Add driver for the ACM gadget controller of the Espressif ESP32S3 SoC. Hardware specification is available at the following URL: https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf (Chapter 33 USB Serial/JTAG Controller) Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx> --- Changes v4->v5: - fix commit message formatting - rename device from ttyACM to ttyiGS - drop ttyACM device name mention from the Kconfig entry help - use PORT_GENERIC instead of unique PORT_ESP32ACM - add the word 'gadget' to the commit description and to Kconfig text to make it more consistent with linux terminology Changes v2->v3: - use HZ instead of msecs_to_jiffies(1000) in esp32_acm_put_char_sync - add early return to esp32_acm_transmit_buffer - use request_irq/free_irq instead of devm_* versions Changes v1->v2: - redefine register fields using BIT and GENMASK - drop _MASK suffix from register field definitions - drop *_SHIFT definitions where possible - split register reads/writes and bitwise operations into multiple lines - use u8 instead of unsigned char in internal functions - add timeout to esp32_acm_put_char_sync - use uart_port_tx_limited in esp32_acm_transmit_buffer - use IRQ_RETVAL in esp32_acm_int - drop esp32s3_acm_console_putchar and esp32s3_acm_earlycon_putchar - turn num_read into unsigned int in esp32_acm_earlycon_read - drop MODULE_DESCRIPTION drivers/tty/serial/Kconfig | 13 + drivers/tty/serial/Makefile | 1 + drivers/tty/serial/esp32_acm.c | 459 +++++++++++++++++++++++++++++++++ 3 files changed, 473 insertions(+) create mode 100644 drivers/tty/serial/esp32_acm.c diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index d9ca6b268f01..732c893c8d16 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1591,6 +1591,19 @@ config SERIAL_ESP32 earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000 earlycon=esp32uart,mmio32,0x3ff40000,115200n8 +config SERIAL_ESP32_ACM + tristate "Espressif ESP32 USB ACM gadget support" + depends on XTENSA_PLATFORM_ESP32 || (COMPILE_TEST && OF) + select SERIAL_CORE + select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON + help + Driver for the CDC ACM gadget controller of the Espressif ESP32S3 + SoCs that share separate USB controller with the JTAG adapter. + When earlycon option is enabled the following kernel command line + snippet may be used: + earlycon=esp32s3acm,mmio32,0x60038000 + endmenu config SERIAL_MCTRL_GPIO diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index 7b73137df7f3..970a292ca418 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o obj-$(CONFIG_SERIAL_SUNPLUS) += sunplus-uart.o obj-$(CONFIG_SERIAL_ESP32) += esp32_uart.o +obj-$(CONFIG_SERIAL_ESP32_ACM) += esp32_acm.o # GPIOLIB helpers for modem control lines obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o diff --git a/drivers/tty/serial/esp32_acm.c b/drivers/tty/serial/esp32_acm.c new file mode 100644 index 000000000000..cb28a87736aa --- /dev/null +++ b/drivers/tty/serial/esp32_acm.c @@ -0,0 +1,459 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/console.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/serial_core.h> +#include <linux/slab.h> +#include <linux/tty_flip.h> +#include <asm/serial.h> + +#define DRIVER_NAME "esp32s3-acm" +#define DEV_NAME "ttyGS" +#define UART_NR 4 + +#define ESP32S3_ACM_TX_FIFO_SIZE 64 + +#define USB_SERIAL_JTAG_EP1_REG 0x00 +#define USB_SERIAL_JTAG_EP1_CONF_REG 0x04 +#define USB_SERIAL_JTAG_WR_DONE BIT(0) +#define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE BIT(1) +#define USB_SERIAL_JTAG_INT_ST_REG 0x0c +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST BIT(2) +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST BIT(3) +#define USB_SERIAL_JTAG_INT_ENA_REG 0x10 +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA BIT(2) +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA BIT(3) +#define USB_SERIAL_JTAG_INT_CLR_REG 0x14 +#define USB_SERIAL_JTAG_IN_EP1_ST_REG 0x2c +#define USB_SERIAL_JTAG_IN_EP1_WR_ADDR GENMASK(8, 2) +#define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c +#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT GENMASK(22, 16) + +static const struct of_device_id esp32s3_acm_dt_ids[] = { + { + .compatible = "esp,esp32s3-acm", + }, { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, esp32s3_acm_dt_ids); + +static struct uart_port *esp32s3_acm_ports[UART_NR]; + +static void esp32s3_acm_write(struct uart_port *port, unsigned long reg, u32 v) +{ + writel(v, port->membase + reg); +} + +static u32 esp32s3_acm_read(struct uart_port *port, unsigned long reg) +{ + return readl(port->membase + reg); +} + +static u32 esp32s3_acm_tx_fifo_free(struct uart_port *port) +{ + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG); + + return status & USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE; +} + +static