Merge tag 'tty-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial driver updates from Greg KH: "Here is the big set of tty and serial driver changes for 6.0-rc1. It was delayed from last week as I wanted to make sure the last commit here got some good testing in linux-next and elsewhere as it seemed to show up only late in testing for some reason. Nothing major here, just lots of cleanups from Jiri and Ilpo to make the tty core cleaner (Jiri) and the rs485 code simpler to use (Ilpo). Also included in here is the obligatory n_gsm updates from Daniel Starke and lots of tiny driver updates and minor fixes and tweaks for other smaller serial drivers. All of these have been in linux-next for a while with no reported problems" * tag 'tty-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (186 commits) tty: serial: qcom-geni-serial: Fix %lu -> %u in print statements tty: amiserial: Fix comment typo tty: serial: document uart_get_console() tty: serial: serial_core, reformat kernel-doc for functions Documentation: serial: link uart_ops properly Documentation: serial: move GPIO kernel-doc to the functions Documentation: serial: dedup kernel-doc for uart functions Documentation: serial: move uart_ops documentation to the struct dt-bindings: serial: snps-dw-apb-uart: Document Rockchip RV1126 serial: mvebu-uart: uart2 error bits clearing tty: serial: fsl_lpuart: correct the count of break characters serial: stm32: make info structs static to avoid sparse warnings serial: fsl_lpuart: zero out parity bit in CS7 mode tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate. serial: 8250_bcm2835aux: Add missing clk_disable_unprepare() tty: vt: initialize unicode screen buffer serial: remove VR41XX serial driver serial: 8250: lpc18xx: Remove redundant sanity check for RS485 flags serial: 8250_dwlib: remove redundant sanity check for RS485 flags dt_bindings: rs485: Correct delay values ...
2026-01-06 11:08:10 -08:00 · 2022-08-08 11:31:40 -07:00
parent 1daf117f1d 0fec518018
commit 607ca0f742
97 changed files with 3344 additions and 3188 deletions
--- a/Documentation/devicetree/bindings/serial/8250.yaml
+++ b/Documentation/devicetree/bindings/serial/8250.yaml
@@ -62,6 +62,7 @@ properties:
      - const: mrvl,pxa-uart
      - const: nuvoton,wpcm450-uart
      - const: nuvoton,npcm750-uart
+      - const: nuvoton,npcm845-uart
      - const: nvidia,tegra20-uart
      - const: nxp,lpc3220-uart
      - items:
--- a/Documentation/devicetree/bindings/serial/mediatek,uart.yaml
+++ b/Documentation/devicetree/bindings/serial/mediatek,uart.yaml
@@ -0,0 +1,120 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/mediatek,uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek Universal Asynchronous Receiver/Transmitter (UART)
+
+maintainers:
+  - Matthias Brugger <matthias.bgg@gmail.com>
+
+allOf:
+  - $ref: serial.yaml#
+
+description: |
+  The MediaTek UART is based on the basic 8250 UART and compatible
+  with 16550A, with enhancements for high speed baud rates and
+  support for DMA.
+
+properties:
+  compatible:
+    oneOf:
+      - const: mediatek,mt6577-uart
+      - items:
+          - enum:
+              - mediatek,mt2701-uart
+              - mediatek,mt2712-uart
+              - mediatek,mt6580-uart
+              - mediatek,mt6582-uart
+              - mediatek,mt6589-uart
+              - mediatek,mt6755-uart
+              - mediatek,mt6765-uart
+              - mediatek,mt6779-uart
+              - mediatek,mt6795-uart
+              - mediatek,mt6797-uart
+              - mediatek,mt7622-uart
+              - mediatek,mt7623-uart
+              - mediatek,mt7629-uart
+              - mediatek,mt7986-uart
+              - mediatek,mt8127-uart
+              - mediatek,mt8135-uart
+              - mediatek,mt8173-uart
+              - mediatek,mt8183-uart
+              - mediatek,mt8186-uart
+              - mediatek,mt8192-uart
+              - mediatek,mt8195-uart
+              - mediatek,mt8516-uart
+          - const: mediatek,mt6577-uart
+
+  reg:
+    description: The base address of the UART register bank
+    maxItems: 1
+
+  clocks:
+    minItems: 1
+    items:
+      - description: The clock the baudrate is derived from
+      - description: The bus clock for register accesses
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: baud
+      - const: bus
+
+  dmas:
+    items:
+      - description: phandle to TX DMA
+      - description: phandle to RX DMA
+
+  dma-names:
+    items:
+      - const: tx
+      - const: rx
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+
+  interrupt-names:
+    description:
+      The UART interrupt and optionally the RX in-band wakeup interrupt.
