read device characteristics
read_conf_data()
+read_conf_data_lpm()
read configuration data.
ccw_device_get_ciw()
get commands from extended sense data.
ccw_device_start()
+ccw_device_start_timeout()
+ccw_device_start_key()
+ccw_device_start_key_timeout()
initiate an I/O request.
ccw_device_resume()
In order not to introduce a new I/O concept to the common Linux code,
Linux/390 preserves the IRQ concept and semantically maps the ESA/390
subchannels to Linux as IRQs. This allows Linux/390 to support up to 64k
-different IRQs, uniquely representig a single device each.
+different IRQs, uniquely representing a single device each.
Up to kernel 2.4, Linux/390 used to provide interfaces via the IRQ (subchannel).
For internal use of the common I/O layer, these are still there. However,
of those devices is uniquely defined by a so called subchannel by the ESA/390
channel subsystem. While the subchannel numbers are system generated, each
subchannel also takes a user defined attribute, the so called device number.
-Both subchannel number and device number can not exceed 65535. During driverfs
+Both subchannel number and device number cannot exceed 65535. During driverfs
initialisation, the information about control unit type and device types that
imply specific I/O commands (channel command words - CCWs) in order to operate
the device are gathered. Device drivers can retrieve this set of hardware
The function is meant to be called with an irq handler in place; that is,
at earliest during set_online() processing.
-While the request is procesed synchronously, the device interrupt
+While the request is processed synchronously, the device interrupt
handler is called for final ending status. In case of error situations the
interrupt handler may recover appropriately. The device irq handler can
recognize the corresponding interrupts by the interruption parameter be
-0x00524443.The ccw_device must not be locked prior to calling read_dev_chars().
+0x00524443. The ccw_device must not be locked prior to calling read_dev_chars().
The function may be called enabled or disabled.
operational.
-read_conf_data() - Read Configuration Data
+read_conf_data(), read_conf_data_lpm() - Read Configuration Data
Retrieve the device dependent configuration data. Please have a look at your
device dependent I/O commands for the device specific layout of the node
-descriptor elements.
+descriptor elements. read_conf_data_lpm() will retrieve the configuration data
+for a specific path.
-The function is meant to be called with an irq handler in place; that is,
+The function is meant to be called with the device already enabled; that is,
at earliest during set_online() processing.
The function may be called enabled or disabled, but the device must not be
locked
-int read_conf_data(struct ccw_device, void **buffer, int *length, __u8 lpm);
+int read_conf_data(struct ccw_device, void **buffer, int *length);
+int read_conf_data_lpm(struct ccw_device, void **buffer, int *length, __u8 lpm);
cdev - the ccw_device the data is requested for.
buffer - Pointer to a buffer pointer. The read_conf_data() routine
unsigned long intparm,
__u8 lpm,
unsigned long flags);
+int ccw_device_start_timeout(struct ccw_device *cdev,
+ struct ccw1 *cpa,
+ unsigned long intparm,
+ __u8 lpm,
+ unsigned long flags,
+ int expires);
+int ccw_device_start_key(struct ccw_device *cdev,
+ struct ccw1 *cpa,
+ unsigned long intparm,
+ __u8 lpm,
+ __u8 key,
+ unsigned long flags);
+int ccw_device_start_key_timeout(struct ccw_device *cdev,
+ struct ccw1 *cpa,
+ unsigned long intparm,
+ __u8 lpm,
+ __u8 key,
+ unsigned long flags,
+ int expires);
cdev : ccw_device the I/O is destined for
cpa : logical start address of channel program
particular I/O request.
lpm : defines the channel path to be used for a specific I/O
request. A value of 0 will make cio use the opm.
+key : the storage key to use for the I/O (useful for operating on a
+ storage with a storage key != default key)
flag : defines the action to be performed for I/O processing
+expires : timeout value in jiffies. The common I/O layer will terminate
+ the running program after this and call the interrupt handler
+ with ERR_PTR(-ETIMEDOUT) as irb.
Possible flag values are :
CCW_FLAG_DC - data chaining
CCW_FLAG_CC - command chaining
-CCW_FLAG_SLI - suppress incorrct length
+CCW_FLAG_SLI - suppress incorrect length
CCW_FLAG_SKIP - skip
CCW_FLAG_PCI - PCI
CCW_FLAG_IDA - indirect addressing
not online.
When the I/O request completes, the CDS first level interrupt handler will
-accumalate the status in a struct irb and then call the device interrupt handler.
+accumulate the status in a struct irb and then call the device interrupt handler.
The intparm field will contain the value the device driver has associated with a
particular I/O request. If a pending device status was recognized,
intparm will be set to 0 (zero). This may happen during I/O initiation or delayed
interrupt will be presented to indicate I/O completion as the I/O request was
never started, even though ccw_device_start() returned with successful completion.
+The irb may contain an error value, and the device driver should check for this
+first:
+
+-ETIMEDOUT: the common I/O layer terminated the request after the specified
+ timeout value
+-EIO: the common I/O layer terminated the request due to an error state
+
If the concurrent sense flag in the extended status word in the irb is set, the
field irb->scsw.count describes the numer of device specific sense bytes
available in the extended control word irb->scsw.ecw[0]. No device sensing by
The device driver is allowed to issue the next ccw_device_start() call from
within its interrupt handler already. It is not required to schedule a
-bottom-half, unless an non deterministicly long running error recovery procedure
+bottom-half, unless an non deterministically long running error recovery procedure
or similar needs to be scheduled. During I/O processing the Linux/390 generic
I/O device driver support has already obtained the IRQ lock, i.e. the handler
must not try to obtain it again when calling ccw_device_start() or we end in a
projects / linux-2.6 / blobdiff