The Tegra Combined UART (TCU) is a mailbox-based mechanism that allows multiplexing multiple "virtual UARTs" into a single hardware serial port. The TCU is the primary serial port on Tegra194 devices. Add a TCU driver utilizing the mailbox framework, as the used mailboxes are part of Tegra HSP blocks that are already controlled by the Tegra HSP mailbox driver. Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx> --- drivers/tty/serial/Kconfig | 9 ++ drivers/tty/serial/Makefile | 1 + drivers/tty/serial/tegra-tcu.c | 302 +++++++++++++++++++++++++++++++++++++++ include/uapi/linux/serial_core.h | 3 + 4 files changed, 315 insertions(+) create mode 100644 drivers/tty/serial/tegra-tcu.c diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index eca55187539a..494db7afe230 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -322,6 +322,15 @@ config SERIAL_TEGRA are enabled). This driver uses the APB DMA to achieve higher baudrate and better performance. +config SERIAL_TEGRA_TCU + tristate "NVIDIA Tegra Combined UART" + depends on ARCH_TEGRA && MAILBOX + select SERIAL_CORE + help + Support for the mailbox-based TCU (Tegra Combined UART) serial port. + TCU is a virtual serial port that allows multiplexing multiple data + streams into a single hardware serial port. + config SERIAL_MAX3100 tristate "MAX3100 support" depends on SPI diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index daac675612df..4ad82231ff8a 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -76,6 +76,7 @@ obj-$(CONFIG_SERIAL_LANTIQ) += lantiq.o obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o obj-$(CONFIG_SERIAL_TEGRA) += serial-tegra.o +obj-$(CONFIG_SERIAL_TEGRA_TCU) += tegra-tcu.o obj-$(CONFIG_SERIAL_AR933X) += ar933x_uart.o obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o obj-$(CONFIG_SERIAL_ARC) += arc_uart.o diff --git a/drivers/tty/serial/tegra-tcu.c b/drivers/tty/serial/tegra-tcu.c new file mode 100644 index 000000000000..8b46fe3a4b0c --- /dev/null +++ b/drivers/tty/serial/tegra-tcu.c @@ -0,0 +1,302 @@ +// 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> + +static struct uart_driver tegra_tcu_uart_driver; +static struct uart_port tegra_tcu_uart_port; + +struct tegra_tcu { + 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) +{ + (void)port; + (void)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) +{ + (void)port; +} + +static void tegra_tcu_write(const char *s, unsigned int count) +{ + struct tegra_tcu *tcu = tegra_tcu_uart_port.private_data; + unsigned int written = 0, i = 0; + bool insert_nl = false; + uint32_t value = 0; + + while (i < count) { + if (insert_nl) { + value |= '\n' << (written++ * 8); + insert_nl = false; + i++; + } else if (s[i] == '\n') { + value |= '\r' << (written++ * 8); + insert_nl = true; + } else { + value |= s[i++] << (written++ * 8); + } + + if (written == 3) { + value |= 3 << 24; + value |= BIT(26); + mbox_send_message(tcu->tx, &value); + value = 0; + written = 0; + } + } + + if (written) { + value |= written << 24; + value |= BIT(26); + mbox_send_message(tcu->tx, &value); + } +} + +static void tegra_tcu_uart_start_tx(struct uart_port *port) +{ + 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(&xmit->buf[xmit->tail], count); + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); + } + + uart_write_wakeup(port); +} + +static void tegra_tcu_uart_stop_rx(struct uart_port *port) +{ + (void)port; +} + +static void tegra_tcu_uart_break_ctl(struct uart_port *port, int ctl) +{ + (void)port; + (void)ctl; +} + +static int tegra_tcu_uart_startup(struct uart_port *port) +{ + (void)port; + + return 0; +} + +static void tegra_tcu_uart_shutdown(struct uart_port *port) +{ + (void)port; +} + +static void tegra_tcu_uart_set_termios(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) +{ + (void)port; + (void)new; + (void)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, +}; + +static void tegra_tcu_console_write(struct console *cons, const char *s, + unsigned int count) +{ + (void)cons; + + tegra_tcu_write(s, count); +} + +static int tegra_tcu_console_setup(struct console *cons, char *options) +{ + (void)options; + + if (!tegra_tcu_uart_port.private_data) + return -ENODEV; + + return uart_set_options(&tegra_tcu_uart_port, cons, + 115200, 'n', 8, 'n'); +} + +static struct console tegra_tcu_console = { + .name = "ttyTCU", + .device = uart_console_device, + .flags = CON_PRINTBUFFER | CON_ANYTIME, + .index = -1, + .write = tegra_tcu_console_write, + .setup = tegra_tcu_console_setup, + .data = &tegra_tcu_uart_driver, +}; + +static struct uart_driver tegra_tcu_uart_driver = { + .owner = THIS_MODULE, + .driver_name = "tegra-tcu", + .dev_name = "ttyTCU", + .cons = &tegra_tcu_console, + .nr = 1, +}; + +static void tegra_tcu_receive(struct mbox_client *client, void *msg_p) +{ + struct tty_port *port = &tegra_tcu_uart_port.state->port; + uint32_t msg = *(uint32_t *)msg_p; + unsigned int num_bytes; + int i; + + num_bytes = (msg >> 24) & 0x3; + for (i = 0; i < num_bytes; i++) + tty_insert_flip_char(port, (msg >> (i*8)) & 0xff, TTY_NORMAL); + + tty_flip_buffer_push(port); +} + +static int tegra_tcu_probe(struct platform_device *pdev) +{ + struct uart_port *port = &tegra_tcu_uart_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; + } + + err = uart_register_driver(&tegra_tcu_uart_driver); + if (err) { + dev_err(&pdev->dev, "failed to register UART driver: %d\n", + err); + goto free_rx; + } + + 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(&tegra_tcu_uart_driver, port); + if (err) { + dev_err(&pdev->dev, "failed to add UART port: %d\n", err); + goto unregister_uart; + } + + return 0; + +unregister_uart: + uart_unregister_driver(&tegra_tcu_uart_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) +{ + uart_remove_one_port(&tegra_tcu_uart_driver, &tegra_tcu_uart_port); + uart_unregister_driver(&tegra_tcu_uart_driver); + + 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, +}; + +static int __init tegra_tcu_init(void) +{ + int err; + + err = platform_driver_register(&tegra_tcu_driver); + if (err) + return err; + + register_console(&tegra_tcu_console); + + return 0; +} +module_init(tegra_tcu_init); + +static void __exit tegra_tcu_exit(void) +{ + unregister_console(&tegra_tcu_console); + platform_driver_unregister(&tegra_tcu_driver); +} +module_exit(tegra_tcu_exit); + +MODULE_AUTHOR("Mikko Perttunen <mperttunen@xxxxxxxxxx>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("NVIDIA Tegra Combined UART driver"); diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h index dce5f9dae121..eaf3c303cba6 100644 --- a/include/uapi/linux/serial_core.h +++ b/include/uapi/linux/serial_core.h @@ -281,4 +281,7 @@ /* MediaTek BTIF */ #define PORT_MTK_BTIF 117 +/* NVIDIA Tegra Combined UART */ +#define PORT_TEGRA_TCU 118 + #endif /* _UAPILINUX_SERIAL_CORE_H */ -- 2.16.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html