/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2003, 04, 05 Ralf Baechle ([email protected])
* Copyright (C) 2007 Maciej W. Rozycki
* Copyright (C) 2008 Thiemo Seufer
* Copyright (C) 2012 MIPS Technologies, Inc.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <asm/bugs.h>
#include <asm/cacheops.h>
#include <asm/cpu-type.h>
#include <asm/inst.h>
#include <asm/io.h>
#include <asm/page.h>
#include <asm/prefetch.h>
#include <asm/bootinfo.h>
#include <asm/mipsregs.h>
#include <asm/mmu_context.h>
#include <asm/regdef.h>
#include <asm/cpu.h>
#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_dma.h>
#endif
#include <asm/uasm.h>
/* Handle labels (which must be positive integers). */
enum label_id {
label_clear_nopref = 1,
label_clear_pref,
label_copy_nopref,
label_copy_pref_both,
label_copy_pref_store,
};
UASM_L_LA(_clear_nopref)
UASM_L_LA(_clear_pref)
UASM_L_LA(_copy_nopref)
UASM_L_LA(_copy_pref_both)
UASM_L_LA(_copy_pref_store)
/* We need one branch and therefore one relocation per target label. */
static struct uasm_label labels[5];
static struct uasm_reloc relocs[5];
#define cpu_is_r4600_v1_x() ((read_c0_prid() & 0xfffffff0) == 0x00002010)
#define cpu_is_r4600_v2_x() ((read_c0_prid() & 0xfffffff0) == 0x00002020)
/*
* R6 has a limited offset of the pref instruction.
* Skip it if the offset is more than 9 bits.
*/
#define _uasm_i_pref(a, b, c, d) \
do { \
if (cpu_has_mips_r6) { \
if (c <= 0xff && c >= -0x100) \
uasm_i_pref(a, b, c, d);\
} else { \
uasm_i_pref(a, b, c, d); \
} \
} while(0)
static int pref_bias_clear_store;
static int pref_bias_copy_load;
static int pref_bias_copy_store;
static u32 pref_src_mode;
static u32 pref_dst_mode;
static int clear_word_size;
static int copy_word_size;
static int half_clear_loop_size;
static int half_copy_loop_size;
static int cache_line_size;
#define cache_line_mask() (cache_line_size - 1)
static inline void
pg_addiu(u32 **buf, unsigned int reg1, unsigned int reg2, unsigned int off)
{
if (cpu_has_64bit_gp_regs &&
IS_ENABLED(CONFIG_CPU_DADDI_WORKAROUNDS) &&
r4k_daddiu_bug()) {
if (off > 0x7fff) {
uasm_i_lui(buf, GPR_T9, uasm_rel_hi(off));
uasm_i_addiu(buf, GPR_T9, GPR_T9, uasm_rel_lo(off));
} else
uasm_i_addiu(buf, GPR_T9, GPR_ZERO, off);
uasm_i_daddu(buf, reg1, reg2, GPR_T9);
} else {
if (off > 0x7fff) {
uasm_i_lui(buf, GPR_T9, uasm_rel_hi(off));
uasm_i_addiu(buf, GPR_T9, GPR_T9, uasm_rel_lo(off));
UASM_i_ADDU(buf, reg1, reg2, GPR_T9);
} else
UASM_i_ADDIU(buf, reg1, reg2, off);
}
}
static void set_prefetch_parameters(void)
{
if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg)
clear_word_size = 8;
else
clear_word_size = 4;
if (cpu_has_64bit_gp_regs)
copy_word_size = 8;
else
copy_word_size = 4;
/*
* The pref's used here are using "streaming" hints, which cause the
* copied data to be kicked out of the cache sooner. A page copy often
* ends up copying a lot more data than is commonly used, so this seems
* to make sense in terms of reducing cache pollution, but I've no real
* performance data to back this up.
*/
if (cpu_has_prefetch) {
/*
* XXX: Most prefetch bias values in here are based on
* guesswork.
