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 <[email protected]>
Signed-off-by: Fabien Dessenne <[email protected]>
---
Documentation/serial/tty_rpmsg.rst | 45 ++++
drivers/tty/Kconfig | 9 +
drivers/tty/Makefile | 1 +
drivers/tty/rpmsg_tty.c | 418 +++++++++++++++++++++++++++++++++++++
4 files changed, 473 insertions(+)
create mode 100644 Documentation/serial/tty_rpmsg.rst
create mode 100644 drivers/tty/rpmsg_tty.c
diff --git a/Documentation/serial/tty_rpmsg.rst b/Documentation/serial/tty_rpmsg.rst
new file mode 100644
index 000000000000..fc1d3fba73c5
--- /dev/null
+++ b/Documentation/serial/tty_rpmsg.rst
@@ -0,0 +1,45 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+The rpmsg TTY
+=============
+
+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-raw" RPMsg service, for TTY raw data support without flow control
+- a "rpmsg-tty-ctrl" RPMSg service, for TTY support with flow control.
+
+Information related to the RPMsg and associated tty device is available in
+/sys/bus/rpmsg/devices/.
+
+RPMsg TTY without control
+---------------------
+
+The default end point associated with the "rpmsg-tty-raw" service is directly
+used for data exchange. No flow control is available.
+
+To be compliant with this driver, the remote firmware must create its data end point associated with the "rpmsg-tty-raw" service.
+
+RPMsg TTY with control
+---------------------
+
+The default end point associated with the "rpmsg-tty-ctrl" service is reserved for
+the control. A second endpoint must be created for data exchange.
+
+The control channel is used to transmit to the remote processor the CTS status,
+as well as the end point address for data transfer.
+
+To be compatible with this driver, the remote firmware must create or use its end point associated with "rpmsg-tty-ctrl" service, plus a second endpoint for the data flow.
+On Linux rpmsg_tty probes, the data endpoint address and the CTS (set to disable)
+is sent to the remote processor.
+The remote processor has to respect following rules:
+- It only transmits data when Linux remote cts is enable, otherwise message
+ could be lost.
+- It can pause/resume reception by sending a control message (rely on CTS state).
+
+Control message structure:
+struct rpmsg_tty_ctrl {
+ u8 cts; /* remote reception status */
+ u16 d_ept_addr; /* data endpoint address */
+};
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index c7623f99ac0f..1046bf4aa709 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -454,6 +454,15 @@ config VCC
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.
+
config LDISC_AUTOLOAD
bool "Automatically load TTY Line Disciplines"
default y
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index 020b1cd9294f..c2465e7ebc2a 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -34,5 +34,6 @@ 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..3e4d0e1a6663
--- /dev/null
+++ b/drivers/tty/rpmsg_tty.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2019 - All Rights Reserved
+ * Authors: Arnaud Pouliquen <[email protected]> for STMicroelectronics.
+ */
+
+#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
+
+#define TTY_CH_NAME_RAW "rpmsg-tty-raw"
+#define TTY_CH_NAME_WITH_CTS "rpmsg-tty-ctrl"
+
+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_ctrl {
+ u8 cts; /* remote reception status */
+ u16 d_ept_addr; /* data endpoint address */
+};
+
+struct rpmsg_tty_port {
+ struct tty_port port; /* TTY port data */
+ int id; /* TTY rpmsg index */
+ bool cts; /* remote reception status */
+ struct rpmsg_device *rpdev; /* rpmsg device */
+ struct rpmsg_endpoint *cs_ept; /* channel control endpoint */
+ struct rpmsg_endpoint *d_ept; /* data endpoint */
+ u32 data_dst; /* data destination endpoint address */
+};
+
+typedef void (*rpmsg_tty_rx_cb_t)(struct rpmsg_device *, void *, int, void *,
+ u32);
+
+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 (src == cport->data_dst) {
+ /* data message */
+ if (!len)
+ return -EINVAL;
+ /* data message */
+ copied = tty_insert_flip_string_fixed_flag(&cport->port, data,
+ TTY_NORMAL, len);
+ if (copied != len)
+ dev_dbg(&rpdev->dev, "trunc buffer: available space is %d\n",
+ copied);
+ tty_flip_buffer_push(&cport->port);
+ } else {
