[PATCH v2 0/4] rework quirks for the "kt" serial port

[PATCH v2 0/4] rework quirks for the "kt" serial port

[Dan Williams]

Changes since v1: http://marc.info/?l=linux-serial&m=133373702606784&w=2

1/ rebased series on 3.4-rc2 to fix up a collision in patch 2 and
   dropped the recently accepted patches out of this series

2/ introduced quirk infrastructure for open firmware serial devices and
   hooked it up for Tegra's serial quirk

3/ updated the changelog in patch 4 to show the problems with quirk
   handling during resume

4/ added Alan's ack to patches 2-4.  patch 1 is new.

Patch 1-3 are targetted at 3.5 (pending an ack from Tegra folks), patch
4 is a RFC as the KT resume case was already fixed by "Revert
"serial/8250_pci: init-quirk msi support for kt serial controller"

---

Dan Williams (3):
      of_serial: add support for setup quirks
      tegra, serial8250: add ->handle_break() uart_port op
      serial/8250_pci: fix suspend/resume vs init/exit quirks

Sudhakar Mamillapalli (1):
      serial/8250_pci: Clear FIFOs for Intel ME Serial Over Lan device on BI


 arch/arm/configs/tegra_defconfig      |    1 
 arch/arm/mach-tegra/board-harmony.c   |    4 +
 arch/arm/mach-tegra/board-paz00.c     |    5 ++
 arch/arm/mach-tegra/board-seaboard.c  |    4 +
 arch/arm/mach-tegra/board-trimslice.c |    4 +
 arch/arm/mach-tegra/devices.h         |    1 
 drivers/tty/serial/8250/8250.c        |   44 +++++----------
 drivers/tty/serial/8250/8250.h        |    2 +
 drivers/tty/serial/8250/8250_pci.c    |   45 ++++++++++++++++
 drivers/tty/serial/Kconfig            |    8 +++
 drivers/tty/serial/of_serial.c        |   95 ++++++++++++++++++++++++++-------
 include/linux/of_serial.h             |   17 ++++++
 include/linux/serial_8250.h           |    1 
 include/linux/serial_core.h           |    5 ++
 14 files changed, 183 insertions(+), 53 deletions(-)
 create mode 100644 include/linux/of_serial.h

[PATCH v2 1/4] of_serial: add support for setup quirks

[Dan Williams]

Benign conversion of of_serial.c to offer the option of 'setup' quirks
similar to how 8250_pci.c houses the pci-serial-device quirks.

A setup quirk allows custom uart_port ops to specified in the
of_serial_info data fed to each serial of_device_id.

Tegra's 'break' quirk is the target consumer.

Cc: Colin Cross <ccross@android.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/tty/serial/of_serial.c |   68 ++++++++++++++++++++++++++++------------
 1 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index e8c9cee..4621cf9 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -22,13 +22,15 @@
 struct of_serial_info {
 	int type;
 	int line;
+	void (*setup)(struct uart_port *);
 };
 
 /*
  * Fill a struct uart_port for a given device node
  */
 static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
-					int type, struct uart_port *port)
+					      struct of_serial_info *info,
+					      struct uart_port *port)
 {
 	struct resource resource;
 	struct device_node *np = ofdev->dev.of_node;
@@ -78,12 +80,15 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
 		}
 	}
 
-	port->type = type;
+	port->type = info->type;
 	port->uartclk = clk;
 	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
 	port->dev = &ofdev->dev;
 
+	if (info->setup)
+		info->setup(port);
+
 	return 0;
 }
 
@@ -96,7 +101,6 @@ static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 	const struct of_device_id *match;
 	struct of_serial_info *info;
 	struct uart_port port;
-	int port_type;
 	int ret;
 
 	match = of_match_device(of_platform_serial_table, &ofdev->dev);
@@ -106,16 +110,12 @@ static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 		return -EBUSY;
 
-	info = kmalloc(sizeof(*info), GFP_KERNEL);
-	if (info == NULL)
-		return -ENOMEM;
-
-	port_type = (unsigned long)match->data;
-	ret = of_platform_serial_setup(ofdev, port_type, &port);
+	info = match->data;
+	ret = of_platform_serial_setup(ofdev, info, &port);
 	if (ret)
 		goto out;
 
