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 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 >>