*/
cache_line_size = cpu_dcache_line_size();
switch (current_cpu_type()) {
case CPU_R5500:
case CPU_TX49XX:
/* These processors only support the Pref_Load. */
pref_bias_copy_load = 256;
break;
case CPU_R10000:
case CPU_R12000:
case CPU_R14000:
case CPU_R16000:
/*
* Those values have been experimentally tuned for an
* Origin 200.
*/
pref_bias_clear_store = 512;
pref_bias_copy_load = 256;
pref_bias_copy_store = 256;
pref_src_mode = Pref_LoadStreamed;
pref_dst_mode = Pref_StoreStreamed;
break;
case CPU_SB1:
case CPU_SB1A:
pref_bias_clear_store = 128;
pref_bias_copy_load = 128;
pref_bias_copy_store = 128;
/*
* SB1 pass1 Pref_LoadStreamed/Pref_StoreStreamed
* hints are broken.
*/
if (current_cpu_type() == CPU_SB1 &&
(current_cpu_data.processor_id & 0xff) < 0x02) {
pref_src_mode = Pref_Load;
pref_dst_mode = Pref_Store;
} else {
pref_src_mode = Pref_LoadStreamed;
pref_dst_mode = Pref_StoreStreamed;
}
break;
case CPU_LOONGSON64:
/* Loongson-3 only support the Pref_Load/Pref_Store. */
pref_bias_clear_store = 128;
pref_bias_copy_load = 128;
pref_bias_copy_store = 128;
pref_src_mode = Pref_Load;
pref_dst_mode = Pref_Store;
break;
default:
pref_bias_clear_store = 128;
pref_bias_copy_load = 256;
pref_bias_copy_store = 128;
pref_src_mode = Pref_LoadStreamed;
if (cpu_has_mips_r6)
/*
* Bit 30 (Pref_PrepareForStore) has been
* removed from MIPS R6. Use bit 5
* (Pref_StoreStreamed).
*/
pref_dst_mode = Pref_StoreStreamed;
else
pref_dst_mode = Pref_PrepareForStore;
break;
}
} else {
if (cpu_has_cache_cdex_s)
cache_line_size = cpu_scache_line_size();
else if (cpu_has_cache_cdex_p)
cache_line_size = cpu_dcache_line_size();
}
/*
* Too much unrolling will overflow the available space in
* clear_space_array / copy_page_array.
*/
half_clear_loop_size = min(16 * clear_word_size,
max(cache_line_size >> 1,
4 * clear_word_size));
half_copy_loop_size = min(16 * copy_word_size,
max(cache_line_size >> 1,
4 * copy_word_size));
}
static void build_clear_store(u32 **buf, int off)
{
if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg) {
uasm_i_sd(buf, GPR_ZERO, off, GPR_A0);
} else {
uasm_i_sw(buf, GPR_ZERO, off, GPR_A0);
}
}
static inline void build_clear_pref(u32 **buf, int off)
{
if (off & cache_line_mask())
return;
if (pref_bias_clear_store) {
_uasm_i_pref(buf, pref_dst_mode, pref_bias_clear_store + off,
GPR_A0);
} else if (cache_line_size == (half_clear_loop_size << 1)) {
if (cpu_has_cache_cdex_s) {
uasm_i_cache(buf, Create_Dirty_Excl_SD, off, GPR_A0);
} else if (cpu_has_cache_cdex_p) {
if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
cpu_is_r4600_v1_x()) {
uasm_i_nop(buf);
uasm_i_nop(buf);
uasm_i_nop(buf);
uasm_i_nop(buf);
}
if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
cpu_is_r4600_v2_x())
uasm_i_lw(buf, GPR_ZERO, GPR_ZERO, GPR_AT);
uasm_i_cache(buf, Create_Dirty_Excl_D, off, GPR_A0);
}
}
}
extern u32 __clear_page_start;
extern u32 __clear_page_end;
extern u32 __copy_page_start;
extern u32 __copy_page_end;
void build_clear_page(void)
{
int off;
u32 *buf = &__clear_page_start;
struct uasm_label *l = labels;
struct uasm_reloc *r = relocs;
int i;
static atomic_t run_once = ATOMIC_INIT(0);
if (atomic_xchg(&run_once, 1)) {
return;
}
memset(labels, 0, sizeof(labels));
memset(relocs, 0, sizeof(relocs));
set_prefetch_parameters();
/*
* This algorithm makes the following assumptions:
* - The prefetch bias is a multiple of 2 words.
