* [PATCH v10 1/2] rpmsg: core: add API to get MTU
2021-10-15 9:46 [PATCH v10 0/2] Add rpmsg tty driver Arnaud Pouliquen
@ 2021-10-15 9:47 ` Arnaud Pouliquen
2021-10-15 9:47 ` [PATCH v10 2/2] tty: add rpmsg driver Arnaud Pouliquen
2021-11-01 7:27 ` [PATCH v10 0/2] Add rpmsg tty driver Jiri Slaby
2 siblings, 0 replies; 5+ messages in thread
From: Arnaud Pouliquen @ 2021-10-15 9:47 UTC (permalink / raw)
To: Ohad Ben-Cohen, Bjorn Andersson, Jonathan Corbet, Mathieu Poirier
Cc: Greg Kroah-Hartman, Jiri Slaby, arnaud.pouliquen, Suman Anna,
linux-stm32, linux-doc, linux-kernel, linux-remoteproc
Return the rpmsg buffer MTU for sending message, so rpmsg users
can split a long message in several sub rpmsg buffers.
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Acked-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
drivers/rpmsg/rpmsg_core.c | 21 +++++++++++++++++++++
drivers/rpmsg/rpmsg_internal.h | 2 ++
drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
include/linux/rpmsg.h | 10 ++++++++++
4 files changed, 43 insertions(+)
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 9151836190ce..d3eb60059ef1 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -327,6 +327,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
}
EXPORT_SYMBOL(rpmsg_trysend_offchannel);
+/**
+ * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
+ * @ept: the rpmsg endpoint
+ *
+ * This function returns maximum buffer size available for a single outgoing message.
+ *
+ * Return: the maximum transmission size on success and an appropriate error
+ * value on failure.
+ */
+
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+ if (WARN_ON(!ept))
+ return -EINVAL;
+ if (!ept->ops->get_mtu)
+ return -ENOTSUPP;
+
+ return ept->ops->get_mtu(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_mtu);
+
/*
* match a rpmsg channel with a channel info struct.
* this is used to make sure we're not creating rpmsg devices for channels
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index a76c344253bf..b1245d3ed7c6 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -53,6 +53,7 @@ struct rpmsg_device_ops {
* @trysendto: see @rpmsg_trysendto(), optional
* @trysend_offchannel: see @rpmsg_trysend_offchannel(), optional
* @poll: see @rpmsg_poll(), optional
+ * @get_mtu: see @rpmsg_get_mtu(), optional
*
* Indirection table for the operations that a rpmsg backend should implement.
* In addition to @destroy_ept, the backend must at least implement @send and
@@ -72,6 +73,7 @@ struct rpmsg_endpoint_ops {
void *data, int len);
__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
poll_table *wait);
+ ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
};
struct device *rpmsg_find_device(struct device *parent,
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 8e49a3bacfc7..05fd06fc67e9 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -149,6 +149,7 @@ static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
int len, u32 dst);
static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
u32 dst, void *data, int len);
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
struct rpmsg_channel_info *chinfo);
@@ -160,6 +161,7 @@ static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
.trysend = virtio_rpmsg_trysend,
.trysendto = virtio_rpmsg_trysendto,
.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
+ .get_mtu = virtio_rpmsg_get_mtu,
};
/**
@@ -696,6 +698,14 @@ static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+ struct rpmsg_device *rpdev = ept->rpdev;
+ struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+ return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
+}
+
static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
struct rpmsg_hdr *msg, unsigned int len)
{
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index d97dcd049f18..990b80fb49ad 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -186,6 +186,8 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
poll_table *wait);
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
+
#else
static inline int rpmsg_register_device(struct rpmsg_device *rpdev)
@@ -296,6 +298,14 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
return 0;
}
+static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+ /* This shouldn't be possible */
+ WARN_ON(1);
+
+ return -ENXIO;
+}
+
#endif /* IS_ENABLED(CONFIG_RPMSG) */
/* use a macro to avoid include chaining to get THIS_MODULE */
--
2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v10 2/2] tty: add rpmsg driver
2021-10-15 9:46 [PATCH v10 0/2] Add rpmsg tty driver Arnaud Pouliquen
2021-10-15 9:47 ` [PATCH v10 1/2] rpmsg: core: add API to get MTU Arnaud Pouliquen
@ 2021-10-15 9:47 ` Arnaud Pouliquen
2021-11-01 7:27 ` [PATCH v10 0/2] Add rpmsg tty driver Jiri Slaby
2 siblings, 0 replies; 5+ messages in thread
From: Arnaud Pouliquen @ 2021-10-15 9:47 UTC (permalink / raw)
To: Ohad Ben-Cohen, Bjorn Andersson, Jonathan Corbet, Mathieu Poirier
Cc: Greg Kroah-Hartman, Jiri Slaby, arnaud.pouliquen, Suman Anna,
linux-stm32, linux-doc, linux-kernel, linux-remoteproc
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>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
Update from V9
=> Update based on Mathieu Poirier comments:
- replace dev print by it's ratelimited version.
- add Reviewed-by: Mathieu Poirier
---
drivers/tty/Kconfig | 12 ++
drivers/tty/Makefile | 1 +
drivers/tty/rpmsg_tty.c | 274 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 287 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..813076341ffd
--- /dev/null
+++ b/drivers/tty/rpmsg_tty.c
@@ -0,0 +1,274 @@
+// 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_ratelimited(&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_ratelimited(&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");
--
2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread