diff options
Diffstat (limited to 'drivers/tty/serial/tegra-tcu.c')
| -rw-r--r-- | drivers/tty/serial/tegra-tcu.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/tty/serial/tegra-tcu.c b/drivers/tty/serial/tegra-tcu.c new file mode 100644 index 000000000..31ae705aa --- /dev/null +++ b/drivers/tty/serial/tegra-tcu.c @@ -0,0 +1,298 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved. + */ + +#include <linux/console.h> +#include <linux/mailbox_client.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/serial.h> +#include <linux/serial_core.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> + +#define TCU_MBOX_BYTE(i, x) ((x) << (i * 8)) +#define TCU_MBOX_BYTE_V(x, i) (((x) >> (i * 8)) & 0xff) +#define TCU_MBOX_NUM_BYTES(x) ((x) << 24) +#define TCU_MBOX_NUM_BYTES_V(x) (((x) >> 24) & 0x3) + +struct tegra_tcu { + struct uart_driver driver; +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) + struct console console; +#endif + struct uart_port port; + + struct mbox_client tx_client, rx_client; + struct mbox_chan *tx, *rx; +}; + +static unsigned int tegra_tcu_uart_tx_empty(struct uart_port *port) +{ + return TIOCSER_TEMT; +} + +static void tegra_tcu_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +static unsigned int tegra_tcu_uart_get_mctrl(struct uart_port *port) +{ + return 0; +} + +static void tegra_tcu_uart_stop_tx(struct uart_port *port) +{ +} + +static void tegra_tcu_write_one(struct tegra_tcu *tcu, u32 value, + unsigned int count) +{ + void *msg; + + value |= TCU_MBOX_NUM_BYTES(count); + msg = (void *)(unsigned long)value; + mbox_send_message(tcu->tx, msg); + mbox_flush(tcu->tx, 1000); +} + +static void tegra_tcu_write(struct tegra_tcu *tcu, const char *s, + unsigned int count) +{ + unsigned int written = 0, i = 0; + bool insert_nl = false; + u32 value = 0; + + while (i < count) { + if (insert_nl) { + value |= TCU_MBOX_BYTE(written++, '\n'); + insert_nl = false; + i++; + } else if (s[i] == '\n') { + value |= TCU_MBOX_BYTE(written++, '\r'); + insert_nl = true; + } else { + value |= TCU_MBOX_BYTE(written++, s[i++]); + } + + if (written == 3) { + tegra_tcu_write_one(tcu, value, 3); + value = written = 0; + } + } + + if (written) + tegra_tcu_write_one(tcu, value, written); +} + +static void tegra_tcu_uart_start_tx(struct uart_port *port) +{ + struct tegra_tcu *tcu = port->private_data; + struct circ_buf *xmit = &port->state->xmit; + unsigned long count; + + for (;;) { + count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + if (!count) + break; + + tegra_tcu_write(tcu, &xmit->buf[xmit->tail], count); + uart_xmit_advance(port, count); + } + + uart_write_wakeup(port); +} + +static void tegra_tcu_uart_stop_rx(struct uart_port *port) +{ +} + +static void tegra_tcu_uart_break_ctl(struct uart_port *port, int ctl) +{ +} + +static int tegra_tcu_uart_startup(struct uart_port *port) +{ + return 0; +} + +static void tegra_tcu_uart_shutdown(struct uart_port *port) +{ +} + +static void tegra_tcu_uart_set_termios(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) +{ +} + +static const struct uart_ops tegra_tcu_uart_ops = { + .tx_empty = tegra_tcu_uart_tx_empty, + .set_mctrl = tegra_tcu_uart_set_mctrl, + .get_mctrl = tegra_tcu_uart_get_mctrl, + .stop_tx = tegra_tcu_uart_stop_tx, + .start_tx = tegra_tcu_uart_start_tx, + .stop_rx = tegra_tcu_uart_stop_rx, + .break_ctl = tegra_tcu_uart_break_ctl, + .startup = tegra_tcu_uart_startup, + .shutdown = tegra_tcu_uart_shutdown, + .set_termios = tegra_tcu_uart_set_termios, +}; + +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) +static void tegra_tcu_console_write(struct console *cons, const char *s, + unsigned int count) +{ + struct tegra_tcu *tcu = container_of(cons, struct