cxl: Add documentation for userspace APIs

This documentation gives an overview of the hardware architecture, userspace
APIs via /dev/cxl/afuM.N and the syfs files. It also adds a MAINTAINERS file
entry for cxl.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 4 insertions, 3 deletions

diff --git a/include/uapi/misc/cxl.h b/include/uapi/misc/cxl.h
index c232be6ae21f..cd6d789b73ec 100644
--- a/include/uapi/misc/cxl.h
+++ b/include/uapi/misc/cxl.h
@@ -13,7 +13,7 @@
 #include <linux/types.h>
 #include <linux/ioctl.h>
 
-/* Structs for IOCTLS for userspace to talk to the kernel */
+
 struct cxl_ioctl_start_work {
         __u64 flags;
         __u64 work_element_descriptor;
@@ -26,19 +26,20 @@ struct cxl_ioctl_start_work {
         __u64 reserved5;
         __u64 reserved6;
 };
+
 #define CXL_START_WORK_AMR              0x0000000000000001ULL
 #define CXL_START_WORK_NUM_IRQS         0x0000000000000002ULL
 #define CXL_START_WORK_ALL              (CXL_START_WORK_AMR |\
                                          CXL_START_WORK_NUM_IRQS)
 
-/* IOCTL numbers */
+/* ioctl numbers */
 #define CXL_MAGIC 0xCA
 #define CXL_IOCTL_START_WORK            _IOW(CXL_MAGIC, 0x00, struct cxl_ioctl_start_work)
 #define CXL_IOCTL_GET_PROCESS_ELEMENT   _IOR(CXL_MAGIC, 0x01, __u32)
 
-/* Events from read() */
 #define CXL_READ_MIN_SIZE 0x1000 /* 4K */
 
+/* Events from read() */
 enum cxl_event_type {
         CXL_EVENT_RESERVED      = 0,
         CXL_EVENT_AFU_INTERRUPT = 1,