+    minItems: 1
+    items:
+      - const: uart
+      - const: wakeup
+
+  pinctrl-0: true
+  pinctrl-1: true
+
+  pinctrl-names:
+    minItems: 1
+    items:
+      - const: default
+      - const: sleep
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    serial@11006000 {
+        compatible = "mediatek,mt6589-uart", "mediatek,mt6577-uart";
+        reg = <0x11006000 0x400>;
+        interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>,
+                     <GIC_SPI 52 IRQ_TYPE_EDGE_FALLING>;
+        interrupt-names = "uart", "wakeup";
+        clocks = <&uart_clk>, <&bus_clk>;
+        clock-names = "baud", "bus";
+        pinctrl-0 = <&uart_pin>;
+        pinctrl-1 = <&uart_pin_sleep>;
+        pinctrl-names = "default", "sleep";
+    };
--- a/Documentation/devicetree/bindings/serial/mtk-uart.txt
+++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
@@ -1,59 +0,0 @@
-* MediaTek Universal Asynchronous Receiver/Transmitter (UART)
-
-Required properties:
- compatible should contain:
-  * "mediatek,mt2701-uart" for MT2701 compatible UARTS
-  * "mediatek,mt2712-uart" for MT2712 compatible UARTS
-  * "mediatek,mt6580-uart" for MT6580 compatible UARTS
-  * "mediatek,mt6582-uart" for MT6582 compatible UARTS
-  * "mediatek,mt6589-uart" for MT6589 compatible UARTS
-  * "mediatek,mt6755-uart" for MT6755 compatible UARTS
-  * "mediatek,mt6765-uart" for MT6765 compatible UARTS
-  * "mediatek,mt6779-uart" for MT6779 compatible UARTS
-  * "mediatek,mt6795-uart" for MT6795 compatible UARTS
-  * "mediatek,mt6797-uart" for MT6797 compatible UARTS
-  * "mediatek,mt7622-uart" for MT7622 compatible UARTS
-  * "mediatek,mt7623-uart" for MT7623 compatible UARTS
-  * "mediatek,mt7629-uart" for MT7629 compatible UARTS
-  * "mediatek,mt7986-uart", "mediatek,mt6577-uart" for MT7986 compatible UARTS
-  * "mediatek,mt8127-uart" for MT8127 compatible UARTS
-  * "mediatek,mt8135-uart" for MT8135 compatible UARTS
-  * "mediatek,mt8173-uart" for MT8173 compatible UARTS
-  * "mediatek,mt8183-uart", "mediatek,mt6577-uart" for MT8183 compatible UARTS
-  * "mediatek,mt8186-uart", "mediatek,mt6577-uart" for MT8183 compatible UARTS
-  * "mediatek,mt8192-uart", "mediatek,mt6577-uart" for MT8192 compatible UARTS
-  * "mediatek,mt8195-uart", "mediatek,mt6577-uart" for MT8195 compatible UARTS
-  * "mediatek,mt8516-uart" for MT8516 compatible UARTS
-  * "mediatek,mt6577-uart" for MT6577 and all of the above
-
- reg: The base address of the UART register bank.
-
- interrupts:
-  index 0: an interrupt specifier for the UART controller itself
-  index 1: optional, an interrupt specifier with edge sensitivity on Rx pin to
-           support Rx in-band wake up. If one would like to use this feature,
-           one must create an addtional pinctrl to reconfigure Rx pin to normal
-           GPIO before suspend.
-
- clocks : Must contain an entry for each entry in clock-names.
-  See ../clocks/clock-bindings.txt for details.
- clock-names:
-  - "baud": The clock the baudrate is derived from
-  - "bus": The bus clock for register accesses (optional)
-
-For compatibility with older device trees an unnamed clock is used for the
-baud clock if the baudclk does not exist. Do not use this for new designs.
-
-Example:
-
-	uart0: serial@11006000 {
-		compatible = "mediatek,mt6589-uart", "mediatek,mt6577-uart";
-		reg = <0x11006000 0x400>;
-		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>,
-			     <GIC_SPI 52 IRQ_TYPE_EDGE_FALLING>;
-		clocks = <&uart_clk>, <&bus_clk>;
-		clock-names = "baud", "bus";
-		pinctrl-names = "default", "sleep";
-		pinctrl-0 = <&uart_pin>;
-		pinctrl-1 = <&uart_pin_sleep>;
-	};
--- a/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
+++ b/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
@@ -57,6 +57,7 @@ properties:
      - items:
          - enum:
              - renesas,hscif-r8a779a0     # R-Car V3U
+              - renesas,hscif-r8a779f0     # R-Car S4-8
              - renesas,hscif-r8a779g0     # R-Car V4H
          - const: renesas,rcar-gen4-hscif # R-Car Gen4
          - const: renesas,hscif           # generic HSCIF compatible UART
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -22,12 +22,12 @@ properties:
        - description: Delay between rts signal and beginning of data sent in
            milliseconds. It corresponds to the delay before sending data.
          default: 0
-          maximum: 1000
+          maximum: 100
        - description: Delay between end of data sent and rts signal in milliseconds.
            It corresponds to the delay after sending data and actual release
            of the line.
          default: 0
-          maximum: 1000
+          maximum: 100

