[PATCH v4 1/3] tegra, serial8250: add ->handle_break() uart_port op

From: Dan Williams
Date: Tue Apr 10 2012 - 16:56:29 EST

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@xxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Stephen Warren <swarren@xxxxxxxxxx>
[stephen: kill CONFIG_SERIAL_TEGRA in favor just using CONFIG_ARCH_TEGRA]
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Sudhakar Mamillapalli <sudhakar@xxxxxx>
Reported-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
arch/arm/mach-tegra/board-harmony.c | 2 ++
arch/arm/mach-tegra/board-paz00.c | 3 +++
arch/arm/mach-tegra/board-seaboard.c | 2 ++
arch/arm/mach-tegra/board-trimslice.c | 2 ++
drivers/tty/serial/8250/8250.c | 34 +++------------------------------
drivers/tty/serial/of_serial.c | 26 +++++++++++++++++++++++++
include/linux/of_serial.h | 17 +++++++++++++++++
include/linux/serial_8250.h | 1 +
include/linux/serial_core.h | 5 +++++
9 files changed, 61 insertions(+), 31 deletions(-)
create mode 100644 include/linux/of_serial.h

diff --git a/arch/arm/mach-tegra/board-harmony.c b/arch/arm/mach-tegra/board-harmony.c
index c00aadb..222182e 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 330afdf..d0735c7 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 d669847..5b687b8 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 cd52820..f735858 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 5c27f7e..cbd94c3 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 e8c9cee..5410c06 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 0000000..4a73ed8
--- /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 8f012f8..a522fd9 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 2db407a..65db992 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) {

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