Merge tag 'tty-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial updates from Greg KH:
 "Here is the big tty/serial driver update for 4.18-rc1.

  There's nothing major here, just lots of serial driver updates. Full
  details are in the shortlog, nothing anything specific to call out
  here.

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

* tag 'tty-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (55 commits)
  vt: Perform safe console erase only once
  serial: imx: disable UCR4_OREN on shutdown
  serial: imx: drop CTS/RTS handling from shutdown
  tty: fix typo in ASYNCB_FOURPORT comment
  serial: samsung: check DMA engine capabilities before using DMA mode
  tty: Fix data race in tty_insert_flip_string_fixed_flag
  tty: serial: msm_geni_serial: Fix TX infinite loop
  serial: 8250_dw: Fix runtime PM handling
  serial: 8250: omap: Fix idling of clocks for unused uarts
  tty: serial: drop ATH79 specific SoC symbols
  serial: 8250: Add missing rxtrig_bytes on Altera 16550 UART
  serial/aspeed-vuart: fix a couple mod_timer() calls
  serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding version
  serial: 8250_of: Add IO space support
  tty/serial: atmel: use port->name as name in request_irq()
  serial: imx: dma_unmap_sg buffers on shutdown
  serial: imx: cleanup imx_uart_disable_dma()
  tty: serial: qcom_geni_serial: Add early console support
  tty: serial: qcom_geni_serial: Return IRQ_NONE for spurious interrupts
  tty: serial: qcom_geni_serial: Use iowrite32_rep to write to FIFO
  ...

Author: torvalds

Documentation/admin-guide/kernel-parameters.txt

@@ -1020,6 +1020,12 @@
 			address. The serial port must already be setup
 			and configured. Options are not yet supported.
 
+		qcom_geni,<addr>
+			Start an early, polled-mode console on a Qualcomm
+			Generic Interface (GENI) based serial port at the
+			specified address. The serial port must already be
+			setup and configured. Options are not yet supported.
+
 	earlyprintk=	[X86,SH,ARM,M68k,S390]
 			earlyprintk=vga
 			earlyprintk=efi

arch/arm/boot/dts/armada-38x.dtsi

@@ -163,7 +163,7 @@
 			};
 
 			uart0: serial@12000 {
-				compatible = "snps,dw-apb-uart";
+				compatible = "marvell,armada-38x-uart";
 				reg = <0x12000 0x100>;
 				reg-shift = <2>;
 				interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>;
@@ -173,7 +173,7 @@
 			};
 
 			uart1: serial@12100 {
-				compatible = "snps,dw-apb-uart";
+				compatible = "marvell,armada-38x-uart";
 				reg = <0x12100 0x100>;
 				reg-shift = <2>;
 				interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>;

drivers/tty/ipwireless/network.c

@@ -416,7 +416,7 @@ void ipwireless_network_packet_received(struct ipw_network *network,
 struct ipw_network *ipwireless_network_create(struct ipw_hardware *hw)
 {
 	struct ipw_network *network =
-		kzalloc(sizeof(struct ipw_network), GFP_ATOMIC);
+		kzalloc(sizeof(struct ipw_network), GFP_KERNEL);
 
 	if (!network)
 		return NULL;

drivers/tty/n_gsm.c

@@ -2675,7 +2675,7 @@ static inline void muxnet_put(struct gsm_mux_net *mux_net)
 	kref_put(&mux_net->ref, net_free);
 }
 
-static int gsm_mux_net_start_xmit(struct sk_buff *skb,
+static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
 				      struct net_device *net)
 {
 	struct gsm_mux_net *mux_net = netdev_priv(net);

drivers/tty/nozomi.c

@@ -72,19 +72,19 @@ do {							\
 
 #define TMP_BUF_MAX 256
 
-#define DUMP(buf__,len__) \
-  do {  \
-    char tbuf[TMP_BUF_MAX] = {0};\
-    if (len__ > 1) {\
-	snprintf(tbuf, len__ > TMP_BUF_MAX ? TMP_BUF_MAX : len__, "%s", buf__);\
-	if (tbuf[len__-2] == '\r') {\
-		tbuf[len__-2] = 'r';\
-	} \
-	DBG1("SENDING: '%s' (%d+n)", tbuf, len__);\
-    } else {\
-	DBG1("SENDING: '%s' (%d)", tbuf, len__);\
-    } \
-} while (0)
+#define DUMP(buf__, len__)						\
+	do {								\
+		char tbuf[TMP_BUF_MAX] = {0};				\
+		if (len__ > 1) {					\
+			u32 data_len = min_t(u32, len__, TMP_BUF_MAX);	\
+			strscpy(tbuf, buf__, data_len);			\
+			if (tbuf[data_len - 2] == '\r')			\
+				tbuf[data_len - 2] = 'r';		\
+			DBG1("SENDING: '%s' (%d+n)", tbuf, len__);	\
+		} else {						\
+			DBG1("SENDING: '%s' (%d)", tbuf, len__);	\
+		}							\
+	} while (0)
 
 /*    Defines */
 #define NOZOMI_NAME		"nozomi"
@@ -102,41 +102,41 @@ do {							\
 #define RECEIVE_BUF_MAX		4
 
 
-#define R_IIR		0x0000	/* Interrupt Identity Register */
-#define R_FCR		0x0000	/* Flow Control Register */
-#define R_IER		0x0004	/* Interrupt Enable Register */
+#define R_IIR			0x0000	/* Interrupt Identity Register */
+#define R_FCR			0x0000	/* Flow Control Register */
+#define R_IER			0x0004	/* Interrupt Enable Register */
 
 #define NOZOMI_CONFIG_MAGIC	0xEFEFFEFE
 #define TOGGLE_VALID		0x0000
 
 /* Definition of interrupt tokens */
-#define MDM_DL1		0x0001
-#define MDM_UL1		0x0002
-#define MDM_DL2		0x0004
-#define MDM_UL2		0x0008
-#define DIAG_DL1	0x0010
-#define DIAG_DL2	0x0020
-#define DIAG_UL		0x0040
-#define APP1_DL		0x0080
-#define APP1_UL		0x0100
-#define APP2_DL		0x0200
-#define APP2_UL		0x0400
-#define CTRL_DL		0x0800
-#define CTRL_UL		0x1000
-#define RESET		0x8000
-
-#define MDM_DL		(MDM_DL1  | MDM_DL2)
-#define MDM_UL		(MDM_UL1  | MDM_UL2)
-#define DIAG_DL		(DIAG_DL1 | DIAG_DL2)
+#define MDM_DL1			0x0001
+#define MDM_UL1			0x0002
+#define MDM_DL2			0x0004
+#define MDM_UL2			0x0008
+#define DIAG_DL1		0x0010
+#define DIAG_DL2		0x0020
+#define DIAG_UL			0x0040
+#define APP1_DL			0x0080
+#define APP1_UL			0x0100
+#define APP2_DL			0x0200
+#define APP2_UL			0x0400
+#define CTRL_DL			0x0800
+#define CTRL_UL			0x1000
+#define RESET			0x8000
+
+#define MDM_DL			(MDM_DL1  | MDM_DL2)
+#define MDM_UL			(MDM_UL1  | MDM_UL2)
+#define DIAG_DL			(DIAG_DL1 | DIAG_DL2)
 
 /* modem signal definition */
-#define CTRL_DSR	0x0001
-#define CTRL_DCD	0x0002
-#define CTRL_RI		0x0004
-#define CTRL_CTS	0x0008
+#define CTRL_DSR		0x0001
+#define CTRL_DCD		0x0002
+#define CTRL_RI			0x0004
+#define CTRL_CTS		0x0008
 
-#define CTRL_DTR	0x0001
-#define CTRL_RTS	0x0002
+#define CTRL_DTR		0x0001
+#define CTRL_RTS		0x0002
 
 #define MAX_PORT		4
 #define NOZOMI_MAX_PORTS	5
@@ -155,7 +155,7 @@ enum card_type {
 
 /* Initialization states a card can be in */
 enum card_state {
-	NOZOMI_STATE_UKNOWN	= 0,
+	NOZOMI_STATE_UNKNOWN	= 0,
 	NOZOMI_STATE_ENABLED	= 1,	/* pci device enabled */
 	NOZOMI_STATE_ALLOCATED	= 2,	/* config setup done */
 	NOZOMI_STATE_READY	= 3,	/* flowcontrols received */
@@ -365,7 +365,7 @@ struct buffer {
 	u8 *data;
 } __attribute__ ((packed));
 
