Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index df90747..23b7bda 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -240,8 +240,8 @@
 		 * cleared by the sequence [read SR - read DR].
 		 */
 		if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
-			stm32_clr_bits(port, ofs->icr, USART_ICR_ORECF |
-				       USART_ICR_PECF | USART_ICR_FECF);
+			writel_relaxed(sr & USART_SR_ERR_MASK,
+				       port->membase + ofs->icr);
 
 		c = stm32_get_char(port, &sr, &stm32_port->last_res);
 		port->icount.rx++;
@@ -435,7 +435,7 @@
 	if (ofs->icr == UNDEF_REG)
 		stm32_clr_bits(port, ofs->isr, USART_SR_TC);
 	else
-		stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);
+		writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
 
 	if (stm32_port->tx_ch)
 		stm32_transmit_chars_dma(port);
@@ -502,7 +502,10 @@
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
-	return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
+	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
+		return TIOCSER_TEMT;
+
+	return 0;
 }
 
 static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -688,8 +691,9 @@
 	unsigned int baud, bits;
 	u32 usartdiv, mantissa, fraction, oversampling;
 	tcflag_t cflag = termios->c_cflag;
-	u32 cr1, cr2, cr3;
+	u32 cr1, cr2, cr3, isr;
 	unsigned long flags;
+	int ret;
 
 	if (!stm32_port->hw_flow_control)
 		cflag &= ~CRTSCTS;
@@ -698,6 +702,15 @@
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
+						isr,
+						(isr & USART_SR_TC),
+						10, 100000);
+
+	/* Send the TC error message only when ISR_TC is not set. */
+	if (ret)
+		dev_err(port->dev, "Transmission is not complete\n");
+
 	/* Stop serial port and reset value */
 	writel_relaxed(0, port->membase + ofs->cr1);
 
@@ -937,7 +950,7 @@
 	stm32_init_rs485(port, pdev);
 
 	if (stm32port->info->cfg.has_wakeup) {
-		stm32port->wakeirq = platform_get_irq(pdev, 1);
+		stm32port->wakeirq = platform_get_irq_optional(pdev, 1);
 		if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
 			return stm32port->wakeirq ? : -ENODEV;
 	}