Merge tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here are the big set of tty and serial driver updates for 5.6-rc1

  Included in here are:
   - dummy_con cleanups (touches lots of arch code)
   - sysrq logic cleanups (touches lots of serial drivers)
   - samsung driver fixes (wasn't really being built)
   - conmakeshash move to tty subdir out of scripts
   - lots of small tty/serial driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits)
  tty: n_hdlc: Use flexible-array member and struct_size() helper
  tty: baudrate: SPARC supports few more baud rates
  tty: baudrate: Synchronise baud_table[] and baud_bits[]
  tty: serial: meson_uart: Add support for kernel debugger
  serial: imx: fix a race condition in receive path
  serial: 8250_bcm2835aux: Document struct bcm2835aux_data
  serial: 8250_bcm2835aux: Use generic remapping code
  serial: 8250_bcm2835aux: Allocate uart_8250_port on stack
  serial: 8250_bcm2835aux: Suppress register_port error on -EPROBE_DEFER
  serial: 8250_bcm2835aux: Suppress clk_get error on -EPROBE_DEFER
  serial: 8250_bcm2835aux: Fix line mismatch on driver unbind
  serial_core: Remove unused member in uart_port
  vt: Correct comment documenting do_take_over_console()
  vt: Delete comment referencing non-existent unbind_con_driver()
  arch/xtensa/setup: Drop dummy_con initialization
  arch/x86/setup: Drop dummy_con initialization
  arch/unicore32/setup: Drop dummy_con initialization
  arch/sparc/setup: Drop dummy_con initialization
  arch/sh/setup: Drop dummy_con initialization
  arch/s390/setup: Drop dummy_con initialization
  ...

1 files changed, 18 insertions, 5 deletions

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index f6c45a796433..60a9c53fa7cb 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -7,10 +7,6 @@
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  */
 
-#if defined(CONFIG_SERIAL_MSM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
-# define SUPPORT_SYSRQ
-#endif
-
 #include <linux/kernel.h>
 #include <linux/atomic.h>
 #include <linux/dma-mapping.h>
@@ -610,7 +606,7 @@ static void msm_start_rx_dma(struct msm_port *msm_port)
 				   UARTDM_RX_SIZE, dma->dir);
 	ret = dma_mapping_error(uart->dev, dma->phys);
 	if (ret)
-		return;
+		goto sw_mode;
 
 	dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 						UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
@@ -661,6 +657,22 @@ static void msm_start_rx_dma(struct msm_port *msm_port)
 	return;
 unmap:
 	dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
+
+sw_mode:
+	/*
+	 * Switch from DMA to SW/FIFO mode. After clearing Rx BAM (UARTDM_DMEN),
+	 * receiver must be reset.
+	 */
+	msm_write(uart, UART_CR_CMD_RESET_RX, UART_CR);
+	msm_write(uart, UART_CR_RX_ENABLE, UART_CR);
+
+	msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
+	msm_write(uart, 0xFFFFFF, UARTDM_DMRX);
+	msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+
+	/* Re-enable RX interrupts */
+	msm_port->imr |= (UART_IMR_RXLEV | UART_IMR_RXSTALE);
+	msm_write(uart, msm_port->imr, UART_IMR);
 }
 
 static void msm_stop_rx(struct uart_port *port)
@@ -1810,6 +1822,7 @@ static int msm_serial_probe(struct platform_device *pdev)
 	if (unlikely(irq < 0))
 		return -ENXIO;
 	port->irq = irq;
+	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MSM_CONSOLE);
 
 	platform_set_drvdata(pdev, port);