[RFC PATCH 8/9] tty: serial: add tty over I3C master side driver

Frank Li
2023-09-05T21:39:31Z

This is master side tty driver for tty over i3c.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
drivers/tty/serial/Kconfig | 6 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/ttyi3c.c | 276 ++++++++++++++++++++++++++++++++++++
3 files changed, 283 insertions(+)
create mode 100644 drivers/tty/serial/ttyi3c.c

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index bdc568a4ab669..2ceafe94cd1dc 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1578,6 +1578,12 @@ config SERIAL_NUVOTON_MA35D1_CONSOLE
but you can alter that using a kernel command line option such as
"console=ttyNVTx".

+config SERIAL_I3C
+ tristate "tty over i3c"
+ depends on I3C
+ help
+ Select this options if you'd like use UART over I3C master controller
+
endmenu

config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 138abbc897381..60c101809cdcf 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o
+obj-$(CONFIG_SERIAL_I3C) += ttyi3c.o

# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/ttyi3c.c b/drivers/tty/serial/ttyi3c.c
new file mode 100644
index 0000000000000..e2912c8bac87d
--- /dev/null
+++ b/drivers/tty/serial/ttyi3c.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 NXP.
+ *
+ * Author: Frank Li <Frank.Li@nxp.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/i3c/device.h>
+#include <linux/i3c/master.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/serial_core.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/tty_flip.h>
+
+#define DEVICE_NAME "ttyI3C"
+#define PORT_I3C 124
+
+struct ttyi3c_port {
+ struct uart_port port;
+ unsigned int txfifo_size;
+ unsigned int rxfifo_size;
+ void *buffer;
+ struct i3c_device *i3cdev;
+ struct work_struct work;
+ struct workqueue_struct *workqueue;
+};
+
+static struct uart_driver ttyi3c_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = "fsl_ttyi3c",
+ .dev_name = DEVICE_NAME,
+ .nr = 1,
+};
+
+static const struct i3c_device_id fsl_tty_i3c_ids[] = {
+ I3C_DEVICE(0x011B, 0x1000, NULL),
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(i3c, fsl_tty_i3c_ids);
+
+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 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,
+};
+
+static void
+i3c_controller_irq_handler(struct i3c_device *dev, const struct i3c_ibi_payload *payload)
+{
+
+ struct ttyi3c_port *sport = dev_get_drvdata(&dev->dev);
+ struct i3c_priv_xfer xfers;
+ int i = 0;
+
+ memset(&xfers, 0, sizeof(xfers));
+
+ xfers.data.in = sport->buffer;
+ xfers.len = 16;
+ xfers.rnw = 1;
+
+ i3c_device_do_priv_xfers(sport->i3cdev, &xfers, 1);
+
+ for (i = 0; i < xfers.actual; i++)
+ if (tty_insert_flip_char(&sport->port.state->port, *(u8 *)(sport->buffer + i), 0)
+ == 0)
+ sport->port.icount.buf_overrun++;
+
+ tty_flip_buffer_push(&sport->port.state->port);
+}
+
+static void fsl_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);
+ struct i3c_priv_xfer xfers;
+ int actual;
+ int ret;
+
+ if (cnt == 0)
+ return;
+
+ if (cnt > 0) {
+ xfers.rnw = 0;
+ xfers.len = ((xmit->tail + cnt) > UART_XMIT_SIZE) ? UART_XMIT_SIZE - xmit->tail :
+ cnt;
+ xfers.data.out = xmit->buf + xmit->tail;
+
+ ret = i3c_device_do_priv_xfers(sport->i3cdev, &xfers, 1);
+
+ actual = ret ? xfers.actual : xfers.len;
+
+ uart_xmit_advance(&sport->port, actual);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&sport->port);
+
+ cnt -= actual;
+ }
+
+ if (cnt)
+ queue_work(sport->workqueue, &sport->work);
+}
+
+static int fsl_tty_i3c_probe(struct i3c_device *i3cdev)
+{
+ struct ttyi3c_port *port;
+ struct i3c_ibi_setup req;
+ int ret;
+
+ port = devm_kzalloc(&i3cdev->dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->i3cdev = i3cdev;
+ port->port.ops = &ttyi3c_pops;
+ port->port.type = PORT_I3C;
+ port->port.dev = &i3cdev->dev;
+ port->buffer = devm_kzalloc(&i3cdev->dev, UART_XMIT_SIZE, GFP_KERNEL);
+
+ req.max_payload_len = 8;
+ req.num_slots = 4;
+ req.handler = &i3c_controller_irq_handler;
+
+ dev_set_drvdata(&i3cdev->dev, port);
+
+ INIT_WORK(&port->work, fsl_tty_i3c_work);
+ port->workqueue = alloc_workqueue("%s", 0, 0, dev_name(&i3cdev->dev));
+ if (!port->workqueue)
+ return -ENOMEM;
+
+ ret = uart_register_driver(&ttyi3c_reg);
+ if (ret)
+ return ret;
+
+ ret = uart_add_one_port(&ttyi3c_reg, &port->port);
+ if (ret)
+ goto err_add_one_port;
+
+ ret = i3c_device_request_ibi(i3cdev, &req);
+ if (ret)
+ goto err_request_ibi;
+
+ ret = i3c_device_enable_ibi(i3cdev);
+ if (ret)
+ goto err_enable_ibi;
+
+ return 0;
+
+err_enable_ibi:
+ i3c_device_free_ibi(i3cdev);
+err_request_ibi:
+ uart_remove_one_port(&ttyi3c_reg, &port->port);
+err_add_one_port:
+ uart_unregister_driver(&ttyi3c_reg);
+
+ return ret;
+}
+
+static struct i3c_driver fsl_tty_i3c_driver = {
+ .driver = {
+ .name = "ttyi3c",
+ },
+ .probe = fsl_tty_i3c_probe,
+ .id_table = fsl_tty_i3c_ids,
+};
+
+module_i3c_driver(fsl_tty_i3c_driver);
+MODULE_LICENSE("GPL");