Merge tag 'tty-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are some small tty and serial driver fixes for 5.1-rc3.

  Nothing major here, just a number of potential problems fixes for
  error handling paths, as well as some other minor bugfixes for
  reported issues with 5.1-rc1.

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

* tag 'tty-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: fix NULL pointer issue when tty_port ops is not set
  Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc
  dt-bindings: serial: Add compatible for Mediatek MT8183
  tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped
  tty/serial: atmel: Add is_half_duplex helper
  serial: sh-sci: Fix setting SCSCR_TIE while transferring data
  serial: ar933x_uart: Fix build failure with disabled console
  tty: serial: qcom_geni_serial: Initialize baud in qcom_geni_console_setup
  sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()
  tty: mxs-auart: fix a potential NULL pointer dereference
  tty: atmel_serial: fix a potential NULL pointer dereference
  serial: max310x: Fix to avoid potential NULL pointer dereference
  serial: mvebu-uart: Fix to avoid a potential NULL pointer dereference

11 files changed, 75 insertions, 51 deletions

diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
index 742cb470595b..bcfb13194f16 100644
--- a/Documentation/devicetree/bindings/serial/mtk-uart.txt
+++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
@@ -16,6 +16,7 @@ Required properties:
   * "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,mt6577-uart" for MT6577 and all of the above
 
 - reg: The base address of the UART register bank.
diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index db5df3d54818..3bdd56a1021b 100644
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -49,11 +49,6 @@ struct ar933x_uart_port {
         struct clk              *clk;
 };
 
-static inline bool ar933x_uart_console_enabled(void)
-{
-        return IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);
-}
-
 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
                                             int offset)
 {
@@ -508,6 +503,7 @@ static const struct uart_ops ar933x_uart_ops = {
         .verify_port    = ar933x_uart_verify_port,
 };
 
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
 static struct ar933x_uart_port *
 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
 
@@ -604,14 +600,7 @@ static struct console ar933x_uart_console = {
         .index          = -1,
         .data           = &ar933x_uart_driver,
 };
-
-static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
-{
-        if (!ar933x_uart_console_enabled())
-                return;
-
-        ar933x_console_ports[up->port.line] = up;
-}
+#endif /* CONFIG_SERIAL_AR933X_CONSOLE */
 
 static struct uart_driver ar933x_uart_driver = {
         .owner          = THIS_MODULE,
@@ -700,7 +689,9 @@ static int ar933x_uart_probe(struct platform_device *pdev)
         baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
         up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
 
-        ar933x_uart_add_console_port(up);
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
+        ar933x_console_ports[up->port.line] = up;
+#endif
 
         ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
         if (ret)
@@ -749,8 +740,9 @@ static int __init ar933x_uart_init(void)
 {
         int ret;
 
-        if (ar933x_uart_console_enabled())
-                ar933x_uart_driver.cons = &ar933x_uart_console;
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
+        ar933x_uart_driver.cons = &ar933x_uart_console;
+#endif
 
         ret = uart_register_driver(&ar933x_uart_driver);
         if (ret)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..0b4f36905321 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -166,6 +166,8 @@ struct atmel_uart_port {
         unsigned int            pending_status;
         spinlock_t              lock_suspended;
 
+        bool                    hd_start_rx;    /* can start RX during half-duplex operation */
+
         /* ISO7816 */
         unsigned int            fidi_min;
         unsigned int            fidi_max;
@@ -231,6 +233,13 @@ static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
         __raw_writeb(value, port->membase + ATMEL_US_THR);
 }
 
+static inline int atmel_uart_is_half_duplex(struct uart_port *port)
+{
+        return ((port->rs485.flags & SER_RS485_ENABLED) &&
+                !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
+                (port->iso7816.flags & SER_ISO7816_ENABLED);
+}
+
 #ifdef CONFIG_SERIAL_ATMEL_PDC
 static bool atmel_use_pdc_rx(struct uart_port *port)
 {
@@ -608,10 +617,9 @@ static void atmel_stop_tx(struct uart_port *port)
         /* Disable interrupts */
         atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
-        if (((port->rs485.flags & SER_RS485_ENABLED) &&
-             !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-            port->iso7816.flags & SER_ISO7816_ENABLED)
+        if (atmel_uart_is_half_duplex(port))
                 atmel_start_rx(port);
+
 }
 
