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MIPS: TXx9: Cache fixup
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TX39/TX49 can enable/disable I/D cache at runtime.  Add kernel options
to control them.  This is useful to debug some cache-related issues,
such as aliasing or I/D coherency.  Also enable CWF bit for TX49 SoCs.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Atsushi Nemoto authored and Ralf Baechle committed Oct 11, 2008
1 parent 860e546 commit d10e025
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Showing 6 changed files with 124 additions and 26 deletions.
113 changes: 113 additions & 0 deletions arch/mips/txx9/generic/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include <asm/bootinfo.h>
#include <asm/time.h>
#include <asm/reboot.h>
#include <asm/r4kcache.h>
#include <asm/txx9/generic.h>
#include <asm/txx9/pci.h>
#ifdef CONFIG_CPU_TX49XX
Expand Down Expand Up @@ -186,6 +187,110 @@ static void __init prom_init_cmdline(void)
}
}

static int txx9_ic_disable __initdata;
static int txx9_dc_disable __initdata;

#if defined(CONFIG_CPU_TX49XX)
/* flush all cache on very early stage (before 4k_cache_init) */
static void __init early_flush_dcache(void)
{
unsigned int conf = read_c0_config();
unsigned int dc_size = 1 << (12 + ((conf & CONF_DC) >> 6));
unsigned int linesz = 32;
unsigned long addr, end;

end = INDEX_BASE + dc_size / 4;
/* 4way, waybit=0 */
for (addr = INDEX_BASE; addr < end; addr += linesz) {
cache_op(Index_Writeback_Inv_D, addr | 0);
cache_op(Index_Writeback_Inv_D, addr | 1);
cache_op(Index_Writeback_Inv_D, addr | 2);
cache_op(Index_Writeback_Inv_D, addr | 3);
}
}

static void __init txx9_cache_fixup(void)
{
unsigned int conf;

conf = read_c0_config();
/* flush and disable */
if (txx9_ic_disable) {
conf |= TX49_CONF_IC;
write_c0_config(conf);
}
if (txx9_dc_disable) {
early_flush_dcache();
conf |= TX49_CONF_DC;
write_c0_config(conf);
}

/* enable cache */
conf = read_c0_config();
if (!txx9_ic_disable)
conf &= ~TX49_CONF_IC;
if (!txx9_dc_disable)
conf &= ~TX49_CONF_DC;
write_c0_config(conf);

if (conf & TX49_CONF_IC)
pr_info("TX49XX I-Cache disabled.\n");
if (conf & TX49_CONF_DC)
pr_info("TX49XX D-Cache disabled.\n");
}
#elif defined(CONFIG_CPU_TX39XX)
/* flush all cache on very early stage (before tx39_cache_init) */
static void __init early_flush_dcache(void)
{
unsigned int conf = read_c0_config();
unsigned int dc_size = 1 << (10 + ((conf & TX39_CONF_DCS_MASK) >>
TX39_CONF_DCS_SHIFT));
unsigned int linesz = 16;
unsigned long addr, end;

end = INDEX_BASE + dc_size / 2;
/* 2way, waybit=0 */
for (addr = INDEX_BASE; addr < end; addr += linesz) {
cache_op(Index_Writeback_Inv_D, addr | 0);
cache_op(Index_Writeback_Inv_D, addr | 1);
}
}

static void __init txx9_cache_fixup(void)
{
unsigned int conf;

conf = read_c0_config();
/* flush and disable */
if (txx9_ic_disable) {
conf &= ~TX39_CONF_ICE;
write_c0_config(conf);
}
if (txx9_dc_disable) {
early_flush_dcache();
conf &= ~TX39_CONF_DCE;
write_c0_config(conf);
}

/* enable cache */
conf = read_c0_config();
if (!txx9_ic_disable)
conf |= TX39_CONF_ICE;
if (!txx9_dc_disable)
conf |= TX39_CONF_DCE;
write_c0_config(conf);

if (!(conf & TX39_CONF_ICE))
pr_info("TX39XX I-Cache disabled.\n");
if (!(conf & TX39_CONF_DCE))
pr_info("TX39XX D-Cache disabled.\n");
}
#else
static inline void txx9_cache_fixup(void)
{
}
#endif

static void __init preprocess_cmdline(void)
{
char cmdline[CL_SIZE];
Expand All @@ -204,11 +309,19 @@ static void __init preprocess_cmdline(void)
if (strict_strtoul(str + 10, 10, &val) == 0)
txx9_master_clock = val;
continue;
} else if (strcmp(str, "icdisable") == 0) {
txx9_ic_disable = 1;
continue;
} else if (strcmp(str, "dcdisable") == 0) {
txx9_dc_disable = 1;
continue;
}
if (arcs_cmdline[0])
strcat(arcs_cmdline, " ");
strcat(arcs_cmdline, str);
}

