diff options
Diffstat (limited to 'arch/mips/mm/sc-rm7k.c')
| -rw-r--r-- | arch/mips/mm/sc-rm7k.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/mips/mm/sc-rm7k.c b/arch/mips/mm/sc-rm7k.c new file mode 100644 index 000000000000..4e92f931aaba --- /dev/null +++ b/arch/mips/mm/sc-rm7k.c @@ -0,0 +1,193 @@ +/* + * sc-rm7k.c: RM7000 cache management functions. + * + * Copyright (C) 1997, 2001, 2003, 2004 Ralf Baechle (ralf@linux-mips.org) + */ + +#undef DEBUG + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/mm.h> + +#include <asm/addrspace.h> +#include <asm/bcache.h> +#include <asm/cacheops.h> +#include <asm/mipsregs.h> +#include <asm/processor.h> + +/* Primary cache parameters. */ +#define sc_lsize 32 +#define tc_pagesize (32*128) + +/* Secondary cache parameters. */ +#define scache_size (256*1024) /* Fixed to 256KiB on RM7000 */ + +extern unsigned long icache_way_size, dcache_way_size; + +#include <asm/r4kcache.h> + +int rm7k_tcache_enabled; + +/* + * Writeback and invalidate the primary cache dcache before DMA. + * (XXX These need to be fixed ...) + */ +static void rm7k_sc_wback_inv(unsigned long addr, unsigned long size) +{ + unsigned long end, a; + + pr_debug("rm7k_sc_wback_inv[%08lx,%08lx]", addr, size); + + /* Catch bad driver code */ + BUG_ON(size == 0); + + a = addr & ~(sc_lsize - 1); + end = (addr + size - 1) & ~(sc_lsize - 1); + while (1) { + flush_scache_line(a); /* Hit_Writeback_Inv_SD */ + if (a == end) + break; + a += sc_lsize; + } + + if (!rm7k_tcache_enabled) + return; + + a = addr & ~(tc_pagesize - 1); + end = (addr + size - 1) & ~(tc_pagesize - 1); + while(1) { + invalidate_tcache_page(a); /* Page_Invalidate_T */ + if (a == end) + break; + a += tc_pagesize; + } +} + +static void rm7k_sc_inv(unsigned long addr, unsigned long size) +{ + unsigned long end, a; + + pr_debug("rm7k_sc_inv[%08lx,%08lx]", addr, size); + + /* Catch bad driver code */ + BUG_ON(size == 0); + + a = addr & ~(sc_lsize - 1); + end = (addr + size - 1) & ~(sc_lsize - 1); + while (1) { + invalidate_scache_line(a); /* Hit_Invalidate_SD */ + if (a == end) + break; + a += sc_lsize; + } + + if (!rm7k_tcache_enabled) + return; + + a = addr & ~(tc_pagesize - 1); + end = (addr + size - 1) & ~(tc_pagesize - 1); + while(1) { + invalidate_tcache_page(a); /* Page_Invalidate_T */ + if (a == end) + break; + a += tc_pagesize; + } +} + +/* + * This function is executed in the uncached segment CKSEG1. + * It must not touch the stack, because the stack pointer still points + * into CKSEG0. + * + * Three options: + * - Write it in assembly and guarantee that we don't use the stack. + * - Disable caching for CKSEG0 before calling it. + * - Pray that GCC doesn't randomly start using the stack. + * + * This being Linux, we obviously take the least sane of those options - + * following DaveM's lead in c-r4k.c + * + * It seems we get our kicks from relying on unguaranteed behaviour in GCC + */ +static __init void __rm7k_sc_enable(void) +{ + int i; + + set_c0_config(1 << 3); /* CONF_SE */ + + write_c0_taglo(0); + write_c0_taghi(0); + + for (i = 0; i < scache_size; i += sc_lsize) { + __asm__ __volatile__ ( + ".set noreorder\n\t" + ".set mips3\n\t" + "cache %1, (%0)\n\t" + ".set mips0\n\t" + ".set reorder" + : + : "r" (KSEG0ADDR(i)), "i" (Index_Store_Tag_SD)); + } +} + +static __init void rm7k_sc_enable(void) +{ + void (*func)(void) = (void *) KSEG1ADDR(&__rm7k_sc_enable); + + if (read_c0_config() & 0x08) /* CONF_SE */ + return; + + printk(KERN_INFO "Enabling secondary cache..."); + func(); +} + +static void rm7k_sc_disable(void) +{ + clear_c0_config(1<<3); /* CONF_SE */ +} + +struct bcache_ops rm7k_sc_ops = { + .bc_enable = rm7k_sc_enable, + .bc_disable = rm7k_sc_disable, + .bc_wback_inv = rm7k_sc_wback_inv, + .bc_inv = rm7k_sc_inv +}; + +void __init rm7k_sc_init(void) +{ + unsigned int config = read_c0_config(); + + if ((config >> 31) & 1) /* Bit 31 set -> no S-Cache */ + return; + + printk(KERN_INFO "Secondary cache size %dK, linesize %d bytes.\n", + (scache_size >> 10), sc_lsize); + + if (!((config >> 3) & 1)) /* CONF_SE */ + rm7k_sc_enable(); + + /* + * While we're at it let's deal with the tertiary cache. + */ + if (!((config >> 17) & 1)) { + + /* + * We can't enable the L3 cache yet. There may be board-specific + * magic necessary to turn it on, and blindly asking the CPU to + * start using it would may give cache errors. + * + * Also, board-specific knowledge may allow us to use the + * CACHE Flash_Invalidate_T instruction if the tag RAM supports + * it, and may specify the size of the L3 cache so we don't have + * to probe it. + */ + printk(KERN_INFO "Tertiary cache present, %s enabled\n", + config&(1<<12) ? "already" : "not (yet)"); + + if ((config >> 12) & 1) + rm7k_tcache_enabled = 1; + } + + bcops = &rm7k_sc_ops; +} |