icmd(D2sdi)

icmd -- perform a request immediately on a Host Bus Adapter

Synopsis

   #include <sys/sdi.h>
   #include <sys/ddi.h>

   long prefixicmd(struct hbadata *hbap, int flag);

Description

icmd(D2sdi) is a special case of the Host Bus Adapter (HBA) send(D2sdi) routine. It sends the request directly to the controller, bypassing the queue mechanism used by send( ).

Arguments

hbap: a pointer to the device-specific request block defining the request to be performed
flag: indicates whether subsequent allocation requests, if any, can sleep or not, and is set to either KM_SLEEP or KM_NOSLEEP

Return values

On success, icmd returns SDI_RET_OK. On failure, it returns SDI_RET_ERR.

Usage

The icmd( ) this routine is used most frequently when the HBA controller is in some bad state and flushing the jobs from the queue is required to return the controller to a normal state. The caller, typically the target driver, expects immediate service for calls to icmd( ) and will suspend all other processing until the callback for the immediate command occurs.

See sfb(D4sdi) for a list of commands that must be supported by all HBA drivers and commands that are required only when the hot add/remove feature is supported for the attached target drivers.

In addition to these SCSI SFB commands, the HBA's icmd( ) routine should accept and pass to the controller all supported SCSI SCB commands.

The HBA driver should not autosuspend operations, but must wait for an SFB_SUSPEND immediate command from the target. This synchronization between the target driver and HBA driver is necessary to avoid deadlock. A suspend command can be expected by the HBA when a CHECK CONDITION occurs. After the sequence of commands to get sense data have been executed, the target driver will follow up with the SFB_RESUME command.

An HBA driver should never suspend the queue, unless requested by the target driver. Only target drivers should issue suspend/resume requests.

Context and synchronization

If flag is KM_SLEEP, blockable context. If flag is KM_NOSLEEP, non-blockable context.

Applicable hardware

All

Version applicability

sdi: 1, 2, 3, 4 HBA drivers.