+ /* control message */
+ struct rpmsg_tty_ctrl *msg = data;
+
+ if (len != sizeof(*msg))
+ return -EINVAL;
+
+ cport->data_dst = msg->d_ept_addr;
+
+ /* Update remote cts state */
+ cport->cts = msg->cts ? 1 : 0;
+
+ if (cport->cts)
+ tty_port_tty_wakeup(&cport->port);
+ }
+
+ return 0;
+}
+
+static void rpmsg_tty_send_term_ready(struct tty_struct *tty, u8 state)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+ struct rpmsg_tty_ctrl m_ctrl;
+ int ret;
+
+ m_ctrl.cts = state;
+ m_ctrl.d_ept_addr = cport->d_ept->addr;
+
+ ret = rpmsg_trysend(cport->cs_ept, &m_ctrl, sizeof(m_ctrl));
+ if (ret < 0)
+ dev_dbg(tty->dev, "cannot send control (%d)\n", ret);
+};
+
+static void rpmsg_tty_throttle(struct tty_struct *tty)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+
+ /* Disable remote transmission */
+ if (cport->cs_ept)
+ rpmsg_tty_send_term_ready(tty, 0);
+};
+
+static void rpmsg_tty_unthrottle(struct tty_struct *tty)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+
+ /* Enable remote transmission */
+ if (cport->cs_ept)
+ rpmsg_tty_send_term_ready(tty, 1);
+};
+
+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;
+ }
+
+ 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;
+ u8 *tmpbuf;
+
+ /* If cts not set, the message is not sent*/
+ if (!cport->cts)
+ return 0;
+
+ rpdev = cport->rpdev;
+
+ dev_dbg(&rpdev->dev, "%s: send msg from tty->index = %d, len = %d\n",
+ __func__, tty->index, len);
+
+ msg_max_size = rpmsg_get_mtu(rpdev->ept);
+
+ msg_size = min(len, msg_max_size);
+ tmpbuf = kzalloc(msg_size, GFP_KERNEL);
+ if (!tmpbuf)
+ return -ENOMEM;
+
+ memcpy(tmpbuf, buf, msg_size);
+
+ /*
+ * Try to send the message to remote processor, if failed return 0 as
+ * no data sent
+ */
+ ret = rpmsg_trysendto(cport->d_ept, tmpbuf, msg_size, cport->data_dst);
+ kfree(tmpbuf);
+ if (ret) {
+ dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
+ return 0;
+ }
+
+ return msg_size;
+}
+
+static int rpmsg_tty_write_room(struct tty_struct *tty)
+{
+ struct rpmsg_tty_port *cport = tty->driver_data;
+
+ return cport->cts ? rpmsg_get_mtu(cport->rpdev->ept) : 0;
+}
+
+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,
+ .throttle = rpmsg_tty_throttle,
+ .unthrottle = rpmsg_tty_unthrottle,
+};
+
+static 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_port_activate(struct tty_port *p, struct tty_struct *tty)
+{
+ p->low_latency = (p->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
+
+ /* Allocate the buffer we use for writing data */
+ return tty_port_alloc_xmit_buf(p);
+}
+
+static void rpmsg_tty_port_shutdown(struct tty_port *p)
+{
+ /* Free the write buffer */
+ tty_port_free_xmit_buf(p);
+}
+
+static void rpmsg_tty_dtr_rts(struct tty_port *port, int raise)
+{
+ dev_dbg(port->tty->dev, "%s: dtr_rts state %d\n", __func__, raise);
+
+ if (raise)
+ rpmsg_tty_unthrottle(port->tty);
+ else
+ rpmsg_tty_throttle(port->tty);
+}
+
+static const struct tty_port_operations rpmsg_tty_port_ops = {
+ .activate = rpmsg_tty_port_activate,
+ .shutdown = rpmsg_tty_port_shutdown,
+ .dtr_rts = rpmsg_tty_dtr_rts,
+};
+
+static int rpmsg_tty_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_tty_port *cport;
+ struct device *dev = &rpdev->dev;
+ struct rpmsg_channel_info chinfo;
+ 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);
+ }
+
+ if (!strncmp(rpdev->id.name, TTY_CH_NAME_WITH_CTS,
+ sizeof(TTY_CH_NAME_WITH_CTS))) {
+ /*
+ * the default endpoint is used for control. Create a second
+ * endpoint for the data that would be exchanges trough control
+ * endpoint. address of the data endpoint will be provided with
+ * the cts state
+ */
+ cport->cs_ept = rpdev->ept;
+ cport->data_dst = RPMSG_ADDR_ANY;
+
+ strscpy(chinfo.name, TTY_CH_NAME_WITH_CTS, sizeof(chinfo.name));
+ chinfo.src = RPMSG_ADDR_ANY;
+ chinfo.dst = RPMSG_ADDR_ANY;
+
+ cport->d_ept = rpmsg_create_ept(rpdev, rpmsg_tty_cb, cport,
+ chinfo);
+ if (!cport->d_ept) {
+ dev_err(dev, "failed to create tty control channel\n");
+ ret = -ENOMEM;
+ goto err_r_cport;
+ }
+ dev_dbg(dev, "%s: creating data endpoint with address %#x\n",
+ __func__, cport->d_ept->addr);
+ } else {
+ /*
+ * TTY over rpmsg without CTS management the default endpoint
+ * is use for raw data transmission.
