NetBSD/sys/arch/sun3/sun3x/dvma.c

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/* $NetBSD: dvma.c,v 1.9 1998/02/05 04:57:55 gwr Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Gordon W. Ross and Jeremy Cooper.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* DVMA (Direct Virtual Memory Access - like DMA)
*
* In the Sun3 architecture, memory cycles initiated by secondary bus
* masters (DVMA devices) passed through the same MMU that governed CPU
* accesses. All DVMA devices were wired in such a way so that an offset
* was added to the addresses they issued, causing them to access virtual
* memory starting at address 0x0FF00000 - the offset. The task of
* enabling a DVMA device to access main memory only involved creating
* valid mapping in the MMU that translated these high addresses into the
* appropriate physical addresses.
*
* The Sun3x presents a challenge to programming DVMA because the MMU is no
* longer shared by both secondary bus masters and the CPU. The MC68030's
* built-in MMU serves only to manage virtual memory accesses initiated by
* the CPU. Secondary bus master bus accesses pass through a different MMU,
* aptly named the 'I/O Mapper'. To enable every device driver that uses
* DVMA to understand that these two address spaces are disconnected would
* require a tremendous amount of code re-writing. To avoid this, we will
* ensure that the I/O Mapper and the MC68030 MMU are programmed together,
* so that DVMA mappings are consistent in both the CPU virtual address
* space and secondary bus master address space - creating an environment
* just like the Sun3 system.
*
* The maximum address space that any DVMA device in the Sun3x architecture
* is capable of addressing is 24 bits wide (16 Megabytes.) We can alias
* all of the mappings that exist in the I/O mapper by duplicating them in
* a specially reserved section of the CPU's virtual address space, 16
* Megabytes in size. Whenever a DVMA buffer is allocated, the allocation
* code will enter in a mapping both in the MC68030 MMU page tables and the
* I/O mapper.
*
* The address returned by the allocation routine is a virtual address that
* the requesting driver must use to access the buffer. It is up to the
* device driver to convert this virtual address into the appropriate slave
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* address that its device should issue to access the buffer. (There will be
* routines that assist the driver in doing so.)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/map.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/user.h>
#include <sys/core.h>
#include <sys/exec.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <machine/autoconf.h>
#include <machine/cpu.h>
#include <machine/dvma.h>
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#include <machine/pmap.h>
/* #include <machine/reg.h> */
#include <sun3/sun3/machdep.h>
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#include <sun3/sun3x/enable.h>
#include <sun3/sun3x/iommu.h>
/*
* Use a resource map to manage DVMA scratch-memory pages.
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* Note: SunOS says last three pages are reserved (PROM?)
* Note: need a separate map (sub-map?) for last 1MB for
* use by VME slave interface.
*/
/* Number of slots in dvmamap. */
int dvma_max_segs = btoc(DVMA_MAP_SIZE);
struct map *dvmamap;
void
dvma_init()
{
/*
* Create the resource map for DVMA pages.
*/
dvmamap = malloc((sizeof(struct map) * dvma_max_segs),
M_DEVBUF, M_WAITOK);
rminit(dvmamap, btoc(DVMA_MAP_AVAIL), btoc(DVMA_MAP_BASE),
"dvmamap", dvma_max_segs);
/*
* Enable DVMA in the System Enable register.
* Note: This is only necessary for VME slave accesses.
* On-board devices are always capable of DVMA.
*/
*enable_reg |= ENA_SDVMA;
}
/*
* Given a DVMA address, return the physical address that
* would be used by some OTHER bus-master besides the CPU.
* (Examples: on-board ie/le, VME xy board).
*/
u_long
dvma_kvtopa(kva, bustype)
void * kva;
int bustype;
{
u_long addr, mask;
addr = (u_long)kva;
if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE)
panic("dvma_kvtopa: bad dmva addr=0x%x\n", addr);
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switch (bustype) {
case BUS_OBIO:
case BUS_OBMEM:
mask = DVMA_OBIO_SLAVE_MASK;
break;
default: /* VME bus device. */
mask = DVMA_VME_SLAVE_MASK;
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break;
}
return(addr & mask);
}
/*
* Map a range [va, va+len] of wired virtual addresses in the given map
* to a kernel address in DVMA space.
