Linux I2O User Space Interface
rev 0.3 - 04/20/99
=============================================================================
Originally written by Deepak Saxena(deepak@plexity.net)
Currently maintained by Deepak Saxena(deepak@plexity.net)
=============================================================================
I. Introduction
The Linux I2O subsystem provides a set of ioctl() commands that can be
utilized by user space applications to communicate with IOPs and devices
on individual IOPs. This document defines the specific ioctl() commands
that are available to the user and provides examples of their uses.
This document assumes the reader is familiar with or has access to the
I2O specification as no I2O message parameters are outlined. For information
on the specification, see http://www.i2osig.org
This document and the I2O user space interface are currently maintained
by Deepak Saxena. Please send all comments, errata, and bug fixes to
deepak@csociety.purdue.edu
II. IOP Access
Access to the I2O subsystem is provided through the device file named
/dev/i2o/ctl. This file is a character file with major number 10 and minor
number 166. It can be created through the following command:
mknod /dev/i2o/ctl c 10 166
III. Determining the IOP Count
SYNOPSIS
ioctl(fd, I2OGETIOPS, int *count);
u8 count[MAX_I2O_CONTROLLERS];
DESCRIPTION
This function returns the system's active IOP table. count should
point to a buffer containing MAX_I2O_CONTROLLERS entries. Upon
returning, each entry will contain a non-zero value if the given
IOP unit is active, and NULL if it is inactive or non-existent.
RETURN VALUE.
Returns 0 if no errors occur, and -1 otherwise. If an error occurs,
errno is set appropriately:
EFAULT Invalid user space pointer was passed
IV. Getting Hardware Resource Table
SYNOPSIS
ioctl(fd, I2OHRTGET, struct i2o_cmd_hrt *hrt);
struct i2o_cmd_hrtlct
{
u32 iop; /* IOP unit number */
void *resbuf; /* Buffer for result */
u32 *reslen; /* Buffer length in bytes */
};
DESCRIPTION
This function returns the Hardware Resource Table of the IOP specified
by hrt->iop in the buffer pointed to by hrt->resbuf. The actual size of
the data is written into *(hrt->reslen).
RETURNS
This function returns 0 if no errors occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ENOBUFS Buffer not large enough. If this occurs, the required
buffer length is written into *(hrt->reslen)
V. Getting Logical Configuration Table
SYNOPSIS
ioctl(fd, I2OLCTGET, struct i2o_cmd_lct *lct);
struct i2o_cmd_hrtlct
{
u32 iop; /* IOP unit number */
void *resbuf; /* Buffer for result */
u32 *reslen; /* Buffer length in bytes */
};
DESCRIPTION
This function returns the Logical Configuration Table of the IOP specified
by lct->iop in the buffer pointed to by lct->resbuf. The actual size of
the data is written into *(lct->reslen).
RETURNS
This function returns 0 if no errors occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ENOBUFS Buffer not large enough. If this occurs, the required
buffer length is written into *(lct->reslen)
VI. Setting Parameters
SYNOPSIS
ioctl(fd, I2OPARMSET, struct i2o_parm_setget *ops);
struct i2o_cmd_psetget
{
u32 iop; /* IOP unit number */
u32 tid; /* Target device TID */
void *opbuf; /* Operation List buffer */
u32 oplen; /* Operation List buffer length in bytes */
void *resbuf; /* Result List buffer */
u32 *reslen; /* Result List buffer length in bytes */
};
DESCRIPTION
This function posts a UtilParamsSet message to the device identified
by ops->iop and ops->tid. The operation list for the message is
sent through the ops->opbuf buffer, and the result list is written
into the buffer pointed to by ops->resbuf. The number of bytes
written is placed into *(ops->reslen).
RETURNS
The return value is the size in bytes of the data written into
ops->resbuf if no errors occur. If an error occurs, -1 is returned
and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ENOBUFS Buffer not large enough. If this occurs, the required
buffer length is written into *(ops->reslen)
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
A return value of 0 does not mean that the value was actually
changed properly on the IOP. The user should check the result
list to determine the specific status of the transaction.
VII. Getting Parameters
SYNOPSIS
ioctl(fd, I2OPARMGET, struct i2o_parm_setget *ops);
struct i2o_parm_setget
{
u32 iop; /* IOP unit number */
u32 tid; /* Target device TID */
void *opbuf; /* Operation List buffer */
u32 oplen; /* Operation List buffer length in bytes */
void *resbuf; /* Result List buffer */
u32 *reslen; /* Result List buffer length in bytes */
};
DESCRIPTION
This function posts a UtilParamsGet message to the device identified
by ops->iop and ops->tid. The operation list for the message is
sent through the ops->opbuf buffer, and the result list is written
into the buffer pointed to by ops->resbuf. The actual size of data
written is placed into *(ops->reslen).
RETURNS
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ENOBUFS Buffer not large enough. If this occurs, the required
buffer length is written into *(ops->reslen)
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
A return value of 0 does not mean that the value was actually
properly retrieved. The user should check the result list
to determine the specific status of the transaction.