+ */
+ cport->cs_ept = NULL;
+ cport->cts = 1;
+ cport->d_ept = rpdev->ept;
+ cport->data_dst = rpdev->dst;
+ }
+
+ 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);
+ if (cport->cs_ept)
+ rpmsg_destroy_ept(cport->d_ept);
+err_r_cport:
+ 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);
+ if (cport->cs_ept)
+ rpmsg_destroy_ept(cport->d_ept);
+ rpmsg_tty_release_cport(cport);
+}
+
+static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = {
+ { .name = TTY_CH_NAME_RAW },
+ { .name = TTY_CH_NAME_WITH_CTS},
+ { },
+};
+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:
+ 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 <[email protected]>");
+MODULE_DESCRIPTION("remote processor messaging tty driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
Hi Arnaud,
Le 04/09/2019 à 15:09, Arnaud Pouliquen a écrit :
> 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 <[email protected]>
> Signed-off-by: Fabien Dessenne <[email protected]>
> ---
> Documentation/serial/tty_rpmsg.rst | 45 ++++
> drivers/tty/Kconfig | 9 +
> drivers/tty/Makefile | 1 +
> drivers/tty/rpmsg_tty.c | 418 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 473 insertions(+)
> create mode 100644 Documentation/serial/tty_rpmsg.rst
> create mode 100644 drivers/tty/rpmsg_tty.c
>
> diff --git a/Documentation/serial/tty_rpmsg.rst b/Documentation/serial/tty_rpmsg.rst
> new file mode 100644
> index 000000000000..fc1d3fba73c5
> --- /dev/null
> +++ b/Documentation/serial/tty_rpmsg.rst
> @@ -0,0 +1,45 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=============
> +The rpmsg TTY
> +=============
> +
> +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-raw" RPMsg service, for TTY raw data support without flow control
> +- a "rpmsg-tty-ctrl" RPMSg service, for TTY support with flow control.
> +
> +Information related to the RPMsg and associated tty device is available in
> +/sys/bus/rpmsg/devices/.
> +
> +RPMsg TTY without control
> +---------------------
> +
> +The default end point associated with the "rpmsg-tty-raw" service is directly
> +used for data exchange. No flow control is available.
> +
> +To be compliant with this driver, the remote firmware must create its data end point associated with the "rpmsg-tty-raw" service.
> +
> +RPMsg TTY with control
> +---------------------
> +
> +The default end point associated with the "rpmsg-tty-ctrl" service is reserved for
> +the control. A second endpoint must be created for data exchange.
> +
> +The control channel is used to transmit to the remote processor the CTS status,
> +as well as the end point address for data transfer.
> +
> +To be compatible with this driver, the remote firmware must create or use its end point associated with "rpmsg-tty-ctrl" service, plus a second endpoint for the data flow.
> +On Linux rpmsg_tty probes, the data endpoint address and the CTS (set to disable)
> +is sent to the remote processor.
> +The remote processor has to respect following rules:
> +- It only transmits data when Linux remote cts is enable, otherwise message
> + could be lost.
> +- It can pause/resume reception by sending a control message (rely on CTS state).
> +
> +Control message structure:
> +struct rpmsg_tty_ctrl {
> + u8 cts; /* remote reception status */
> + u16 d_ept_addr; /* data endpoint address */
> +};
Correct me if I'm wrong, but I think this structure should be packed,
shouldn't it ?