-	switch (port_type) {
+	switch (info->type) {
 #ifdef CONFIG_SERIAL_8250
 	case PORT_8250 ... PORT_MAX_8250:
 		ret = serial8250_register_port(&port);
@@ -136,12 +136,10 @@ static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 	if (ret < 0)
 		goto out;
 
-	info->type = port_type;
 	info->line = ret;
 	dev_set_drvdata(&ofdev->dev, info);
 	return 0;
 out:
-	kfree(info);
 	irq_dispose_mapping(port.irq);
 	return ret;
 }
@@ -167,24 +165,52 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
 		/* need to add code for these */
 		break;
 	}
-	kfree(info);
 	return 0;
 }
 
 /*
+ * contiguous OF_ number space for serial port types so the
+ * __sinfo array does not have holes, and to allow cases of:
+ *  .type = 'common type', .setup = 'device specific quirk'
+ */
+enum {
+	OF_PORT_8250,
+	OF_PORT_16450,
+	OF_PORT_16550A,
+	OF_PORT_16550,
+	OF_PORT_16750,
+	OF_PORT_16850,
+	OF_PORT_TEGRA,
+	OF_PORT_NWPSERIAL,
+	OF_PORT_UNKNOWN,
+};
+
+static struct of_serial_info __refdata __sinfo[] = {
+	[OF_PORT_8250] = { .type = PORT_8250, },
+	[OF_PORT_16450] = { .type = PORT_16450, },
+	[OF_PORT_16550A] = { .type = PORT_16550A, },
+	[OF_PORT_16550] = { .type = PORT_16550, },
+	[OF_PORT_16750] = { .type = PORT_16750, },
+	[OF_PORT_16850] = { .type = PORT_16850, },
+	[OF_PORT_TEGRA] = { .type = PORT_TEGRA, },
+	[OF_PORT_NWPSERIAL] = { .type = PORT_NWPSERIAL, },
+	[OF_PORT_UNKNOWN] = { .type = PORT_UNKNOWN,  },
+};
+
+/*
  * A few common types, add more as needed.
  */
 static struct of_device_id __devinitdata of_platform_serial_table[] = {
-	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
-	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
-	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
-	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
-	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
-	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
-	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
+	{ .compatible = "ns8250",   .data = &__sinfo[OF_PORT_8250], },
+	{ .compatible = "ns16450",  .data = &__sinfo[OF_PORT_16450], },
+	{ .compatible = "ns16550a", .data = &__sinfo[OF_PORT_16550A], },
+	{ .compatible = "ns16550",  .data = &__sinfo[OF_PORT_16550], },
+	{ .compatible = "ns16750",  .data = &__sinfo[OF_PORT_16750], },
+	{ .compatible = "ns16850",  .data = &__sinfo[OF_PORT_16850], },
+	{ .compatible = "nvidia,tegra20-uart", .data = &__sinfo[OF_PORT_TEGRA], },
 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 	{ .compatible = "ibm,qpace-nwp-serial",
-		.data = (void *)PORT_NWPSERIAL, },
+		.data = &__sinfo[OF_PORT_NWPSERIAL], },
 #endif
 	{ .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 	{ /* end of list */ },

[PATCH v2 2/4] tegra, serial8250: add ->handle_break() uart_port op

[Dan Williams]

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 (CONFIG_TEGRA_SERIAL,
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>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
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>
---
 arch/arm/configs/tegra_defconfig      |    1 +
 arch/arm/mach-tegra/board-harmony.c   |    4 ++++
 arch/arm/mach-tegra/board-paz00.c     |    5 +++++
 arch/arm/mach-tegra/board-seaboard.c  |    4 ++++
 arch/arm/mach-tegra/board-trimslice.c |    4 ++++
 arch/arm/mach-tegra/devices.h         |    1 -
 drivers/tty/serial/8250/8250.c        |   34 +++------------------------------
 drivers/tty/serial/Kconfig            |    8 ++++++++
 drivers/tty/serial/of_serial.c        |   29 +++++++++++++++++++++++++++-
 include/linux/of_serial.h             |   17 +++++++++++++++++
 include/linux/serial_8250.h           |    1 +
 include/linux/serial_core.h           |    5 +++++
 12 files changed, 80 insertions(+), 33 deletions(-)
 create mode 100644 include/linux/of_serial.h

diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defconfig
index 351d670..de7288a 100644
--- a/arch/arm/configs/tegra_defconfig
+++ b/arch/arm/configs/tegra_defconfig
@@ -97,6 +97,7 @@ CONFIG_INPUT_EVDEV=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SERIAL_TEGRA=y
 # CONFIG_HW_RANDOM is not set
 CONFIG_I2C=y
 # CONFIG_I2C_COMPAT is not set
diff --git a/arch/arm/mach-tegra/board-harmony.c b/arch/arm/mach-tegra/board-harmony.c
index c00aadb..b8ceac3 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,
@@ -115,7 +117,9 @@ static void __init harmony_i2c_init(void)
 }
 
 static struct platform_device *harmony_devices[] __initdata = {
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA)
 	&debug_uart,
+#endif
 	&tegra_sdhci_device1,
 	&tegra_sdhci_device2,
 	&tegra_sdhci_device4,
diff --git a/arch/arm/mach-tegra/board-paz00.c b/arch/arm/mach-tegra/board-paz00.c
index 330afdf..1113dab 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,
@@ -142,7 +145,9 @@ static struct platform_device gpio_keys_device = {
 };
 
 static struct platform_device *paz00_devices[] __initdata = {
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA)
 	&debug_uart,
+#endif
 	&tegra_sdhci_device4,
 	&tegra_sdhci_device1,
 	&wifi_rfkill_device,
diff --git a/arch/arm/mach-tegra/board-seaboard.c b/arch/arm/mach-tegra/board-seaboard.c
index d669847..59a30ab 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,
@@ -145,7 +147,9 @@ static struct platform_device seaboard_audio_device = {
 };
 
 static struct platform_device *seaboard_devices[] __initdata = {
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA)
 	&debug_uart,
+#endif
 	&tegra_pmu_device,
 	&tegra_sdhci_device4,
 	&tegra_sdhci_device3,
diff --git a/arch/arm/mach-tegra/board-trimslice.c b/arch/arm/mach-tegra/board-trimslice.c
index cd52820..b156f55 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,
@@ -81,7 +83,9 @@ static struct platform_device trimslice_audio_device = {
 };
 
 static struct platform_device *trimslice_devices[] __initdata = {
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA)
 	&debug_uart,
+#endif
 	&tegra_sdhci_device1,
 	&tegra_sdhci_device4,
 	&tegra_i2s_device1,
diff --git a/arch/arm/mach-tegra/devices.h b/arch/arm/mach-tegra/devices.h
index ec45567..6e5f852 100644
--- a/arch/arm/mach-tegra/devices.h
+++ b/arch/arm/mach-tegra/devices.h
@@ -53,5 +53,4 @@ extern struct platform_device tegra_i2s_device1;
 extern struct platform_device tegra_i2s_device2;
 extern struct platform_device tegra_das_device;
 extern struct platform_device tegra_pcm_device;
-
 #endif
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/Kconfig b/drivers/tty/serial/Kconfig
index 665beb6..33fa6ec 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -380,6 +380,14 @@ config SERIAL_PXA_CONSOLE
 	  your boot loader (lilo or loadlin) about how to pass options to the
 	  kernel at boot time.)
 
