>> > >>>> This driver exposes a standard tty interface on top of the rpmsg > >>>> framework through the "rpmsg-tty-channel" rpmsg service. > >>>> > >>>> This driver supports multi-instances, offering a /dev/ttyRPMSGx entry > >>>> per rpmsg endpoint. > >>>> > >>> > >>> How to support multi-instances from the same remoteproc instance? I > >>> saw that the channel name is fixed to "rpmsg-tty-channel" which mean > >>> only one channel can be created for each remote side. > >> The driver is multi-instance based on muti-endpoints on top of the > >> "rpmsg-tty-channel" service. > >> On remote side you just have to call rpmsg_create_ept with destination > >> address set to ANY. The result is a NS service announcement that trigs a > >> probe with a new endpoint. > >> You can find code example for the remote side here: > >> https://github.com/STMicroelectronics/STM32CubeMP1/blob/master/Projects/STM32MP157C-DK2/Applications/OpenAMP/OpenAMP_TTY_echo/Src/main.c > > > > Demo code create two uarts(huart0 and huart1), and both use the same > > channel name( "rpmsg-tty-channel"). > > But rpmsg_create_channel in kernel will complain the duplication: > > /* make sure a similar channel doesn't already exist */ > > tmp = rpmsg_find_device(dev, chinfo); > > if (tmp) { > > /* decrement the matched device's refcount back */ > > put_device(tmp); > > dev_err(dev, "channel %s:%x:%x already exist\n", > > chinfo->name, chinfo->src, chinfo->dst); > > return NULL; > > } > > Do you have some local change not upstream yet? > Nothing is missing. There is no complain as the function > rpmsg_device_match returns 0, because the chinfo->dst (that corresponds > to the remote ept address) is different. > Yes, you are right. > If i well remember you have also a similar implementation of the service > on your side. Do you see any incompatibility with your implementation? > Our implementation is similar to yours, but has two major difference: 1.Each instance has a different channel name but share the same prefix "rpmsg-tty*", the benefit is that: a.Device name(/dev/tty*) is derived from rpmsg-tty*, instead the random /dev/ttyRPMSGx b.Don't need tty_idr to allocate the unique device id 2.Each transfer need get response from peer to avoid the buffer overflow. This is very important if the peer use pull model(read/write) instead of push model(callback). Here is the patch for kernel side: https://github.com/xiaoxiang781216/linux/commit/f04d2386eb11e0781f0eb47d99fae838abf7eb53 https://github.com/xiaoxiang781216/linux/commit/1a41be362d916eb9104bf21065cb38a0a63d2e91 And RTOS side: https://github.com/PineconeCode/nuttx/blob/song-u1/include/nuttx/serial/uart_rpmsg.h https://github.com/PineconeCode/nuttx/blob/song-u1/drivers/serial/uart_rpmsg.c Maybe, we can consider how to unify these two implementation into one. > > > >> using some wrapper functions available here: > >> https://github.com/STMicroelectronics/STM32CubeMP1/tree/master/Middlewares/Third_Party/OpenAMP > >> > >> > >> Best Regards > >> Arnaud > >> > >>> > >>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> > >>>> Signed-off-by: Fabien Dessenne <fabien.dessenne@xxxxxx> > >>>> --- > >>>> drivers/tty/Kconfig | 9 ++ > >>>> drivers/tty/Makefile | 1 + > >>>> drivers/tty/rpmsg_tty.c | 309 ++++++++++++++++++++++++++++++++++++++++++++++++ > >>>> 3 files changed, 319 insertions(+) > >>>> create mode 100644 drivers/tty/rpmsg_tty.c > >>>> > >>>> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig > >>>> index 0840d27..42696e6 100644 > >>>> --- a/drivers/tty/Kconfig > >>>> +++ b/drivers/tty/Kconfig > >>>> @@ -441,4 +441,13 @@ config VCC > >>>> depends on SUN_LDOMS > >>>> help > >>>> Support for Sun logical domain consoles. > >>>> + > >>>> +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. > >>>> endif # TTY > >>>> diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile > >>>> index c72cafd..90a98a2 100644 > >>>> --- a/drivers/tty/Makefile > >>>> +++ b/drivers/tty/Makefile > >>>> @@ -33,5 +33,6 @@ 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 0000000..9c2a629 > >>>> --- /dev/null > >>>> +++ b/drivers/tty/rpmsg_tty.c > >>>> @@ -0,0 +1,309 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +/* > >>>> + * Copyright (C) STMicroelectronics 2019 - All Rights Reserved > >>>> + * Authors: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> for STMicroelectronics. > >>>> + * Fabien Dessenne <fabien.dessenne@xxxxxx> for STMicroelectronics. > >>>> + * Derived from the imx-rpmsg and omap-rpmsg implementations. > >>>> + */ > >>>> + > >>>> +#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 */ > >>>> + unsigned int id; /* TTY rpmsg index */ > >>>> + spinlock_t rx_lock; /* message reception lock */ > >>>> + struct rpmsg_device *rpdev; /* rpmsg device */ > >>>> +}; > >>>> + > >>>> +static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, > >>>> + void *priv, u32 src) > >>>> +{ > >>>> + int space; > >>>> + unsigned char *cbuf; > >>>> + struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev); > >>>> + > >>>> + dev_dbg(&rpdev->dev, "msg(<- src 0x%x) len %d\n", src, len); > >>>> + > >>>> + print_hex_dump_debug(__func__, DUMP_PREFIX_NONE, 16, 1, data, len, > >>>> + true); > >>>> + > >>>> + /* Flush the recv-ed none-zero data to tty node */ > >>>> + if (!len) > >>>> + return -EINVAL; > >>>> + > >>>> + spin_lock(&cport->rx_lock); > >>>> + space = tty_prepare_flip_string(&cport->port, &cbuf, len); > >>>> + if (space <= 0) { > >>>> + dev_err(&rpdev->dev, "No memory for tty_prepare_flip_string\n"); > >>>> + spin_unlock(&cport->rx_lock); > >>>> + return -ENOMEM; > >>>> + } > >>>> + > >>>> + if (space != len) > >>>> + dev_warn(&rpdev->dev, "Trunc buffer from %d to %d\n", > >>>> + len, space); > >>>> + > >>>> + memcpy(cbuf, data, space); > >>>> + tty_flip_buffer_push(&cport->port); > >>>> + spin_unlock(&cport->rx_lock); > >>>> + > >>>> + 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); > >>>> + > >>>> + if (!cport) { > >>>> + dev_err(tty->dev, "cannot get cport\n"); > >>>> + return -ENODEV; > >>>> + } > >>>> + > >>>> + 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 unsigned char *buf, > >>>> + int total) > >>>> +{ > >>>> + int count, ret = 0; > >>>> + const unsigned char *tbuf; > >>>> + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); > >>>> + struct rpmsg_device *rpdev; > >>>> + int msg_size; > >>>> + > >>>> + if (!cport) { > >>>> + dev_err(tty->dev, "cannot get cport\n"); > >>>> + return -ENODEV; > >>>> + } > >>>> + > >>>> + rpdev = cport->rpdev; > >>>> + > >>>> + dev_dbg(&rpdev->dev, "%s: send message from tty->index = %d\n", > >>>> + __func__, tty->index); > >>>> + > >>>> + if (!buf) { > >>>> + dev_err(&rpdev->dev, "buf shouldn't be null.\n"); > >>>> + return -ENOMEM; > >>>> + } > >>>> + > >>>> + msg_size = rpmsg_get_buf_payload_size(rpdev->ept); > >>>> + if (msg_size < 0) > >>>> + return msg_size; > >>>> + > >>>> + count = total; > >>>> + tbuf = buf; > >>>> + do { > >>>> + /* send a message to our remote processor */ > >>>> + ret = rpmsg_send(rpdev->ept, (void *)tbuf, > >>>> + min(count, msg_size)); > >>>> + if (ret) { > >>>> + dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret); > >>>> + return ret; > >>>> + } > >>>> + > >>>> + if (count > msg_size) { > >>>> + count -= msg_size; > >>>> + tbuf += msg_size; > >>>> + } else { > >>>> + count = 0; > >>>> + } > >>>> + } while (count > 0); > >>>> + > >>> > >>> We need the flow control(or handshake) here, otherwise it's very easy > >>> to lose the data if kernel keep send the data as fast as possible. > >>> > >>>> + return total; > >>>> +} > >>>> + > >>>> +static int rpmsg_tty_write_room(struct tty_struct *tty) > >>>> +{ > >>>> + struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index); > >>>> + > >>>> + if (!cport) { > >>>> + dev_err(tty->dev, "cannot get cport\n"); > >>>> + return -ENODEV; > >>>> + } > >>>> + > >>>> + /* report the space in the rpmsg buffer */ > >>>> + return rpmsg_get_buf_payload_size(cport->rpdev->ept); > >>>> +} > >>>> + > >>>> +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, > >>>> +}; > >>>> + > >>>> +struct rpmsg_tty_port *rpmsg_tty_alloc_cport(void) > >>>> +{ > >>>> + struct rpmsg_tty_port *cport; > >>>> + > >>>> + 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) { > >>>> + kfree(cport); > >>>> + return ERR_PTR(-ENOSPC); > >>>> + } > >>>> + > >>>> + 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 int rpmsg_tty_probe(struct rpmsg_device *rpdev) > >>>> +{ > >>>> + struct rpmsg_tty_port *cport; > >>>> + struct device *tty_dev; > >>>> + int ret; > >>>> + > >>>> + cport = rpmsg_tty_alloc_cport(); > >>>> + if (IS_ERR(cport)) { > >>>> + dev_err(&rpdev->dev, "failed to alloc tty port\n"); > >>>> + return PTR_ERR(cport); > >>>> + } > >>>> + > >>>> + tty_port_init(&cport->port); > >>>> + cport->port.low_latency = cport->port.flags | ASYNC_LOW_LATENCY; > >>>> + > >>>> + tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver, > >>>> + cport->id, &rpdev->dev); > >>>> + if (IS_ERR(tty_dev)) { > >>>> + dev_err(&rpdev->dev, "failed to register tty port\n"); > >>>> + ret = PTR_ERR(tty_dev); > >>>> + goto err_destroy; > >>>> + } > >>>> + > >>>> + spin_lock_init(&cport->rx_lock); > >>>> + cport->rpdev = rpdev; > >>>> + > >>>> + dev_set_drvdata(&rpdev->dev, cport); > >>>> + > >>>> + dev_info(&rpdev->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_info(&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-channel" }, > >>>> + { }, > >>>> +}; > >>>> +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; > >>>> + rpmsg_tty_driver->init_termios = tty_std_termios; > >>>> + > >>>> + 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: > >>>> + put_tty_driver(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); > >>>> + put_tty_driver(rpmsg_tty_driver); > >>>> + idr_destroy(&tty_idr); > >>>> +} > >>>> + > >>>> +module_init(rpmsg_tty_init); > >>>> +module_exit(rpmsg_tty_exit); > >>>> + > >>>> +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>"); > >>>> +MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@xxxxxx>"); > >>>> +MODULE_DESCRIPTION("virtio remote processor messaging tty driver"); > >>>> +MODULE_LICENSE("GPL v2"); > >>>> -- > >>>> 2.7.4 > >>>>