It's working ok on the STM32MP127, between M4 and A7, but the alignment
may be not the same on another architecture ?
> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
> index c7623f99ac0f..1046bf4aa709 100644
> --- a/drivers/tty/Kconfig
> +++ b/drivers/tty/Kconfig
> @@ -454,6 +454,15 @@ config VCC
> 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.
> +
> config LDISC_AUTOLOAD
> bool "Automatically load TTY Line Disciplines"
> default y
> diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
> index 020b1cd9294f..c2465e7ebc2a 100644
> --- a/drivers/tty/Makefile
> +++ b/drivers/tty/Makefile
> @@ -34,5 +34,6 @@ 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..3e4d0e1a6663
> --- /dev/null
> +++ b/drivers/tty/rpmsg_tty.c
> @@ -0,0 +1,418 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) STMicroelectronics 2019 - All Rights Reserved
> + * Authors: Arnaud Pouliquen <[email protected]> for STMicroelectronics.
> + */
> +
> +#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
> +
> +#define TTY_CH_NAME_RAW "rpmsg-tty-raw"
> +#define TTY_CH_NAME_WITH_CTS "rpmsg-tty-ctrl"
> +
> +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_ctrl {
> + u8 cts; /* remote reception status */
> + u16 d_ept_addr; /* data endpoint address */
> +};
> +
> +struct rpmsg_tty_port {
> + struct tty_port port; /* TTY port data */
> + int id; /* TTY rpmsg index */
> + bool cts; /* remote reception status */
> + struct rpmsg_device *rpdev; /* rpmsg device */
> + struct rpmsg_endpoint *cs_ept; /* channel control endpoint */
> + struct rpmsg_endpoint *d_ept; /* data endpoint */
> + u32 data_dst; /* data destination endpoint address */
> +};
> +
> +typedef void (*rpmsg_tty_rx_cb_t)(struct rpmsg_device *, void *, int, void *,
> + u32);
> +
> +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 (src == cport->data_dst) {
> + /* data message */
> + if (!len)
> + return -EINVAL;
> + /* data message */
> + copied = tty_insert_flip_string_fixed_flag(&cport->port, data,
> + TTY_NORMAL, len);
> + if (copied != len)
> + dev_dbg(&rpdev->dev, "trunc buffer: available space is %d\n",
> + copied);
> + tty_flip_buffer_push(&cport->port);
> + } else {
> + /* control message */
> + struct rpmsg_tty_ctrl *msg = data;
> +
> + if (len != sizeof(*msg))
> + return -EINVAL;
> +
> + cport->data_dst = msg->d_ept_addr;
> +
> + /* Update remote cts state */
> + cport->cts = msg->cts ? 1 : 0;
> +
> + if (cport->cts)
> + tty_port_tty_wakeup(&cport->port);
> + }
> +
> + return 0;
> +}
> +
> +static void rpmsg_tty_send_term_ready(struct tty_struct *tty, u8 state)
> +{
> + struct rpmsg_tty_port *cport = tty->driver_data;
> + struct rpmsg_tty_ctrl m_ctrl;
> + int ret;
> +
> + m_ctrl.cts = state;
> + m_ctrl.d_ept_addr = cport->d_ept->addr;
> +
> + ret = rpmsg_trysend(cport->cs_ept, &m_ctrl, sizeof(m_ctrl));
> + if (ret < 0)
> + dev_dbg(tty->dev, "cannot send control (%d)\n", ret);
> +};
> +
> +static void rpmsg_tty_throttle(struct tty_struct *tty)
> +{
> + struct rpmsg_tty_port *cport = tty->driver_data;
> +
> + /* Disable remote transmission */
> + if (cport->cs_ept)
> + rpmsg_tty_send_term_ready(tty, 0);
> +};
> +
> +static void rpmsg_tty_unthrottle(struct tty_struct *tty)
> +{
> + struct rpmsg_tty_port *cport = tty->driver_data;
> +
> + /* Enable remote transmission */
> + if (cport->cs_ept)
> + rpmsg_tty_send_term_ready(tty, 1);
> +};
> +
