460 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2 3#include <linux/bitfield.h>4#include <linux/bits.h>5#include <linux/console.h>6#include <linux/delay.h>7#include <linux/io.h>8#include <linux/irq.h>9#include <linux/module.h>10#include <linux/of.h>11#include <linux/platform_device.h>12#include <linux/serial_core.h>13#include <linux/slab.h>14#include <linux/tty_flip.h>15#include <asm/serial.h>16 17#define DRIVER_NAME "esp32s3-acm"18#define DEV_NAME "ttyGS"19#define UART_NR 420 21#define ESP32S3_ACM_TX_FIFO_SIZE 6422 23#define USB_SERIAL_JTAG_EP1_REG 0x0024#define USB_SERIAL_JTAG_EP1_CONF_REG 0x0425#define USB_SERIAL_JTAG_WR_DONE BIT(0)26#define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE BIT(1)27#define USB_SERIAL_JTAG_INT_ST_REG 0x0c28#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST BIT(2)29#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST BIT(3)30#define USB_SERIAL_JTAG_INT_ENA_REG 0x1031#define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA BIT(2)32#define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA BIT(3)33#define USB_SERIAL_JTAG_INT_CLR_REG 0x1434#define USB_SERIAL_JTAG_IN_EP1_ST_REG 0x2c35#define USB_SERIAL_JTAG_IN_EP1_WR_ADDR GENMASK(8, 2)36#define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c37#define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT GENMASK(22, 16)38 39static const struct of_device_id esp32s3_acm_dt_ids[] = {40 {41 .compatible = "esp,esp32s3-acm",42 }, { /* sentinel */ }43};44MODULE_DEVICE_TABLE(of, esp32s3_acm_dt_ids);45 46static struct uart_port *esp32s3_acm_ports[UART_NR];47 48static void esp32s3_acm_write(struct uart_port *port, unsigned long reg, u32 v)49{50 writel(v, port->membase + reg);51}52 53static u32 esp32s3_acm_read(struct uart_port *port, unsigned long reg)54{55 return readl(port->membase + reg);56}57 58static u32 esp32s3_acm_tx_fifo_free(struct uart_port *port)59{60 u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG);61 62 return status & USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE;63}64 65static u32 esp32s3_acm_tx_fifo_cnt(struct uart_port *port)66{67 u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_IN_EP1_ST_REG);68 69 return FIELD_GET(USB_SERIAL_JTAG_IN_EP1_WR_ADDR, status);70}71 72static u32 esp32s3_acm_rx_fifo_cnt(struct uart_port *port)73{74 u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_OUT_EP1_ST_REG);75 76 return FIELD_GET(USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT, status);77}78 79/* return TIOCSER_TEMT when transmitter is not busy */80static unsigned int esp32s3_acm_tx_empty(struct uart_port *port)81{82 return esp32s3_acm_tx_fifo_cnt(port) == 0 ? TIOCSER_TEMT : 0;83}84 85static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl)86{87}88 89static unsigned int esp32s3_acm_get_mctrl(struct uart_port *port)90{91 return TIOCM_CAR;92}93 94static void esp32s3_acm_stop_tx(struct uart_port *port)95{96 u32 int_ena;97 98 int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);99 int_ena &= ~USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA;100 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);101}102 103static void esp32s3_acm_rxint(struct uart_port *port)104{105 struct tty_port *tty_port = &port->state->port;106 u32 rx_fifo_cnt = esp32s3_acm_rx_fifo_cnt(port);107 unsigned long flags;108 u32 i;109 110 if (!rx_fifo_cnt)111 return;112 113 spin_lock_irqsave(&port->lock, flags);114 115 for (i = 0; i < rx_fifo_cnt; ++i) {116 u32 rx = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG);117 118 ++port->icount.rx;119 tty_insert_flip_char(tty_port, rx, TTY_NORMAL);120 }121 spin_unlock_irqrestore(&port->lock, flags);122 123 tty_flip_buffer_push(tty_port);124}125 126static void esp32s3_acm_push(struct uart_port *port)127{128 if (esp32s3_acm_tx_fifo_free(port))129 esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG,130 USB_SERIAL_JTAG_WR_DONE);131}132 133static void esp32s3_acm_put_char(struct uart_port *port, u8 c)134{135 esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_REG, c);136}137 138static void esp32s3_acm_put_char_sync(struct uart_port *port, u8 c)139{140 unsigned long timeout = jiffies + HZ;141 142 while (!esp32s3_acm_tx_fifo_free(port)) {143 if (time_after(jiffies, timeout)) {144 dev_warn(port->dev, "timeout waiting for TX FIFO\n");145 return;146 }147 cpu_relax();148 }149 esp32s3_acm_put_char(port, c);150 esp32s3_acm_push(port);151}152 153static void esp32s3_acm_transmit_buffer(struct uart_port *port)154{155 u32 tx_fifo_used;156 unsigned int pending;157 u8 ch;158 159 if (!esp32s3_acm_tx_fifo_free(port))160 return;161 162 tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port);163 pending = uart_port_tx_limited(port, ch,164 ESP32S3_ACM_TX_FIFO_SIZE - tx_fifo_used,165 true, esp32s3_acm_put_char(port, ch),166 ({}));167 if (pending) {168 u32 int_ena;169 170 int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);171 int_ena |= USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA;172 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);173 }174 esp32s3_acm_push(port);175}176 177static void esp32s3_acm_txint(struct uart_port *port)178{179 esp32s3_acm_transmit_buffer(port);180}181 182static irqreturn_t esp32s3_acm_int(int irq, void *dev_id)183{184 struct uart_port *port = dev_id;185 u32 status;186 187 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ST_REG);188 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_CLR_REG, status);189 190 if (status & USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST)191 esp32s3_acm_rxint(port);192 if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST)193 esp32s3_acm_txint(port);194 195 return IRQ_RETVAL(status);196}197 198static void esp32s3_acm_start_tx(struct uart_port *port)199{200 esp32s3_acm_transmit_buffer(port);201}202 203static void esp32s3_acm_stop_rx(struct uart_port *port)204{205 u32 int_ena;206 207 int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);208 int_ena &= ~USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA;209 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, int_ena);210}211 212static int esp32s3_acm_startup(struct uart_port *port)213{214 int ret;215 216 ret = request_irq(port->irq, esp32s3_acm_int, 0, DRIVER_NAME, port);217 if (ret)218 return ret;219 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG,220 USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA);221 222 return 0;223}224 225static void esp32s3_acm_shutdown(struct uart_port *port)226{227 esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, 0);228 free_irq(port->irq, port);229}230 231static void esp32s3_acm_set_termios(struct uart_port *port,232 struct ktermios *termios,233 const struct ktermios *old)234{235}236 237static const char *esp32s3_acm_type(struct uart_port *port)238{239 return "ESP32S3 ACM";240}241 242/* configure/auto-configure the port */243static void esp32s3_acm_config_port(struct uart_port *port, int flags)244{245 if (flags & UART_CONFIG_TYPE)246 port->type = PORT_GENERIC;247}248 249#ifdef CONFIG_CONSOLE_POLL250static void esp32s3_acm_poll_put_char(struct uart_port *port, unsigned char c)251{252 esp32s3_acm_put_char_sync(port, c);253}254 255static int esp32s3_acm_poll_get_char(struct uart_port *port)256{257 if (esp32s3_acm_rx_fifo_cnt(port))258 return esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG);259 else260 return NO_POLL_CHAR;261}262#endif263 264static const struct uart_ops esp32s3_acm_pops = {265 .tx_empty = esp32s3_acm_tx_empty,266 .set_mctrl = esp32s3_acm_set_mctrl,267 .get_mctrl = esp32s3_acm_get_mctrl,268 .stop_tx = esp32s3_acm_stop_tx,269 .start_tx = esp32s3_acm_start_tx,270 .stop_rx = esp32s3_acm_stop_rx,271 .startup = esp32s3_acm_startup,272 .shutdown = esp32s3_acm_shutdown,273 .set_termios = esp32s3_acm_set_termios,274 .type = esp32s3_acm_type,275 .config_port = esp32s3_acm_config_port,276#ifdef CONFIG_CONSOLE_POLL277 .poll_put_char = esp32s3_acm_poll_put_char,278 .poll_get_char = esp32s3_acm_poll_get_char,279#endif280};281 282static void esp32s3_acm_string_write(struct uart_port *port, const char *s,283 unsigned int count)284{285 uart_console_write(port, s, count, esp32s3_acm_put_char_sync);286}287 288static void289esp32s3_acm_console_write(struct console *co, const char *s, unsigned int count)290{291 struct uart_port *port = esp32s3_acm_ports[co->index];292 