| /* |
| * Copyright 2010 Tilera Corporation. All Rights Reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation, version 2. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
| * NON INFRINGEMENT. See the GNU General Public License for |
| * more details. |
| */ |
| |
| #ifndef _ASM_TILE_CACHE_H |
| #define _ASM_TILE_CACHE_H |
| |
| #include <arch/chip.h> |
| |
| /* bytes per L1 data cache line */ |
| #define L1_CACHE_SHIFT CHIP_L1D_LOG_LINE_SIZE() |
| #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) |
| |
| /* bytes per L2 cache line */ |
| #define L2_CACHE_SHIFT CHIP_L2_LOG_LINE_SIZE() |
| #define L2_CACHE_BYTES (1 << L2_CACHE_SHIFT) |
| #define L2_CACHE_ALIGN(x) (((x)+(L2_CACHE_BYTES-1)) & -L2_CACHE_BYTES) |
| |
| /* |
| * TILEPro I/O is not always coherent (networking typically uses coherent |
| * I/O, but PCI traffic does not) and setting ARCH_DMA_MINALIGN to the |
| * L2 cacheline size helps ensure that kernel heap allocations are aligned. |
| * TILE-Gx I/O is always coherent when used on hash-for-home pages. |
| * |
| * However, it's possible at runtime to request not to use hash-for-home |
| * for the kernel heap, in which case the kernel will use flush-and-inval |
| * to manage coherence. As a result, we use L2_CACHE_BYTES for the |
| * DMA minimum alignment to avoid false sharing in the kernel heap. |
| */ |
| #define ARCH_DMA_MINALIGN L2_CACHE_BYTES |
| |
| /* use the cache line size for the L2, which is where it counts */ |
| #define SMP_CACHE_BYTES_SHIFT L2_CACHE_SHIFT |
| #define SMP_CACHE_BYTES L2_CACHE_BYTES |
| #define INTERNODE_CACHE_SHIFT L2_CACHE_SHIFT |
| #define INTERNODE_CACHE_BYTES L2_CACHE_BYTES |
| |
| /* Group together read-mostly things to avoid cache false sharing */ |
| #define __read_mostly __attribute__((__section__(".data..read_mostly"))) |
| |
| /* |
| * Originally we used small TLB pages for kernel data and grouped some |
| * things together as "write once", enforcing the property at the end |
| * of initialization by making those pages read-only and non-coherent. |
| * This allowed better cache utilization since cache inclusion did not |
| * need to be maintained. However, to do this requires an extra TLB |
| * entry, which on balance is more of a performance hit than the |
| * non-coherence is a performance gain, so we now just make "read |
| * mostly" and "write once" be synonyms. We keep the attribute |
| * separate in case we change our minds at a future date. |
| */ |
| #define __write_once __read_mostly |
| |
| #endif /* _ASM_TILE_CACHE_H */ |