  rs485-rts-active-low:
    description: drive RTS low when sending (default is high).
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -33,7 +33,9 @@ properties:
              - rockchip,rk3368-uart
              - rockchip,rk3399-uart
              - rockchip,rk3568-uart
+              - rockchip,rk3588-uart
              - rockchip,rv1108-uart
+              - rockchip,rv1126-uart
          - const: snps,dw-apb-uart
      - items:
          - enum:
--- a/Documentation/driver-api/serial/driver.rst
+++ b/Documentation/driver-api/serial/driver.rst
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -38,10 +38,14 @@ RS485 Serial Communications
   the values given by the device tree.

   Any driver for devices capable of working both as RS232 and RS485 should
-   implement the rs485_config callback in the uart_port structure. The
-   serial_core calls rs485_config to do the device specific part in response
-   to TIOCSRS485 and TIOCGRS485 ioctls (see below). The rs485_config callback
-   receives a pointer to struct serial_rs485.
+   implement the rs485_config callback and provide rs485_supported in the
+   uart_port structure. The serial core calls rs485_config to do the device
+   specific part in response to TIOCSRS485 ioctl (see below). The rs485_config
+   callback receives a pointer to a sanitizated serial_rs485 structure. The
+   serial_rs485 userspace provides is sanitized before calling rs485_config
+   using rs485_supported that indicates what RS485 features the driver supports
+   for the uart_port. TIOCGRS485 ioctl can be used to read back the
+   serial_rs485 structure matching to the current configuration.

 4. Usage from user-level
 ========================
@@ -95,7 +99,31 @@ RS485 Serial Communications
 		/* Error handling. See errno. */
 	}

-5. References
+5. Multipoint Addressing
+========================
+
+   The Linux kernel provides addressing mode for multipoint RS-485 serial
+   communications line. The addressing mode is enabled with SER_RS485_ADDRB
+   flag in serial_rs485. Struct serial_rs485 has two additional flags and
+   fields for enabling receive and destination addresses.
+
+   Address mode flags:
+	- SER_RS485_ADDRB: Enabled addressing mode (sets also ADDRB in termios).
+	- SER_RS485_ADDR_RECV: Receive (filter) address enabled.
+	- SER_RS485_ADDR_DEST: Set destination address.
+
+   Address fields (enabled with corresponding SER_RS485_ADDR_* flag):
+	- addr_recv: Receive address.
+	- addr_dest: Destination address.
+
+   Once a receive address is set, the communication can occur only with the
+   particular device and other peers are filtered out. It is left up to the
+   receiver side to enforce the filtering. Receive address will be cleared
+   if SER_RS485_ADDR_RECV is not set.
+
+   Note: not all devices supporting RS485 support multipoint addressing.
+
+6. References
 =============

 [1]	include/uapi/linux/serial.h
--- a/3
+++ b/3
@@ -19622,8 +19622,9 @@ F:	Documentation/devicetree/bindings/gpio/snps,creg-gpio.txt
 F:	drivers/gpio/gpio-creg-snps.c

