[PATCH v3 6/7] ocxl: Add an IOCTL so userspace knows what OCXL features are available

From: Alastair D'Silva
Date: Tue May 08 2018 - 20:44:52 EST


From: Alastair D'Silva <alastair@xxxxxxxxxxx>

In order for a userspace AFU driver to call the POWER9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
---
drivers/misc/ocxl/file.c | 25 +++++++++++++++++++++++++
include/uapi/misc/ocxl.h | 4 ++++
2 files changed, 29 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index eb409a469f21..33ae46ce0a8a 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
}
#endif

+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+ struct ocxl_ioctl_features __user *uarg)
+{
+ struct ocxl_ioctl_features arg;
+
+ memset(&arg, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+ if (cpu_has_feature(CPU_FTR_P9_TIDR))
+ arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+ if (copy_to_user(uarg, &arg, sizeof(arg)))
+ return -EFAULT;
+
+ return 0;
+}
+
#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" : \
x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" : \
x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : \
+ x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"UNKNOWN")

static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
break;
#endif

+ case OCXL_IOCTL_GET_FEATURES:
+ rc = afu_ioctl_get_features(ctx,
+ (struct ocxl_ioctl_features __user *) args);
+ break;
+
default:
rc = -EINVAL;
}
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 8d2748e69c84..bb80f294b429 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
__u64 reserved3[3];
};

+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT 0x01
+struct ocxl_ioctl_features {
+ __u64 flags[4];
};

struct ocxl_ioctl_irq_fd {
@@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
#define OCXL_IOCTL_IRQ_SET_FD _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
#define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct ocxl_ioctl_metadata)
#define OCXL_IOCTL_ENABLE_P9_WAIT _IOR(OCXL_MAGIC, 0x15, struct ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct ocxl_ioctl_platform)

#endif /* _UAPI_MISC_OCXL_H */
--
2.14.3