-/*    Global variables */
+/* Global variables */
 static const struct pci_device_id nozomi_pci_tbl[] = {
 	{PCI_DEVICE(0x1931, 0x000c)},	/* Nozomi HSDPA */
 	{},
@@ -1686,12 +1686,12 @@ static int ntty_tiocmget(struct tty_struct *tty)
 
 	/* Note: these could change under us but it is not clear this
 	   matters if so */
-	return	(ctrl_ul->RTS ? TIOCM_RTS : 0) |
-		(ctrl_ul->DTR ? TIOCM_DTR : 0) |
-		(ctrl_dl->DCD ? TIOCM_CAR : 0) |
-		(ctrl_dl->RI  ? TIOCM_RNG : 0) |
-		(ctrl_dl->DSR ? TIOCM_DSR : 0) |
-		(ctrl_dl->CTS ? TIOCM_CTS : 0);
+	return (ctrl_ul->RTS ? TIOCM_RTS : 0)
+		| (ctrl_ul->DTR ? TIOCM_DTR : 0)
+		| (ctrl_dl->DCD ? TIOCM_CAR : 0)
+		| (ctrl_dl->RI  ? TIOCM_RNG : 0)
+		| (ctrl_dl->DSR ? TIOCM_DSR : 0)
+		| (ctrl_dl->CTS ? TIOCM_CTS : 0);
 }
 
 /* Sets io controls parameters */
@@ -1722,10 +1722,10 @@ static int ntty_cflags_changed(struct port *port, unsigned long flags,
 	const struct async_icount cnow = port->tty_icount;
 	int ret;
 
-	ret =	((flags & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
-		((flags & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
-		((flags & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
-		((flags & TIOCM_CTS) && (cnow.cts != cprev->cts));
+	ret = ((flags & TIOCM_RNG) && (cnow.rng != cprev->rng))
+		|| ((flags & TIOCM_DSR) && (cnow.dsr != cprev->dsr))
+		|| ((flags & TIOCM_CD)  && (cnow.dcd != cprev->dcd))
+		|| ((flags & TIOCM_CTS) && (cnow.cts != cprev->cts));
 
 	*cprev = cnow;
 

drivers/tty/pty.c

@@ -110,16 +110,19 @@ static void pty_unthrottle(struct tty_struct *tty)
 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 {
 	struct tty_struct *to = tty->link;
+	unsigned long flags;
 
 	if (tty->stopped)
 		return 0;
 
 	if (c > 0) {
+		spin_lock_irqsave(&to->port->lock, flags);
 		/* Stuff the data into the input queue of the other end */
 		c = tty_insert_flip_string(to->port, buf, c);
 		/* And shovel */
 		if (c)
 			tty_flip_buffer_push(to->port);
+		spin_unlock_irqrestore(&to->port->lock, flags);
 	}
 	return c;
 }

drivers/tty/serial/8250/8250_aspeed_vuart.c

@@ -10,6 +10,8 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/clk.h>
 
 #include "8250.h"
@@ -28,8 +30,17 @@ struct aspeed_vuart {
 	void __iomem		*regs;
 	struct clk		*clk;
 	int			line;
+	struct timer_list	unthrottle_timer;
+	struct uart_8250_port	*port;
 };
 
+/*
+ * If we fill the tty flip buffers, we throttle the data ready interrupt
+ * to prevent dropped characters. This timeout defines how long we wait
+ * to (conditionally, depending on buffer state) unthrottle.
+ */
+static const int unthrottle_timeout = HZ/10;
+
 /*
  * The VUART is basically two UART 'front ends' connected by their FIFO
  * (no actual serial line in between). One is on the BMC side (management
@@ -179,6 +190,114 @@ static void aspeed_vuart_shutdown(struct uart_port *uart_port)
 	serial8250_do_shutdown(uart_port);
 }
 