+# FIXME remove this option when Tegra completes conversion to open firmware
+config SERIAL_TEGRA
+	bool "Tegra serial port support"
+	depends on SERIAL_OF_PLATFORM=y
+	help
+	  If you have a machine based on NVIDIA Tegra you can enable its
+	  onboard serial ports by enabling this option.
+
 config SERIAL_SA1100
 	bool "SA1100 serial port support"
 	depends on ARM && ARCH_SA1100
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 4621cf9..5a3b3f6 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -12,8 +12,10 @@
 #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_platform.h>
@@ -168,6 +170,31 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_SERIAL_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
+
+static void tegra_setup_quirk(struct uart_port *port)
+{
+	port->handle_break = tegra_serial_handle_break;
+}
+
 /*
  * contiguous OF_ number space for serial port types so the
  * __sinfo array does not have holes, and to allow cases of:
@@ -192,7 +219,7 @@ static struct of_serial_info __refdata __sinfo[] = {
 	[OF_PORT_16550] = { .type = PORT_16550, },
 	[OF_PORT_16750] = { .type = PORT_16750, },
 	[OF_PORT_16850] = { .type = PORT_16850, },
-	[OF_PORT_TEGRA] = { .type = PORT_TEGRA, },
+	[OF_PORT_TEGRA] = { .type = PORT_TEGRA, .setup = tegra_setup_quirk, },
 	[OF_PORT_NWPSERIAL] = { .type = PORT_NWPSERIAL, },
 	[OF_PORT_UNKNOWN] = { .type = PORT_UNKNOWN,  },
 };
diff --git a/include/linux/of_serial.h b/include/linux/of_serial.h
new file mode 100644
index 0000000..2035d96
--- /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.
+ */
+#if IS_ENABLED(CONFIG_SERIAL_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) {

[PATCH v2 3/4] serial/8250_pci: Clear FIFOs for Intel ME Serial Over Lan device on BI

[Dan Williams]

From: Sudhakar Mamillapalli <sudhakar@fb.com>

When using Serial Over Lan (SOL) over the virtual serial port in a Intel
management engine (ME) device, on device reset the serial FIFOs need to
be cleared to keep the FIFO indexes in-sync between the host and the
engine.

On a reset the serial device assertes BI, so using that as a cue FIFOs
are cleared.  So for this purpose a new handle_break callback has been
added.  One other problem is that the serial registers might temporarily
go to 0 on reset of this device.  So instead of using the IER register
read, if 0 returned use the ier value in uart_8250_port. This is hidden
under a custom serial_in.

Cc: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Sudhakar Mamillapalli <sudhakar@fb.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/tty/serial/8250/8250.c     |   10 +++++++++
 drivers/tty/serial/8250/8250.h     |    2 ++
 drivers/tty/serial/8250/8250_pci.c |   39 ++++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index cbd94c3..182efcc 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -568,6 +568,16 @@ static void serial8250_clear_fifos(struct uart_8250_port *p)
 	}
 }
 
+void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
+{
+	unsigned char fcr;
+
+	serial8250_clear_fifos(p);
+	fcr = uart_config[p->port.type].fcr;
+	serial_out(p, UART_FCR, fcr);
+}
+EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
+
 /*
  * IER sleep support.  UARTs which have EFRs need the "extended
  * capability" bit enabled.  Note that on XR16C850s, we need to
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 2868a1d..c9d0ebe 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -96,6 +96,8 @@ static inline void serial_out(struct uart_8250_port *up, int offset, int value)
 	up->port.serial_out(&up->port, offset, value);
 }
 
+void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p);
+
 #if defined(__alpha__) && !defined(CONFIG_PCI)
 /*
  * Digital did something really horribly wrong with the OUT1 and OUT2
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 858dca8..024551a 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/tty.h>
+#include <linux/serial_reg.h>
 #include <linux/serial_core.h>
 #include <linux/8250_pci.h>
 #include <linux/bitops.h>
@@ -1092,11 +1093,49 @@ static int skip_tx_en_setup(struct serial_private *priv,
 	return pci_default_setup(priv, board, port, idx);
 }
 
