[RFC PATCH 7/9] i3c: slave: func: add tty driver

Frank Li
2023-09-05T21:39:30Z

Add tty over I3C slave function driver.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
drivers/i3c/Kconfig | 1 +
drivers/i3c/Makefile | 1 +
drivers/i3c/func/Kconfig | 9 +
drivers/i3c/func/Makefile | 3 +
drivers/i3c/func/tty.c | 345 ++++++++++++++++++++++++++++++++++++++
5 files changed, 359 insertions(+)
create mode 100644 drivers/i3c/func/Kconfig
create mode 100644 drivers/i3c/func/Makefile
create mode 100644 drivers/i3c/func/tty.c

diff --git a/drivers/i3c/Kconfig b/drivers/i3c/Kconfig
index bdc173bc0da12..fa0f63e0e3e6e 100644
--- a/drivers/i3c/Kconfig
+++ b/drivers/i3c/Kconfig
@@ -50,4 +50,5 @@ config I3C_SLAVE_CONFIGFS

if I3C_SLAVE
source "drivers/i3c/slave/Kconfig"
+source "drivers/i3c/func/Kconfig"
endif #I#C_SLAVE
diff --git a/drivers/i3c/Makefile b/drivers/i3c/Makefile
index ef1acbe13fe60..7814bf2dd9b40 100644
--- a/drivers/i3c/Makefile
+++ b/drivers/i3c/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_I3C) += master/
obj-$(CONFIG_I3C_SLAVE) += slave.o
obj-$(CONFIG_I3C_SLAVE_CONFIGFS) += i3c-cfs.o
obj-$(CONFIG_I3C_SLAVE) += slave/
+obj-$(CONFIG_I3C_SLAVE) += func/
diff --git a/drivers/i3c/func/Kconfig b/drivers/i3c/func/Kconfig
new file mode 100644
index 0000000000000..f122e2cc32de8
--- /dev/null
+++ b/drivers/i3c/func/Kconfig
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config I3C_SLAVE_FUNC_TTY
+ tristate "PCI Endpoint Test driver"
+ depends on I3C_SLAVE
+ help
+ I3C Slave TTY Function Driver
+
+ General TTY over I3C slave controller function drivers.
diff --git a/drivers/i3c/func/Makefile b/drivers/i3c/func/Makefile
new file mode 100644
index 0000000000000..db3262e402edd
--- /dev/null
+++ b/drivers/i3c/func/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_I3C_SLAVE_FUNC_TTY) += tty.o
diff --git a/drivers/i3c/func/tty.c b/drivers/i3c/func/tty.c
new file mode 100644
index 0000000000000..be43878913452
--- /dev/null
+++ b/drivers/i3c/func/tty.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 NXP
+ * Author: Frank Li <Frank.Li@nxp.com>
+ */
+
+#include <linux/i3c/slave.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+
+#define PORT_I3C 124
+
+struct ttyi3c_port {
+ struct uart_port port;
+ struct i3c_slave_func *i3cdev;
+ unsigned long buffer;
+ struct work_struct work;
+ struct workqueue_struct *workqueue;
+};
+
+static struct uart_driver ttyi3c_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = "ttySI3C",
+ .dev_name = "ttySI3C",
+ .nr = 1,
+};
+
+static unsigned int ttyi3c_tx_empty(struct uart_port *port)
+{
+ return 0;
+}
+
+static void ttyi3c_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+
+}
+
+static unsigned int ttyi3c_get_mctrl(struct uart_port *port)
+{
+ return 0;
+}
+
+static void ttyi3c_stop_tx(struct uart_port *port)
+{
+}
+
+static void ttyi3c_stop_rx(struct uart_port *port)
+{
+}
+
+static void ttyi3c_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static int ttyi3c_startup(struct uart_port *port)
+{
+ return 0;
+}
+
+static void ttyi3c_shutdown(struct uart_port *port)
+{
+
+}
+
+static void ttyi3c_uart_pm(struct uart_port *port, unsigned int state, unsigned int oldstate)
+{
+
+}
+
+static void
