295 lines
9.0 KiB
C
295 lines
9.0 KiB
C
/* $NetBSD: dvma.c,v 1.28 2005/01/22 15:36:10 chs Exp $ */
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/*-
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* Copyright (c) 1996 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Gordon W. Ross and Jeremy Cooper.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* DVMA (Direct Virtual Memory Access - like DMA)
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*
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* In the Sun3 architecture, memory cycles initiated by secondary bus
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* masters (DVMA devices) passed through the same MMU that governed CPU
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* accesses. All DVMA devices were wired in such a way so that an offset
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* was added to the addresses they issued, causing them to access virtual
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* memory starting at address 0x0FF00000 - the offset. The task of
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* enabling a DVMA device to access main memory only involved creating
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* valid mapping in the MMU that translated these high addresses into the
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* appropriate physical addresses.
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*
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* The Sun3x presents a challenge to programming DVMA because the MMU is no
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* longer shared by both secondary bus masters and the CPU. The MC68030's
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* built-in MMU serves only to manage virtual memory accesses initiated by
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* the CPU. Secondary bus master bus accesses pass through a different MMU,
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* aptly named the 'I/O Mapper'. To enable every device driver that uses
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* DVMA to understand that these two address spaces are disconnected would
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* require a tremendous amount of code re-writing. To avoid this, we will
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* ensure that the I/O Mapper and the MC68030 MMU are programmed together,
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* so that DVMA mappings are consistent in both the CPU virtual address
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* space and secondary bus master address space - creating an environment
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* just like the Sun3 system.
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*
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* The maximum address space that any DVMA device in the Sun3x architecture
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* is capable of addressing is 24 bits wide (16 Megabytes.) We can alias
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* all of the mappings that exist in the I/O mapper by duplicating them in
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* a specially reserved section of the CPU's virtual address space, 16
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* Megabytes in size. Whenever a DVMA buffer is allocated, the allocation
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* code will enter in a mapping both in the MC68030 MMU page tables and the
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* I/O mapper.
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*
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* The address returned by the allocation routine is a virtual address that
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* the requesting driver must use to access the buffer. It is up to the
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* 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
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* routines that assist the driver in doing so.)
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: dvma.c,v 1.28 2005/01/22 15:36:10 chs Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/extent.h>
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#include <sys/buf.h>
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#include <sys/vnode.h>
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#include <sys/user.h>
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#include <sys/core.h>
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#include <sys/exec.h>
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#include <uvm/uvm_extern.h>
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#include <machine/autoconf.h>
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#include <machine/cpu.h>
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#include <machine/dvma.h>
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#include <machine/pmap.h>
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#include <sun3/sun3/machdep.h>
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#include <sun3/sun3x/enable.h>
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#include <sun3/sun3x/iommu.h>
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/*
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* Use an extent map to manage DVMA scratch-memory pages.
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* Note: SunOS says last three pages are reserved (PROM?)
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* Note: need a separate map (sub-map?) for last 1MB for
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* use by VME slave interface.
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*/
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/* Number of slots in dvmamap. */
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struct extent *dvma_extent;
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void
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dvma_init(void)
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{
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/*
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* Create the extent map for DVMA pages.
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*/
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dvma_extent = extent_create("dvma", DVMA_MAP_BASE,
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DVMA_MAP_BASE + (DVMA_MAP_AVAIL - 1), M_DEVBUF,
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NULL, 0, EX_NOCOALESCE|EX_NOWAIT);
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/*
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* Enable DVMA in the System Enable register.
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* Note: This is only necessary for VME slave accesses.
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* On-board devices are always capable of DVMA.
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*/
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*enable_reg |= ENA_SDVMA;
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}
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/*
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* Given a DVMA address, return the physical address that
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* would be used by some OTHER bus-master besides the CPU.
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* (Examples: on-board ie/le, VME xy board).
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*/
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u_long
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dvma_kvtopa(void *kva, int bustype)
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{
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u_long addr, mask;
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addr = (u_long)kva;
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if ((addr & DVMA_MAP_BASE) != DVMA_MAP_BASE)
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panic("dvma_kvtopa: bad dmva addr=0x%lx", addr);
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switch (bustype) {
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case BUS_OBIO:
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case BUS_OBMEM:
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mask = DVMA_OBIO_SLAVE_MASK;
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break;
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default: /* VME bus device. */
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mask = DVMA_VME_SLAVE_MASK;
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break;
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}
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return(addr & mask);
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}
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/*
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* Map a range [va, va+len] of wired virtual addresses in the given map
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* to a kernel address in DVMA space.