 SYNOPSYS DESIGNWARE 8250 UART DRIVER
+M:	Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
 R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
-S:	Maintained
+S:	Supported
 F:	drivers/tty/serial/8250/8250_dw.c
 F:	drivers/tty/serial/8250/8250_dwlib.*
 F:	drivers/tty/serial/8250/8250_lpss.c
--- a/arch/mips/ath79/early_printk.c
+++ b/arch/mips/ath79/early_printk.c
@@ -8,6 +8,7 @@

 #include <linux/io.h>
 #include <linux/errno.h>
+#include <linux/serial.h>
 #include <linux/serial_reg.h>
 #include <asm/addrspace.h>
 #include <asm/setup.h>
@@ -18,38 +19,34 @@

 static void (*_prom_putchar)(char);

-static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
+static inline void prom_putchar_wait(void __iomem *reg, u32 val)
 {
 	u32 t;

 	do {
 		t = __raw_readl(reg);
-		if ((t & mask) == val)
+		if ((t & val) == val)
 			break;
 	} while (1);
 }

-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
-
 static void prom_putchar_ar71xx(char ch)
 {
 	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));

-	prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
+	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
 	__raw_writel((unsigned char)ch, base + UART_TX * 4);
-	prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
+	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
 }

 static void prom_putchar_ar933x(char ch)
 {
 	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));

-	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
-			  AR933X_UART_DATA_TX_CSR);
+	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
 	__raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch,
 		     base + AR933X_UART_DATA_REG);
-	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
-			  AR933X_UART_DATA_TX_CSR);
+	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
 }

 static void prom_putchar_dummy(char ch)
--- a/drivers/accessibility/braille/braille_console.c
+++ b/drivers/accessibility/braille/braille_console.c
@@ -131,7 +131,7 @@ static void vc_refresh(struct vc_data *vc)
 	for (i = 0; i < WIDTH; i++) {
 		u16 glyph = screen_glyph(vc,
 				2 * (vc_x + i) + vc_y * vc->vc_size_row);
-		buf[i] = inverse_translate(vc, glyph, 1);
+		buf[i] = inverse_translate(vc, glyph, true);
 	}
 	braille_write(buf);
 }
--- a/drivers/accessibility/speakup/main.c
+++ b/drivers/accessibility/speakup/main.c
@@ -470,7 +470,7 @@ static u16 get_char(struct vc_data *vc, u16 *pos, u_char *attribs)
 			c |= 0x100;
 		}

-		ch = inverse_translate(vc, c, 1);
+		ch = inverse_translate(vc, c, true);
 		*attribs = (w & 0xff00) >> 8;
 	}
 	return ch;
--- a/drivers/accessibility/speakup/serialio.h
+++ b/drivers/accessibility/speakup/serialio.h
@@ -33,9 +33,8 @@ struct old_serial_port {
 #define NUM_DISABLE_TIMEOUTS 3
 /* buffer timeout in ms */
 #define SPK_TIMEOUT 100
-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

 #define spk_serial_tx_busy() \
-	((inb(speakup_info.port_tts + UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
+	(!uart_lsr_tx_empty(inb(speakup_info.port_tts + UART_LSR)))

 #endif
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1024,6 +1024,7 @@ int __init early_init_dt_scan_chosen_stdout(void)
 	int l;
 	const struct earlycon_id *match;
 	const void *fdt = initial_boot_params;
+	int ret;

 	offset = fdt_path_offset(fdt, "/chosen");
 	if (offset < 0)
@@ -1056,7 +1057,8 @@ int __init early_init_dt_scan_chosen_stdout(void)
 		if (fdt_node_check_compatible(fdt, offset, match->compatible))
 			continue;

-		if (of_setup_earlycon(match, offset, options) == 0)
+		ret = of_setup_earlycon(match, offset, options);
+		if (!ret || ret == -EALREADY)
 			return 0;
 	}
 	return -ENODEV;
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -12,7 +12,7 @@
 * (non hardware specific) changes to serial.c.
 *
 * The port is registered with the tty driver as minor device 64, and
- * therefore other ports should should only use 65 upwards.
+ * therefore other ports should only use 65 upwards.
 *
 * Richard Lucock 28/12/99
 *
@@ -51,6 +51,7 @@
 #include <linux/seq_file.h>
 #include <linux/serial.h>
 #include <linux/serial_reg.h>
+#include <linux/serial_core.h>
 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
@@ -283,12 +284,12 @@ static void transmit_chars(struct serial_state *info)

 	amiga_custom.serdat = info->xmit.buf[info->xmit.tail++] | 0x100;
 	mb();
-	info->xmit.tail = info->xmit.tail & (SERIAL_XMIT_SIZE-1);
+	info->xmit.tail = info->xmit.tail & (UART_XMIT_SIZE - 1);
 	info->icount.tx++;

 	if (CIRC_CNT(info->xmit.head,
 		     info->xmit.tail,
-		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
+		     UART_XMIT_SIZE) < WAKEUP_CHARS)
 		tty_wakeup(info->tport.tty);

