.\"     $NetBSD: tc.9,v 1.13 2017/07/03 21:28:48 wiz Exp $
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.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Gregory McGarry.
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.Dd October 7, 2001
.Dt TC 9
.Os
.Sh NAME
.Nm TC ,
.Nm tc_intr_establish ,
.Nm tc_intr_disestablish ,
.Nm tc_intr_evcnt .
.Nm tc_mb ,
.Nm tc_wmb ,
.Nm tc_syncbus ,
.Nm tc_badaddr ,
.Nm TC_DENSE_TO_SPARSE ,
.Nm TC_PHYS_TO_UNCACHED
.Nd TURBOchannel bus
.Sh SYNOPSIS
.In sys/bus.h
.In dev/tc/tcvar.h
.In dev/tc/tcdevs.h
.Ft void
.Fn tc_intr_establish "struct device *dev" "void *cookie" \
"int level" "int (*handler)(void *)" "void *arg"
.Ft void
.Fn tc_intr_disestablish "struct device *dev" "void *cookie"
.Ft const struct evcnt *
.Fn tc_intr_evcnt "struct device *dev" "void *cookie"
.Ft void
.Fn tc_mb ""
.Ft void
.Fn tc_wmb ""
.Ft void
.Fn tc_syncbus ""
.Ft int
.Fn tc_badaddr "tc_addr_t tcaddr"
.Ft tc_addr_t
.Fn TC_DENSE_TO_SPARSE "tc_addr_t addr"
.Ft tc_addr_t
.Fn TC_PHYS_TO_UNCACHED "tc_addr_t addr"
.Sh DESCRIPTION
The
.Nm
device provides support for the DEC TURBOchannel bus found on all DEC
TURBOchannel machines with MIPS (DECstation 5000 series, excluding the
5000/200) and Alpha (3000-series) systems.
TURBOchannel is a 32-bit wide synchronous DMA-capable bus, running
at 25 MHz on higher-end machines and at 12.5 MHz on lower-end machines.
.Sh DATA TYPES
Drivers for devices attached to the TURBOchannel bus will make use of
the following data types:
.Bl -tag -width compact
.It Fa struct tc_attach_args
A structure use to inform the driver of TURBOchannel bus properties.
It contains the following members:
.Bd -literal
	bus_space_tag_t	ta_memt;
	bus_dma_tag_t	ta_dmat;
	char		ta_modname[TC_ROM_LLEN+1];
	u_int		ta_slot;
	tc_offset_t	ta_offset;
	tc_addr_t	ta_addr;
	void		*ta_cookie;
	u_int		ta_busspeed;
.Ed
.Pp
The
.Em ta_busspeed
member specifies the TURBOchannel bus speed and is useful for
time-related functions.
Values values are
.Em TC_SPEED_12_5_MHZ
for the 12.5 MHz bus and
.Em TC_SPEED_25_MHZ
for the 50 MHz bus.
.El
.Sh FUNCTIONS
.Bl -tag -width compact
.It Fn tc_intr_establish "dev" "cookie" "level" "handler" "arg"
Establish an interrupt handler with device
.Fa dev
for the interrupt described completely by
.Fa cookie ,
the value passed to the driver in the
.Em ta_cookie
member of the
.Em tc_attach_args
structure.
The priority of the interrupt is specified by
.Fa level .
When the interrupt occurs the function
.Fa handler
is called with argument
.Fa arg .
.It Fn tc_intr_disestablish "dev" "cookie"
Dis-establish the interrupt handler with device
.Fa dev
for the interrupt described completely
.Fa cookie .
.It Fn tc_intr_evcnt "dev" "cookie"
Do interrupt event counting with device
.Fa dev
for the event described completely by
.Fa cookie .
.It Fn tc_mb ""
A read/write memory barrier.
Any CPU-to-memory reads/writes before the barrier must complete before
any CPU-to-memory reads/writes after it.
.It Fn tc_wmb ""
A write memory barrier.
Any CPU-to-memory writes before the barrier must complete
before any CPU-to-memory writes after it.
.It Fn tc_syncbus ""
Synchronise writes on the TURBOchannel bus by ensuring CPU writes are
propagated across the TURBOchannel bus.
.It Fn tc_badaddr "tcaddr"
Returns non-zero if the given address
.Fa tcaddr
is invalid.
.It Fn TC_DENSE_TO_SPARSE "addr"
Convert the given physical address
.Fa addr
in TURBOchannel dense space to the corresponding address in
TURBOchannel sparse space.
.It Fn TC_PHYS_TO_UNCACHED "addr"
Convert the given system memory physical address
.Fa addr
to the physical address of the corresponding region that is not
cached.
.El
.Sh AUTOCONFIGURATION
The TURBOchannel bus is a direct-connection bus.
During autoconfiguration, the parent specifies the name of the found
TURBOchannel module into the
.Fa ta_modname
member of the
.Em tc_attach_args
structure.
Drivers should match on this name.
.Sh DMA SUPPORT
The TURBOchannel bus supports 32-bit, bidirectional DMA transfers.
Support is provided by the standard
.Xr bus_dma 9
interface.
.Sh CODE REFERENCES
The TURBOchannel subsystem itself is implemented within the file
.Pa sys/dev/tc/tc_subr.c .
Machine-dependent portions can be found in
.Pa sys/arch/<arch>/tc/tcbus.c .
.Sh SEE ALSO
.Xr tc 4 ,
.Xr autoconf 9 ,
.Xr bus_dma 9 ,
.Xr bus_space 9 ,
.Xr driver 9