Commit 27d4dc71 authored by Vaibhav Jain's avatar Vaibhav Jain Committed by Michael Ellerman
Browse files

cxl: Implement an ioctl to fetch afu card-id, offset-id and mode 



Given a file descriptor on an afu device, libcxl currently uses the
major/minor number obtained from fstat on the fd to construct path to
the afu's sysfs directory. However it is possible that rather than using
one of the device in /dev/cxl, a kernel driver creates its own device
which export generic cxl interface to the userspace. This causes
problems with libcxl as it tries to use a wrong major/minor number to
construct the sysfs path and fail.

So this patch introduces a new ioctl called CXL_IOCTL_GET_AFU_ID on the
afu file descriptor to fetch the cxl_afu_id struct that holds the
card/offset-id and mode information. These info is then used by libcxl to
construct the correct path to the afu sysfs directory.

Testing:
	- Build against pseries be/le configs
	- Testing with corresponding libcxl changes to verify that it constructs
	  right sysfs path to the afu.

Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: default avatarIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 989898b7

drivers/misc/cxl/cxl.h

+0 −2
Original line number Diff line number Diff line
@@ -315,8 +315,6 @@ static const cxl_p2n_reg_t CXL_PSL_WED_An = {0x0A0}; 
#define CXL_MAX_SLICES 4

#define MAX_AFU_MMIO_REGS 3



#define CXL_MODE_DEDICATED   0x1

#define CXL_MODE_DIRECTED    0x2

#define CXL_MODE_TIME_SLICED 0x4

#define CXL_SUPPORTED_MODES (CXL_MODE_DEDICATED | CXL_MODE_DIRECTED)

drivers/misc/cxl/file.c

+22 −0
Original line number Diff line number Diff line
@@ -212,6 +212,25 @@ static long afu_ioctl_process_element(struct cxl_context *ctx, 
	return 0;

}



static long afu_ioctl_get_afu_id(struct cxl_context *ctx,

				 struct cxl_afu_id __user *upafuid)

{

	struct cxl_afu_id afuid = { 0 };



	afuid.card_id = ctx->afu->adapter->adapter_num;

	afuid.afu_offset = ctx->afu->slice;

	afuid.afu_mode = ctx->afu->current_mode;



	/* set the flag bit in case the afu is a slave */

	if (ctx->afu->current_mode == CXL_MODE_DIRECTED && !ctx->master)

		afuid.flags |= CXL_AFUID_FLAG_SLAVE;



	if (copy_to_user(upafuid, &afuid, sizeof(afuid)))

		return -EFAULT;



	return 0;

}



static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	struct cxl_context *ctx = file->private_data;
@@ -225,6 +244,9 @@ static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);

	case CXL_IOCTL_GET_PROCESS_ELEMENT:

		return afu_ioctl_process_element(ctx, (__u32 __user *)arg);

	case CXL_IOCTL_GET_AFU_ID:

		return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *)

					    arg);

	}

	return -EINVAL;

}

include/uapi/misc/cxl.h

+22 −0
Original line number Diff line number Diff line
@@ -32,10 +32,32 @@ struct cxl_ioctl_start_work { 
#define CXL_START_WORK_ALL		(CXL_START_WORK_AMR |\

					 CXL_START_WORK_NUM_IRQS)





/* Possible modes that an afu can be in */

#define CXL_MODE_DEDICATED   0x1

#define CXL_MODE_DIRECTED    0x2



/* possible flags for the cxl_afu_id flags field */

#define CXL_AFUID_FLAG_SLAVE    0x1  /* In directed-mode afu is in slave mode */



struct cxl_afu_id {

	__u64 flags;     /* One of CXL_AFUID_FLAG_X */

	__u32 card_id;

	__u32 afu_offset;

	__u32 afu_mode;  /* one of the CXL_MODE_X */

	__u32 reserved1;

	__u64 reserved2;

	__u64 reserved3;

	__u64 reserved4;

	__u64 reserved5;

	__u64 reserved6;

};



/* 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)

#define CXL_IOCTL_GET_AFU_ID            _IOR(CXL_MAGIC, 0x02, struct cxl_afu_id)



#define CXL_READ_MIN_SIZE 0x1000 /* 4K */

CRA Git | Maintained and supported by SUSTech CRA and CCSE