+ttyi3c_set_termios(struct uart_port *port, struct ktermios *termios, const struct ktermios *old)
+{
+
+}
+
+static const char *ttyi3c_type(struct uart_port *port)
+{
+ return "I3CTTY";
+}
+
+static void ttyi3c_release_port(struct uart_port *port)
+{
+
+}
+
+static int ttyi3c_request_port(struct uart_port *port)
+{
+ return 0;
+}
+
+static void ttyi3c_config_port(struct uart_port *port, int flags)
+{
+
+}
+
+static int ttyi3c_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+ return 0;
+}
+
+static void ttyi3c_flush_buffer(struct uart_port *port)
+{
+
+}
+
+static void ttyi3c_start_tx(struct uart_port *port)
+{
+ struct ttyi3c_port *sport = container_of(port, struct ttyi3c_port, port);
+
+ queue_work(sport->workqueue, &sport->work);
+}
+
+static void i3c_slave_tty_rx_complete(struct i3c_request *req)
+{
+ struct ttyi3c_port *port = req->context;
+
+ if (req->status == I3C_REQUEST_CANCEL) {
+ i3c_slave_ctrl_free_request(req);
+ return;
+ }
+
+ for (int i = 0; i < req->actual; i++) {
+ if (tty_insert_flip_char(&port->port.state->port, *(u8 *)(req->buf + i), 0) == 0)
+ port->port.icount.buf_overrun++;
+ }
+
+ tty_flip_buffer_push(&port->port.state->port);
+ req->actual = 0;
+ req->status = 0;
+ i3c_slave_ctrl_queue(req, GFP_KERNEL);
+}
+
+
+static void i3c_slave_tty_tx_complete(struct i3c_request *req)
+{
+ struct ttyi3c_port *port = req->context;
+ struct circ_buf *xmit = &port->port.state->xmit;
+
+ if (req->status == I3C_REQUEST_CANCEL) {
+ i3c_slave_ctrl_free_request(req);
+ return;
+ }
+
+ uart_xmit_advance(&port->port, req->actual);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&port->port);
+
+
+ i3c_slave_ctrl_free_request(req);
+}
+
+static void i3c_slave_tty_i3c_work(struct work_struct *work)
+{
+ struct ttyi3c_port *sport = container_of(work, struct ttyi3c_port, work);
+ struct circ_buf *xmit = &sport->port.state->xmit;
+ int cnt = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
+ int actual;
+ int ret;
+
+ if (cnt == 0)
+ return;
+
+ if (cnt > 0) {
+ struct i3c_request *req = i3c_slave_ctrl_alloc_request(sport->i3cdev->ctrl,
+ GFP_KERNEL);
+ if (!req)
+ return;
+
+ req->length = ((xmit->tail + cnt) > UART_XMIT_SIZE) ? UART_XMIT_SIZE - xmit->tail :
+ cnt;
+ req->buf = xmit->buf + xmit->tail;
+ req->complete = i3c_slave_tty_tx_complete;
+ req->context = sport;
+ req->tx = true;
+
+ if (i3c_slave_ctrl_queue(req, GFP_KERNEL))
+ return;
+
+ if ((xmit->tail + cnt) > UART_XMIT_SIZE) {
+ req = i3c_slave_ctrl_alloc_request(sport->i3cdev->ctrl, GFP_KERNEL);
+ if (!req)
+ return;
+ req->buf = xmit->buf;
+ req->length = xmit->tail + cnt - UART_XMIT_SIZE;
+ req->complete = i3c_slave_tty_tx_complete;
+
+ if (i3c_slave_ctrl_queue(req, GFP_KERNEL))
+ return;
+ }
+ }
+
+ i3c_slave_ctrl_raise_ibi(sport->i3cdev->ctrl, NULL, 0);
+}
+
+static const struct uart_ops ttyi3c_pops = {
+ .tx_empty = ttyi3c_tx_empty,
+ .set_mctrl = ttyi3c_set_mctrl,
+ .get_mctrl = ttyi3c_get_mctrl,
+ .stop_tx = ttyi3c_stop_tx,
+ .start_tx = ttyi3c_start_tx,
+ .stop_rx = ttyi3c_stop_rx,
+ .break_ctl = ttyi3c_break_ctl,
+ .startup = ttyi3c_startup,
+ .shutdown = ttyi3c_shutdown,
+ .pm = ttyi3c_uart_pm,
+ .set_termios = ttyi3c_set_termios,
+ .type = ttyi3c_type,