+static void __aspeed_vuart_set_throttle(struct uart_8250_port *up,
+		bool throttle)
+{
+	unsigned char irqs = UART_IER_RLSI | UART_IER_RDI;
+
+	up->ier &= ~irqs;
+	if (!throttle)
+		up->ier |= irqs;
+	serial_out(up, UART_IER, up->ier);
+}
+static void aspeed_vuart_set_throttle(struct uart_port *port, bool throttle)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	__aspeed_vuart_set_throttle(up, throttle);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void aspeed_vuart_throttle(struct uart_port *port)
+{
+	aspeed_vuart_set_throttle(port, true);
+}
+
+static void aspeed_vuart_unthrottle(struct uart_port *port)
+{
+	aspeed_vuart_set_throttle(port, false);
+}
+
+static void aspeed_vuart_unthrottle_exp(struct timer_list *timer)
+{
+	struct aspeed_vuart *vuart = from_timer(vuart, timer, unthrottle_timer);
+	struct uart_8250_port *up = vuart->port;
+
+	if (!tty_buffer_space_avail(&up->port.state->port)) {
+		mod_timer(&vuart->unthrottle_timer,
+			  jiffies + unthrottle_timeout);
+		return;
+	}
+
+	aspeed_vuart_unthrottle(&up->port);
+}
+
+/*
+ * Custom interrupt handler to manage finer-grained flow control. Although we
+ * have throttle/unthrottle callbacks, we've seen that the VUART device can
+ * deliver characters faster than the ldisc has a chance to check buffer space
+ * against the throttle threshold. This results in dropped characters before
+ * the throttle.
+ *
+ * We do this by checking for flip buffer space before RX. If we have no space,
+ * throttle now and schedule an unthrottle for later, once the ldisc has had
+ * a chance to drain the buffers.
+ */
+static int aspeed_vuart_handle_irq(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int iir, lsr;
+	unsigned long flags;
+	int space, count;
+
+	iir = serial_port_in(port, UART_IIR);
+
+	if (iir & UART_IIR_NO_INT)
+		return 0;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	lsr = serial_port_in(port, UART_LSR);
+
+	if (lsr & (UART_LSR_DR | UART_LSR_BI)) {
+		space = tty_buffer_space_avail(&port->state->port);
+
+		if (!space) {
+			/* throttle and schedule an unthrottle later */
+			struct aspeed_vuart *vuart = port->private_data;
+			__aspeed_vuart_set_throttle(up, true);
+
+			if (!timer_pending(&vuart->unthrottle_timer)) {
+				vuart->port = up;
+				mod_timer(&vuart->unthrottle_timer,
+					  jiffies + unthrottle_timeout);
+			}
+
+		} else {
+			count = min(space, 256);
+
+			do {
+				serial8250_read_char(up, lsr);
+				lsr = serial_in(up, UART_LSR);
+				if (--count == 0)
+					break;
+			} while (lsr & (UART_LSR_DR | UART_LSR_BI));
+
+			tty_flip_buffer_push(&port->state->port);
+		}
+	}
+
+	serial8250_modem_status(up);
+	if (lsr & UART_LSR_THRE)
+		serial8250_tx_chars(up);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return 1;
+}
+
 static int aspeed_vuart_probe(struct platform_device *pdev)
 {
 	struct uart_8250_port port;
@@ -195,6 +314,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	vuart->dev = &pdev->dev;
+	timer_setup(&vuart->unthrottle_timer, aspeed_vuart_unthrottle_exp, 0);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	vuart->regs = devm_ioremap_resource(&pdev->dev, res);
@@ -208,6 +328,9 @@ static int aspeed_vuart_probe(struct platform_device *pdev)
 	port.port.mapsize = resource_size(res);
 	port.port.startup = aspeed_vuart_startup;
 	port.port.shutdown = aspeed_vuart_shutdown;
+	port.port.throttle = aspeed_vuart_throttle;
+	port.port.unthrottle = aspeed_vuart_unthrottle;
+	port.port.status = UPSTAT_SYNC_FIFO;
 	port.port.dev = &pdev->dev;
 
 	rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
@@ -253,6 +376,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev)
 
 	port.port.irq = irq_of_parse_and_map(np, 0);
 	port.port.irqflags = IRQF_SHARED;
+	port.port.handle_irq = aspeed_vuart_handle_irq;
 	port.port.iotype = UPIO_MEM;
 	port.port.type = PORT_16550A;
 	port.port.uartclk = clk;
@@ -292,6 +416,7 @@ static int aspeed_vuart_remove(struct platform_device *pdev)
 {
 	struct aspeed_vuart *vuart = platform_get_drvdata(pdev);
 
+	del_timer_sync(&vuart->unthrottle_timer);
 	aspeed_vuart_set_enabled(vuart, false);
 	serial8250_unregister_port(vuart->line);
 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);