[PATCH] 8250: serial device file is out of order

[Scott Yuan <scottzero0@gmail.com>]

 From ebb85a61456bf25f87aeb8a31c92c74540bdf306 Mon Sep 17 00:00:00 2001
From: Scott Yuan <scottzero0@gmail.com>
Date: Sun, 24 Aug 2014 13:46:56 +0800
Subject: [PATCH] 8250: serial device file is out of order

On x86 architecture, the configuration of serial device maybe get from ACPI
DSDT, but the order of DSDT is not mandatory, result as array 
serial8250_ports
is out of order. This situation is more obvious in multiple serial port
mainboard. Sort it by unique id that in DSDT will fix it.

Signed-off-by: Scott Yuan <scottzero0@gmail.com>
---
  drivers/pnp/pnpacpi/core.c          |  1 +
  drivers/tty/serial/8250/8250_core.c | 40 
++++++++++++++++++++++++++++++++++++-
  drivers/tty/serial/8250/8250_pnp.c  | 12 +++++++++++
  include/linux/pnp.h                 |  1 +
  include/linux/serial_8250.h         |  2 ++
  5 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index a5c6cb7..84b518e 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -254,6 +254,7 @@ static int __init pnpacpi_add_device(struct 
acpi_device *device)
  		return -ENOMEM;
   	dev->data = device;
+	dev->is_acpi = 1;
  	/* .enabled means the device can decode the resources */
  	dev->active = device->status.enabled;
  	if (acpi_has_method(device->handle, "_SRS"))
diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 7a91c6d..0e5ece5 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -3221,6 +3221,41 @@ static struct uart_8250_port 
*serial8250_find_match_or_unused(struct uart_port *
  	return NULL;
  }
  +static struct uart_8250_port *
+serial8250_find_match_sorted_port(struct uart_port *port)
+{
+	int i, j;
+	struct uart_8250_port *uart;
+
+	uart = container_of(port, struct uart_8250_port, port);
+
+	/*
+	 * We need sorted array serial8250_ports, it is sort by ACPI
+	 * device unique id, so find an apropriate position to insert.
+	 */
+	for (i = 0; i < nr_uarts; i++) {
+		if (serial8250_ports[i].uid == 0 ||
+			uart->uid < serial8250_ports[i].uid)
+			break;
+	}
+
+	/*
+	 * If current uid that in serial8250_ports is big than port uid,
+	 * then move 8250 port data.
+	 */
+	if (i < nr_uarts - 1 &&
+		uart->uid < serial8250_ports[i].uid) {
+		memmove(&serial8250_ports[i+1], &serial8250_ports[i],
+			(nr_uarts - i - 1) * sizeof(struct uart_8250_port));
+
+		/* modify port.line, since data moved */
+		for (j = i + 1; j < nr_uarts; j++)
+			serial8250_ports[j].port.line += 1;
+	}
+	serial8250_ports[i].uid = uart->uid;
+	return &serial8250_ports[i];
+}
+
  /**
   *	serial8250_register_8250_port - register a serial port
   *	@up: serial port template
@@ -3244,7 +3279,10 @@ int serial8250_register_8250_port(struct 
uart_8250_port *up)
   	mutex_lock(&serial_mutex);
  -	uart = serial8250_find_match_or_unused(&up->port);
+	if (up->is_acpi)
+		uart = serial8250_find_match_sorted_port(&up->port);
+	else
+		uart = serial8250_find_match_or_unused(&up->port);
  	if (uart && uart->port.type != PORT_8250_CIR) {
  		if (uart->port.dev)
  			uart_remove_one_port(&serial8250_reg, &uart->port);
diff --git a/drivers/tty/serial/8250/8250_pnp.c 
b/drivers/tty/serial/8250/8250_pnp.c
index 682a2fb..c880ed3 100644
--- a/drivers/tty/serial/8250/8250_pnp.c
+++ b/drivers/tty/serial/8250/8250_pnp.c
@@ -15,6 +15,8 @@
  #include <linux/pci.h>
  #include <linux/pnp.h>
  #include <linux/string.h>
+#include <acpi/acpi.h>
+#include <acpi/acpi_bus.h>
  #include <linux/kernel.h>
  #include <linux/serial_core.h>
  #include <linux/bitops.h>
@@ -427,6 +429,8 @@ static int
  serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
  {
  	struct uart_8250_port uart;
+	struct acpi_device *acpi_dev;
+	char *serial_uid;
  	int ret, line, flags = dev_id->driver_data;
   	if (flags & UNKNOWN_DEV) {
@@ -451,6 +455,14 @@ serial_pnp_probe(struct pnp_dev *dev, const struct 
pnp_device_id *dev_id)
  	} else
  		return -ENODEV;
  +	if (dev->is_acpi) {
+		acpi_dev = dev->data;
+		serial_uid = acpi_dev->pnp.unique_id;
+		uart.is_acpi = 1;
+		if (kstrtoint(serial_uid, 10, &uart.uid))
+			return -EINVAL;
+	}
+
  #ifdef SERIAL_DEBUG_PNP
  	printk(KERN_DEBUG
  		"Setup PNP port: port %x, mem 0x%lx, irq %d, type %d\n",
diff --git a/include/linux/pnp.h b/include/linux/pnp.h
index 195aafc..d745f14 100644
--- a/include/linux/pnp.h
+++ b/include/linux/pnp.h
@@ -245,6 +245,7 @@ struct pnp_dev {
  	u64 dma_mask;
  	unsigned int number;		/* used as an index, must be unique */
  	int status;
+	unsigned char is_acpi;		/* is acpi device */
   	struct list_head global_list;	/* node in global list of devices */
  	struct list_head protocol_list;	/* node in list of device's protocol */
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index af47a8a..8f1e1bd 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -74,7 +74,9 @@ struct uart_8250_port {
  	struct list_head	list;		/* ports on this IRQ */
  	unsigned short		capabilities;	/* port capabilities */
  	unsigned short		bugs;		/* port bugs */
+	int			uid;		/* ACPI device unique id */
  	unsigned int		tx_loadsz;	/* transmit fifo load size */
+	unsigned char		is_acpi;	/* is acpi device */
  	unsigned char		acr;
  	unsigned char		ier;
  	unsigned char		lcr;
-- 
1.9.1