+ .request_port = ttyi3c_request_port,
+ .release_port = ttyi3c_release_port,
+ .config_port = ttyi3c_config_port,
+ .verify_port = ttyi3c_verify_port,
+ .flush_buffer = ttyi3c_flush_buffer,
+#if defined(CONFIG_CONSOLE_POLL)
+ .poll_init = ttyi3c_poll_init,
+ .poll_get_char = ttyi3c_poll_get_char,
+ .poll_put_char = ttyi3c_poll_put_char,
+#endif
+};
+
+static int i3c_slave_tty_bind(struct i3c_slave_func *func)
+{
+ const struct i3c_slave_ctrl_features *feature;
+ unsigned int rxfifo_size;
+ struct ttyi3c_port *port;
+ struct i3c_request *req;
+ int offset = 0;
+ int ret;
+
+ feature = i3c_slave_ctrl_get_features(func->ctrl);
+ if (!feature)
+ return -EINVAL;
+
+ rxfifo_size = feature->rx_fifo_sz;
+
+ if (!rxfifo_size)
+ rxfifo_size = 16;
+
+ port = dev_get_drvdata(&func->dev);
+
+ port->buffer = get_zeroed_page(GFP_KERNEL);
+ if (!port->buffer)
+ return -ENOMEM;
+
+ if (i3c_slave_ctrl_set_config(func->ctrl, func)) {
+ dev_err(&func->dev, "failure set i3c config\n");
+ return -EINVAL;
+ }
+
+ req = i3c_slave_ctrl_alloc_request(func->ctrl, GFP_KERNEL);
+ do {
+ req->buf = (void *) (port->buffer + offset);
+ req->length = rxfifo_size;
+ req->context = port;
+ req->complete = i3c_slave_tty_rx_complete;
+ offset += rxfifo_size;
+
+ if (i3c_slave_ctrl_queue(req, GFP_KERNEL))
+ break;
+ } while (req == NULL || offset >= PAGE_SIZE);
+
+ if (i3c_slave_ctrl_set_config(func->ctrl, func)) {
+ dev_err(&func->dev, "failure set i3c config\n");
+ return -EINVAL;
+ }
+
+ ret = uart_register_driver(&ttyi3c_reg);
+ if (ret)
+ return ret;
+
+ ret = uart_add_one_port(&ttyi3c_reg, &port->port);
+ if (ret)
+ goto err_one_port;
+
+ ret = i3c_slave_ctrl_enable(func->ctrl);
+ if (ret)
+ goto err_ctrl_enable;
+
+ return 0;
+
+err_ctrl_enable:
+ uart_remove_one_port(&ttyi3c_reg, &port->port);
+err_one_port:
+ uart_unregister_driver(&ttyi3c_reg);
+ dev_err(&func->dev, "bind failure\n");
+
+ return ret;
+}
+
+static void i3c_slave_tty_unbind(struct i3c_slave_func *func)
+{
+ struct ttyi3c_port *port;
+
+ port = dev_get_drvdata(&func->dev);
+
+ i3c_slave_ctrl_disable(func->ctrl);
+ i3c_slave_ctrl_cancel_all_reqs(func->ctrl, 0);
+ i3c_slave_ctrl_cancel_all_reqs(func->ctrl, 1);
+ uart_remove_one_port(&ttyi3c_reg, &port->port);
+ uart_unregister_driver(&ttyi3c_reg);
+
+ free_page(port->buffer);
+}
+
+static struct i3c_slave_func_ops i3c_tty_ops = {
+ .bind = i3c_slave_tty_bind,
+ .unbind = i3c_slave_tty_unbind,
+};
+
+static int i3c_tty_probe(struct i3c_slave_func *func)
+{
+ struct device *dev = &func->dev;
+ struct ttyi3c_port *port;
+
+ port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->i3cdev = func;
+ port->port.dev = &func->dev;
+ port->port.ops = &ttyi3c_pops;
+ port->port.type = PORT_I3C;
+
+ dev_set_drvdata(&func->dev, port);
+
+ port->workqueue = alloc_workqueue("%s", 0, 0, dev_name(&func->dev));
+ if (!port->workqueue)
+ return -ENOMEM;
+
+ INIT_WORK(&port->work, i3c_slave_tty_i3c_work);
+
+ return 0;
+}
+
+static void i3c_tty_remove(struct i3c_slave_func *func)
+{
+ struct ttyi3c_port *port;
+
+ port = dev_get_drvdata(&func->dev);
+
+ destroy_workqueue(port->workqueue);
+}
+
+DECLARE_I3C_SLAVE_INIT(tty, i3c_tty_probe, i3c_tty_remove, &i3c_tty_ops);