write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/drivers/tty/serial/mvebu-uart.c
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@@ -73,6 +73,7 @@
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 #define UART_OSAMP		0x14
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 #define  OSAMP_DEFAULT_DIVISOR	16
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+#define  OSAMP_DIVISORS_MASK	0x3F3F3F3F
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 #define MVEBU_NR_UARTS		2
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@@ -237,6 +238,7 @@
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 	struct tty_port *tport = &port->state->port;
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 	unsigned char ch = 0;
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 	char flag = 0;
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+	int ret;
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 	do {
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 		if (status & STAT_RX_RDY(port)) {
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@@ -247,6 +249,16 @@
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 			if (status & STAT_PAR_ERR)
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 				port->icount.parity++;
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+		}
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+
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+		/*
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+		 * For UART2, error bits are not cleared on buffer read.
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+		 * This causes interrupt loop and system hang.
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+		 */
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+		if (IS_EXTENDED(port) && (status & STAT_BRK_ERR)) {
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+			ret = readl(port->membase + UART_STAT);
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+			ret |= STAT_BRK_ERR;
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+			writel(ret, port->membase + UART_STAT);
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 		}
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 		if (status & STAT_BRK_DET) {
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@@ -442,14 +454,13 @@
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 	}
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 }
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-static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
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+static unsigned int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
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 {
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-	struct mvebu_uart *mvuart = to_mvuart(port);
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 	unsigned int d_divisor, m_divisor;
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-	u32 brdv;
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+	u32 brdv, osamp;
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-	if (IS_ERR(mvuart->clk))
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-		return -PTR_ERR(mvuart->clk);
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+	if (!port->uartclk)
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+		return 0;
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 	/*
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 	 * The baudrate is derived from the UART clock thanks to two divisors:
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@@ -469,7 +480,11 @@
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 	brdv |= d_divisor;
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 	writel(brdv, port->membase + UART_BRDV);
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-	return 0;
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+	osamp = readl(port->membase + UART_OSAMP);
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+	osamp &= ~OSAMP_DIVISORS_MASK;
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+	writel(osamp, port->membase + UART_OSAMP);
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+
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+	return DIV_ROUND_CLOSEST(port->uartclk, d_divisor * m_divisor);
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 }
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 static void mvebu_uart_set_termios(struct uart_port *port,
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@@ -506,15 +521,11 @@
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 	max_baud = 230400;
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 	baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud);
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-	if (mvebu_uart_baud_rate_set(port, baud)) {
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-		/* No clock available, baudrate cannot be changed */
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-		if (old)
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-			baud = uart_get_baud_rate(port, old, NULL,
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-						  min_baud, max_baud);
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-	} else {
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-		tty_termios_encode_baud_rate(termios, baud, baud);
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-		uart_update_timeout(port, termios->c_cflag, baud);
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-	}
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+	baud = mvebu_uart_baud_rate_set(port, baud);
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+
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+	/* In case baudrate cannot be changed, report previous old value */
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+	if (baud == 0 && old)
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+		baud = tty_termios_baud_rate(old);
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 	/* Only the following flag changes are supported */
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 	if (old) {
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@@ -523,6 +534,11 @@
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 		termios->c_cflag &= CREAD | CBAUD;
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 		termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD);
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 		termios->c_cflag |= CS8;
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+	}
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+
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+	if (baud != 0) {
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+		tty_termios_encode_baud_rate(termios, baud, baud);
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+		uart_update_timeout(port, termios->c_cflag, baud);
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 	}
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 	spin_unlock_irqrestore(&port->lock, flags);
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@@ -811,7 +827,7 @@
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 							   &pdev->dev);
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 	struct uart_port *port;
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 	struct mvebu_uart *mvuart;
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-	int ret, id, irq;
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+	int id, irq;
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 	if (!reg) {
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 		dev_err(&pdev->dev, "no registers defined\n");
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@@ -889,10 +905,8 @@
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 	if (platform_irq_count(pdev) == 1) {
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 		/* Old bindings: no name on the single unamed UART0 IRQ */
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 		irq = platform_get_irq(pdev, 0);
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-		if (irq < 0) {
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-			dev_err(&pdev->dev, "unable to get UART IRQ\n");
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+		if (irq < 0)
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 			return irq;
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-		}
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 		mvuart->irq[UART_IRQ_SUM] = irq;
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 	} else {
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@@ -902,18 +916,14 @@
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 		 * uart-sum of UART0 port.
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 		 */
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 		irq = platform_get_irq_byname(pdev, "uart-rx");
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-		if (irq < 0) {
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-			dev_err(&pdev->dev, "unable to get 'uart-rx' IRQ\n");
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+		if (irq < 0)
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 			return irq;
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-		}
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 		mvuart->irq[UART_RX_IRQ] = irq;
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 		irq = platform_get_irq_byname(pdev, "uart-tx");
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-		if (irq < 0) {
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-			dev_err(&pdev->dev, "unable to get 'uart-tx' IRQ\n");
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+		if (irq < 0)
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 			return irq;
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-		}
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 		mvuart->irq[UART_TX_IRQ] = irq;
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 	}
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@@ -923,10 +933,7 @@
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 	udelay(1);
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 	writel(0, port->membase + UART_CTRL(port));
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-	ret = uart_add_one_port(&mvebu_uart_driver, port);
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-	if (ret)
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-		return ret;
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-	return 0;
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+	return uart_add_one_port(&mvebu_uart_driver, port);
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 }
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 static struct mvebu_uart_driver_data uart_std_driver_data = {