 /*
@@ -628,9 +636,7 @@ static void atmel_start_tx(struct uart_port *port)
                 return;
 
         if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
-                if (((port->rs485.flags & SER_RS485_ENABLED) &&
-                     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-                    port->iso7816.flags & SER_ISO7816_ENABLED)
+                if (atmel_uart_is_half_duplex(port))
                         atmel_stop_rx(port);
 
         if (atmel_use_pdc_tx(port))
@@ -928,11 +934,14 @@ static void atmel_complete_tx_dma(void *arg)
          */
         if (!uart_circ_empty(xmit))
                 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
-        else if (((port->rs485.flags & SER_RS485_ENABLED) &&
-                  !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-                 port->iso7816.flags & SER_ISO7816_ENABLED) {
-                /* DMA done, stop TX, start RX for RS485 */
-                atmel_start_rx(port);
+        else if (atmel_uart_is_half_duplex(port)) {
+                /*
+                 * DMA done, re-enable TXEMPTY and signal that we can stop
+                 * TX and start RX for RS485
+                 */
+                atmel_port->hd_start_rx = true;
+                atmel_uart_writel(port, ATMEL_US_IER,
+                                  atmel_port->tx_done_mask);
         }
 
         spin_unlock_irqrestore(&port->lock, flags);
@@ -1288,6 +1297,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
                                          sg_dma_len(&atmel_port->sg_rx)/2,
                                          DMA_DEV_TO_MEM,
                                          DMA_PREP_INTERRUPT);
+        if (!desc) {
+                dev_err(port->dev, "Preparing DMA cyclic failed\n");
+                goto chan_err;
+        }
         desc->callback = atmel_complete_rx_dma;
         desc->callback_param = port;
         atmel_port->desc_rx = desc;
@@ -1376,9 +1389,20 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
         struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
         if (pending & atmel_port->tx_done_mask) {
-                /* Either PDC or interrupt transmission */
                 atmel_uart_writel(port, ATMEL_US_IDR,
                                   atmel_port->tx_done_mask);
+
+                /* Start RX if flag was set and FIFO is empty */
+                if (atmel_port->hd_start_rx) {
+                        if (!(atmel_uart_readl(port, ATMEL_US_CSR)
+                                        & ATMEL_US_TXEMPTY))
+                                dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n");
+
+                        atmel_port->hd_start_rx = false;
+                        atmel_start_rx(port);
+                        return;
+                }
+
                 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
         }
 }
@@ -1508,9 +1532,7 @@ static void atmel_tx_pdc(struct uart_port *port)
                 atmel_uart_writel(port, ATMEL_US_IER,
                                   atmel_port->tx_done_mask);
         } else {
-                if (((port->rs485.flags & SER_RS485_ENABLED) &&
-                     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-                    port->iso7816.flags & SER_ISO7816_ENABLED) {
+                if (atmel_uart_is_half_duplex(port)) {
                         /* DMA done, stop TX, start RX for RS485 */
                         atmel_start_rx(port);
                 }
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index 6fb312e7af71..bfe5e9e034ec 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -148,8 +148,10 @@ static int configure_kgdboc(void)
         char *cptr = config;
         struct console *cons;
 
-        if (!strlen(config) || isspace(config[0]))
+        if (!strlen(config) || isspace(config[0])) {
+                err = 0;
                 goto noconfig;
+        }
 
         kgdboc_io_ops.is_console = 0;
         kgdb_tty_driver = NULL;
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index f5bdde405627..450ba6d7996c 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1415,6 +1415,8 @@ static int max310x_spi_probe(struct spi_device *spi)
         if (spi->dev.of_node) {
                 const struct of_device_id *of_id =
                         of_match_device(max310x_dt_ids, &spi->dev);
+                if (!of_id)
+                        return -ENODEV;
 
                 devtype = (struct max310x_devtype *)of_id->data;
         } else {
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 231f751d1ef4..7e7b1559fa36 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -810,6 +810,9 @@ static int mvebu_uart_probe(struct platform_device *pdev)
                 return -EINVAL;
         }
 