+static void kt_handle_break(struct uart_port *p)
+{
+	struct uart_8250_port *up =
+		container_of(p, struct uart_8250_port, port);
+	/*
+	 * On receipt of a BI, serial device in Intel ME (Intel
+	 * management engine) needs to have its fifos cleared for sane
+	 * SOL (Serial Over Lan) output.
+	 */
+	serial8250_clear_and_reinit_fifos(up);
+}
+
+static unsigned int kt_serial_in(struct uart_port *p, int offset)
+{
+	struct uart_8250_port *up =
+		container_of(p, struct uart_8250_port, port);
+	unsigned int val;
+
+	/*
+	 * When the Intel ME (management engine) gets reset its serial
+	 * port registers could return 0 momentarily.  Functions like
+	 * serial8250_console_write, read and save the IER, perform
+	 * some operation and then restore it.  In order to avoid
+	 * setting IER register inadvertently to 0, if the value read
+	 * is 0, double check with ier value in uart_8250_port and use
+	 * that instead.  up->ier should be the same value as what is
+	 * currently configured.
+	 */
+	val = inb(p->iobase + offset);
+	if (offset == UART_IER) {
+		if (val == 0)
+			val = up->ier;
+	}
+	return val;
+}
+
 static int kt_serial_setup(struct serial_private *priv,
 			   const struct pciserial_board *board,
 			   struct uart_port *port, int idx)
 {
 	port->flags |= UPF_BUG_THRE;
+	port->serial_in = kt_serial_in;
+	port->handle_break = kt_handle_break;
 	return skip_tx_en_setup(priv, board, port, idx);
 }
 

[PATCH v2 4/4] serial/8250_pci: fix suspend/resume vs init/exit quirks

[Dan Williams]

Commit e86ff4a6 "serial/8250_pci: init-quirk msi support for kt serial
controller" introduced a regression in suspend/resume by causing msi's
to be enabled twice without an intervening disable.

00:16.3 Serial controller: Intel Corporation Patsburg KT Controller (rev 05) (prog-if 02 [16550])
       Subsystem: Intel Corporation Device 7270
       Flags: bus master, 66MHz, fast devsel, latency 0, IRQ 72
       I/O ports at 4080 [size=8]
       Memory at d1c30000 (32-bit, non-prefetchable) [size=4K]
       Capabilities: [c8] Power Management version 3
       Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
       Kernel driver in use: serial

[  365.250523] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:16.3/msi_irqs'
[  365.250525] Modules linked in: nls_utf8 ipv6 uinput sg iTCO_wdt
  iTCO_vendor_support ioatdma dca i2c_i801 i2c_core wmi sd_mod ahci libahci isci
  libsas libata scsi_transport_sas [last unloaded: scsi_wait_scan]
[  365.250540] Pid: 9030, comm: kworker/u:1 Tainted: G        W    3.3.0-isci-3.0.213+ #1
[  365.250542] Call Trace:
[  365.250545]  [<ffffffff8115e955>] ? sysfs_add_one+0x99/0xad
[  365.250548]  [<ffffffff8102db8b>] warn_slowpath_common+0x85/0x9e
[  365.250551]  [<ffffffff8102dc96>] warn_slowpath_fmt+0x6e/0x70
[  365.250555]  [<ffffffff8115e8fa>] ? sysfs_add_one+0x3e/0xad
[  365.250558]  [<ffffffff8115e8b4>] ? sysfs_pathname+0x3c/0x44
[  365.250561]  [<ffffffff8115e8b4>] ? sysfs_pathname+0x3c/0x44
[  365.250564]  [<ffffffff8115e8b4>] ? sysfs_pathname+0x3c/0x44
[  365.250567]  [<ffffffff8115e8b4>] ? sysfs_pathname+0x3c/0x44
[  365.250570]  [<ffffffff8115e955>] sysfs_add_one+0x99/0xad
[  365.250573]  [<ffffffff8115f031>] create_dir+0x72/0xa5
[  365.250577]  [<ffffffff8115f194>] sysfs_create_dir+0xa2/0xbe
[  365.250581]  [<ffffffff81262463>] kobject_add_internal+0x126/0x1f8
[  365.250585]  [<ffffffff8126255b>] kset_register+0x26/0x3f
[  365.250588]  [<ffffffff8126275a>] kset_create_and_add+0x62/0x7c
[  365.250592]  [<ffffffff81293619>] populate_msi_sysfs+0x34/0x103
[  365.250595]  [<ffffffff81293e1c>] pci_enable_msi_block+0x1b3/0x216
[  365.250599]  [<ffffffff81303f7c>] try_enable_msi+0x13/0x17
[  365.250603]  [<ffffffff81303fb3>] pciserial_resume_ports+0x21/0x42
[  365.250607]  [<ffffffff81304041>] pciserial_resume_one+0x50/0x57
[  365.250610]  [<ffffffff81283e1a>] pci_legacy_resume+0x38/0x47
[  365.250613]  [<ffffffff81283e7d>] pci_pm_restore+0x54/0x87
[  365.250616]  [<ffffffff81283e29>] ? pci_legacy_resume+0x47/0x47
[  365.250619]  [<ffffffff8131e9e8>] dpm_run_callback+0x48/0x7b
[  365.250623]  [<ffffffff8131f39a>] device_resume+0x342/0x394
[  365.250626]  [<ffffffff8131f5b7>] async_resume+0x21/0x49