> +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;
> + }
> +
> + 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;
> + u8 *tmpbuf;
> +
> + /* If cts not set, the message is not sent*/
> + if (!cport->cts)
> + return 0;
> +
> + rpdev = cport->rpdev;
> +
> + dev_dbg(&rpdev->dev, "%s: send msg from tty->index = %d, len = %d\n",
> + __func__, tty->index, len);
> +
> + msg_max_size = rpmsg_get_mtu(rpdev->ept);
> +
> + msg_size = min(len, msg_max_size);
> + tmpbuf = kzalloc(msg_size, GFP_KERNEL);
> + if (!tmpbuf)
> + return -ENOMEM;
> +
> + memcpy(tmpbuf, buf, msg_size);
> +
> + /*
> + * Try to send the message to remote processor, if failed return 0 as
> + * no data sent
> + */
> + ret = rpmsg_trysendto(cport->d_ept, tmpbuf, msg_size, cport->data_dst);
> + kfree(tmpbuf);
> + if (ret) {
> + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
> + return 0;
> + }
> +
> + return msg_size;
> +}
> +
> +static int rpmsg_tty_write_room(struct tty_struct *tty)
> +{
> + struct rpmsg_tty_port *cport = tty->driver_data;
> +
> + return cport->cts ? rpmsg_get_mtu(cport->rpdev->ept) : 0;
> +}
> +
> +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,
> + .throttle = rpmsg_tty_throttle,
> + .unthrottle = rpmsg_tty_unthrottle,
> +};
> +
> +static 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_port_activate(struct tty_port *p, struct tty_struct *tty)
> +{
> + p->low_latency = (p->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
> +
> + /* Allocate the buffer we use for writing data */
> + return tty_port_alloc_xmit_buf(p);
> +}
> +
> +static void rpmsg_tty_port_shutdown(struct tty_port *p)
> +{
> + /* Free the write buffer */
> + tty_port_free_xmit_buf(p);
> +}
> +
> +static void rpmsg_tty_dtr_rts(struct tty_port *port, int raise)
> +{
> + dev_dbg(port->tty->dev, "%s: dtr_rts state %d\n", __func__, raise);
> +
> + if (raise)
> + rpmsg_tty_unthrottle(port->tty);
> + else
> + rpmsg_tty_throttle(port->tty);
> +}
> +
> +static const struct tty_port_operations rpmsg_tty_port_ops = {
> + .activate = rpmsg_tty_port_activate,
> + .shutdown = rpmsg_tty_port_shutdown,
> + .dtr_rts = rpmsg_tty_dtr_rts,
> +};
> +
> +static int rpmsg_tty_probe(struct rpmsg_device *rpdev)
> +{
> + struct rpmsg_tty_port *cport;
> + struct device *dev = &rpdev->dev;
> + struct rpmsg_channel_info chinfo;
> + 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);
> + }
> +
> + if (!strncmp(rpdev->id.name, TTY_CH_NAME_WITH_CTS,
> + sizeof(TTY_CH_NAME_WITH_CTS))) {
> + /*
> + * the default endpoint is used for control. Create a second
> + * endpoint for the data that would be exchanges trough control
> + * endpoint. address of the data endpoint will be provided with
> + * the cts state
> + */
> + cport->cs_ept = rpdev->ept;
> + cport->data_dst = RPMSG_ADDR_ANY;
> +
> + strscpy(chinfo.name, TTY_CH_NAME_WITH_CTS, sizeof(chinfo.name));
> + chinfo.src = RPMSG_ADDR_ANY;
> + chinfo.dst = RPMSG_ADDR_ANY;
> +
> + cport->d_ept = rpmsg_create_ept(rpdev, rpmsg_tty_cb, cport,
> + chinfo);
> + if (!cport->d_ept) {
> + dev_err(dev, "failed to create tty control channel\n");
> + ret = -ENOMEM;
> + goto err_r_cport;
> + }
> + dev_dbg(dev, "%s: creating data endpoint with address %#x\n",
> + __func__, cport->d_ept->addr);
> + } else {
> + /*
> + * TTY over rpmsg without CTS management the default endpoint
> + * is use for raw data transmission.