+        if (!match)
+                return -ENODEV;
+
         /* Assume that all UART ports have a DT alias or none has */
         id = of_alias_get_id(pdev->dev.of_node, "serial");
         if (!pdev->dev.of_node || id < 0)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 27235a526cce..4c188f4079b3 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1686,6 +1686,10 @@ static int mxs_auart_probe(struct platform_device *pdev)
 
         s->port.mapbase = r->start;
         s->port.membase = ioremap(r->start, resource_size(r));
+        if (!s->port.membase) {
+                ret = -ENOMEM;
+                goto out_disable_clks;
+        }
         s->port.ops = &mxs_auart_ops;
         s->port.iotype = UPIO_MEM;
         s->port.fifosize = MXS_AUART_FIFO_SIZE;
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3bcec1c20219..35e5f9c5d5be 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1050,7 +1050,7 @@ static int __init qcom_geni_console_setup(struct console *co, char *options)
 {
         struct uart_port *uport;
         struct qcom_geni_serial_port *port;
-        int baud;
+        int baud = 9600;
         int bits = 8;
         int parity = 'n';
         int flow = 'n';
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 635178cf3eed..09a183dfc526 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1507,7 +1507,7 @@ static int __init sc16is7xx_init(void)
         ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
         if (ret < 0) {
                 pr_err("failed to init sc16is7xx i2c --> %d\n", ret);
-                return ret;
+                goto err_i2c;
         }
 #endif
 
@@ -1515,10 +1515,18 @@ static int __init sc16is7xx_init(void)
         ret = spi_register_driver(&sc16is7xx_spi_uart_driver);
         if (ret < 0) {
                 pr_err("failed to init sc16is7xx spi --> %d\n", ret);
-                return ret;
+                goto err_spi;
         }
 #endif
         return ret;
+
+err_spi:
+#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
+        i2c_del_driver(&sc16is7xx_i2c_uart_driver);
+#endif
+err_i2c:
+        uart_unregister_driver(&sc16is7xx_uart);
+        return ret;
 }
 module_init(sc16is7xx_init);
 
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 060fcd42b6d5..2d1c626312cd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -838,19 +838,9 @@ static void sci_transmit_chars(struct uart_port *port)
 
         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                 uart_write_wakeup(port);
-        if (uart_circ_empty(xmit)) {
+        if (uart_circ_empty(xmit))
                 sci_stop_tx(port);
-        } else {
-                ctrl = serial_port_in(port, SCSCR);
-
-                if (port->type != PORT_SCI) {
-                        serial_port_in(port, SCxSR); /* Dummy read */
-                        sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
-                }
 
-                ctrl |= SCSCR_TIE;
-                serial_port_out(port, SCSCR, ctrl);
-        }
 }
 
 /* On SH3, SCIF may read end-of-break as a space->mark char */
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 044c3cbdcfa4..a9e12b3bc31d 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -325,7 +325,7 @@ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
                 if (tty && C_HUPCL(tty))
                         tty_port_lower_dtr_rts(port);
 
-                if (port->ops->shutdown)
+                if (port->ops && port->ops->shutdown)
                         port->ops->shutdown(port);
         }
 out:
@@ -398,7 +398,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
  */
 int tty_port_carrier_raised(struct tty_port *port)
 {
-        if (port->ops->carrier_raised == NULL)
+        if (!port->ops || !port->ops->carrier_raised)
                 return 1;
         return port->ops->carrier_raised(port);
 }
@@ -414,7 +414,7 @@ EXPORT_SYMBOL(tty_port_carrier_raised);
  */
 void tty_port_raise_dtr_rts(struct tty_port *port)
 {
-        if (port->ops->dtr_rts)
+        if (port->ops && port->ops->dtr_rts)
                 port->ops->dtr_rts(port, 1);
 }
 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
@@ -429,7 +429,7 @@ EXPORT_SYMBOL(tty_port_raise_dtr_rts);
  */
 void tty_port_lower_dtr_rts(struct tty_port *port)
 {
-        if (port->ops->dtr_rts)
+        if (port->ops && port->ops->dtr_rts)
                 port->ops->dtr_rts(port, 0);
 }
 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
@@ -684,7 +684,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 
         if (!tty_port_initialized(port)) {
                 clear_bit(TTY_IO_ERROR, &tty->flags);
-                if (port->ops->activate) {
+                if (port->ops && port->ops->activate) {
                         int retval = port->ops->activate(port, tty);
                         if (retval) {
                                 mutex_unlock(&port->mutex);