From c557d392fbf5badd693ea1946a4317c87a26a716 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 6 Jul 2014 11:29:52 -0400 Subject: serial: Test for no tx data on tx restart Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c, 'serial_core: Fix conditional start_tx on ring buffer not empty' exposes an incorrect assumption in several drivers' start_tx methods; the tx ring buffer can, in fact, be empty when restarting tx while performing flow control. Affected drivers: sunsab.c ip22zilog.c pmac_zilog.c sunzilog.c m32r_sio.c imx.c Other in-tree serial drivers either are not affected or already test for empty tx ring buffer before transmitting. Test for empty tx ring buffer in start_tx() method, after transmitting x_char (if applicable). Reported-by: Aaro Koskinen Cc: Seth Bollinger Cc: "David S. Miller" Cc: Sam Ravnborg Cc: Thomas Bogendoerfer Signed-off-by: Peter Hurley Cc: stable # 3.15 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 3 +++ drivers/tty/serial/ip22zilog.c | 2 ++ drivers/tty/serial/m32r_sio.c | 8 +++++--- drivers/tty/serial/pmac_zilog.c | 3 +++ drivers/tty/serial/sunsab.c | 3 +++ drivers/tty/serial/sunzilog.c | 2 ++ 6 files changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index e2f9387..56bd9aa 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -567,6 +567,9 @@ static void imx_start_tx(struct uart_port *port) struct imx_port *sport = (struct imx_port *)port; unsigned long temp; + if (uart_circ_empty(&port.state->xmit)) + return; + if (USE_IRDA(sport)) { /* half duplex in IrDA mode; have to disable receive mode */ temp = readl(sport->port.membase + UCR4); diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c index 1efd4c3..99b7b86 100644 --- a/drivers/tty/serial/ip22zilog.c +++ b/drivers/tty/serial/ip22zilog.c @@ -603,6 +603,8 @@ static void ip22zilog_start_tx(struct uart_port *port) } else { struct circ_buf *xmit = &port->state->xmit; + if (uart_circ_empty(xmit)) + return; writeb(xmit->buf[xmit->tail], &channel->data); ZSDELAY(); ZS_WSYNC(channel); diff --git a/drivers/tty/serial/m32r_sio.c b/drivers/tty/serial/m32r_sio.c index 68f2c53..5702828 100644 --- a/drivers/tty/serial/m32r_sio.c +++ b/drivers/tty/serial/m32r_sio.c @@ -266,9 +266,11 @@ static void m32r_sio_start_tx(struct uart_port *port) if (!(up->ier & UART_IER_THRI)) { up->ier |= UART_IER_THRI; serial_out(up, UART_IER, up->ier); - serial_out(up, UART_TX, xmit->buf[xmit->tail]); - xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); - up->port.icount.tx++; + if (!uart_circ_empty(xmit)) { + serial_out(up, UART_TX, xmit->buf[xmit->tail]); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + up->port.icount.tx++; + } } while((serial_in(up, UART_LSR) & UART_EMPTY) != UART_EMPTY); #else diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c index 8193635..f7ad5b9 100644 --- a/drivers/tty/serial/pmac_zilog.c +++ b/drivers/tty/serial/pmac_zilog.c @@ -653,6 +653,8 @@ static void pmz_start_tx(struct uart_port *port) } else { struct circ_buf *xmit = &port->state->xmit; + if (uart_circ_empty(xmit)) + goto out; write_zsdata(uap, xmit->buf[xmit->tail]); zssync(uap); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); @@ -661,6 +663,7 @@ static void pmz_start_tx(struct uart_port *port) if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&uap->port); } + out: pmz_debug("pmz: start_tx() done.