tegra, serial8250: add ->handle_break() uart_port op

The "KT" serial port has another use case for a "received break" quirk,
so before adding another special case to the 8250 core take this
opportunity to push such quirks out of the core and into a uart_port op.

Stephen says:
"If the callback function is to no longer live in 8250.c itself,
 arch/arm/mach-tegra/devices.c isn't logically a good place to put it,
 and that file will be going away once we get rid of all the board files
 and move solely to device tree."

...so since 8250_pci.c houses all the quirks for pci serial devices this
quirk is similarly housed in of_serial.c.  Once the open firmware
conversion completes the infrastructure details
(include/linux/of_serial.h, and the export) can all be removed to make
this self contained to of_serial.c.

Cc: Nhan H Mai <nhan.h.mai@intel.com>
Cc: Colin Cross <ccross@android.com>
Cc: Olof Johansson <olof@lixom.net>
[stephen: kill CONFIG_SERIAL_TEGRA in favor just using CONFIG_ARCH_TEGRA]
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Sudhakar Mamillapalli <sudhakar@fb.com>
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

9 files changed, 61 insertions, 31 deletions

diff --git a/arch/arm/mach-tegra/board-harmony.c b/arch/arm/mach-tegra/board-harmony.c
index c00aadb01e09..222182e00226 100644
--- a/arch/arm/mach-tegra/board-harmony.c
+++ b/arch/arm/mach-tegra/board-harmony.c
@@ -19,6 +19,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/serial_8250.h>
+#include <linux/of_serial.h>
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/pda_power.h>
@@ -52,6 +53,7 @@ static struct plat_serial8250_port debug_uart_platform_data[] = {
                 .irq            = INT_UARTD,
                 .flags          = UPF_BOOT_AUTOCONF | UPF_FIXED_TYPE,
                 .type           = PORT_TEGRA,
+                .handle_break   = tegra_serial_handle_break,
                 .iotype         = UPIO_MEM,
                 .regshift       = 2,
                 .uartclk        = 216000000,
diff --git a/arch/arm/mach-tegra/board-paz00.c b/arch/arm/mach-tegra/board-paz00.c
index 330afdfa2475..d0735c70d688 100644
--- a/arch/arm/mach-tegra/board-paz00.c
+++ b/arch/arm/mach-tegra/board-paz00.c
@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/serial_8250.h>
+#include <linux/of_serial.h>
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/gpio_keys.h>
@@ -55,6 +56,7 @@ static struct plat_serial8250_port debug_uart_platform_data[] = {
                 .irq            = INT_UARTA,
                 .flags          = UPF_BOOT_AUTOCONF | UPF_FIXED_TYPE,
                 .type           = PORT_TEGRA,
+                .handle_break   = tegra_serial_handle_break,
                 .iotype         = UPIO_MEM,
                 .regshift       = 2,
                 .uartclk        = 216000000,
@@ -65,6 +67,7 @@ static struct plat_serial8250_port debug_uart_platform_data[] = {
                 .irq            = INT_UARTC,
                 .flags          = UPF_BOOT_AUTOCONF | UPF_FIXED_TYPE,
                 .type           = PORT_TEGRA,
+                .handle_break   = tegra_serial_handle_break,
                 .iotype         = UPIO_MEM,
                 .regshift       = 2,
                 .uartclk        = 216000000,
diff --git a/arch/arm/mach-tegra/board-seaboard.c b/arch/arm/mach-tegra/board-seaboard.c
index d669847f0485..5b687b8258c0 100644
--- a/arch/arm/mach-tegra/board-seaboard.c
+++ b/arch/arm/mach-tegra/board-seaboard.c
@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/serial_8250.h>
+#include <linux/of_serial.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/input.h>
@@ -47,6 +48,7 @@ static struct plat_serial8250_port debug_uart_platform_data[] = {
                 /* Memory and IRQ filled in before registration */
                 .flags          = UPF_BOOT_AUTOCONF | UPF_FIXED_TYPE,
                 .type           = PORT_TEGRA,
+                .handle_break   = tegra_serial_handle_break,
                 .iotype         = UPIO_MEM,
                 .regshift       = 2,
                 .uartclk        = 216000000,
diff --git a/arch/arm/mach-tegra/board-trimslice.c b/arch/arm/mach-tegra/board-trimslice.c
index cd52820a3e37..f7358586b523 100644
--- a/arch/arm/mach-tegra/board-trimslice.c
+++ b/arch/arm/mach-tegra/board-trimslice.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/serial_8250.h>
+#include <linux/of_serial.h>
 #include <linux/io.h>
 #include <linux/i2c.h>
 #include <linux/gpio.h>
@@ -48,6 +49,7 @@ static struct plat_serial8250_port debug_uart_platform_data[] = {
                 .irq            = INT_UARTA,
                 .flags          = UPF_BOOT_AUTOCONF | UPF_FIXED_TYPE,
                 .type           = PORT_TEGRA,
+                .handle_break   = tegra_serial_handle_break,
                 .iotype         = UPIO_MEM,
                 .regshift       = 2,
                 .uartclk        = 216000000,
diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 5b149b466ec8..dffd623b7974 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -1332,27 +1332,6 @@ static void serial8250_enable_ms(struct uart_port *port)
 }
 
