docs: move s390 under arch

and fix all in-tree references.

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20230718045550.495428-1-costa.shul@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Documentation/admin-guide/kernel-parameters.txt

@@ -553,7 +553,7 @@
 			others).
 
 	ccw_timeout_log	[S390]
-			See Documentation/s390/common_io.rst for details.
+			See Documentation/arch/s390/common_io.rst for details.
 
 	cgroup_disable=	[KNL] Disable a particular controller or optional feature
 			Format: {name of the controller(s) or feature(s) to disable}
@@ -598,7 +598,7 @@
 			Setting checkreqprot to 1 is deprecated.
 
 	cio_ignore=	[S390]
-			See Documentation/s390/common_io.rst for details.
+			See Documentation/arch/s390/common_io.rst for details.
 
 	clearcpuid=X[,X...] [X86]
 			Disable CPUID feature X for the kernel. See

Documentation/arch/index.rst

@@ -21,7 +21,7 @@ implementation.
    parisc/index
    ../powerpc/index
    ../riscv/index
-   ../s390/index
+   s390/index
    sh/index
    sparc/index
    x86/index

Documentation/arch/s390/3270.rst

@@ -116,7 +116,7 @@ Here are the installation steps in detail:
 	as a 3270, not a 3215.
 
 	5. Run the 3270 configuration script config3270.  It is
-	distributed in this same directory, Documentation/s390, as
+	distributed in this same directory, Documentation/arch/s390, as
 	config3270.sh.  Inspect the output script it produces,
 	/tmp/mkdev3270, and then run that script.  This will create the
 	necessary character special device files and make the necessary
@@ -125,7 +125,7 @@ Here are the installation steps in detail:
 	Then notify /sbin/init that /etc/inittab has changed, by issuing
 	the telinit command with the q operand::
 
-		cd Documentation/s390
+		cd Documentation/arch/s390
 		sh config3270.sh
 		sh /tmp/mkdev3270
 		telinit q

Documentation/arch/s390/cds.rst

@@ -39,7 +39,7 @@ some of them are ESA/390 platform specific.
 
 Note:
   In order to write a driver for S/390, you also need to look into the interface
-  described in Documentation/s390/driver-model.rst.
+  described in Documentation/arch/s390/driver-model.rst.
 
 Note for porting drivers from 2.4:
 

Documentation/arch/s390/common_io.rst

@@ -136,5 +136,5 @@ debugfs entries
 
   The level of logging can be changed to be more or less verbose by piping to
   /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the
-  documentation on the S/390 debug feature (Documentation/s390/s390dbf.rst)
+  documentation on the S/390 debug feature (Documentation/arch/s390/s390dbf.rst)
   for details.

Documentation/arch/s390/pci.rst

@@ -40,7 +40,7 @@ For example:
   Change the level of logging to be more or less verbose by piping
   a number between 0 and 6 to  /sys/kernel/debug/s390dbf/pci_*/level. For
   details, see the documentation on the S/390 debug feature at
-  Documentation/s390/s390dbf.rst.
+  Documentation/arch/s390/s390dbf.rst.
 
 Sysfs entries
 =============

Documentation/arch/s390/vfio-ccw.rst

@@ -440,6 +440,6 @@ Reference
 1. ESA/s390 Principles of Operation manual (IBM Form. No. SA22-7832)
 2. ESA/390 Common I/O Device Commands manual (IBM Form. No. SA22-7204)
 3. https://en.wikipedia.org/wiki/Channel_I/O
-4. Documentation/s390/cds.rst
+4. Documentation/arch/s390/cds.rst
 5. Documentation/driver-api/vfio.rst
 6. Documentation/driver-api/vfio-mediated-device.rst

Documentation/driver-api/s390-drivers.rst

@@ -27,7 +27,7 @@ not strictly considered I/O devices. They are considered here as well,
 although they are not the focus of this document.
 
 Some additional information can also be found in the kernel source under
-Documentation/s390/driver-model.rst.
+Documentation/arch/s390/driver-model.rst.
 
 The css bus
 ===========
@@ -38,7 +38,7 @@ into several categories:
 * Standard I/O subchannels, for use by the system. They have a child
   device on the ccw bus and are described below.
 * I/O subchannels bound to the vfio-ccw driver. See
-  Documentation/s390/vfio-ccw.rst.
+  Documentation/arch/s390/vfio-ccw.rst.
 * Message subchannels. No Linux driver currently exists.
 * CHSC subchannels (at most one). The chsc subchannel driver can be used
   to send asynchronous chsc commands.