tegra_tcu, console); + + tegra_tcu_write(tcu, s, count); +} + +static int tegra_tcu_console_setup(struct console *cons, char *options) +{ + return 0; +} +#endif + +static void tegra_tcu_receive(struct mbox_client *cl, void *msg) +{ + struct tegra_tcu *tcu = container_of(cl, struct tegra_tcu, rx_client); + struct tty_port *port = &tcu->port.state->port; + u32 value = (u32)(unsigned long)msg; + unsigned int num_bytes, i; + + num_bytes = TCU_MBOX_NUM_BYTES_V(value); + + for (i = 0; i < num_bytes; i++) + tty_insert_flip_char(port, TCU_MBOX_BYTE_V(value, i), + TTY_NORMAL); + + tty_flip_buffer_push(port); +} + +static int tegra_tcu_probe(struct platform_device *pdev) +{ + struct uart_port *port; + struct tegra_tcu *tcu; + int err; + + tcu = devm_kzalloc(&pdev->dev, sizeof(*tcu), GFP_KERNEL); + if (!tcu) + return -ENOMEM; + + tcu->tx_client.dev = &pdev->dev; + tcu->rx_client.dev = &pdev->dev; + tcu->rx_client.rx_callback = tegra_tcu_receive; + + tcu->tx = mbox_request_channel_byname(&tcu->tx_client, "tx"); + if (IS_ERR(tcu->tx)) { + err = PTR_ERR(tcu->tx); + dev_err(&pdev->dev, "failed to get tx mailbox: %d\n", err); + return err; + } + + tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx"); + if (IS_ERR(tcu->rx)) { + err = PTR_ERR(tcu->rx); + dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err); + goto free_tx; + } + +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) + /* setup the console */ + strcpy(tcu->console.name, "ttyTCU"); + tcu->console.device = uart_console_device; + tcu->console.flags = CON_PRINTBUFFER | CON_ANYTIME; + tcu->console.index = -1; + tcu->console.write = tegra_tcu_console_write; + tcu->console.setup = tegra_tcu_console_setup; + tcu->console.data = &tcu->driver; +#endif + + /* setup the driver */ + tcu->driver.owner = THIS_MODULE; + tcu->driver.driver_name = "tegra-tcu"; + tcu->driver.dev_name = "ttyTCU"; +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) + tcu->driver.cons = &tcu->console; +#endif + tcu->driver.nr = 1; + + err = uart_register_driver(&tcu->driver); + if (err) { + dev_err(&pdev->dev, "failed to register UART driver: %d\n", + err); + goto free_rx; + } + + /* setup the port */ + port = &tcu->port; + spin_lock_init(&port->lock); + port->dev = &pdev->dev; + port->type = PORT_TEGRA_TCU; + port->ops = &tegra_tcu_uart_ops; + port->fifosize = 1; + port->iotype = UPIO_MEM; + port->flags = UPF_BOOT_AUTOCONF; + port->private_data = tcu; + + err = uart_add_one_port(&tcu->driver, port); + if (err) { + dev_err(&pdev->dev, "failed to add UART port: %d\n", err); + goto unregister_uart; + } + + platform_set_drvdata(pdev, tcu); +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) + register_console(&tcu->console); +#endif + + return 0; + +unregister_uart: + uart_unregister_driver(&tcu->driver); +free_rx: + mbox_free_channel(tcu->rx); +free_tx: + mbox_free_channel(tcu->tx); + + return err; +} + +static int tegra_tcu_remove(struct platform_device *pdev) +{ + struct tegra_tcu *tcu = platform_get_drvdata(pdev); + +#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) + unregister_console(&tcu->console); +#endif + uart_remove_one_port(&tcu->driver, &tcu->port); + uart_unregister_driver(&tcu->driver); + mbox_free_channel(tcu->rx); + mbox_free_channel(tcu->tx); + + return 0; +} + +static const struct of_device_id tegra_tcu_match[] = { + { .compatible = "nvidia,tegra194-tcu" }, + { } +}; + +static struct platform_driver tegra_tcu_driver = { + .driver = { + .name = "tegra-tcu", + .of_match_table = tegra_tcu_match, + }, + .probe = tegra_tcu_probe, + .remove = tegra_tcu_remove, +}; +module_platform_driver(tegra_tcu_driver); + +MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("NVIDIA Tegra Combined UART driver"); |