zdev: Integrate firmware auto-configuration with initramfs-tools

Add initramfs-tools scripts that apply firmware-provided I/O
configuration data as auto-configuration during boot. This way, all I/O
devices configured by DPM are automatically brought online without
further user interaction.

This mechanism is active by default. It can be deactivated by specifying
the following parameter on the kernel command line:

  rd.zdev=no-auto

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

README.md

@@ -271,6 +271,7 @@ This table lists additional build or install options:
 | __COMPONENT__  | __OPTION__       | __TOOLS__                       |
 |----------------|:----------------:|:-------------------------------:|
 | dracut         | `HAVE_DRACUT`    | zdev                            |
+| initramfs-tools| `HAVE_INITRAMFS` | zdev                            |
 
 The s390-tools build process uses "pkg-config" if available and hard-coded
 compiler and linker options otherwise.

zdev/Makefile

@@ -8,6 +8,7 @@ install: all
 	$(MAKE) -C src install
 	$(MAKE) -C man install
 	$(MAKE) -C dracut install
+	$(MAKE) -C initramfs install
 
 clean:
 	$(MAKE) -C src clean

zdev/initramfs/Makefile

@@ -0,0 +1,22 @@
+# Common definitions
+include ../../common.mak
+
+INITRAMFSDIR := /usr/share/initramfs-tools
+HOOKDIR := $(INITRAMFSDIR)/hooks
+INITTOP := $(INITRAMFSDIR)/scripts/init-top
+
+# HAVE_INITRAMFS
+#
+# This install time parameter determines whether the zdev initramfs support is
+# installed (HAVE_INITRAMFS=1) or not (default). When installed, the module
+# performs the following functions when mkinitramfs is run:
+#
+#  - install a boot-time hook to apply firmware-provided configuration data
+#    to the system
+#
+ifeq ($(HAVE_INITRAMFS),1)
+install:
+	$(INSTALL) -m 755 -d $(DESTDIR)/$(HOOKDIR) $(DESTDIR)/$(INITTOP)
+	$(INSTALL) -m 755 hooks/zdev $(DESTDIR)/$(HOOKDIR)
+	$(INSTALL) -m 755 scripts/init-top/zdev $(DESTDIR)/$(INITTOP)
+endif

zdev/initramfs/hooks/zdev

@@ -0,0 +1,39 @@
+#!/bin/sh
+#
+# Copyright IBM Corp. 2016, 2017
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+# hooks/zdev
+#   This hook script adds files required to apply firmware-provided I/O
+#   configuration data during boot.
+#
+
+PREREQ=""
+
+prereqs()
+{
+	echo "$PREREQ"
+}
+
+case $1 in
+	prereqs)
+	prereqs
+	exit 0
+	;;
+esac
+
+. /usr/share/initramfs-tools/hook-functions
+
+# Add modules for all device types supported by chzdev (required for
+# auto-configuration)
+zdev_modules="lcs qeth qeth_l2 qeth_l3 dasd_mod dasd_eckd_mod dasd_fba_mod dasd_diag_mod zfcp"
+
+for x in $zdev_modules ; do
+	manual_add_modules ${x}
+done
+
+copy_exec /sbin/chzdev
+copy_exec /sbin/lszdev
+copy_exec /sbin/vmcp

zdev/initramfs/scripts/init-top/zdev

@@ -0,0 +1,67 @@
+#!/bin/sh
+#
+# Copyright IBM Corp. 2017
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+# scripts/init-top/zdev
+#   Parse the kernel command line for rd.zdev kernel parameters. These
+#   parameters are evaluated and used to configure z Systems specific devices.
+#
+# Format:
+#   rd.zdev=no-auto
+#
+#     where
+#
+#   no-auto:       Indicates that firmware-provided I/O configuration data
+#                  should not be applied.
+#
+
+PREREQ="udev"
+
+prereqs()
+{
+	echo "$PREREQ"
+}
+
+case $1 in
+prereqs)
+	prereqs
+	exit 0
+	;;
+esac
+
+. /scripts/functions
+
+zdev_fw_file="/sys/firmware/sclp_sd/config/data"
+zdev_base_args="--force --yes --no-root-update --no-settle --auto-conf --quiet"
+
+if [ -e "$zdev_fw_file" ] ; then
+	zdev_auto=1
+else
+	zdev_auto=0
+fi
+
+for x in $(cat /proc/cmdline); do
+        case ${x} in
+	rd.zdev=*)
+		zdev_arg=${x#*=}
+		if [ "$zdev_arg" = "no-auto" ] ; then
+			zdev_auto=0
+		fi
+		;;
+	esac
+done
+
+if [ $zdev_auto -eq 1 ] ; then
+	log_begin_msg "Starting firmware auto-configuration"
+	chzdev --import "$zdev_fw_file" $zdev_base_args
+	log_end_msg
+
+	# Repeat cold-plug after creating udev rules
+	udevadm control --reload
+	udevadm trigger --type=subsystems --action=add
+	udevadm trigger --action=add
+	udevadm settle || true
+fi