* - The prefetch bias is less than one page.
*/
BUG_ON(pref_bias_clear_store % (2 * clear_word_size));
BUG_ON(PAGE_SIZE < pref_bias_clear_store);
off = PAGE_SIZE - pref_bias_clear_store;
if (off > 0xffff || !pref_bias_clear_store)
pg_addiu(&buf, GPR_A2, GPR_A0, off);
else
uasm_i_ori(&buf, GPR_A2, GPR_A0, off);
if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
uasm_i_lui(&buf, GPR_AT, uasm_rel_hi(0xa0000000));
off = cache_line_size ? min(8, pref_bias_clear_store / cache_line_size)
* cache_line_size : 0;
while (off) {
build_clear_pref(&buf, -off);
off -= cache_line_size;
}
uasm_l_clear_pref(&l, buf);
do {
build_clear_pref(&buf, off);
build_clear_store(&buf, off);
off += clear_word_size;
} while (off < half_clear_loop_size);
pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
off = -off;
do {
build_clear_pref(&buf, off);
if (off == -clear_word_size)
uasm_il_bne(&buf, &r, GPR_A0, GPR_A2, label_clear_pref);
build_clear_store(&buf, off);
off += clear_word_size;
} while (off < 0);
if (pref_bias_clear_store) {
pg_addiu(&buf, GPR_A2, GPR_A0, pref_bias_clear_store);
uasm_l_clear_nopref(&l, buf);
off = 0;
do {
build_clear_store(&buf, off);
off += clear_word_size;
} while (off < half_clear_loop_size);
pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
off = -off;
do {
if (off == -clear_word_size)
uasm_il_bne(&buf, &r, GPR_A0, GPR_A2,
label_clear_nopref);
build_clear_store(&buf, off);
off += clear_word_size;
} while (off < 0);
}
uasm_i_jr(&buf, GPR_RA);
uasm_i_nop(&buf);
BUG_ON(buf > &__clear_page_end);
uasm_resolve_relocs(relocs, labels);
pr_debug("Synthesized clear page handler (%u instructions).\n",
(u32)(buf - &__clear_page_start));
pr_debug("\t.set push\n");
pr_debug("\t.set noreorder\n");
for (i = 0; i < (buf - &__clear_page_start); i++)
pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
pr_debug("\t.set pop\n");
}
static void build_copy_load(u32 **buf, int reg, int off)
{
if (cpu_has_64bit_gp_regs) {
uasm_i_ld(buf, reg, off, GPR_A1);
} else {
uasm_i_lw(buf, reg, off, GPR_A1);
}
}
static void build_copy_store(u32 **buf, int reg, int off)
{
if (cpu_has_64bit_gp_regs) {
uasm_i_sd(buf, reg, off, GPR_A0);
} else {
uasm_i_sw(buf, reg, off, GPR_A0);
}
}
static inline void build_copy_load_pref(u32 **buf, int off)
{
if (off & cache_line_mask())
return;
if (pref_bias_copy_load)
_uasm_i_pref(buf, pref_src_mode, pref_bias_copy_load + off, GPR_A1);
}
static inline void build_copy_store_pref(u32 **buf, int off)
{
if (off & cache_line_mask())
return;
if (pref_bias_copy_store) {
_uasm_i_pref(buf, pref_dst_mode, pref_bias_copy_store + off,
GPR_A0);
} else if (cache_line_size == (half_copy_loop_size << 1)) {
if (cpu_has_cache_cdex_s) {
uasm_i_cache(buf, Create_Dirty_Excl_SD, off, GPR_A0);
} else if (cpu_has_cache_cdex_p) {
if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
cpu_is_r4600_v1_x()) {
uasm_i_nop(buf);
uasm_i_nop(buf);
uasm_i_nop(buf);
uasm_i_nop(buf);
}
if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
cpu_is_r4600_v2_x())
uasm_i_lw(buf, GPR_ZERO, GPR_ZERO, GPR_AT);
uasm_i_cache(buf, Create_Dirty_Excl_D, off, GPR_A0);
}
}
}
void build_copy_page(void)
{
int off;
u32 *buf = &__copy_page_start;
struct uasm_label *l = labels;
struct uasm_reloc *r = relocs;
int i;
static atomic_t run_once = ATOMIC_INIT(0);
if (atomic_xchg(&run_once, 1)) {
return;
}
memset(labels, 0, sizeof(labels));
memset(relocs, 0, sizeof(relocs));
set_prefetch_parameters();
/*
* This algorithm makes the following assumptions:
* - All prefetch biases are multiples of 8 words.