u32 esp32s3_acm_tx_fifo_cnt(struct uart_port *port) +{ + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_IN_EP1_ST_REG); + + return FIELD_GET(USB_SERIAL_JTAG_IN_EP1_WR_ADDR, status); +} + +static u32 esp32s3_acm_rx_fifo_cnt(struct uart_port *port) +{ + u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_OUT_EP1_ST_REG); + + return FIELD_GET(USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT, status); +} + +/* return TIOCSER_TEMT when transmitter is not busy */ +static unsigned int esp32s3_acm_tx_empty(struct uart_port *port) +{ + return esp32s3_acm_tx_fifo_cnt(port) == 0 ? TIOCSER_TEMT : 0; +} + +static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +static unsigned int esp32s3_acm_get_mctrl(struct uart_port *port) +{ + return TIOCM_CAR; +} + +static void esp32s3_acm_stop_tx(struct uart_port *port) +{ + u32 int_ena; + + int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); + int_ena &= ~USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA; + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena); +} + +static void esp32s3_acm_rxint(struct uart_port *port) +{ + struct tty_port *tty_port = &port->state->port; + u32 rx_fifo_cnt = esp32s3_acm_rx_fifo_cnt(port); + unsigned long flags; + u32 i; + + if (!rx_fifo_cnt) + return; + + spin_lock_irqsave(&port->lock, flags); + + for (i = 0; i < rx_fifo_cnt; ++i) { + u32 rx = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG); + + ++port->icount.rx; + tty_insert_flip_char(tty_port, rx, TTY_NORMAL); + } + spin_unlock_irqrestore(&port->lock, flags); + + tty_flip_buffer_push(tty_port); +} + +static void esp32s3_acm_push(struct uart_port *port) +{ + if (esp32s3_acm_tx_fifo_free(port)) + esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG, + USB_SERIAL_JTAG_WR_DONE); +} + +static void esp32s3_acm_put_char(struct uart_port *port, u8 c) +{ + esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_REG, c); +} + +static void esp32s3_acm_put_char_sync(struct uart_port *port, u8 c) +{ + unsigned long timeout = jiffies + HZ; + + while (!esp32s3_acm_tx_fifo_free(port)) { + if (time_after(jiffies, timeout)) { + dev_warn(port->dev, "timeout waiting for TX FIFO\n"); + return; + } + cpu_relax(); + } + esp32s3_acm_put_char(port, c); + esp32s3_acm_push(port); +} + +static void esp32s3_acm_transmit_buffer(struct uart_port *port) +{ + u32 tx_fifo_used; + unsigned int pending; + u8 ch; + + if (!esp32s3_acm_tx_fifo_free(port)) + return; + + tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port); + pending = uart_port_tx_limited(port, ch, + ESP32S3_ACM_TX_FIFO_SIZE - tx_fifo_used, + true, esp32s3_acm_put_char(port, ch), + ({})); + if (pending) { + u32 int_ena; + + int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); + int_ena |= USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA; + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena); + } + esp32s3_acm_push(port); +} + +static void esp32s3_acm_txint(struct uart_port *port) +{ + esp32s3_acm_transmit_buffer(port); +} + +static irqreturn_t esp32s3_acm_int(int irq, void *dev_id) +{ + struct uart_port *port = dev_id; + u32 status; + + status = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ST_REG); + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_CLR_REG, status); + + if (status & USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST) + esp32s3_acm_rxint(port); + if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST) + esp32s3_acm_txint(port); + + return IRQ_RETVAL(status); +} + +static void esp32s3_acm_start_tx(struct uart_port *port) +{ + esp32s3_acm_transmit_buffer(port); +} + +static void esp32s3_acm_stop_rx(struct uart_port *port) +{ + u32 int_ena; + + int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); + int_ena &= ~USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA; + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena); +} + +static int esp32s3_acm_startup(struct uart_port *port) +{ + int ret; + + ret = request_irq(port->irq, esp32s3_acm_int, 0, DRIVER_NAME, port); + if (ret) + return ret; + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, + USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA); + + return 0; +} + +static void esp32s3_acm_shutdown(struct uart_port *port) +{ + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, 0); + free_irq(port->irq, port); +} + +static void esp32s3_acm_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ +} + +static const char *esp32s3_acm_type(struct uart_port *port) +{ + return "ESP32S3 ACM"; +} + +/* configure/auto-configure the port */ +static void esp32s3_acm_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) + port->type = PORT_GENERIC; +} + +#ifdef CONFIG_CONSOLE_POLL +static void esp32s3_acm_poll_put_char(struct uart_port *port, unsigned char c) +{ + esp32s3_acm_put_char_sync(port, c); +} + +static int