\n"); } diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c index 80a58ec..2f57df9 100644 --- a/drivers/tty/serial/sunsab.c +++ b/drivers/tty/serial/sunsab.c @@ -427,6 +427,9 @@ static void sunsab_start_tx(struct uart_port *port) struct circ_buf *xmit = &up->port.state->xmit; int i; + if (uart_circ_empty(xmit)) + return; + up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR); writeb(up->interrupt_mask1, &up->regs->w.imr1); diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c index a85db8b..02df394 100644 --- a/drivers/tty/serial/sunzilog.c +++ b/drivers/tty/serial/sunzilog.c @@ -703,6 +703,8 @@ static void sunzilog_start_tx(struct uart_port *port) } else { struct circ_buf *xmit = &port->state->xmit; + if (uart_circ_empty(xmit)) + return; writeb(xmit->buf[xmit->tail], &channel->data); ZSDELAY(); ZS_WSYNC(channel); -- cgit v1.1 From 99ecb001f52ef10ebf686d4e55b1cf64b1e56aa6 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 6 Jul 2014 11:29:53 -0400 Subject: serial: arc_uart: Use uart_circ_empty() for open-coded comparison Replace open-coded test for empty tx ring buffer with equivalent helper function, uart_circ_empty(). No functional change. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/arc_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c index c9f5c9d..008c223 100644 --- a/drivers/tty/serial/arc_uart.c +++ b/drivers/tty/serial/arc_uart.c @@ -177,7 +177,7 @@ static void arc_serial_tx_chars(struct arc_uart_port *uart) uart->port.icount.tx++; uart->port.x_char = 0; sent = 1; - } else if (xmit->tail != xmit->head) { /* TODO: uart_circ_empty */ + } else if (!uart_circ_empty(xmit)) { ch = xmit->buf[xmit->tail]; xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); uart->port.icount.tx++; -- cgit v1.1 From 8bec751bd63847b4044aab8b215db52aa6abde61 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 10 Jul 2014 22:36:46 -0400 Subject: serial: imx: Fix build breakage Fix breakage introduced by commit c557d392fbf5badd693ea1946a4317c87a26a716, 'serial: Test for no tx data on tx restart'. Reported-by: Stephen Rothwell Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 56bd9aa..044e86d 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -567,7 +567,7 @@ static void imx_start_tx(struct uart_port *port) struct imx_port *sport = (struct imx_port *)port; unsigned long temp; - if (uart_circ_empty(&port.state->xmit)) + if (uart_circ_empty(&port->state->xmit)) return; if (USE_IRDA(sport)) { -- cgit v1.1 From 34c4eda809e1efb16c554c07bb5df4c8ace9424e Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Fri, 11 Jul 2014 11:11:08 +0200 Subject: serial: sh-sci: Add device tree support for r8a7{778,740,3a4} and sh73a0 Simply document new compat strings. There appears to be no need for a driver updates. Signed-off-by: Simon Horman Signed-off-by: Greg Kroah-Hartman --- Documentation/devicetree/bindings/serial/renesas,sci-serial.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt index 64fd7de..b355660 100644 --- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt +++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt @@ -4,6 +4,13 @@ Required properties: - compatible: Must contain one of the following: + - "renesas,scifa-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFA compatible UART. + - "renesas,scifb-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFB compatible UART. + - "renesas,scifa-r8a73a4" for R8A73A4 (R-Mobile APE6) SCIFA compatible UART. + - "renesas,scifb-r8a73a4" for R8A73A4 (R-Mobile APE6) SCIFB compatible UART. + - "renesas,scifa-r8a7740" for R8A7740 (R-Mobile A1) SCIFA compatible UART. + - "renesas,scifb-r8a7740" for R8A7740 (R-Mobile A1) SCIFB compatible UART. + - "renesas,scif-r8a7778" for R8A7778 (R-Car M1) SCIF compatible UART. - "renesas,scif-r8a7779" for R8A7779 (R-Car H1) SCIF compatible UART. - "renesas,scif-r8a7790" for R8A7790 (R-Car H2) SCIF compatible UART. - "renesas,scifa-r8a7790" for R8A7790 (R-Car H2) SCIFA compatible UART. -- cgit v1.1