arch/sparc/include/asm/viking.h

Source file repositories/reference/linux-study-clean/arch/sparc/include/asm/viking.h

File Facts

System
Linux kernel
Corpus path
arch/sparc/include/asm/viking.h
Extension
.h
Size
8343 bytes
Lines
256
Domain
Architecture Layer
Bucket
arch/sparc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _SPARC_VIKING_H
#define _SPARC_VIKING_H

#include <asm/asi.h>
#include <asm/mxcc.h>
#include <asm/pgtable.h>
#include <asm/pgtsrmmu.h>

/* Bits in the SRMMU control register for GNU/Viking modules.
 *
 * -----------------------------------------------------------
 * |impl-vers| RSV |TC|AC|SP|BM|PC|MBM|SB|IC|DC|PSO|RSV|NF|ME|
 * -----------------------------------------------------------
 *  31     24 23-17 16 15 14 13 12 11  10  9  8  7  6-2  1  0
 *
 * TC: Tablewalk Cacheable -- 0 = Twalks are not cacheable in E-cache
 *                            1 = Twalks are cacheable in E-cache
 *
 * GNU/Viking will only cache tablewalks in the E-cache (mxcc) if present
 * and never caches them internally (or so states the docs).  Therefore
 * for machines lacking an E-cache (ie. in MBUS mode) this bit must
 * remain cleared.
 *
 * AC: Alternate Cacheable -- 0 = Passthru physical accesses not cacheable
 *                            1 = Passthru physical accesses cacheable
 *
 * This indicates whether accesses are cacheable when no cachable bit
 * is present in the pte when the processor is in boot-mode or the
 * access does not need pte's for translation (ie. pass-thru ASI's).
 * "Cachable" is only referring to E-cache (if present) and not the
 * on chip split I/D caches of the GNU/Viking.
 *
 * SP: SnooP Enable -- 0 = bus snooping off, 1 = bus snooping on
 *
 * This enables snooping on the GNU/Viking bus.  This must be on
 * for the hardware cache consistency mechanisms of the GNU/Viking
 * to work at all.  On non-mxcc GNU/Viking modules the split I/D
 * caches will snoop regardless of whether they are enabled, this
 * takes care of the case where the I or D or both caches are turned
 * off yet still contain valid data.  Note also that this bit does
 * not affect GNU/Viking store-buffer snoops, those happen if the
 * store-buffer is enabled no matter what.
 *
 * BM: Boot Mode -- 0 = not in boot mode, 1 = in boot mode
 *
 * This indicates whether the GNU/Viking is in boot-mode or not,
 * if it is then all instruction fetch physical addresses are
 * computed as 0xff0000000 + low 28 bits of requested address.
 * GNU/Viking boot-mode does not affect data accesses.  Also,
 * in boot mode instruction accesses bypass the split on chip I/D
 * caches, they may be cached by the GNU/MXCC if present and enabled.
 *
 * MBM: MBus Mode -- 0 = not in MBus mode, 1 = in MBus mode
 *
 * This indicated the GNU/Viking configuration present.  If in
 * MBUS mode, the GNU/Viking lacks a GNU/MXCC E-cache.  If it is
 * not then the GNU/Viking is on a module VBUS connected directly
 * to a GNU/MXCC cache controller.  The GNU/MXCC can be thus connected
 * to either an GNU/MBUS (sun4m) or the packet-switched GNU/XBus (sun4d).
 *
 * SB: StoreBuffer enable -- 0 = store buffer off, 1 = store buffer on
 *
 * The GNU/Viking store buffer allows the chip to continue execution
 * after a store even if the data cannot be placed in one of the
 * caches during that cycle.  If disabled, all stores operations
 * occur synchronously.
 *
 * IC: Instruction Cache -- 0 = off, 1 = on
 * DC: Data Cache -- 0 = off, 1 = 0n
 *
 * These bits enable the on-cpu GNU/Viking split I/D caches.  Note,
 * as mentioned above, these caches will snoop the bus in GNU/MBUS
 * configurations even when disabled to avoid data corruption.
 *
 * NF: No Fault -- 0 = faults generate traps, 1 = faults don't trap
 * ME: MMU enable -- 0 = mmu not translating, 1 = mmu translating
 *
 */

#define VIKING_MMUENABLE    0x00000001
#define VIKING_NOFAULT      0x00000002
#define VIKING_PSO          0x00000080
#define VIKING_DCENABLE     0x00000100   /* Enable data cache */
#define VIKING_ICENABLE     0x00000200   /* Enable instruction cache */
#define VIKING_SBENABLE     0x00000400   /* Enable store buffer */
#define VIKING_MMODE        0x00000800   /* MBUS mode */
#define VIKING_PCENABLE     0x00001000   /* Enable parity checking */
#define VIKING_BMODE        0x00002000   
#define VIKING_SPENABLE     0x00004000   /* Enable bus cache snooping */
#define VIKING_ACENABLE     0x00008000   /* Enable alternate caching */

Annotation

Implementation Notes