diff options
Diffstat (limited to 'arch/mips/kernel/spram.c')
| -rw-r--r-- | arch/mips/kernel/spram.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/mips/kernel/spram.c b/arch/mips/kernel/spram.c new file mode 100644 index 000000000000..6ddb507a87ef --- /dev/null +++ b/arch/mips/kernel/spram.c @@ -0,0 +1,221 @@ +/* + * MIPS SPRAM support + * + * 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; either version + * 2 of the License, or (at your option) any later version. + * + * Copyright (C) 2007, 2008 MIPS Technologies, Inc. + */ +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/ptrace.h> +#include <linux/stddef.h> + +#include <asm/cpu.h> +#include <asm/fpu.h> +#include <asm/mipsregs.h> +#include <asm/system.h> +#include <asm/r4kcache.h> +#include <asm/hazards.h> + +/* + * These definitions are correct for the 24K/34K/74K SPRAM sample + * implementation. The 4KS interpreted the tags differently... + */ +#define SPRAM_TAG0_ENABLE 0x00000080 +#define SPRAM_TAG0_PA_MASK 0xfffff000 +#define SPRAM_TAG1_SIZE_MASK 0xfffff000 + +#define SPRAM_TAG_STRIDE 8 + +#define ERRCTL_SPRAM (1 << 28) + +/* errctl access */ +#define read_c0_errctl(x) read_c0_ecc(x) +#define write_c0_errctl(x) write_c0_ecc(x) + +/* + * Different semantics to the set_c0_* function built by __BUILD_SET_C0 + */ +static __cpuinit unsigned int bis_c0_errctl(unsigned int set) +{ + unsigned int res; + res = read_c0_errctl(); + write_c0_errctl(res | set); + return res; +} + +static __cpuinit void ispram_store_tag(unsigned int offset, unsigned int data) +{ + unsigned int errctl; + + /* enable SPRAM tag access */ + errctl = bis_c0_errctl(ERRCTL_SPRAM); + ehb(); + + write_c0_taglo(data); + ehb(); + + cache_op(Index_Store_Tag_I, CKSEG0|offset); + ehb(); + + write_c0_errctl(errctl); + ehb(); +} + + +static __cpuinit unsigned int ispram_load_tag(unsigned int offset) +{ + unsigned int data; + unsigned int errctl; + + /* enable SPRAM tag access */ + errctl = bis_c0_errctl(ERRCTL_SPRAM); + ehb(); + cache_op(Index_Load_Tag_I, CKSEG0 | offset); + ehb(); + data = read_c0_taglo(); + ehb(); + write_c0_errctl(errctl); + ehb(); + + return data; +} + +static __cpuinit void dspram_store_tag(unsigned int offset, unsigned int data) +{ + unsigned int errctl; + + /* enable SPRAM tag access */ + errctl = bis_c0_errctl(ERRCTL_SPRAM); + ehb(); + write_c0_dtaglo(data); + ehb(); + cache_op(Index_Store_Tag_D, CKSEG0 | offset); + ehb(); + write_c0_errctl(errctl); + ehb(); +} + + +static __cpuinit unsigned int dspram_load_tag(unsigned int offset) +{ + unsigned int data; + unsigned int errctl; + + errctl = bis_c0_errctl(ERRCTL_SPRAM); + ehb(); + cache_op(Index_Load_Tag_D, CKSEG0 | offset); + ehb(); + data = read_c0_dtaglo(); + ehb(); + write_c0_errctl(errctl); + ehb(); + + return data; +} + +static __cpuinit void probe_spram(char *type, + unsigned int base, + unsigned int (*read)(unsigned int), + void (*write)(unsigned int, unsigned int)) +{ + unsigned int firstsize = 0, lastsize = 0; + unsigned int firstpa = 0, lastpa = 0, pa = 0; + unsigned int offset = 0; + unsigned int size, tag0, tag1; + unsigned int enabled; + int i; + + /* + * The limit is arbitrary but avoids the loop running away if + * the SPRAM tags are implemented differently + */ + + for (i = 0; i < 8; i++) { + tag0 = read(offset); + tag1 = read(offset+SPRAM_TAG_STRIDE); + pr_debug("DBG %s%d: tag0=%08x tag1=%08x\n", + type, i, tag0, tag1); + + size = tag1 & SPRAM_TAG1_SIZE_MASK; + + if (size == 0) + break; + + if (i != 0) { + /* tags may repeat... */ + if ((pa == firstpa && size == firstsize) || + (pa == lastpa && size == lastsize)) + break; + } + + /* Align base with size */ + base = (base + size - 1) & ~(size-1); + + /* reprogram the base address base address and enable */ + tag0 = (base & SPRAM_TAG0_PA_MASK) | SPRAM_TAG0_ENABLE; + write(offset, tag0); + + base += size; + + /* reread the tag */ + tag0 = read(offset); + pa = tag0 & SPRAM_TAG0_PA_MASK; + enabled = tag0 & SPRAM_TAG0_ENABLE; + + if (i == 0) { + firstpa = pa; + firstsize = size; + } + + lastpa = pa; + lastsize = size; + + if (strcmp(type, "DSPRAM") == 0) { + unsigned int *vp = (unsigned int *)(CKSEG1 | pa); + unsigned int v; +#define TDAT 0x5a5aa5a5 + vp[0] = TDAT; + vp[1] = ~TDAT; + + mb(); + + v = vp[0]; + if (v != TDAT) + printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n", + vp, TDAT, v); + v = vp[1]; + if (v != ~TDAT) + printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n", + vp+1, ~TDAT, v); + } + + pr_info("%s%d: PA=%08x,Size=%08x%s\n", + type, i, pa, size, enabled ? ",enabled" : ""); + offset += 2 * SPRAM_TAG_STRIDE; + } +} + +__cpuinit void spram_config(void) +{ + struct cpuinfo_mips *c = ¤t_cpu_data; + unsigned int config0; + + switch (c->cputype) { + case CPU_24K: + case CPU_34K: + case CPU_74K: + config0 = read_c0_config(); + /* FIXME: addresses are Malta specific */ + if (config0 & (1<<24)) { + probe_spram("ISPRAM", 0x1c000000, + &ispram_load_tag, &ispram_store_tag); + } + if (config0 & (1<<23)) + probe_spram("DSPRAM", 0x1c100000, + &dspram_load_tag, &dspram_store_tag); + } +} |