 /*
- * Clear the Tegra rx fifo after a break
- *
- * FIXME: This needs to become a port specific callback once we have a
- * framework for this
- */
-static void clear_rx_fifo(struct uart_8250_port *up)
-{
-        unsigned int status, tmout = 10000;
-        do {
-                status = serial_in(up, UART_LSR);
-                if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
-                        status = serial_in(up, UART_RX);
-                else
-                        break;
-                if (--tmout == 0)
-                        break;
-                udelay(1);
-        } while (1);
-}
-
-/*
  * serial8250_rx_chars: processes according to the passed in LSR
  * value, and returns the remaining LSR bits not handled
  * by this Rx routine.
@@ -1386,20 +1365,10 @@ serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
                 up->lsr_saved_flags = 0;
 
                 if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
-                        /*
-                         * For statistics only
-                         */
                         if (lsr & UART_LSR_BI) {
                                 lsr &= ~(UART_LSR_FE | UART_LSR_PE);
                                 port->icount.brk++;
                                 /*
-                                 * If tegra port then clear the rx fifo to
-                                 * accept another break/character.
-                                 */
-                                if (port->type == PORT_TEGRA)
-                                        clear_rx_fifo(up);
-
-                                /*
                                  * We do the SysRQ and SAK checking
                                  * here because otherwise the break
                                  * may get masked by ignore_status_mask
@@ -3037,6 +3006,7 @@ static int __devinit serial8250_probe(struct platform_device *dev)
                 port.serial_in          = p->serial_in;
                 port.serial_out         = p->serial_out;
                 port.handle_irq         = p->handle_irq;
+                port.handle_break       = p->handle_break;
                 port.set_termios        = p->set_termios;
                 port.pm                 = p->pm;
                 port.dev                = &dev->dev;
@@ -3209,6 +3179,8 @@ int serial8250_register_port(struct uart_port *port)
                         uart->port.set_termios = port->set_termios;
                 if (port->pm)
                         uart->port.pm = port->pm;
+                if (port->handle_break)
+                        uart->port.handle_break = port->handle_break;
 
                 if (serial8250_isa_config != NULL)
                         serial8250_isa_config(0, &uart->port,
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index e8c9cee07d00..5410c0637266 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -12,10 +12,13 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 #include <linux/serial_core.h>
 #include <linux/serial_8250.h>
+#include <linux/serial_reg.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/of_serial.h>
 #include <linux/of_platform.h>
 #include <linux/nwpserial.h>
 
@@ -24,6 +27,26 @@ struct of_serial_info {
         int line;
 };
 
+#ifdef CONFIG_ARCH_TEGRA
+void tegra_serial_handle_break(struct uart_port *p)
+{
+        unsigned int status, tmout = 10000;
+
+        do {
+                status = p->serial_in(p, UART_LSR);
+                if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
+                        status = p->serial_in(p, UART_RX);
+                else
+                        break;
+                if (--tmout == 0)
+                        break;
+                udelay(1);
+        } while (1);
+}
+/* FIXME remove this export when tegra finishes conversion to open firmware */
+EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
+#endif
+
 /*
  * Fill a struct uart_port for a given device node
  */
@@ -84,6 +107,9 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
         port->dev = &ofdev->dev;
 
+        if (type == PORT_TEGRA)
+                port->handle_break = tegra_serial_handle_break;
+
         return 0;
 }
 
diff --git a/include/linux/of_serial.h b/include/linux/of_serial.h
new file mode 100644
index 000000000000..4a73ed80b4c0
--- /dev/null
+++ b/include/linux/of_serial.h
@@ -0,0 +1,17 @@
+#ifndef __LINUX_OF_SERIAL_H
+#define __LINUX_OF_SERIAL_H
+
+/*
+ * FIXME remove this file when tegra finishes conversion to open firmware,
+ * expectation is that all quirks will then be self-contained in
+ * drivers/tty/serial/of_serial.c.
+ */
+#ifdef CONFIG_ARCH_TEGRA
+extern void tegra_serial_handle_break(struct uart_port *port);
+#else
+static inline void tegra_serial_handle_break(struct uart_port *port)
+{
+}
+#endif
+
+#endif /* __LINUX_OF_SERIAL */
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 8f012f8ac8e9..a522fd977aad 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -38,6 +38,7 @@ struct plat_serial8250_port {
         int             (*handle_irq)(struct uart_port *);
         void            (*pm)(struct uart_port *, unsigned int state,
                               unsigned old);
+        void            (*handle_break)(struct uart_port *);
 };
 
 /*
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index f51bf2e70c69..0dd752f3039d 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -310,6 +310,7 @@ struct uart_port {
         int                     (*handle_irq)(struct uart_port *);
         void                    (*pm)(struct uart_port *, unsigned int state,
                                       unsigned int old);
+        void                    (*handle_break)(struct uart_port *);
         unsigned int            irq;                    /* irq number */
         unsigned long           irqflags;               /* irq flags  */
         unsigned int            uartclk;                /* base uart clock */
@@ -533,6 +534,10 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 static inline int uart_handle_break(struct uart_port *port)
 {
         struct uart_state *state = port->state;
+
+        if (port->handle_break)
+                port->handle_break(port);
+
 #ifdef SUPPORT_SYSRQ
         if (port->cons && port->cons->index == port->line) {
                 if (!port->sysrq) {