On Wed, 13 Sep 2023, Max Filippov wrote: > Add driver for the ACM 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> > --- > drivers/tty/serial/Kconfig | 14 + > drivers/tty/serial/Makefile | 1 + > drivers/tty/serial/esp32_acm.c | 473 +++++++++++++++++++++++++++++++ > include/uapi/linux/serial_core.h | 3 + > 4 files changed, 491 insertions(+) > create mode 100644 drivers/tty/serial/esp32_acm.c Please go through this with the comments against the other patch in mind, I don't want to spend my time on reviewing it yet just to mark all the similar issues. -- i. > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig > index d9ca6b268f01..85807db8f7ce 100644 > --- a/drivers/tty/serial/Kconfig > +++ b/drivers/tty/serial/Kconfig > @@ -1591,6 +1591,20 @@ config SERIAL_ESP32 > earlycon=esp32s3uart,mmio32,0x60000000,115200n8,40000000 > earlycon=esp32uart,mmio32,0x3ff40000,115200n8 > > +config SERIAL_ESP32_ACM > + tristate "Espressif ESP32 USB ACM 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 controllers of the Espressif ESP32S3 SoCs > + that share separate USB controller with the JTAG adapter. > + The device name used for this controller is ttyACM. > + 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..f178e6af93f3 > --- /dev/null > +++ b/drivers/tty/serial/esp32_acm.c > @@ -0,0 +1,473 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > + > +#include <linux/console.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 <linux/delay.h> > +#include <asm/serial.h> > + > +#define DRIVER_NAME "esp32s3-acm" > +#define DEV_NAME "ttyACM" > +#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_MASK 0x00000001 > +#define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE_MASK 0x00000002 > +#define USB_SERIAL_JTAG_SERIAL_OUT_EP_DATA_AVAIL_MASK 0x00000008 > +#define USB_SERIAL_JTAG_INT_ST_REG 0x0c > +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST_MASK 0x00000004 > +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST_MASK 0x00000008 > +#define USB_SERIAL_JTAG_INT_ENA_REG 0x10 > +#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA_MASK 0x00000004 > +#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA_MASK 0x00000008 > +#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_MASK 0x000001fc > +#define USB_SERIAL_JTAG_IN_EP1_WR_ADDR_SHIFT 2 > +#define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c > +#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT_MASK 0x007f0000 > +#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT_SHIFT 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) > +{ > + return esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG) & > + USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE_MASK; > +} > + > +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 (status & USB_SERIAL_JTAG_IN_EP1_WR_ADDR_MASK) >> > + USB_SERIAL_JTAG_IN_EP1_WR_ADDR_SHIFT; > +} > + > +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 (status & USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT_MASK) >> > + USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT_SHIFT; > +} > + > +/* 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); > + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, > + int_ena & ~USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA_MASK); > +} > + > +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_MASK); > +} > + > +static void esp32s3_acm_put_char(struct uart_port *port, unsigned char c) > +{ > + esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_REG, c); > +} > + > +static void esp32s3_acm_put_char_sync(struct uart_port *port, unsigned char c) > +{ > + while (!esp32s3_acm_tx_fifo_free(port)) > + cpu_relax(); > + esp32s3_acm_put_char(port, c); > + esp32s3_acm_push(port); > +} > + > +static void esp32s3_acm_transmit_buffer(struct uart_port *port) > +{ > + struct circ_buf *xmit = &port->state->xmit; > + u32 tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port); > + > + if (esp32s3_acm_tx_fifo_free(port)) { > + while (!uart_circ_empty(xmit) && tx_fifo_used < ESP32S3_ACM_TX_FIFO_SIZE) { > + esp32s3_acm_put_char(port, xmit->buf[xmit->tail]); > + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); > + port->icount.tx++; > + ++tx_fifo_used; > + } > + } > + > + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) > + uart_write_wakeup(port); > + > + if (uart_circ_empty(xmit)) { > + esp32s3_acm_stop_tx(port); > + } else { > + u32 int_ena; > + > + int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); > + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, > + int_ena | USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA_MASK); > + } > + > + if (tx_fifo_used > 0 && tx_fifo_used < ESP32S3_ACM_TX_FIFO_SIZE) > + esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG, > + USB_SERIAL_JTAG_WR_DONE_MASK); > +} > + > +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_MASK) > + esp32s3_acm_rxint(port); > + if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST_MASK) > + esp32s3_acm_txint(port); > + > + return IRQ_HANDLED; > +} > + > +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); > + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, > + int_ena & ~USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA_MASK); > +} > + > +static int esp32s3_acm_startup(struct uart_port *port) > +{ > + int ret = 0; > + > + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, > + USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA_MASK); > + ret = devm_request_irq(port->dev, port->irq, esp32s3_acm_int, 0, > + DRIVER_NAME, port); > + return ret; > +} > + > +static void esp32s3_acm_shutdown(struct uart_port *port) > +{ > + esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, 0); > + devm_free_irq(port->dev, 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_ESP32ACM; > +} > + > +#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_console_putchar(struct uart_port *port, unsigned char c) > +{ > + esp32s3_acm_put_char_sync(port, c); > +} > + > +static void esp32s3_acm_string_write(struct uart_port *port, const char *s, > + unsigned int count) > +{ > + uart_console_write(port, s, count, esp32s3_acm_console_putchar); > +} > + > +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; > + int locked = 1; > + > + if (port->sysrq) > + locked = 0; > + 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_putchar(struct uart_port *port, unsigned char c) > +{ > + esp32s3_acm_put_char_sync(port, c); > +} > + > +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_earlycon_putchar); > +} > + > +#ifdef CONFIG_CONSOLE_POLL > +static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n) > +{ > + struct earlycon_device *dev = con->data; > + 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_ESP32ACM; > + 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); > + > + ret = uart_add_one_port(&esp32s3_acm_reg, port); > + return ret; > +} > + > +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_DESCRIPTION("Espressif ESP32S3 USB ACM driver."); > +MODULE_AUTHOR("Max Filippov <jcmvbkbc@xxxxxxxxx>"); > +MODULE_LICENSE("GPL"); > diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h > index ff076d6be159..1045bf096837 100644 > --- a/include/uapi/linux/serial_core.h > +++ b/include/uapi/linux/serial_core.h > @@ -248,4 +248,7 @@ > /* Espressif ESP32 UART */ > #define PORT_ESP32UART 124 > > +/* Espressif ESP32 ACM */ > +#define PORT_ESP32ACM 125 > + > #endif /* _UAPILINUX_SERIAL_CORE_H */ >