*/
void *
dvma_mapin(kmem_va, len, canwait)
void * kmem_va;
int len, canwait;
{
void * dvma_addr;
vm_offset_t kva, tva;
register int npf, s;
register vm_offset_t pa;
long off, pn;
kva = (u_long)kmem_va;
#ifdef DIAGNOSTIC
/*
* Addresses below VM_MIN_KERNEL_ADDRESS are not part of the kernel
* map and should not participate in DVMA.
*/
if (kva < VM_MIN_KERNEL_ADDRESS)
panic("dvma_mapin: bad kva");
#endif
/*
* Calculate the offset of the data buffer from a page boundary.
*/
off = (int)kva & PGOFSET;
kva -= off; /* Truncate starting address to nearest page. */
len = round_page(len + off); /* Round the buffer length to pages. */
npf = btoc(len); /* Determine the number of pages to be mapped. */
s = splimp();
for (;;) {
/*
* Try to allocate DVMA space of the appropriate size
* in which to do a transfer.
*/
pn = rmalloc(dvmamap, npf);
if (pn != 0)
break;
if (canwait) {
(void)tsleep(dvmamap, PRIBIO+1, "physio", 0);
continue;
}
splx(s);
return NULL;
}
splx(s);
/*
* Tva is the starting page to which the data buffer will be double
* mapped. Dvma_addr is the starting address of the buffer within
* that page and is the return value of the function.
*/
tva = ctob(pn);
dvma_addr = (void *) (tva + off);
for (;npf--; kva += NBPG, tva += NBPG) {
/*
* Retrieve the physical address of each page in the buffer
* and enter mappings into the I/O MMU so they may be seen
* by external bus masters and into the special DVMA space
* in the MC68030 MMU so they may be seen by the CPU.
*/
pa = pmap_extract(pmap_kernel(), kva);
#ifdef DEBUG
if (pa == 0)
panic("dvma_mapin: null page frame");
#endif DEBUG
iommu_enter((tva & IOMMU_VA_MASK), pa);
pmap_enter(pmap_kernel(), tva, pa | PMAP_NC,
VM_PROT_READ|VM_PROT_WRITE, 1);
}
return (dvma_addr);
}
/*
* Remove double map of `va' in DVMA space at `kva'.
*
* TODO - This function might be the perfect place to handle the
* synchronization between the DVMA cache and central RAM
* on the 3/470.
*/
void
dvma_mapout(dvma_addr, len)
void * dvma_addr;
int len;
{
u_long kva;
int s, off;
kva = (u_long)dvma_addr;
off = (int)kva & PGOFSET;
kva -= off;
len = round_page(len + off);
iommu_remove((kva & IOMMU_VA_MASK), len);
/*
* XXX - don't call pmap_remove() with DVMA space yet.
* XXX It cannot (currently) handle the removal
* XXX of address ranges which do not participate in the
* XXX PV system by virtue of their _virtual_ addresses.
* XXX DVMA is one of these special address spaces.
*/
#ifdef DVMA_ON_PVLIST
pmap_remove(pmap_kernel(), kva, kva + len);
#endif /* DVMA_ON_PVLIST */
s = splimp();
rmfree(dvmamap, btoc(len), btoc(kva));
wakeup(dvmamap);
splx(s);
}
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/*
* Allocate actual memory pages in DVMA space.
* (For sun3 compatibility - the ie driver.)
*/
void *
dvma_malloc(bytes)
size_t bytes;
{
void *new_mem, *dvma_mem;
vm_size_t new_size;
if (!bytes)
return NULL;
new_size = m68k_round_page(bytes);
new_mem = (void*)kmem_alloc(kernel_map, new_size);
if (!new_mem)
return NULL;
dvma_mem = dvma_mapin(new_mem, new_size, 1);
return (dvma_mem);
}
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/*
* Free pages from dvma_malloc()
*/
void
dvma_free(addr, size)
void *addr;
size_t size;
{
vm_size_t sz = m68k_round_page(size);
dvma_mapout(addr, sz);
/* XXX: need kmem address to free it...
Oh well, we never call this anyway. */
}