Improve compatibility handling

From: Mauro Carvalho Chehab <mchehab@infradead.org>

V4L/DVB tree keeps backward compatibility with vanilla 2.6.x kernels.
However, if some API changes happens on 2.6.x.y, this wouldn't be
handled.

This patch improves the compatibility capabilities of the tree by
allowing customized scripts to be added on make_config_compat.pl.
So, when generating config-compat.h, some compat checks can be done
against the kernel tree.

The practical effect is allowing compilation on 2.6.17.x trees, used by
several distros, where some changes on netdevice.h affects dvb-net,
stopping its compilation.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

4 files changed, 68 insertions, 18 deletions

diff --git a/linux/drivers/media/dvb/dvb-core/dvb_net.c b/linux/drivers/media/dvb/dvb-core/dvb_net.c
index 408c3b638..e180cdf53 100644
--- a/linux/drivers/media/dvb/dvb-core/dvb_net.c
+++ b/linux/drivers/media/dvb/dvb-core/dvb_net.c
@@ -1171,7 +1171,7 @@ static void wq_set_multicast_list (struct work_struct *work)
 
 	dvb_net_feed_stop(dev);
 	priv->rx_mode = RX_MODE_UNI;
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18)
+#ifdef OLD_XMIT_LOCK	/* Kernels equal or lower than 2.6.17 */
 	spin_lock_bh(&dev->xmit_lock);
 #else
 	netif_tx_lock_bh(dev);
@@ -1200,7 +1200,7 @@ static void wq_set_multicast_list (struct work_struct *work)
 		}
 	}
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18)
+#ifdef OLD_XMIT_LOCK	/* Kernels equal or lower than 2.6.17 */
 	spin_unlock_bh(&dev->xmit_lock);
 #else
 	netif_tx_unlock_bh(dev);
diff --git a/v4l/Makefile b/v4l/Makefile
index ad499751d..954d5227e 100644
--- a/v4l/Makefile
+++ b/v4l/Makefile
@@ -238,21 +238,8 @@ links::
 oss:
 	ln -sf . oss
 
-config-compat.h:: .myconfig
-	@perl \
-	-e 'print "#ifndef __CONFIG_COMPAT_H__\n";' \
-	-e 'print "#define __CONFIG_COMPAT_H__\n\n";' \
-	-e 'print "#include <linux/autoconf.h>\n\n";' \
-	-e 'while(<>) {' \
-	-e '    next unless /^(\S+)\s*:= (\S+)$$/;' \
-	-e '    print "#undef $$1\n";' \
-	-e '	print "#undef $$1_MODULE\n";' \
-	-e '       if($$2 eq "n") { next; }' \
-	-e '    elsif($$2 eq "m") { print "#define $$1_MODULE 1\n"; }' \
-	-e '    elsif($$2 eq "y") { print "#define $$1 1\n"; }' \
-	-e '    else              { print "#define $$1 $$2\n"; }' \
-	-e '} print "\n#endif\n";' \
-		< .myconfig > config-compat.h
+config-compat.h:: $(obj)/.version .myconfig
+	perl scripts/make_config_compat.pl $(KDIR) $(obj)/.myconfig $(obj)/config-compat.h
 
 kernel-links makelinks::
 	cd ..;	v4l/scripts/makelinks.sh $(KDIR)
diff --git a/v4l/scripts/gentree.pl b/v4l/scripts/gentree.pl
index f9f56bd7c..08969dab3 100755
--- a/v4l/scripts/gentree.pl
+++ b/v4l/scripts/gentree.pl
@@ -64,7 +64,10 @@ my %defs = (
 	'CONFIG_XC3028' => 0,
 	'CONFIG_TUNER_TEA5761' => 0,
 	'I2C_CLASS_TV_ANALOG' => 1,
-	'I2C_CLASS_TV_DIGITAL' => 1);
+	'I2C_CLASS_TV_DIGITAL' => 1,
+	'OLD_XMIT_LOCK' => 0,
+	'CONFIG_VIVI_SCATTER' => 0,
+);
 
 #################################################################
 # helpers
diff --git a/v4l/scripts/make_config_compat.pl b/v4l/scripts/make_config_compat.pl
new file mode 100644
index 000000000..be577d247
--- /dev/null
+++ b/v4l/scripts/make_config_compat.pl
@@ -0,0 +1,60 @@
+#!/usr/bin/perl
+use strict;
+
+my $kdir=shift or die "should specify a kernel dir";
+my $infile=shift or die "should specify an input config file";
+my $outfile=shift or die "should specify an output config file";
+
+my $out;
+
+sub check_spin_lock()
+{
+	my $file = "$kdir/include/linux/netdevice.h";
+	my $old_syntax = 1;
+
+	open INNET, "<$file" or die "File not found: $file";
+	while (<INNET>) {
+		if (m/netif_tx_lock_bh/) {
+			$old_syntax = 0;
+			last;
+		}
+	}
+
+	if ($old_syntax) {
+		$out.= "\n#define OLD_XMIT_LOCK 1\n";
+	}
+	close INNET;
+}
+
+sub check_other_dependencies()
+{
+	check_spin_lock();
+}
+
+# Do the basic rules
+open IN, "<$infile" or die "File not found: $infile";
+
+$out.= "#ifndef __CONFIG_COMPAT_H__\n";
+$out.= "#define __CONFIG_COMPAT_H__\n\n";
+$out.= "#include <linux/autoconf.h>\n\n";
+while(<IN>) {
+	next unless /^(\S+)\s*:= (\S+)$/;
+	$out.= "#undef $1\n";
+	$out.= "#undef $1_MODULE\n";
+	if($2 eq "n") {
+		next;
+	} elsif($2 eq "m") {
+		$out.= "#define $1_MODULE 1\n";
+	} elsif($2 eq "y") {
+		$out.= "#define $1 1\n";
+	} else {
+		$out.= "#define $1 $2\n";
+	}
+}
+close IN;
+
+check_other_dependencies();
+
+open OUT, ">$outfile" or die 'Unable to write $outfile';
+print OUT "$out\n#endif\n";
+close OUT