From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB
---
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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