From: Daniel Scheller <[email protected]>

drivers/media/pci/ddbridge exposes a few IOCTLs which are used by userspace
utilities to ie. update PCIe card's FPGA firmware.

The IOCTLs chosen are in the range 0xDD/0xE0 up to 0xDD/0xFF, with 0xDD as
sort of gimmick for "Digital Devices". To not conflict with the zfpc driver
the upper range (0xE0-0xFF) is used. It is not clear if and which IOCTL
numbers the zfpc driver really uses, from reading the sources at
drivers/s390/scsi/ I couldn't really determine if IOCTLs are in use at all.
Maybe the S390 maintainers can double-check or comment, thus Cc linux-s390.

The upstream dddvb driver currently exposes 12 IOCTLs from which we're
going to handle two at the moment (DDB_FLASHIO and DDB_ID), which is all
that's required to perform the FPGA update on this hardware. The
"reservation" of 32 IDs may seem way too much in this regard, however,
we'd like to be able to stay compatible with the upstream out-of-tree
driver as much as possible, so should any of the remaining 10 IOCTLs be
required at any time (or even more, should upstream add more in the
future), we can just add them into this range without any hassles or
without creating conflicts anywhere.

Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Scheller <[email protected]>
---
 Documentation/ioctl/ioctl-number.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/ioctl/ioctl-number.txt 
b/Documentation/ioctl/ioctl-number.txt
index 84bb74dcae12..feac1b56900b 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -334,6 +334,7 @@ Code  Seq#(hex)     Include File            Comments
 0xDB   00-0F   drivers/char/mwave/mwavepub.h
 0xDD   00-3F   ZFCP device driver      see drivers/s390/scsi/
                                        <mailto:[email protected]>
+0xDD   E0-FF   linux/ddbridge-ioctl.h
 0xE5   00-3F   linux/fuse.h
 0xEC   00-01   drivers/platform/chrome/cros_ec_dev.h   ChromeOS EC driver
 0xF3   00-3F   drivers/usb/misc/sisusbvga/sisusb.h     sisfb (in development)
-- 
2.16.1

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to