 #ifdef SERIAL_DEBUG_INTR
@@ -708,13 +709,13 @@ static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 	local_irq_save(flags);
 	if (CIRC_SPACE(info->xmit.head,
 		       info->xmit.tail,
-		       SERIAL_XMIT_SIZE) == 0) {
+		       UART_XMIT_SIZE) == 0) {
 		local_irq_restore(flags);
 		return 0;
 	}

 	info->xmit.buf[info->xmit.head++] = ch;
-	info->xmit.head &= SERIAL_XMIT_SIZE-1;
+	info->xmit.head &= UART_XMIT_SIZE - 1;
 	local_irq_restore(flags);
 	return 1;
 }
@@ -753,15 +754,14 @@ static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count
 	while (1) {
 		c = CIRC_SPACE_TO_END(info->xmit.head,
 				      info->xmit.tail,
-				      SERIAL_XMIT_SIZE);
+				      UART_XMIT_SIZE);
 		if (count < c)
 			c = count;
 		if (c <= 0) {
 			break;
 		}
 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
-		info->xmit.head = ((info->xmit.head + c) &
-				   (SERIAL_XMIT_SIZE-1));
+		info->xmit.head = (info->xmit.head + c) & (UART_XMIT_SIZE - 1);
 		buf += c;
 		count -= c;
 		ret += c;
@@ -788,14 +788,14 @@ static unsigned int rs_write_room(struct tty_struct *tty)
 {
 	struct serial_state *info = tty->driver_data;

-	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
+	return CIRC_SPACE(info->xmit.head, info->xmit.tail, UART_XMIT_SIZE);
 }

 static unsigned int rs_chars_in_buffer(struct tty_struct *tty)
 {
 	struct serial_state *info = tty->driver_data;

-	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
+	return CIRC_CNT(info->xmit.head, info->xmit.tail, UART_XMIT_SIZE);
 }

 static void rs_flush_buffer(struct tty_struct *tty)
--- a/drivers/tty/mips_ejtag_fdc.c
+++ b/drivers/tty/mips_ejtag_fdc.c
@@ -916,7 +916,7 @@ static int mips_ejtag_fdc_tty_probe(struct mips_cdmm_device *dev)
 	mips_ejtag_fdc_write(priv, REG_FDCFG, cfg);

 	/* Make each port's xmit FIFO big enough to fill FDC TX FIFO */
-	priv->xmit_size = min(tx_fifo * 4, (unsigned int)SERIAL_XMIT_SIZE);
+	priv->xmit_size = min(tx_fifo * 4, (unsigned int)UART_XMIT_SIZE);

 	driver = tty_alloc_driver(NUM_TTY_CHANNELS, TTY_DRIVER_REAL_RAW);
 	if (IS_ERR(driver))
@@ -1222,7 +1222,7 @@ static void kgdbfdc_push_one(void)

 	/* Construct a word from any data in buffer */
 	word = mips_ejtag_fdc_encode(bufs, &kgdbfdc_wbuflen, 1);
-	/* Relocate any remaining data to beginnning of buffer */
+	/* Relocate any remaining data to beginning of buffer */
 	kgdbfdc_wbuflen -= word.bytes;
 	for (i = 0; i < kgdbfdc_wbuflen; ++i)
 		kgdbfdc_wbuf[i] = kgdbfdc_wbuf[i + word.bytes];
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -118,6 +118,9 @@ struct n_tty_data {
 	size_t read_tail;
 	size_t line_start;

+	/* # of chars looked ahead (to find software flow control chars) */
+	size_t lookahead_count;
+
 	/* protected by output lock */
 	unsigned int column;
 	unsigned int canon_column;
@@ -333,6 +336,8 @@ static void reset_buffer_flags(struct n_tty_data *ldata)
 	ldata->erasing = 0;
 	bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
 	ldata->push = 0;
+
+	ldata->lookahead_count = 0;
 }

 static void n_tty_packet_mode_flush(struct tty_struct *tty)
@@ -1225,12 +1230,30 @@ static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
 	return c == START_CHAR(tty) || c == STOP_CHAR(tty);
 }

