From 554adccf11f2ba2947ed221307ddd703c0889967 Mon Sep 17 00:00:00 2001
From: Leonardo Graboski Veiga <leogveiga@gmail.com>
Date: Thu, 23 Mar 2017 14:44:19 +0100
Subject: apalis/colibri-imx6/t30/tk1: read ahead cache configuration

Configure the read_ahead cache size to optimal value, for the
mmcblk devices (eMMC and SD card).

The cache values are module specific, tests were run on the pre-built
image (BSP V2.7 Beta 1). The measurement of read speed for a range of
cache sizes (16kB to 256MB) was made using hdparm -t.

Signed-off-by: Leonardo Graboski Veiga <leogveiga@gmail.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
---
 recipes-core/udev/files/hotplug.rules       |  2 ++
 recipes-core/udev/files/hotplug.sh          | 48 +++++++++++++++++++++++++++++
 recipes-core/udev/udev-extraconf_%.bbappend | 12 ++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 recipes-core/udev/files/hotplug.rules
 create mode 100644 recipes-core/udev/files/hotplug.sh

diff --git a/recipes-core/udev/files/hotplug.rules b/recipes-core/udev/files/hotplug.rules
new file mode 100644
index 0000000..a36a47d
--- /dev/null
+++ b/recipes-core/udev/files/hotplug.rules
@@ -0,0 +1,2 @@
+# SD card hotplug configuration of read_ahead cache size
+KERNEL=="mmcblk?", ACTION=="add"    RUN+="/etc/udev/scripts/hotplug.sh"
diff --git a/recipes-core/udev/files/hotplug.sh b/recipes-core/udev/files/hotplug.sh
new file mode 100644
index 0000000..b34c2a3
--- /dev/null
+++ b/recipes-core/udev/files/hotplug.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+#
+# Called from udev
+#
+# Set the read_ahead cache size of SD card on hotplug
+
+SYSNAME=$(uname -n)
+DISKNUM=$(echo $DEVNAME | sed -e 's/\(^.*\)\(.$\)/\2/')
+DISKNAME=$(echo $DEVNAME | sed 's/.*\///g;s/p.*//g')
+CORES=$(cat /proc/cpuinfo | grep processor | wc -l)
+
+set_read_ahead_size () {
+	if [ $DISKNUM == "0" ]; then #eMMC
+		echo $1 > /sys/block/$DISKNAME/queue/read_ahead_kb
+	else #SD card
+		echo $2 > /sys/block/$DISKNAME/queue/read_ahead_kb
+	fi
+}
+
+if [ "$ACTION" = "add" ] && [ -n "$DEVNAME" ] && [ "$DEVTYPE" = "disk" ]; then
+	#Set read_ahead cache of mmcblk? SD card
+	if test -e /sys/block/$DISKNAME/queue/read_ahead_kb
+	then
+		if [ $SYSNAME == "colibri-imx6" ]; then
+			if [ $CORES -eq 1 ]; then #imx6s
+				set_read_ahead_size 512 512
+			else #imx6dl
+				set_read_ahead_size 1024 512
+			fi
+		elif [ $SYSNAME == "colibri-t30" ]; then
+			set_read_ahead_size 2048 1024
+		elif [ $SYSNAME == "apalis-imx6" ]; then
+			if [ $CORES -eq 2 ]; then #imx6d
+				set_read_ahead_size 1024 512
+			else #imx6q
+				set_read_ahead_size 1024 512
+			fi
+		elif [ $SYSNAME == "apalis-t30" ]; then
+			set_read_ahead_size 4096 1024
+		elif [ $SYSNAME == "apalis-tk1" ]; then
+			set_read_ahead_size 4096 1024
+		else
+			logger "sd_hotplug.sh" "System name not compatible"
+		fi
+	else
+		logger "sd_hotplug" "No read_ahead_kb configuration file found"
+    fi
+fi
diff --git a/recipes-core/udev/udev-extraconf_%.bbappend b/recipes-core/udev/udev-extraconf_%.bbappend
index e9cf79a..7b03d77 100644
--- a/recipes-core/udev/udev-extraconf_%.bbappend
+++ b/recipes-core/udev/udev-extraconf_%.bbappend
@@ -1 +1,13 @@
 FILESEXTRAPATHS_prepend := "${THISDIR}/files/:"
+
+SRC_URI_append = " file://hotplug.rules \
+                   file://hotplug.sh \
+"
+
+do_install_append() {
+    install -d ${D}${sysconfdir}/udev/rules.d
+    install -m 0644 ${WORKDIR}/hotplug.rules    ${D}${sysconfdir}/udev/rules.d/hotplug.rules
+
+    install -d ${D}${sysconfdir}/udev/scripts/
+    install -m 0755 ${WORKDIR}/hotplug.sh ${D}${sysconfdir}/udev/scripts/hotplug.sh
+}
-- 
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