illumos: manual page: ddi_fm_acc_err

DDI_FM_ACC_ERR_GET(9F) Kernel Functions for Drivers DDI_FM_ACC_ERR_GET(9F)

NAME

ddi_fm_acc_err_get, ddi_fm_dma_err_get - get the error status for an
access or DMA handle

SYNOPSIS

#include <sys/ddifm.h>

void ddi_fm_acc_err_get(ddi_acc_handle_t acc_handle,
ddi_fm_error_t *error_status, int version);

void ddi_fm_dma_err_get(ddi_dma_handle_t dma_handle,
ddi_fm_error_t *error_status, int version);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

acc_handle
Data access handle obtained from a previous call to
ddi_regs_map_setup(9F), ddi_dma_mem_alloc(9F), or to a
similar function.

dma_handle
DMA handle obtained from a previous call to
ddi_dma_mem_alloc(9F) or one of its derivatives.

error_status
Pointer to where the error status for the access or DMA
handle should be returned.

version
Version number of ddi_fm_error_t. The driver should
always set this to DDI_FME_VERSION.

DESCRIPTION

The ddi_fm_dma_err_get() and ddi_fm_acc_err_get() functions return the
error status for a DMA or access handle respectively. If a fault has
occurred that affects the resource mapped by the supplied handle, the
supplied error_status structure is updated to reflect error information
captured during error handling by a bus or other device driver in the I/O
data path.

If an error is indicated for an access handle, the driver might no longer
be able to access the mapped registers or memory using programmed I/O
through the handle. Typically, this might occur after the device has
failed to respond to an I/O access - in the case of a bus error, for
instance, or a timeout. The effect of programmed I/O access made at the
time of a fault is undefined. Read access via ddi_get8(9F), for example,
can return random values, while write access via ddi_put8(9F) might or
might not have an effect. It is possible, however, that the error might
be transient. In that case, the driver can attempt to recover by calling
ddi_fm_acc_err_clear(), resetting the device to return it to a known
state, then retrying any potentially failed transactions.

If an error is indicated for a DMA handle, it implies that an error has
been detected that has or will affect DMA transactions between the device
and the memory currently bound to the handle - or the memory most
recently bound, if the handle is currently unbound. Possible causes
include the failure of a component in the DMA data path or an attempt by
the device to make an invalid DMA access. The contents of any memory
currently or previously bound to the handle should be considered
indeterminate. The driver might be able to continue by freeing memory
that is bound to the handle back to the system, resetting the device to
return it to a known state, then retrying any potentially failed
transactions.

If the driver is unable to recover, the operating state should be changed
by a call to ddi_fm_service_impact() that specifies DDI_SERVICE_LOST for
the impacted device instance. If the recovery and retry succeed, a call
should still be made to ddi_fm_service_impact() but
DDI_SERVICE_UNAFFECTED should be specified.

CONTEXT

The ddi_fm_acc_err_get() and ddi_fm_dma_err_get() functions can be called
from user, kernel, or high-level interrupt context.

ATTRIBUTES