-/* Returns true if c is consumed as flow-control character */
-static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
+/**
+ * n_tty_receive_char_flow_ctrl - receive flow control chars
+ * @tty: terminal device
+ * @c: character
+ * @lookahead_done: lookahead has processed this character already
+ *
+ * Receive and process flow control character actions.
+ *
+ * In case lookahead for flow control chars already handled the character in
+ * advance to the normal receive, the actions are skipped during normal
+ * receive.
+ *
+ * Returns true if @c is consumed as flow-control character, the character
+ * must not be treated as normal character.
+ */
+static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c,
+					 bool lookahead_done)
 {
 	if (!n_tty_is_char_flow_ctrl(tty, c))
 		return false;

+	if (lookahead_done)
+		return true;
+
 	if (c == START_CHAR(tty)) {
 		start_tty(tty);
 		process_echoes(tty);
@@ -1242,11 +1265,12 @@ static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c
 	return true;
 }

-static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
+static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c,
+				       bool lookahead_done)
 {
 	struct n_tty_data *ldata = tty->disc_data;

-	if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c))
+	if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c, lookahead_done))
 		return;

 	if (L_ISIG(tty)) {
@@ -1401,7 +1425,8 @@ static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 	put_tty_queue(c, ldata);
 }

-static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
+static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c,
+				       bool lookahead_done)
 {
 	if (I_ISTRIP(tty))
 		c &= 0x7f;
@@ -1409,12 +1434,10 @@ static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
 		c = tolower(c);

 	if (I_IXON(tty)) {
-		if (c == STOP_CHAR(tty))
-			stop_tty(tty);
-		else if (c == START_CHAR(tty) ||
-			 (tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) &&
-			  c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
-			  c != SUSP_CHAR(tty))) {
+		if (!n_tty_receive_char_flow_ctrl(tty, c, lookahead_done) &&
+		    tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) &&
+		    c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
+		    c != SUSP_CHAR(tty)) {
 			start_tty(tty);
 			process_echoes(tty);
 		}
@@ -1457,6 +1480,27 @@ n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
 		n_tty_receive_char_flagged(tty, c, flag);
 }

+/* Caller must ensure count > 0 */
+static void n_tty_lookahead_flow_ctrl(struct tty_struct *tty, const unsigned char *cp,
+				      const unsigned char *fp, unsigned int count)
+{
+	struct n_tty_data *ldata = tty->disc_data;
+	unsigned char flag = TTY_NORMAL;
+
+	ldata->lookahead_count += count;
+
+	if (!I_IXON(tty))
+		return;
+
+	while (count--) {
+		if (fp)
+			flag = *fp++;
+		if (likely(flag == TTY_NORMAL))
+			n_tty_receive_char_flow_ctrl(tty, *cp, false);
+		cp++;
+	}
+}
+
 static void
 n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
 			   const char *fp, int count)
@@ -1496,7 +1540,7 @@ n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,

 static void
 n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
-			  const char *fp, int count)
+			  const char *fp, int count, bool lookahead_done)
 {
 	char flag = TTY_NORMAL;

@@ -1504,12 +1548,12 @@ n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
 		if (fp)
 			flag = *fp++;
 		if (likely(flag == TTY_NORMAL))
-			n_tty_receive_char_closing(tty, *cp++);
+			n_tty_receive_char_closing(tty, *cp++, lookahead_done);
 	}
 }

 static void n_tty_receive_buf_standard(struct tty_struct *tty,
-		const unsigned char *cp, const char *fp, int count)
+		const unsigned char *cp, const char *fp, int count, bool lookahead_done)
 {
 	struct n_tty_data *ldata = tty->disc_data;
 	char flag = TTY_NORMAL;
@@ -1540,7 +1584,7 @@ static void n_tty_receive_buf_standard(struct tty_struct *tty,
 		}

 		if (test_bit(c, ldata->char_map))
-			n_tty_receive_char_special(tty, c);
+			n_tty_receive_char_special(tty, c, lookahead_done);
 		else
 			n_tty_receive_char(tty, c);
 	}
@@ -1551,21 +1595,30 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
 {
 	struct n_tty_data *ldata = tty->disc_data;
 	bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
+	size_t la_count = min_t(size_t, ldata->lookahead_count, count);