* - The prefetch biases are less than one page.
* - The store prefetch bias isn't greater than the load
* prefetch bias.
*/
BUG_ON(pref_bias_copy_load % (8 * copy_word_size));
BUG_ON(pref_bias_copy_store % (8 * copy_word_size));
BUG_ON(PAGE_SIZE < pref_bias_copy_load);
BUG_ON(pref_bias_copy_store > pref_bias_copy_load);
off = PAGE_SIZE - pref_bias_copy_load;
if (off > 0xffff || !pref_bias_copy_load)
pg_addiu(&buf, GPR_A2, GPR_A0, off);
else
uasm_i_ori(&buf, GPR_A2, GPR_A0, off);
if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
uasm_i_lui(&buf, GPR_AT, uasm_rel_hi(0xa0000000));
off = cache_line_size ? min(8, pref_bias_copy_load / cache_line_size) *
cache_line_size : 0;
while (off) {
build_copy_load_pref(&buf, -off);
off -= cache_line_size;
}
off = cache_line_size ? min(8, pref_bias_copy_store / cache_line_size) *
cache_line_size : 0;
while (off) {
build_copy_store_pref(&buf, -off);
off -= cache_line_size;
}
uasm_l_copy_pref_both(&l, buf);
do {
build_copy_load_pref(&buf, off);
build_copy_load(&buf, GPR_T0, off);
build_copy_load_pref(&buf, off + copy_word_size);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load_pref(&buf, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load_pref(&buf, off + 3 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store_pref(&buf, off);
build_copy_store(&buf, GPR_T0, off);
build_copy_store_pref(&buf, off + copy_word_size);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store_pref(&buf, off + 2 * copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_store_pref(&buf, off + 3 * copy_word_size);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < half_copy_loop_size);
pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
off = -off;
do {
build_copy_load_pref(&buf, off);
build_copy_load(&buf, GPR_T0, off);
build_copy_load_pref(&buf, off + copy_word_size);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load_pref(&buf, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load_pref(&buf, off + 3 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store_pref(&buf, off);
build_copy_store(&buf, GPR_T0, off);
build_copy_store_pref(&buf, off + copy_word_size);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store_pref(&buf, off + 2 * copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_store_pref(&buf, off + 3 * copy_word_size);
if (off == -(4 * copy_word_size))
uasm_il_bne(&buf, &r, GPR_A2, GPR_A0, label_copy_pref_both);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < 0);
if (pref_bias_copy_load - pref_bias_copy_store) {
pg_addiu(&buf, GPR_A2, GPR_A0,
pref_bias_copy_load - pref_bias_copy_store);
uasm_l_copy_pref_store(&l, buf);
off = 0;
do {
build_copy_load(&buf, GPR_T0, off);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store_pref(&buf, off);
build_copy_store(&buf, GPR_T0, off);
build_copy_store_pref(&buf, off + copy_word_size);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store_pref(&buf, off + 2 * copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_store_pref(&buf, off + 3 * copy_word_size);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < half_copy_loop_size);
pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
off = -off;
do {
build_copy_load(&buf, GPR_T0, off);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store_pref(&buf, off);
build_copy_store(&buf, GPR_T0, off);
build_copy_store_pref(&buf, off + copy_word_size);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store_pref(&buf, off + 2 * copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_store_pref(&buf, off + 3 * copy_word_size);