esp32s3_acm_poll_get_char(struct uart_port *port) +{ + if (esp32s3_acm_rx_fifo_cnt(port)) + return esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG); + else + return NO_POLL_CHAR; +} +#endif + +static const struct uart_ops esp32s3_acm_pops = { + .tx_empty = esp32s3_acm_tx_empty, + .set_mctrl = esp32s3_acm_set_mctrl, + .get_mctrl = esp32s3_acm_get_mctrl, + .stop_tx = esp32s3_acm_stop_tx, + .start_tx = esp32s3_acm_start_tx, + .stop_rx = esp32s3_acm_stop_rx, + .startup = esp32s3_acm_startup, + .shutdown = esp32s3_acm_shutdown, + .set_termios = esp32s3_acm_set_termios, + .type = esp32s3_acm_type, + .config_port = esp32s3_acm_config_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_put_char = esp32s3_acm_poll_put_char, + .poll_get_char = esp32s3_acm_poll_get_char, +#endif +}; + +static void esp32s3_acm_string_write(struct uart_port *port, const char *s, + unsigned int count) +{ + uart_console_write(port, s, count, esp32s3_acm_put_char_sync); +} + +static void +esp32s3_acm_console_write(struct console *co, const char *s, unsigned int count) +{ + struct uart_port *port = esp32s3_acm_ports[co->index]; + unsigned long flags; + bool locked = true; + + if (port->sysrq) + locked = false; + else if (oops_in_progress) + locked = spin_trylock_irqsave(&port->lock, flags); + else + spin_lock_irqsave(&port->lock, flags); + + esp32s3_acm_string_write(port, s, count); + + if (locked) + spin_unlock_irqrestore(&port->lock, flags); +} + +static struct uart_driver esp32s3_acm_reg; +static struct console esp32s3_acm_console = { + .name = DEV_NAME, + .write = esp32s3_acm_console_write, + .device = uart_console_device, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &esp32s3_acm_reg, +}; + +static void esp32s3_acm_earlycon_write(struct console *con, const char *s, + unsigned int n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, esp32s3_acm_put_char_sync); +} + +#ifdef CONFIG_CONSOLE_POLL +static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + unsigned int num_read = 0; + + while (num_read < n) { + int c = esp32s3_acm_poll_get_char(&dev->port); + + if (c == NO_POLL_CHAR) + break; + s[num_read++] = c; + } + return num_read; +} +#endif + +static int __init esp32s3_acm_early_console_setup(struct earlycon_device *device, + const char *options) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = esp32s3_acm_earlycon_write; +#ifdef CONFIG_CONSOLE_POLL + device->con->read = esp32s3_acm_earlycon_read; +#endif + return 0; +} + +OF_EARLYCON_DECLARE(esp32s3acm, "esp,esp32s3-acm", + esp32s3_acm_early_console_setup); + +static struct uart_driver esp32s3_acm_reg = { + .owner = THIS_MODULE, + .driver_name = DRIVER_NAME, + .dev_name = DEV_NAME, + .nr = ARRAY_SIZE(esp32s3_acm_ports), + .cons = &esp32s3_acm_console, +}; + +static int esp32s3_acm_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct uart_port *port; + struct resource *res; + int ret; + + port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL); + if (!port) + return -ENOMEM; + + ret = of_alias_get_id(np, "serial"); + if (ret < 0) { + dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret); + return ret; + } + if (ret >= UART_NR) { + dev_err(&pdev->dev, "driver limited to %d serial ports\n", + UART_NR); + return -ENOMEM; + } + + port->line = ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + port->mapbase = res->start; + port->membase = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(port->membase)) + return PTR_ERR(port->membase); + + port->dev = &pdev->dev; + port->type = PORT_GENERIC; + port->iotype = UPIO_MEM; + port->irq = platform_get_irq(pdev, 0); + port->ops = &esp32s3_acm_pops; + port->flags = UPF_BOOT_AUTOCONF; + port->has_sysrq = 1; + port->fifosize = ESP32S3_ACM_TX_FIFO_SIZE; + + esp32s3_acm_ports[port->line] = port; + + platform_set_drvdata(pdev, port); + + return uart_add_one_port(&esp32s3_acm_reg, port); +} + +static int esp32s3_acm_remove(struct platform_device *pdev) +{ + struct uart_port *port = platform_get_drvdata(pdev); + + uart_remove_one_port(&esp32s3_acm_reg, port); + return 0; +} + + +static struct platform_driver esp32s3_acm_driver = { + .probe = esp32s3_acm_probe, + .remove = esp32s3_acm_remove, + .driver = { + .name = DRIVER_NAME, + .of_match_table = esp32s3_acm_dt_ids, + }, +}; + +static int __init esp32s3_acm_init(void) +{ + int ret; + + ret = uart_register_driver(&esp32s3_acm_reg); + if (ret) + return ret; + + ret = platform_driver_register(&esp32s3_acm_driver); + if (ret) + uart_unregister_driver(&esp32s3_acm_reg); + + return ret; +} + +static void __exit esp32s3_acm_exit(void) +{ + platform_driver_unregister(&esp32s3_acm_driver); + uart_unregister_driver(&esp32s3_acm_reg); +} + +module_init(esp32s3_acm_init); +module_exit(esp32s3_acm_exit); + +MODULE_AUTHOR("Max Filippov <jcmvbkbc@xxxxxxxxx>"); +MODULE_LICENSE("GPL"); -- 2.30.2