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*/
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void *
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dvma_mapin(void *kmem_va, int len, int canwait)
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{
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void * dvma_addr;
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vaddr_t kva, tva;
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int npf, s, error;
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paddr_t pa;
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long off;
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boolean_t rv;
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kva = (vaddr_t)kmem_va;
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#ifdef DIAGNOSTIC
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/*
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* Addresses below VM_MIN_KERNEL_ADDRESS are not part of the kernel
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* map and should not participate in DVMA.
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*/
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if (kva < VM_MIN_KERNEL_ADDRESS)
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panic("dvma_mapin: bad kva");
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#endif
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/*
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* Calculate the offset of the data buffer from a page boundary.
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*/
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off = kva & PGOFSET;
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kva -= off; /* Truncate starting address to nearest page. */
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len = round_page(len + off); /* Round the buffer length to pages. */
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npf = btoc(len); /* Determine the number of pages to be mapped. */
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/*
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* Try to allocate DVMA space of the appropriate size
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* in which to do a transfer.
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*/
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s = splvm();
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error = extent_alloc(dvma_extent, len, PAGE_SIZE, 0,
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EX_FAST | EX_NOWAIT | (canwait ? EX_WAITSPACE : 0), &tva);
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splx(s);
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if (error)
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return (NULL);
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/*
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* Tva is the starting page to which the data buffer will be double
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* mapped. Dvma_addr is the starting address of the buffer within
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* that page and is the return value of the function.
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*/
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dvma_addr = (void *) (tva + off);
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for (;npf--; kva += PAGE_SIZE, tva += PAGE_SIZE) {
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/*
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* Retrieve the physical address of each page in the buffer
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* and enter mappings into the I/O MMU so they may be seen
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* by external bus masters and into the special DVMA space
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* in the MC68030 MMU so they may be seen by the CPU.
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*/
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rv = pmap_extract(pmap_kernel(), kva, &pa);
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#ifdef DEBUG
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if (rv == FALSE)
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panic("dvma_mapin: null page frame");
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#endif /* DEBUG */
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iommu_enter((tva & IOMMU_VA_MASK), pa);
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pmap_kenter_pa(tva, pa | PMAP_NC, VM_PROT_READ | VM_PROT_WRITE);
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}
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pmap_update(pmap_kernel());
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return (dvma_addr);
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}
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/*
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* Remove double map of `va' in DVMA space at `kva'.
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*
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* TODO - This function might be the perfect place to handle the
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* synchronization between the DVMA cache and central RAM
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* on the 3/470.
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*/
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void
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dvma_mapout(void *dvma_addr, int len)
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{
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u_long kva;
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int s, off;
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kva = (u_long)dvma_addr;
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off = (int)kva & PGOFSET;
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kva -= off;
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len = round_page(len + off);
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iommu_remove((kva & IOMMU_VA_MASK), len);
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pmap_kremove(kva, len);
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pmap_update(pmap_kernel());
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s = splvm();
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if (extent_free(dvma_extent, kva, len, EX_NOWAIT | EX_MALLOCOK))
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panic("dvma_mapout: unable to free region: 0x%lx,0x%x",
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kva, len);
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splx(s);
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}
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/*
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* Allocate actual memory pages in DVMA space.
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* (For sun3 compatibility - the ie driver.)
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*/
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void *
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dvma_malloc(size_t bytes)
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{
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void *new_mem, *dvma_mem;
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vsize_t new_size;
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if (!bytes)
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return NULL;
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new_size = m68k_round_page(bytes);
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new_mem = (void*)uvm_km_alloc(kernel_map, new_size);
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if (!new_mem)
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return NULL;
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dvma_mem = dvma_mapin(new_mem, new_size, 1);
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return (dvma_mem);
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}
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/*
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* Free pages from dvma_malloc()
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*/
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void
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dvma_free(void *addr, size_t size)
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{
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vsize_t sz = m68k_round_page(size);
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dvma_mapout(addr, sz);
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/* XXX: need kmem address to free it...
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Oh well, we never call this anyway. */
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}
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