 	if (ldata->real_raw)
 		n_tty_receive_buf_real_raw(tty, cp, fp, count);
 	else if (ldata->raw || (L_EXTPROC(tty) && !preops))
 		n_tty_receive_buf_raw(tty, cp, fp, count);
-	else if (tty->closing && !L_EXTPROC(tty))
-		n_tty_receive_buf_closing(tty, cp, fp, count);
-	else {
-		n_tty_receive_buf_standard(tty, cp, fp, count);
+	else if (tty->closing && !L_EXTPROC(tty)) {
+		if (la_count > 0)
+			n_tty_receive_buf_closing(tty, cp, fp, la_count, true);
+		if (count > la_count)
+			n_tty_receive_buf_closing(tty, cp, fp, count - la_count, false);
+	} else {
+		if (la_count > 0)
+			n_tty_receive_buf_standard(tty, cp, fp, la_count, true);
+		if (count > la_count)
+			n_tty_receive_buf_standard(tty, cp, fp, count - la_count, false);

 		flush_echoes(tty);
 		if (tty->ops->flush_chars)
 			tty->ops->flush_chars(tty);
 	}

+	ldata->lookahead_count -= la_count;
+
 	if (ldata->icanon && !L_EXTPROC(tty))
 		return;

@@ -2446,6 +2499,7 @@ static struct tty_ldisc_ops n_tty_ops = {
 	.receive_buf     = n_tty_receive_buf,
 	.write_wakeup    = n_tty_write_wakeup,
 	.receive_buf2	 = n_tty_receive_buf2,
+	.lookahead_buf	 = n_tty_lookahead_flow_ctrl,
 };

 /**
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -123,6 +123,26 @@ static inline void serial_out(struct uart_8250_port *up, int offset, int value)
 	up->port.serial_out(&up->port, offset, value);
 }

+/**
+ *	serial_lsr_in - Read LSR register and preserve flags across reads
+ *	@up:	uart 8250 port
+ *
+ *	Read LSR register and handle saving non-preserved flags across reads.
+ *	The flags that are not preserved across reads are stored into
+ *	up->lsr_saved_flags.
+ *
+ *	Returns LSR value or'ed with the preserved flags (if any).
+ */
+static inline u16 serial_lsr_in(struct uart_8250_port *up)
+{
+	u16 lsr = up->lsr_saved_flags;
+
+	lsr |= serial_in(up, UART_LSR);
+	up->lsr_saved_flags = lsr & up->lsr_save_mask;
+
+	return lsr;
+}
+
 /*
 * For the 16C950
 */
@@ -183,10 +203,12 @@ void serial8250_rpm_put(struct uart_8250_port *p);
 void serial8250_rpm_get_tx(struct uart_8250_port *p);
 void serial8250_rpm_put_tx(struct uart_8250_port *p);

-int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485);
+int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
+			    struct serial_rs485 *rs485);
 void serial8250_em485_start_tx(struct uart_8250_port *p);
 void serial8250_em485_stop_tx(struct uart_8250_port *p);
 void serial8250_em485_destroy(struct uart_8250_port *p);
+extern struct serial_rs485 serial8250_em485_supported;

 /* MCR <-> TIOCM conversion */
 static inline int serial8250_TIOCM_to_MCR(int tiocm)
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -108,6 +108,7 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	up.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE |
 			UPF_SKIP_TEST | UPF_IOREMAP;
 	up.port.rs485_config = serial8250_em485_config;
+	up.port.rs485_supported = serial8250_em485_supported;
 	up.rs485_start_tx = bcm2835aux_rs485_start_tx;
 	up.rs485_stop_tx = bcm2835aux_rs485_stop_tx;

@@ -166,8 +167,10 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	uartclk = clk_get_rate(data->clk);
 	if (!uartclk) {
 		ret = device_property_read_u32(&pdev->dev, "clock-frequency", &uartclk);
-		if (ret)
-			return dev_err_probe(&pdev->dev, ret, "could not get clk rate\n");
+		if (ret) {
+			dev_err_probe(&pdev->dev, ret, "could not get clk rate\n");
+			goto dis_clk;
+		}
 	}

 	/* the HW-clock divider for bcm2835aux is 8,
--- a/Show More
+++ b/Show More