The current debugfs interface to scom is essentially unused
and racy. It uses two different files "address" and "data"
to perform accesses which is at best impractical for anything
but manual use by a developer.
This replaces it with an "access" file which represent the entire
scom address space which can be lseek/read/writen too.
This file only supports accesses that are 8 bytes aligned and
multiple of 8 bytes in size. The offset is logically the SCOM
address multiplied by 8.
Since nothing in userspace exploits that file at the moment, the ABI
change is a no-brainer.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is the traditional name for device-tree path, used in sysfs,
do the same for the XSCOM debugfs files.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When creating the debugfs scom files, use "ibm,chip-id" as the scom%d
index rather than a simple made up number when possible.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When devices are direct children of a scom controller node, they
should be able to use the normal "reg" property instead of "scom-reg".
In that case, they also use #address-cells rather than #scom-cells
to indicate the size of an entry.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
scom_read() now returns the read value via a pointer argument and
both functions return an int error code
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Commit c22618a1, "drivers/of: Constify device_node->name and
->path_component_name" changes device_node name to a const value, but
the PowerPC scom code still assigns it to a non-void field in
debugfs_blob_wrapper. The /right/ solution might be to change the
debugfs_blob_wrapper->data to also be const, but that is a bit
risky. Instead, cast the value to (void*). It is a bit ugly, but it
is the safest change until it can be investigated where
debugfs_blob_wrapper can be modified.
Reported-by: Michael Neuling <mikey@neuling.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The following shows up in chroma_defconfig:
CC arch/powerpc/sysdev/scom.o
arch/powerpc/sysdev/scom.c: In function 'scom_debug_init':
arch/powerpc/sysdev/scom.c:182:36: error: 'powerpc_debugfs_root' undeclared (first use in this function)
arch/powerpc/sysdev/scom.c:182:36: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [arch/powerpc/sysdev/scom.o] Error 1
make[1]: *** [arch/powerpc/sysdev/scom.o] Error 2
A bisect leads to commit 9ffc93f203
"Remove all #inclusions of asm/system.h"
Add the debug header which contains powerpc_debugfs_root.
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
With module.h being implicitly everywhere via device.h, the absence
of explicitly including something for EXPORT_SYMBOL went unnoticed.
Since we are heading to fix things up and clean module.h from the
device.h file, we need to explicitly include these files now.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
SCOM is a side-band configuration bus implemented on some processors.
This code provides a way for code to map and operate on devices via
SCOM, while the details of how that is implemented is left up to a
SCOM "controller" in the platform code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Benjamin Herrenschmidt
Grant Likely
Paul Gortmaker