> + */
> + cport->cs_ept = NULL;
> + cport->cts = 1;
> + cport->d_ept = rpdev->ept;
> + cport->data_dst = rpdev->dst;
> + }
> +
> + 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);
> + if (cport->cs_ept)
> + rpmsg_destroy_ept(cport->d_ept);
> +err_r_cport:
> + 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);
> + if (cport->cs_ept)
> + rpmsg_destroy_ept(cport->d_ept);
> + rpmsg_tty_release_cport(cport);
> +}
> +
> +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = {
> + { .name = TTY_CH_NAME_RAW },
> + { .name = TTY_CH_NAME_WITH_CTS},
> + { },
> +};
> +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:
> + 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 <[email protected]>");
> +MODULE_DESCRIPTION("remote processor messaging tty driver");
> +MODULE_LICENSE("GPL v2");
>
Best regards,
Richard
Hi Richard,
On 9/5/19 12:50 PM, Richard Genoud wrote:
> Hi Arnaud,
>
> Le 04/09/2019 à 15:09, Arnaud Pouliquen a écrit :
>> 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 <[email protected]>
>> Signed-off-by: Fabien Dessenne <[email protected]>
>> ---
>> Documentation/serial/tty_rpmsg.rst | 45 ++++
>> drivers/tty/Kconfig | 9 +
>> drivers/tty/Makefile | 1 +
>> drivers/tty/rpmsg_tty.c | 418 +++++++++++++++++++++++++++++++++++++
>> 4 files changed, 473 insertions(+)
>> create mode 100644 Documentation/serial/tty_rpmsg.rst
>> create mode 100644 drivers/tty/rpmsg_tty.c
>>
>> diff --git a/Documentation/serial/tty_rpmsg.rst b/Documentation/serial/tty_rpmsg.rst
>> new file mode 100644
>> index 000000000000..fc1d3fba73c5
>> --- /dev/null
>> +++ b/Documentation/serial/tty_rpmsg.rst
>> @@ -0,0 +1,45 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +=============
>> +The rpmsg TTY
>> +=============
>> +
>> +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-raw" RPMsg service, for TTY raw data support without flow control
>> +- a "rpmsg-tty-ctrl" RPMSg service, for TTY support with flow control.
>> +
>> +Information related to the RPMsg and associated tty device is available in
>> +/sys/bus/rpmsg/devices/.
>> +
>> +RPMsg TTY without control
>> +---------------------
>> +
>> +The default end point associated with the "rpmsg-tty-raw" service is directly
>> +used for data exchange. No flow control is available.
>> +
>> +To be compliant with this driver, the remote firmware must create its data end point associated with the "rpmsg-tty-raw" service.
>> +
>> +RPMsg TTY with control
>> +---------------------
>> +
>> +The default end point associated with the "rpmsg-tty-ctrl" service is reserved for
>> +the control. A second endpoint must be created for data exchange.
>> +
>> +The control channel is used to transmit to the remote processor the CTS status,
>> +as well as the end point address for data transfer.
>> +
>> +To be compatible with this driver, the remote firmware must create or use its end point associated with "rpmsg-tty-ctrl" service, plus a second endpoint for the data flow.
>> +On Linux rpmsg_tty probes, the data endpoint address and the CTS (set to disable)
>> +is sent to the remote processor.
>> +The remote processor has to respect following rules:
>> +- It only transmits data when Linux remote cts is enable, otherwise message
>> + could be lost.
>> +- It can pause/resume reception by sending a control message (rely on CTS state).
>> +
>> +Control message structure:
>> +struct rpmsg_tty_ctrl {
>> + u8 cts; /* remote reception status */
>> + u16 d_ept_addr; /* data endpoint address */
>> +};
> Correct me if I'm wrong, but I think this structure should be packed,
> shouldn't it ?
> It's working ok on the STM32MP127, between M4 and A7, but the alignment
> may be not the same on another architecture ?
you are right, i have to fix this.
Thanks,
Arnaud
>
>
>
>> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
>> index c7623f99ac0f..1046bf4aa709 100644
>> --- a/drivers/tty/Kconfig
>> +++ b/drivers/tty/Kconfig
>> @@ -454,6 +454,15 @@ config VCC
>> 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.
>> +
>> config LDISC_AUTOLOAD
>> bool "Automatically load TTY Line Disciplines"
>> default y
>> diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
>> index 020b1cd9294f..c2465e7ebc2a 100644
>> --- a/drivers/tty/Makefile
>> +++ b/drivers/tty/Makefile
>> @@ -34,5 +34,6 @@ 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..3e4d0e1a6663
>> --- /dev/null
>> +++ b/drivers/tty/rpmsg_tty.c
>> @@ -0,0 +1,418 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) STMicroelectronics 2019 - All Rights Reserved
>> + * Authors: Arnaud Pouliquen <[email protected]> for STMicroelectronics.