unsigned long flags;293 bool locked = true;294 295 if (port->sysrq)296 locked = false;297 else if (oops_in_progress)298 locked = spin_trylock_irqsave(&port->lock, flags);299 else300 spin_lock_irqsave(&port->lock, flags);301 302 esp32s3_acm_string_write(port, s, count);303 304 if (locked)305 spin_unlock_irqrestore(&port->lock, flags);306}307 308static struct uart_driver esp32s3_acm_reg;309static struct console esp32s3_acm_console = {310 .name = DEV_NAME,311 .write = esp32s3_acm_console_write,312 .device = uart_console_device,313 .flags = CON_PRINTBUFFER,314 .index = -1,315 .data = &esp32s3_acm_reg,316};317 318static void esp32s3_acm_earlycon_write(struct console *con, const char *s,319 unsigned int n)320{321 struct earlycon_device *dev = con->data;322 323 uart_console_write(&dev->port, s, n, esp32s3_acm_put_char_sync);324}325 326#ifdef CONFIG_CONSOLE_POLL327static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n)328{329 struct earlycon_device *dev = con->data;330 unsigned int num_read = 0;331 332 while (num_read < n) {333 int c = esp32s3_acm_poll_get_char(&dev->port);334 335 if (c == NO_POLL_CHAR)336 break;337 s[num_read++] = c;338 }339 return num_read;340}341#endif342 343static int __init esp32s3_acm_early_console_setup(struct earlycon_device *device,344 const char *options)345{346 if (!device->port.membase)347 return -ENODEV;348 349 device->con->write = esp32s3_acm_earlycon_write;350#ifdef CONFIG_CONSOLE_POLL351 device->con->read = esp32s3_acm_earlycon_read;352#endif353 return 0;354}355 356OF_EARLYCON_DECLARE(esp32s3acm, "esp,esp32s3-acm",357 esp32s3_acm_early_console_setup);358 359static struct uart_driver esp32s3_acm_reg = {360 .owner = THIS_MODULE,361 .driver_name = DRIVER_NAME,362 .dev_name = DEV_NAME,363 .nr = ARRAY_SIZE(esp32s3_acm_ports),364 .cons = &esp32s3_acm_console,365};366 367static int esp32s3_acm_probe(struct platform_device *pdev)368{369 struct device_node *np = pdev->dev.of_node;370 struct uart_port *port;371 struct resource *res;372 int ret;373 374 port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);375 if (!port)376 return -ENOMEM;377 378 ret = of_alias_get_id(np, "serial");379 if (ret < 0) {380 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);381 return ret;382 }383 if (ret >= UART_NR) {384 dev_err(&pdev->dev, "driver limited to %d serial ports\n",385 UART_NR);386 return -ENOMEM;387 }388 389 port->line = ret;390 391 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);392 if (!res)393 return -ENODEV;394 395 port->mapbase = res->start;396 port->membase = devm_ioremap_resource(&pdev->dev, res);397 if (IS_ERR(port->membase))398 return PTR_ERR(port->membase);399 400 port->dev = &pdev->dev;401 port->type = PORT_GENERIC;402 port->iotype = UPIO_MEM;403 port->irq = platform_get_irq(pdev, 0);404 port->ops = &esp32s3_acm_pops;405 port->flags = UPF_BOOT_AUTOCONF;406 port->has_sysrq = 1;407 port->fifosize = ESP32S3_ACM_TX_FIFO_SIZE;408 409 esp32s3_acm_ports[port->line] = port;410 411 platform_set_drvdata(pdev, port);412 413 return uart_add_one_port(&esp32s3_acm_reg, port);414}415 416static void esp32s3_acm_remove(struct platform_device *pdev)417{418 struct uart_port *port = platform_get_drvdata(pdev);419 420 uart_remove_one_port(&esp32s3_acm_reg, port);421}422 423 424static struct platform_driver esp32s3_acm_driver = {425 .probe = esp32s3_acm_probe,426 .remove_new = esp32s3_acm_remove,427 .driver = {428 .name = DRIVER_NAME,429 .of_match_table = esp32s3_acm_dt_ids,430 },431};432 433static int __init esp32s3_acm_init(void)434{435 int ret;436 437 ret = uart_register_driver(&esp32s3_acm_reg);438 if (ret)439 return ret;440 441 ret = platform_driver_register(&esp32s3_acm_driver);442 if (ret)443 uart_unregister_driver(&esp32s3_acm_reg);444 445 return ret;446}447 448static void __exit esp32s3_acm_exit(void)449{450 platform_driver_unregister(&esp32s3_acm_driver);451 uart_unregister_driver(&esp32s3_acm_reg);452}453 454module_init(esp32s3_acm_init);455module_exit(esp32s3_acm_exit);456 457MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");458MODULE_DESCRIPTION("Espressif ESP32 USB ACM gadget support");459MODULE_LICENSE("GPL");460