if (off == -(4 * copy_word_size))
uasm_il_bne(&buf, &r, GPR_A2, GPR_A0,
label_copy_pref_store);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < 0);
}
if (pref_bias_copy_store) {
pg_addiu(&buf, GPR_A2, GPR_A0, pref_bias_copy_store);
uasm_l_copy_nopref(&l, buf);
off = 0;
do {
build_copy_load(&buf, GPR_T0, off);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store(&buf, GPR_T0, off);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < half_copy_loop_size);
pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
off = -off;
do {
build_copy_load(&buf, GPR_T0, off);
build_copy_load(&buf, GPR_T1, off + copy_word_size);
build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
build_copy_store(&buf, GPR_T0, off);
build_copy_store(&buf, GPR_T1, off + copy_word_size);
build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
if (off == -(4 * copy_word_size))
uasm_il_bne(&buf, &r, GPR_A2, GPR_A0,
label_copy_nopref);
build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
off += 4 * copy_word_size;
} while (off < 0);
}
uasm_i_jr(&buf, GPR_RA);
uasm_i_nop(&buf);
BUG_ON(buf > &__copy_page_end);
uasm_resolve_relocs(relocs, labels);
pr_debug("Synthesized copy page handler (%u instructions).\n",
(u32)(buf - &__copy_page_start));
pr_debug("\t.set push\n");
pr_debug("\t.set noreorder\n");
for (i = 0; i < (buf - &__copy_page_start); i++)
pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
pr_debug("\t.set pop\n");
}
#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
extern void clear_page_cpu(void *page);
extern void copy_page_cpu(void *to, void *from);
/*
* Pad descriptors to cacheline, since each is exclusively owned by a
* particular CPU.
*/
struct dmadscr {
u64 dscr_a;
u64 dscr_b;
u64 pad_a;
u64 pad_b;
} ____cacheline_aligned_in_smp page_descr[DM_NUM_CHANNELS];
void clear_page(void *page)
{
u64 to_phys = CPHYSADDR((unsigned long)page);
unsigned int cpu = smp_processor_id();
/* if the page is not in KSEG0, use old way */
if ((long)KSEGX((unsigned long)page) != (long)CKSEG0)
return clear_page_cpu(page);
page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_ZERO_MEM |
M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
page_descr[cpu].dscr_b = V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
/*
* Don't really want to do it this way, but there's no
* reliable way to delay completion detection.
*/
while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
& M_DM_DSCR_BASE_INTERRUPT))
;
__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
}
EXPORT_SYMBOL(clear_page);
void copy_page(void *to, void *from)
{
u64 from_phys = CPHYSADDR((unsigned long)from);
u64 to_phys = CPHYSADDR((unsigned long)to);
unsigned int cpu = smp_processor_id();
/* if any page is not in KSEG0, use old way */
if ((long)KSEGX((unsigned long)to) != (long)CKSEG0
|| (long)KSEGX((unsigned long)from) != (long)CKSEG0)
return copy_page_cpu(to, from);
page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_L2C_DEST |
M_DM_DSCRA_INTERRUPT;
page_descr[cpu].dscr_b = from_phys | V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
/*
* Don't really want to do it this way, but there's no
* reliable way to delay completion detection.
*/
while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
& M_DM_DSCR_BASE_INTERRUPT))
;
__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
}
EXPORT_SYMBOL(copy_page);
#endif /* CONFIG_SIBYTE_DMA_PAGEOPS */
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