txx9_cache_fixup();
}

static void __init select_board(void)
Expand Down
18 changes: 8 additions & 10 deletions arch/mips/txx9/generic/setup_tx3927.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,16 +99,14 @@ void __init tx3927_setup(void)
txx9_gpio_init(TX3927_PIO_REG, 0, 16);

conf = read_c0_conf();
if (!(conf & TX39_CONF_ICE))
printk(KERN_INFO "TX3927 I-Cache disabled.\n");
if (!(conf & TX39_CONF_DCE))
printk(KERN_INFO "TX3927 D-Cache disabled.\n");
else if (!(conf & TX39_CONF_WBON))
printk(KERN_INFO "TX3927 D-Cache WriteThrough.\n");
else if (!(conf & TX39_CONF_CWFON))
printk(KERN_INFO "TX3927 D-Cache WriteBack.\n");
else
printk(KERN_INFO "TX3927 D-Cache WriteBack (CWF) .\n");
if (conf & TX39_CONF_DCE) {
if (!(conf & TX39_CONF_WBON))
pr_info("TX3927 D-Cache WriteThrough.\n");
else if (!(conf & TX39_CONF_CWFON))
pr_info("TX3927 D-Cache WriteBack.\n");
else
pr_info("TX3927 D-Cache WriteBack (CWF) .\n");
}
}

void __init tx3927_time_init(unsigned int evt_tmrnr, unsigned int src_tmrnr)
Expand Down
1 change: 1 addition & 0 deletions arch/mips/txx9/generic/setup_tx4927.c
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ void __init tx4927_setup(void)

txx9_reg_res_init(TX4927_REV_PCODE(), TX4927_REG_BASE,
TX4927_REG_SIZE);
set_c0_config(TX49_CONF_CWFON);

/* SDRAMC,EBUSC are configured by PROM */
for (i = 0; i < 8; i++) {
Expand Down
1 change: 1 addition & 0 deletions arch/mips/txx9/generic/setup_tx4938.c
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ void __init tx4938_setup(void)

txx9_reg_res_init(TX4938_REV_PCODE(), TX4938_REG_BASE,
TX4938_REG_SIZE);
set_c0_config(TX49_CONF_CWFON);

/* SDRAMC,EBUSC are configured by PROM */
for (i = 0; i < 8; i++) {
Expand Down
11 changes: 1 addition & 10 deletions arch/mips/txx9/jmr3927/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,6 @@ static void __init jmr3927_time_init(void)
}

#define DO_WRITE_THROUGH
#define DO_ENABLE_CACHE

static void jmr3927_board_init(void);

Expand All @@ -77,11 +76,6 @@ static void __init jmr3927_mem_setup(void)
/* cache setup */
{
unsigned int conf;
#ifdef DO_ENABLE_CACHE
int mips_ic_disable = 0, mips_dc_disable = 0;
#else
int mips_ic_disable = 1, mips_dc_disable = 1;
#endif
#ifdef DO_WRITE_THROUGH
int mips_config_cwfon = 0;
int mips_config_wbon = 0;
Expand All @@ -91,10 +85,7 @@ static void __init jmr3927_mem_setup(void)
#endif

conf = read_c0_conf();
conf &= ~(TX39_CONF_ICE | TX39_CONF_DCE |
TX39_CONF_WBON | TX39_CONF_CWFON);
conf |= mips_ic_disable ? 0 : TX39_CONF_ICE;
conf |= mips_dc_disable ? 0 : TX39_CONF_DCE;
conf &= ~(TX39_CONF_WBON | TX39_CONF_CWFON);
conf |= mips_config_wbon ? TX39_CONF_WBON : 0;
conf |= mips_config_cwfon ? TX39_CONF_CWFON : 0;

Expand Down
6 changes: 0 additions & 6 deletions arch/mips/txx9/rbtx4927/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -186,14 +186,8 @@ static void __init rbtx4937_clock_init(void);

static void __init rbtx4927_mem_setup(void)
{
u32 cp0_config;
char *argptr;

/* enable caches -- HCP5 does this, pmon does not */
cp0_config = read_c0_config();
cp0_config = cp0_config & ~(TX49_CONF_IC | TX49_CONF_DC);
write_c0_config(cp0_config);

if (TX4927_REV_PCODE() == 0x4927) {
rbtx4927_clock_init();
tx4927_setup();
Expand Down

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