>> + */
>> +
>> +#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
>> +
>> +#define TTY_CH_NAME_RAW "rpmsg-tty-raw"
>> +#define TTY_CH_NAME_WITH_CTS "rpmsg-tty-ctrl"
>> +
>> +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_ctrl {
>> + u8 cts; /* remote reception status */
>> + u16 d_ept_addr; /* data endpoint address */
>> +};
>> +
>> +struct rpmsg_tty_port {
>> + struct tty_port port; /* TTY port data */
>> + int id; /* TTY rpmsg index */
>> + bool cts; /* remote reception status */
>> + struct rpmsg_device *rpdev; /* rpmsg device */
>> + struct rpmsg_endpoint *cs_ept; /* channel control endpoint */
>> + struct rpmsg_endpoint *d_ept; /* data endpoint */
>> + u32 data_dst; /* data destination endpoint address */
>> +};
>> +
>> +typedef void (*rpmsg_tty_rx_cb_t)(struct rpmsg_device *, void *, int, void *,
>> + u32);
>> +
>> +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 (src == cport->data_dst) {
>> + /* data message */
>> + if (!len)
>> + return -EINVAL;
>> + /* data message */
>> + copied = tty_insert_flip_string_fixed_flag(&cport->port, data,
>> + TTY_NORMAL, len);
>> + if (copied != len)
>> + dev_dbg(&rpdev->dev, "trunc buffer: available space is %d\n",
>> + copied);
>> + tty_flip_buffer_push(&cport->port);
>> + } else {
>> + /* control message */
>> + struct rpmsg_tty_ctrl *msg = data;
>> +
>> + if (len != sizeof(*msg))
>> + return -EINVAL;
>> +
>> + cport->data_dst = msg->d_ept_addr;
>> +
>> + /* Update remote cts state */
>> + cport->cts = msg->cts ? 1 : 0;
>> +
>> + if (cport->cts)
>> + tty_port_tty_wakeup(&cport->port);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void rpmsg_tty_send_term_ready(struct tty_struct *tty, u8 state)
>> +{
>> + struct rpmsg_tty_port *cport = tty->driver_data;
>> + struct rpmsg_tty_ctrl m_ctrl;
>> + int ret;
>> +
>> + m_ctrl.cts = state;
>> + m_ctrl.d_ept_addr = cport->d_ept->addr;
>> +
>> + ret = rpmsg_trysend(cport->cs_ept, &m_ctrl, sizeof(m_ctrl));
>> + if (ret < 0)
>> + dev_dbg(tty->dev, "cannot send control (%d)\n", ret);
>> +};
>> +
>> +static void rpmsg_tty_throttle(struct tty_struct *tty)
>> +{
>> + struct rpmsg_tty_port *cport = tty->driver_data;
>> +
>> + /* Disable remote transmission */
>> + if (cport->cs_ept)
>> + rpmsg_tty_send_term_ready(tty, 0);
>> +};
>> +
>> +static void rpmsg_tty_unthrottle(struct tty_struct *tty)
>> +{
>> + struct rpmsg_tty_port *cport = tty->driver_data;
>> +
>> + /* Enable remote transmission */
>> + if (cport->cs_ept)
>> + rpmsg_tty_send_term_ready(tty, 1);
>> +};
>> +
>> +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;
>> + }
>> +
>> + 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;
>> + u8 *tmpbuf;
>> +
>> + /* If cts not set, the message is not sent*/
>> + if (!cport->cts)
>> + return 0;
>> +
>> + rpdev = cport->rpdev;
>> +
>> + dev_dbg(&rpdev->dev, "%s: send msg from tty->index = %d, len = %d\n",
>> + __func__, tty->index, len);
>> +
>> + msg_max_size = rpmsg_get_mtu(rpdev->ept);
>> +
>> + msg_size = min(len, msg_max_size);
>> + tmpbuf = kzalloc(msg_size, GFP_KERNEL);
>> + if (!tmpbuf)
>> + return -ENOMEM;
>> +
>> + memcpy(tmpbuf, buf, msg_size);
>> +
>> + /*
>> + * Try to send the message to remote processor, if failed return 0 as
>> + * no data sent
>> + */
>> + ret = rpmsg_trysendto(cport->d_ept, tmpbuf, msg_size, cport->data_dst);
>> + kfree(tmpbuf);
>> + if (ret) {
>> + dev_dbg(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
>> + return 0;
