From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198

---
 kernel/drivers/tty/serial/fsl_lpuart.c |   90 ++++++++++++++++++++++++++++++--------------
 1 files changed, 61 insertions(+), 29 deletions(-)

diff --git a/kernel/drivers/tty/serial/fsl_lpuart.c b/kernel/drivers/tty/serial/fsl_lpuart.c
index 43aca5a..227fb2d 100644
--- a/kernel/drivers/tty/serial/fsl_lpuart.c
+++ b/kernel/drivers/tty/serial/fsl_lpuart.c
@@ -809,11 +809,17 @@
 			struct lpuart_port, port);
 	unsigned long stat = lpuart32_read(port, UARTSTAT);
 	unsigned long sfifo = lpuart32_read(port, UARTFIFO);
+	unsigned long ctrl = lpuart32_read(port, UARTCTRL);
 
 	if (sport->dma_tx_in_progress)
 		return 0;
 
-	if (stat & UARTSTAT_TC && sfifo & UARTFIFO_TXEMPT)
+	/*
+	 * LPUART Transmission Complete Flag may never be set while queuing a break
+	 * character, so avoid checking for transmission complete when UARTCTRL_SBK
+	 * is asserted.
+	 */
+	if ((stat & UARTSTAT_TC && sfifo & UARTFIFO_TXEMPT) || ctrl & UARTCTRL_SBK)
 		return TIOCSER_TEMT;
 
 	return 0;
@@ -1056,8 +1062,8 @@
 		unsigned long sr = lpuart32_read(&sport->port, UARTSTAT);
 
 		if (sr & (UARTSTAT_PE | UARTSTAT_FE)) {
-			/* Read DR to clear the error flags */
-			lpuart32_read(&sport->port, UARTDATA);
+			/* Clear the error flags */
+			lpuart32_write(&sport->port, sr, UARTSTAT);
 
 			if (sr & UARTSTAT_PE)
 				sport->port.icount.parity++;
@@ -1214,7 +1220,7 @@
 	 * 10ms at any baud rate.
 	 */
 	sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud /  bits / 1000) * 2;
-	sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
+	sport->rx_dma_rng_buf_len = (1 << fls(sport->rx_dma_rng_buf_len));
 	if (sport->rx_dma_rng_buf_len < 16)
 		sport->rx_dma_rng_buf_len = 16;
 
@@ -1278,6 +1284,7 @@
 	struct dma_chan *chan = sport->dma_rx_chan;
 
 	dmaengine_terminate_all(chan);
+	del_timer_sync(&sport->lpuart_timer);
 	dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
 	kfree(sport->rx_ring.buf);
 	sport->rx_ring.tail = 0;
@@ -1450,12 +1457,34 @@
 {
 	unsigned long temp;
 
-	temp = lpuart32_read(port, UARTCTRL) & ~UARTCTRL_SBK;
+	temp = lpuart32_read(port, UARTCTRL);
 
-	if (break_state != 0)
-		temp |= UARTCTRL_SBK;
-
-	lpuart32_write(port, temp, UARTCTRL);
+	/*
+	 * LPUART IP now has two known bugs, one is CTS has higher priority than the
+	 * break signal, which causes the break signal sending through UARTCTRL_SBK
+	 * may impacted by the CTS input if the HW flow control is enabled. It
+	 * exists on all platforms we support in this driver.
+	 * Another bug is i.MX8QM LPUART may have an additional break character
+	 * being sent after SBK was cleared.
+	 * To avoid above two bugs, we use Transmit Data Inversion function to send
+	 * the break signal instead of UARTCTRL_SBK.
+	 */
+	if (break_state != 0) {
+		/*
+		 * Disable the transmitter to prevent any data from being sent out
+		 * during break, then invert the TX line to send break.
+		 */
+		temp &= ~UARTCTRL_TE;
+		lpuart32_write(port, temp, UARTCTRL);
+		temp |= UARTCTRL_TXINV;
+		lpuart32_write(port, temp, UARTCTRL);
+	} else {
+		/* Disable the TXINV to turn off break and re-enable transmitter. */
+		temp &= ~UARTCTRL_TXINV;
+		lpuart32_write(port, temp, UARTCTRL);
+		temp |= UARTCTRL_TE;
+		lpuart32_write(port, temp, UARTCTRL);
+	}
 }
 
