From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 References: <1553183239-13253-1-git-send-email-fabien.dessenne@st.com> <1553183239-13253-3-git-send-email-fabien.dessenne@st.com> <4857555a-812d-0b96-9a70-2984ffb50ca9@st.com> In-Reply-To: <4857555a-812d-0b96-9a70-2984ffb50ca9@st.com> From: xiang xiao Date: Fri, 5 Apr 2019 18:12:35 +0800 Message-ID: Subject: Re: [PATCH 2/2] tty: add rpmsg driver Content-Type: text/plain; charset="UTF-8" To: Arnaud Pouliquen Cc: Fabien Dessenne , Ohad Ben-Cohen , Bjorn Andersson , Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org, Benjamin Gaignard List-ID: On Fri, Apr 5, 2019 at 12:14 AM Arnaud Pouliquen wrote: > > Hello Xiang, > > > On 4/3/19 2:47 PM, xiang xiao wrote: > > On Thu, Mar 21, 2019 at 11:48 PM Fabien Dessenne 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? > 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 > >> Signed-off-by: Fabien Dessenne > >> --- > >> 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 for STMicroelectronics. > >> + * Fabien Dessenne for STMicroelectronics. > >> + * Derived from the imx-rpmsg and omap-rpmsg implementations. > >> + */ > >> + > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> + > >> +#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 "); > >> +MODULE_AUTHOR("Fabien Dessenne "); > >> +MODULE_DESCRIPTION("virtio remote processor messaging tty driver"); > >> +MODULE_LICENSE("GPL v2"); > >> -- > >> 2.7.4 > >>