>> + }
>> +
>> + return msg_size;
>> +}
>> +
>> +static int rpmsg_tty_write_room(struct tty_struct *tty)
>> +{
>> + struct rpmsg_tty_port *cport = tty->driver_data;
>> +
>> + return cport->cts ? rpmsg_get_mtu(cport->rpdev->ept) : 0;
>> +}
>> +
>> +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,
>> + .throttle = rpmsg_tty_throttle,
>> + .unthrottle = rpmsg_tty_unthrottle,
>> +};
>> +
>> +static 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_port_activate(struct tty_port *p, struct tty_struct *tty)
>> +{
>> + p->low_latency = (p->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
>> +
>> + /* Allocate the buffer we use for writing data */
>> + return tty_port_alloc_xmit_buf(p);
>> +}
>> +
>> +static void rpmsg_tty_port_shutdown(struct tty_port *p)
>> +{
>> + /* Free the write buffer */
>> + tty_port_free_xmit_buf(p);
>> +}
>> +
>> +static void rpmsg_tty_dtr_rts(struct tty_port *port, int raise)
>> +{
>> + dev_dbg(port->tty->dev, "%s: dtr_rts state %d\n", __func__, raise);
>> +
>> + if (raise)
>> + rpmsg_tty_unthrottle(port->tty);
>> + else
>> + rpmsg_tty_throttle(port->tty);
>> +}
>> +
>> +static const struct tty_port_operations rpmsg_tty_port_ops = {
>> + .activate = rpmsg_tty_port_activate,
>> + .shutdown = rpmsg_tty_port_shutdown,
>> + .dtr_rts = rpmsg_tty_dtr_rts,
>> +};
>> +
>> +static int rpmsg_tty_probe(struct rpmsg_device *rpdev)
>> +{
>> + struct rpmsg_tty_port *cport;
>> + struct device *dev = &rpdev->dev;
>> + struct rpmsg_channel_info chinfo;
>> + 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);
>> + }
>> +
>> + if (!strncmp(rpdev->id.name, TTY_CH_NAME_WITH_CTS,
>> + sizeof(TTY_CH_NAME_WITH_CTS))) {
>> + /*
>> + * the default endpoint is used for control. Create a second
>> + * endpoint for the data that would be exchanges trough control
>> + * endpoint. address of the data endpoint will be provided with
>> + * the cts state
>> + */
>> + cport->cs_ept = rpdev->ept;
>> + cport->data_dst = RPMSG_ADDR_ANY;
>> +
>> + strscpy(chinfo.name, TTY_CH_NAME_WITH_CTS, sizeof(chinfo.name));
>> + chinfo.src = RPMSG_ADDR_ANY;
>> + chinfo.dst = RPMSG_ADDR_ANY;
>> +
>> + cport->d_ept = rpmsg_create_ept(rpdev, rpmsg_tty_cb, cport,
>> + chinfo);
>> + if (!cport->d_ept) {
>> + dev_err(dev, "failed to create tty control channel\n");
>> + ret = -ENOMEM;
>> + goto err_r_cport;
>> + }
>> + dev_dbg(dev, "%s: creating data endpoint with address %#x\n",
>> + __func__, cport->d_ept->addr);
>> + } else {
>> + /*
>> + * TTY over rpmsg without CTS management the default endpoint
>> + * is use for raw data transmission.
>> + */
>> + cport->cs_ept = NULL;
>> + cport->cts = 1;
>> + cport->d_ept = rpdev->ept;
>> + cport->data_dst = rpdev->dst;
>> + }
>> +
>> + 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);
>> + if (cport->cs_ept)
>> + rpmsg_destroy_ept(cport->d_ept);
>> +err_r_cport:
>> + 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);
>> + if (cport->cs_ept)
>> + rpmsg_destroy_ept(cport->d_ept);
>> + rpmsg_tty_release_cport(cport);
>> +}
>> +
>> +static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = {
>> + { .name = TTY_CH_NAME_RAW },
>> + { .name = TTY_CH_NAME_WITH_CTS},
>> + { },
>> +};
>> +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:
>> + 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 <[email protected]>");
>> +MODULE_DESCRIPTION("remote processor messaging tty driver");
>> +MODULE_LICENSE("GPL v2");
>>
>
> Best regards,
> Richard
>