 static void lpuart_setup_watermark(struct lpuart_port *sport)
@@ -1723,7 +1752,6 @@
 static void lpuart_dma_shutdown(struct lpuart_port *sport)
 {
 	if (sport->lpuart_dma_rx_use) {
-		del_timer_sync(&sport->lpuart_timer);
 		lpuart_dma_rx_free(&sport->port);
 		sport->lpuart_dma_rx_use = false;
 	}
@@ -1874,10 +1902,8 @@
 	 * Since timer function acqures sport->port.lock, need to stop before
 	 * acquring same lock because otherwise del_timer_sync() can deadlock.
 	 */
-	if (old && sport->lpuart_dma_rx_use) {
-		del_timer_sync(&sport->lpuart_timer);
+	if (old && sport->lpuart_dma_rx_use)
 		lpuart_dma_rx_free(&sport->port);
-	}
 
 	spin_lock_irqsave(&sport->port.lock, flags);
 
@@ -2109,10 +2135,8 @@
 	 * Since timer function acqures sport->port.lock, need to stop before
 	 * acquring same lock because otherwise del_timer_sync() can deadlock.
 	 */
-	if (old && sport->lpuart_dma_rx_use) {
-		del_timer_sync(&sport->lpuart_timer);
+	if (old && sport->lpuart_dma_rx_use)
 		lpuart_dma_rx_free(&sport->port);
-	}
 
 	spin_lock_irqsave(&sport->port.lock, flags);
 
@@ -2139,9 +2163,15 @@
 	/* update the per-port timeout */
 	uart_update_timeout(port, termios->c_cflag, baud);
 
-	/* wait transmit engin complete */
-	lpuart32_write(&sport->port, 0, UARTMODIR);
-	lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
+	/*
+	 * LPUART Transmission Complete Flag may never be set while queuing a break
+	 * character, so skip waiting for transmission complete when UARTCTRL_SBK is
+	 * asserted.
+	 */
+	if (!(old_ctrl & UARTCTRL_SBK)) {
+		lpuart32_write(&sport->port, 0, UARTMODIR);
+		lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
+	}
 
 	/* disable transmit and receive */
 	lpuart32_write(&sport->port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE),
@@ -2559,6 +2589,7 @@
 OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup);
 OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1028a-lpuart", ls1028a_early_console_setup);
 OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
+OF_EARLYCON_DECLARE(lpuart32, "fsl,imx8ulp-lpuart", lpuart32_imx_early_console_setup);
 OF_EARLYCON_DECLARE(lpuart32, "fsl,imx8qxp-lpuart", lpuart32_imx_early_console_setup);
 EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
 EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);
@@ -2586,6 +2617,7 @@
 	struct device_node *np = pdev->dev.of_node;
 	struct lpuart_port *sport;
 	struct resource *res;
+	irq_handler_t handler;
 	int ret;
 
 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
@@ -2658,16 +2690,11 @@
 
 	if (lpuart_is_32(sport)) {
 		lpuart_reg.cons = LPUART32_CONSOLE;
-		ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart32_int, 0,
-					DRIVER_NAME, sport);
+		handler = lpuart32_int;
 	} else {
 		lpuart_reg.cons = LPUART_CONSOLE;
-		ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart_int, 0,
-					DRIVER_NAME, sport);
+		handler = lpuart_int;
 	}
-
-	if (ret)
-		goto failed_irq_request;
 
 	ret = uart_get_rs485_mode(&sport->port);
 	if (ret)
@@ -2684,11 +2711,17 @@
 	if (ret)
 		goto failed_attach_port;
 
+	ret = devm_request_irq(&pdev->dev, sport->port.irq, handler, 0,
+				DRIVER_NAME, sport);
+	if (ret)
+		goto failed_irq_request;
+
 	return 0;
 
+failed_irq_request:
+	uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_get_rs485:
 failed_attach_port:
-failed_irq_request:
 	lpuart_disable_clks(sport);
 	return ret;
 }
@@ -2738,11 +2771,10 @@
 		 * EDMA driver during suspend will forcefully release any
 		 * non-idle DMA channels. If port wakeup is enabled or if port
 		 * is console port or 'no_console_suspend' is set the Rx DMA
-		 * cannot resume as as expected, hence gracefully release the
+		 * cannot resume as expected, hence gracefully release the
 		 * Rx DMA path before suspend and start Rx DMA path on resume.
 		 */
 		if (irq_wake) {
-			del_timer_sync(&sport->lpuart_timer);
 			lpuart_dma_rx_free(&sport->port);
 		}
 

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