That patch has since been reverted, but by inspection it seems that
pciserial_suspend_ports() should be invoking .exit() quirks to release
resources acquired during .init().

Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/tty/serial/8250/8250_pci.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 024551a..24ea98c 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -2814,6 +2814,12 @@ void pciserial_suspend_ports(struct serial_private *priv)
 	for (i = 0; i < priv->nr; i++)
 		if (priv->line[i] >= 0)
 			serial8250_suspend_port(priv->line[i]);
+
+	/*
+	 * Ensure that every init quirk is properly torn down
+	 */
+	if (priv->quirk->exit)
+		priv->quirk->exit(priv->dev);
 }
 EXPORT_SYMBOL_GPL(pciserial_suspend_ports);
 

Re: [PATCH v2 1/4] of_serial: add support for setup quirks

[Arnd Bergmann]

On Monday 09 April 2012, Dan Williams wrote:
> Benign conversion of of_serial.c to offer the option of 'setup' quirks
> similar to how 8250_pci.c houses the pci-serial-device quirks.
> 
> A setup quirk allows custom uart_port ops to specified in the
> of_serial_info data fed to each serial of_device_id.
> 
> Tegra's 'break' quirk is the target consumer.
> 
> Cc: Colin Cross <ccross@android.com>
> Cc: Olof Johansson <olof@lixom.net>
> Cc: Stephen Warren <swarren@nvidia.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/tty/serial/of_serial.c |   68 ++++++++++++++++++++++++++++------------
>  1 files changed, 47 insertions(+), 21 deletions(-)

I don't think this is a good idea. Aside from the bug that you introduce
(you can no longer have multiple ports of the same type because of overwrite
the static info->line number), it seems an unnecessary complication.
Either just add the quirk to the of_serial file based on the compatible value,
or do a trivial new driver that has a subset of the existing one you need,
plus the quirk.

	Arnd 

Re: [PATCH v2 1/4] of_serial: add support for setup quirks

[Williams, Dan J]

On Mon, Apr 9, 2012 at 11:49 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Monday 09 April 2012, Dan Williams wrote:
>> Benign conversion of of_serial.c to offer the option of 'setup' quirks
>> similar to how 8250_pci.c houses the pci-serial-device quirks.
>>
>> A setup quirk allows custom uart_port ops to specified in the
>> of_serial_info data fed to each serial of_device_id.
>>
>> Tegra's 'break' quirk is the target consumer.
>>
>> Cc: Colin Cross <ccross@android.com>
>> Cc: Olof Johansson <olof@lixom.net>
>> Cc: Stephen Warren <swarren@nvidia.com>
>> Cc: Arnd Bergmann <arnd@arndb.de>
>> Cc: Grant Likely <grant.likely@secretlab.ca>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>> ---
>>  drivers/tty/serial/of_serial.c |   68 ++++++++++++++++++++++++++++------------
>>  1 files changed, 47 insertions(+), 21 deletions(-)
>
> I don't think this is a good idea. Aside from the bug that you introduce
> (you can no longer have multiple ports of the same type because of overwrite
> the static info->line number),

ah, yes, good catch.

> it seems an unnecessary complication.
> Either just add the quirk to the of_serial file based on the compatible value,
> or do a trivial new driver that has a subset of the existing one you need,
> plus the quirk.

ok.

The open question was where to house tegra_serial_handle_break, I'd
just as soon keep it all in of_serial.c and maintain the temporary
exports for use in the to-be-removed board files in
arch/arm/mach-tegra.

--
Dan