VIII. Downloading Software
SYNOPSIS
ioctl(fd, I2OSWDL, struct i2o_sw_xfer *sw);
struct i2o_sw_xfer
{
u32 iop; /* IOP unit number */
u8 flags; /* DownloadFlags field */
u8 sw_type; /* Software type */
u32 sw_id; /* Software ID */
void *buf; /* Pointer to software buffer */
u32 *swlen; /* Length of software buffer */
u32 *maxfrag; /* Number of fragments */
u32 *curfrag; /* Current fragment number */
};
DESCRIPTION
This function downloads a software fragment pointed by sw->buf
to the iop identified by sw->iop. The DownloadFlags, SwID, SwType
and SwSize fields of the ExecSwDownload message are filled in with
the values of sw->flags, sw->sw_id, sw->sw_type and *(sw->swlen).
The fragments _must_ be sent in order and be 8K in size. The last
fragment _may_ be shorter, however. The kernel will compute its
size based on information in the sw->swlen field.
Please note that SW transfers can take a long time.
RETURNS
This function returns 0 no errors occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
IX. Uploading Software
SYNOPSIS
ioctl(fd, I2OSWUL, struct i2o_sw_xfer *sw);
struct i2o_sw_xfer
{
u32 iop; /* IOP unit number */
u8 flags; /* UploadFlags */
u8 sw_type; /* Software type */
u32 sw_id; /* Software ID */
void *buf; /* Pointer to software buffer */
u32 *swlen; /* Length of software buffer */
u32 *maxfrag; /* Number of fragments */
u32 *curfrag; /* Current fragment number */
};
DESCRIPTION
This function uploads a software fragment from the IOP identified
by sw->iop, sw->sw_type, sw->sw_id and optionally sw->swlen fields.
The UploadFlags, SwID, SwType and SwSize fields of the ExecSwUpload
message are filled in with the values of sw->flags, sw->sw_id,
sw->sw_type and *(sw->swlen).
The fragments _must_ be requested in order and be 8K in size. The
user is responsible for allocating memory pointed by sw->buf. The
last fragment _may_ be shorter.
Please note that SW transfers can take a long time.
RETURNS
This function returns 0 if no errors occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
X. Removing Software
SYNOPSIS
ioctl(fd, I2OSWDEL, struct i2o_sw_xfer *sw);
struct i2o_sw_xfer
{
u32 iop; /* IOP unit number */
u8 flags; /* RemoveFlags */
u8 sw_type; /* Software type */
u32 sw_id; /* Software ID */
void *buf; /* Unused */
u32 *swlen; /* Length of the software data */
u32 *maxfrag; /* Unused */
u32 *curfrag; /* Unused */
};
DESCRIPTION
This function removes software from the IOP identified by sw->iop.
The RemoveFlags, SwID, SwType and SwSize fields of the ExecSwRemove message
are filled in with the values of sw->flags, sw->sw_id, sw->sw_type and
*(sw->swlen). Give zero in *(sw->len) if the value is unknown. IOP uses
*(sw->swlen) value to verify correct identication of the module to remove.
The actual size of the module is written into *(sw->swlen).
RETURNS
This function returns 0 if no errors occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
X. Validating Configuration
SYNOPSIS
ioctl(fd, I2OVALIDATE, int *iop);
u32 iop;
DESCRIPTION
This function posts an ExecConfigValidate message to the controller
identified by iop. This message indicates that the current
configuration is accepted. The iop changes the status of suspect drivers
to valid and may delete old drivers from its store.
RETURNS
This function returns 0 if no erro occur. If an error occurs, -1 is
returned and errno is set appropriately:
ETIMEDOUT Timeout waiting for reply message
ENXIO Invalid IOP number
XI. Configuration Dialog
SYNOPSIS
ioctl(fd, I2OHTML, struct i2o_html *htquery);
struct i2o_html
{
u32 iop; /* IOP unit number */
u32 tid; /* Target device ID */
u32 page; /* HTML page */
void *resbuf; /* Buffer for reply HTML page */
u32 *reslen; /* Length in bytes of reply buffer */
void *qbuf; /* Pointer to HTTP query string */
u32 qlen; /* Length in bytes of query string buffer */
};
DESCRIPTION
This function posts an UtilConfigDialog message to the device identified
by htquery->iop and htquery->tid. The requested HTML page number is
provided by the htquery->page field, and the resultant data is stored
in the buffer pointed to by htquery->resbuf. If there is an HTTP query
string that is to be sent to the device, it should be sent in the buffer
pointed to by htquery->qbuf. If there is no query string, this field
should be set to NULL. The actual size of the reply received is written
into *(htquery->reslen).
RETURNS
This function returns 0 if no error occur. If an error occurs, -1
is returned and errno is set appropriately:
EFAULT Invalid user space pointer was passed
ENXIO Invalid IOP number
ENOBUFS Buffer not large enough. If this occurs, the required
buffer length is written into *(ops->reslen)
ETIMEDOUT Timeout waiting for reply message
ENOMEM Kernel memory allocation error
XII. Events
In the process of determining this. Current idea is to have use
the select() interface to allow user apps to periodically poll
the /dev/i2o/ctl device for events. When select() notifies the user
that an event is available, the user would call read() to retrieve
a list of all the events that are pending for the specific device.
=============================================================================
Revision History
=============================================================================
Rev 0.1 - 04/01/99
- Initial revision
Rev 0.2 - 04/06/99
- Changed return values to match UNIX ioctl() standard. Only return values
are 0 and -1. All errors are reported through errno.
- Added summary of proposed possible event interfaces
Rev 0.3 - 04/20/99
- Changed all ioctls() to use pointers to user data instead of actual data
- Updated error values to match the code