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Document my adventures in newbus land. Clarify some examples, especially

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that count is in bytes, not bits.  There are some drivers that I think make
this mistake.  (I've seen counts of 16 in the tree).
This commit is contained in:
njl 2004-01-27 06:04:15 +00:00
parent 2bf2495a77
commit fe5f4f64eb
2 changed files with 17 additions and 11 deletions
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27
share/man/man9/bus_alloc_resource.9
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@ -85,17 +85,18 @@ You must not depend on the value you gave it earlier.
and
.Fa end
are the start/end addresses of the resource.
If you specify values of 0 for
If you specify values of 0ul for
.Fa start
and ~0 for
and ~0ul for
.Fa end
and 1 for
.Fa count ,
the default values for the bus are calculated.
.It
.Fa count
is the size of the resource, e.g. the size of an I/O port (often
1, but some devices override this).
is the size of the resource.
For example, the size of an I/O port is usually 1 byte (but some devices
override this).
If you specified the default values for
.Fa start
and
@ -104,7 +105,7 @@ then the default value of the bus is used if
.Fa count
is smaller than the default value and
.Fa count
is used, if it is bigger as the default value.
is used, if it is bigger than the default value.
.It
.Fa flags
sets the flags for the resource.
@ -118,10 +119,14 @@ The resource still needs to be activated with
activate resource atomically.
.It Dv RF_SHAREABLE
resource permits contemporaneous sharing.
Should always be set unless you know, that the resource cannot be shared.
It is the bus-code's task to filter out the flag if the bus doesn't
support sharing, which is, for example, the case for pccard/cardbus,
which can or cannot share devices, depending on the bus.
It should always be set unless you know that the resource cannot be shared.
It is the bus driver's task to filter out the flag if the bus doesn't
support sharing.
For example,
.Xr pccard 4
cannot share IRQs while
.Xr cardbus 4
can.
.It Dv RF_TIMESHARE
resource permits time-division sharing.
.El
@ -131,7 +136,7 @@ A pointer to
.Va struct res
is returned on success, a null pointer otherwise.
.Sh EXAMPLES
This is some example code.
This is some example code that allocates a 32-bit I/O port and an IRQ.
The values of
.Va portid
and
@ -144,7 +149,7 @@ should be saved in the softc of the device after these calls.
portid = 0;
irqid = 0;
portres = bus_alloc_resource(dev, SYS_RES_IOPORT, &portid,
0ul, ~0ul, 32, RF_ACTIVE);
0ul, ~0ul, 4, RF_ACTIVE);
irqres = bus_alloc_resource(dev, SYS_RES_IRQ, &irqid,
0ul, ~0ul, 1, RF_ACTIVE | RF_SHAREABLE);
.Ed

1
share/man/man9/bus_set_resource.9
View File

@ -82,6 +82,7 @@ A pointer to a bus specific handle that identifies the resource being allocated.
The start address of this resource.
.It Fa count
The length of the resource.
For example, the size of the memory in bytes.
.El
.Sh RETURN VALUES
Zero is returned on success, otherwise an error is returned.