NetBSD-5.0.2/sys/arch/sun3/sun3x/iommu.h
/* $NetBSD: iommu.h,v 1.8 2008/04/28 20:23:38 martin Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by 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.
*
* 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.
*/
/*
* Structure and definition of descriptors used in the I/O Mapper.
*/
#ifndef _SUN3X_IOMMU_H
#define _SUN3X_IOMMU_H
/* The I/O Mapper is a special type of MMU in the sun3x architecture
* (and supposedly in the sun4m as well) that translates an address used by a
* device during a DMA transfer into an address on the internal system bus.
* In other words, it is an MMU that stands between devices wishing to do DMA
* transfers and main memory. In this description, the address issued by a
* DMA device is called a ``DVMA address'', while the address as it is
* translated and output from the I/O mapper is called a ``system bus address''
* (sometimes known as a ``physical address'').
*
* The DVMA address space in the sun3x architecture is 24 bits wide, in
* contrast with the system bus address space, which is 32. The mapping of a
* DVMA address to a system bus address is accomplished by dividing the DVMA
* address space into 2048 8K pages. Each DVMA page is then mapped to a
* system bus address using a mapping described by a page descriptor entry
* within the I/O Mapper. This 2048 entry, page descriptor table is located
* at physical address 0x60000000 in the sun3x architecture and can be
* manipulated by the CPU with normal read and write cycles.
*
* In addition to describing an address mapping, a page descriptor entry also
* indicates whether the DVMA page is read-only, should be inhibited from
* caching by system caches, and whether or not DMA write transfers to it will
* be completed in 16 byte aligned blocks. (This last item is used for cache
* optimization in sun3x systems with special DMA caches.)
*
* Since not every DMA device is capable of addressing all 24 bits of the
* DVMA address space, each is wired so that the end of its address space is
* always flush against the end of the DVMA address space. That is, a device
* with a 16 bit address space (and hence an address space size of 64k) is
* wired such that it accesses the top 64k of DVMA space.
*/
/** I/O MAPPER Page Descriptor Entry
* 31 16
* +---.---.---.---.---.---.---.---.---.---.---.---.---.---.---.---+
* | PAGE PHYSICAL ADDRESS BITS (31..13) |
* +---.---.---+---.---.---.---.---.---+---+---+---+---+---+---.---+
* | | UNUSED | CI| BX| M | U | WP| DT |
* +---.---.---+---.---.---.---.---.---+---+---+---+---+---+---.---+
* 15 0
*
* <CI> CACHE INHIBIT - When set, prevents instructions and data from the
* page from being cached in any system cache.
* <BX> FULL BLOCK XFER - When set, acts as an indicator to the caching system
* that all DMA transfers to this DVMA page will fill
* complete I/O cache blocks, eliminating the need for
* the cache block to be filled from main memory first
* before the DMA write can proceed to it.
* <M> MODIFIED - Set when the cpu has modified (written to) the
* physical page.
* <U> USED - Set when the cpu has accessed the physical page.
* <WP> WRITE PROTECT - When set, prevents all DMA devices from writing to
* the page.
* <DT> DESCRIPTOR TYPE - One of the following values:
* 00 = Invalid page
* 01 = Valid page
* 1x = Invalid code for a page descriptor.
*/
struct iommu_pde_struct {
union {
struct {
u_int pa:19; /* Physical Address */
u_int unused:6; /* Unused bits */
u_int ci:1; /* Cache Inhibit */
u_int bx:1; /* Full Block Xfer */
u_int m:1; /* Modified bit */
u_int u:1; /* Used bit */
u_int wp:1; /* Write Protect bit */
u_int dt:2; /* Descriptor type */
/* Masks for the above fields. */
#define IOMMU_PDE_PA 0xFFFFE000
#define IOMMU_PDE_UNUSED 0x00001F80
#define IOMMU_PDE_CI 0x00000040
#define IOMMU_PDE_BX 0x00000020
#define IOMMU_PDE_M 0x00000010
#define IOMMU_PDE_USED 0x00000008
#define IOMMU_PDE_WP 0x00000004
#define IOMMU_PDE_DT 0x00000003
/* The descriptor types */
#define IOMMU_PDE_DT_INVALID 0x00000000 /* Invalid page */
#define IOMMU_PDE_DT_VALID 0x00000001 /* Valid page */
} stc;
uint32_t raw; /* For unstructured access to the above */
} addr;
};
typedef struct iommu_pde_struct iommu_pde_t;
/* Constants */
#define IOMMU_PAGE_SIZE (8 * 1024)
#define IOMMU_PAGE_SHIFT 13
/* Useful macros */
#define IOMMU_PA_PDE(pde) ((pde).addr.raw & IOMMU_PDE_PA)
#define IOMMU_VALID_DT(pde) ((pde).addr.raw & IOMMU_PDE_DT) /* X1 */
#define IOMMU_BTOP(pa) (((u_int) pa) >> IOMMU_PAGE_SHIFT)
/* X1: This macro will incorrectly report the validity for entries which
* contain codes that are invalid. (Do not confuse this with the code for
* 'invalid entry', which means that the descriptor is properly formed, but
* just not used.)
*/
/* Constants for the I/O mapper as used in the sun3x */
#define IOMMU_NENT 2048 /* Number of PTEs in the map */
/* Similarly, the virtual address mask. */
#define IOMMU_VA_MASK 0xFFffff /* 16MB */
#ifdef _KERNEL
/* Interfaces for manipulating the I/O mapper */
void iommu_enter(uint32_t, uint32_t);
void iommu_remove(uint32_t, uint32_t);
#endif /* _KERNEL */
#endif /* _SUN3X_IOMMU_H */