On 20. 09. 23, 4:26, Max Filippov wrote:
Add driver for the UART controllers of the Espressif ESP32 and ESP32S3
SoCs. Hardware specification is available at the following URLs:
...
+static void esp32_uart_rxint(struct uart_port *port)
+{
+ struct tty_port *tty_port = &port->state->port;
+ u32 rx_fifo_cnt = esp32_uart_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 = esp32_uart_read(port, UART_FIFO_REG);
+ u32 brk = 0;
+
+ ++port->icount.rx;
Should yuou increment this only in case of insert_flip_char()?
+ if (!rx) {
+ brk = esp32_uart_read(port, UART_INT_ST_REG) &
+ UART_BRK_DET_INT;
+ }
+ if (brk) {
+ esp32_uart_write(port, UART_INT_CLR_REG, brk);
+ ++port->icount.brk;
+ uart_handle_break(port);
+ } else {
+ if (uart_handle_sysrq_char(port, (unsigned char)rx))
+ continue;
+ tty_insert_flip_char(tty_port, rx, TTY_NORMAL);
+ }
This is heavy. Is it equivalent to:
if (!rx && esp32_uart_read(port, UART_INT_ST_REG) &
UART_BRK_DET_INT) {
esp32_uart_write(port, UART_INT_CLR_REG, brk);
++port->icount.brk;
uart_handle_break(port);
continue;
}
if (uart_handle_sysrq_char(port, (unsigned char)rx))
continue;
tty_insert_flip_char(tty_port, rx, TTY_NORMAL);
?
+ }
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ tty_flip_buffer_push(tty_port);
+}
...
+static void esp32_uart_put_char_sync(struct uart_port *port, u8 c)
+{
+ unsigned long timeout;
+
+ timeout = jiffies + msecs_to_jiffies(1000);
I.e. plus HZ?
+ while (esp32_uart_tx_fifo_cnt(port) >= ESP32_UART_TX_FIFO_SIZE) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(port->dev, "timeout waiting for TX FIFO\n");
+ return;
+ }
+ cpu_relax();
+ }
+ esp32_uart_put_char(port, c);
+}
+
+static void esp32_uart_transmit_buffer(struct uart_port *port)
+{
+ u32 tx_fifo_used = esp32_uart_tx_fifo_cnt(port);
+
+ if (tx_fifo_used < ESP32_UART_TX_FIFO_SIZE) {
Invert the condition and return here?
+ unsigned int pending;
+ u8 ch;
+
+ pending = uart_port_tx_limited(port, ch,
+ ESP32_UART_TX_FIFO_SIZE - tx_fifo_used,
+ true, esp32_uart_put_char(port, ch),
+ ({}));
+ if (pending) {
+ u32 int_ena;
+
+ int_ena = esp32_uart_read(port, UART_INT_ENA_REG);
+ int_ena |= UART_TXFIFO_EMPTY_INT;
+ esp32_uart_write(port, UART_INT_ENA_REG, int_ena);
+ }
+ }
+}
+static irqreturn_t esp32_uart_int(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ u32 status;
+
+ status = esp32_uart_read(port, UART_INT_ST_REG);
+
+ if (status & (UART_RXFIFO_FULL_INT | UART_BRK_DET_INT))
+ esp32_uart_rxint(port);
+ if (status & UART_TXFIFO_EMPTY_INT)
+ esp32_uart_txint(port);
+
+ esp32_uart_write(port, UART_INT_CLR_REG, status);
\n here please.
+ return IRQ_RETVAL(status);
+}
+static int esp32_uart_startup(struct uart_port *port)
+{
+ int ret = 0;
+ unsigned long flags;
+ struct esp32_port *sport = container_of(port, struct esp32_port, port);
+
+ ret = clk_prepare_enable(sport->clk);
+ if (ret)
+ return ret;
+
+ ret = devm_request_irq(port->dev, port->irq, esp32_uart_int, 0,
+ DRIVER_NAME, port);
+ if (ret) {
+ clk_disable_unprepare(sport->clk);
+ return ret;
+ }
+
+ spin_lock_irqsave(&port->lock, flags);
+ esp32_uart_write(port, UART_CONF1_REG,
+ (1 << UART_RXFIFO_FULL_THRHD_SHIFT) |
BIT() ?
+ (1 << port_variant(port)->txfifo_empty_thrhd_shift));
And here?
+ esp32_uart_write(port, UART_INT_CLR_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT);
+ esp32_uart_write(port, UART_INT_ENA_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ pr_debug("%s, conf1 = %08x, int_st = %08x, status = %08x\n",
+ __func__,
+ esp32_uart_read(port, UART_CONF1_REG),
+ esp32_uart_read(port, UART_INT_ST_REG),
+ esp32_uart_read(port, UART_STATUS_REG));
\n here. Is this debug printout somehow useful?
+ return ret;
+}
+
+static void esp32_uart_shutdown(struct uart_port *port)
+{
+ struct esp32_port *sport = container_of(port, struct esp32_port, port);
+
+ esp32_uart_write(port, UART_INT_ENA_REG, 0);
+ devm_free_irq(port->dev, port->irq, port);
I wonder why to use devm_ after all?
+ clk_disable_unprepare(sport->clk);
+}
+
+static bool esp32_uart_set_baud(struct uart_port *port, u32 baud)
+{
+ u32 div = port->uartclk / baud;
+ u32 frag = (port->uartclk * 16) / baud - div * 16;
+
+ if (div <= port_variant(port)->clkdiv_mask) {
+ esp32_uart_write(port, UART_CLKDIV_REG,
+ div | FIELD_PREP(UART_CLKDIV_FRAG, frag));
+ return true;
+ }
\n
+ return false;
+}
...
+static int __init esp32s3_uart_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ device->port.private_data = (void *)&esp32s3_variant;
No need to cast, right?
\n
+ return esp32xx_uart_early_console_setup(device, options);
+}
...
+static int esp32_uart_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ static const struct of_device_id *match;
+ struct uart_port *port;
+ struct esp32_port *sport;
+ struct resource *res;
+ int ret;
+
+ match = of_match_device(esp32_uart_dt_ids, &pdev->dev);
+ if (!match)
+ return -ENODEV;
+
+ sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
+ if (!sport)
+ return -ENOMEM;
+
+ port = &sport->port;
+
+ 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);
+
+ sport->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(sport->clk))
+ return PTR_ERR(sport->clk);
+
+ port->uartclk = clk_get_rate(sport->clk);
+ port->dev = &pdev->dev;
+ port->type = PORT_ESP32UART;
+ port->iotype = UPIO_MEM;
+ port->irq = platform_get_irq(pdev, 0);
+ port->ops = &esp32_uart_pops;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->has_sysrq = 1;
+ port->fifosize = ESP32_UART_TX_FIFO_SIZE;
+ port->private_data = (void *)match->data;
No need to cast.
+
+ esp32_uart_ports[port->line] = sport;
+
+ platform_set_drvdata(pdev, port);
+
+ return uart_add_one_port(&esp32_uart_reg, port);
+}
regards,
--
js
suse labs
