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sh: sh2a: Improve cache flush/invalidate functions
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The cache functions lock out interrupts for long periods; this patch
reduces the impact when operating on large address ranges. In such
cases it will:
- Invalidate the entire cache rather than individual addresses.
- Do nothing when flushing the operand cache in write-through mode.
- When flushing the operand cache in write-back mdoe, index the
  search for matching addresses on the cache entires instead of the
  addresses to flush

Note: sh2a__flush_purge_region was only invalidating the operand
cache, this adds flush.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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Phil Edworthy authored and Paul Mundt committed Jan 12, 2012
1 parent e343a89 commit c1537b4
Showing 1 changed file with 84 additions and 39 deletions.
123 changes: 84 additions & 39 deletions arch/sh/mm/cache-sh2a.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,35 +15,78 @@
#include <asm/cacheflush.h>
#include <asm/io.h>

/*
* The maximum number of pages we support up to when doing ranged dcache
* flushing. Anything exceeding this will simply flush the dcache in its
* entirety.
*/
#define MAX_OCACHE_PAGES 32
#define MAX_ICACHE_PAGES 32

static void sh2a_flush_oc_line(unsigned long v, int way)
{
unsigned long addr = (v & 0x000007f0) | (way << 11);
unsigned long data;

data = __raw_readl(CACHE_OC_ADDRESS_ARRAY | addr);
if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
data &= ~SH_CACHE_UPDATED;
__raw_writel(data, CACHE_OC_ADDRESS_ARRAY | addr);
}
}

static void sh2a_invalidate_line(unsigned long cache_addr, unsigned long v)
{
/* Set associative bit to hit all ways */
unsigned long addr = (v & 0x000007f0) | SH_CACHE_ASSOC;
__raw_writel((addr & CACHE_PHYSADDR_MASK), cache_addr | addr);
}

/*
* Write back the dirty D-caches, but not invalidate them.
*/
static void sh2a__flush_wback_region(void *start, int size)
{
#ifdef CONFIG_CACHE_WRITEBACK
unsigned long v;
unsigned long begin, end;
unsigned long flags;
int nr_ways;

begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
& ~(L1_CACHE_BYTES-1);
nr_ways = current_cpu_data.dcache.ways;

local_irq_save(flags);
jump_to_uncached();

for (v = begin; v < end; v+=L1_CACHE_BYTES) {
unsigned long addr = CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0);
/* If there are too many pages then flush the entire cache */
if (((end - begin) >> PAGE_SHIFT) >= MAX_OCACHE_PAGES) {
begin = CACHE_OC_ADDRESS_ARRAY;
end = begin + (nr_ways * current_cpu_data.dcache.way_size);

for (v = begin; v < end; v += L1_CACHE_BYTES) {
unsigned long data = __raw_readl(v);
if (data & SH_CACHE_UPDATED)
__raw_writel(data & ~SH_CACHE_UPDATED, v);
}
} else {
int way;
for (way = 0; way < 4; way++) {
unsigned long data = __raw_readl(addr | (way << 11));
if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
data &= ~SH_CACHE_UPDATED;
__raw_writel(data, addr | (way << 11));
}
for (way = 0; way < nr_ways; way++) {
for (v = begin; v < end; v += L1_CACHE_BYTES)
sh2a_flush_oc_line(v, way);
}
}

back_to_cached();
local_irq_restore(flags);
#endif
}

/*
* Write back the dirty D-caches and invalidate them.
*/
static void sh2a__flush_purge_region(void *start, int size)
{
unsigned long v;
Expand All @@ -58,13 +101,22 @@ static void sh2a__flush_purge_region(void *start, int size)
jump_to_uncached();

for (v = begin; v < end; v+=L1_CACHE_BYTES) {
__raw_writel((v & CACHE_PHYSADDR_MASK),
CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
#ifdef CONFIG_CACHE_WRITEBACK
int way;
int nr_ways = current_cpu_data.dcache.ways;
for (way = 0; way < nr_ways; way++)
sh2a_flush_oc_line(v, way);
#endif
sh2a_invalidate_line(CACHE_OC_ADDRESS_ARRAY, v);
}

back_to_cached();
local_irq_restore(flags);
}

/*
* Invalidate the D-caches, but no write back please
*/
static void sh2a__flush_invalidate_region(void *start, int size)
{
unsigned long v;
Expand All @@ -74,29 +126,25 @@ static void sh2a__flush_invalidate_region(void *start, int size)
begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
& ~(L1_CACHE_BYTES-1);

local_irq_save(flags);
jump_to_uncached();

#ifdef CONFIG_CACHE_WRITEBACK
__raw_writel(__raw_readl(CCR) | CCR_OCACHE_INVALIDATE, CCR);
/* I-cache invalidate */
for (v = begin; v < end; v+=L1_CACHE_BYTES) {
__raw_writel((v & CACHE_PHYSADDR_MASK),
CACHE_IC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
}
#else
for (v = begin; v < end; v+=L1_CACHE_BYTES) {
__raw_writel((v & CACHE_PHYSADDR_MASK),
CACHE_IC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
__raw_writel((v & CACHE_PHYSADDR_MASK),
CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
/* If there are too many pages then just blow the cache */
if (((end - begin) >> PAGE_SHIFT) >= MAX_OCACHE_PAGES) {
__raw_writel(__raw_readl(CCR) | CCR_OCACHE_INVALIDATE, CCR);
} else {
for (v = begin; v < end; v += L1_CACHE_BYTES)
sh2a_invalidate_line(CACHE_OC_ADDRESS_ARRAY, v);
}
#endif

back_to_cached();
local_irq_restore(flags);
}

/* WBack O-Cache and flush I-Cache */
/*
* Write back the range of D-cache, and purge the I-cache.
*/
static void sh2a_flush_icache_range(void *args)
{
struct flusher_data *data = args;
Expand All @@ -107,23 +155,20 @@ static void sh2a_flush_icache_range(void *args)
start = data->addr1 & ~(L1_CACHE_BYTES-1);
end = (data->addr2 + L1_CACHE_BYTES-1) & ~(L1_CACHE_BYTES-1);

#ifdef CONFIG_CACHE_WRITEBACK
sh2a__flush_wback_region((void *)start, end-start);
#endif

local_irq_save(flags);
jump_to_uncached();

for (v = start; v < end; v+=L1_CACHE_BYTES) {
unsigned long addr = (v & 0x000007f0);
int way;
/* O-Cache writeback */
for (way = 0; way < 4; way++) {
unsigned long data = __raw_readl(CACHE_OC_ADDRESS_ARRAY | addr | (way << 11));
if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
data &= ~SH_CACHE_UPDATED;
__raw_writel(data, CACHE_OC_ADDRESS_ARRAY | addr | (way << 11));
}
}
/* I-Cache invalidate */
__raw_writel(addr,
CACHE_IC_ADDRESS_ARRAY | addr | 0x00000008);
/* I-Cache invalidate */
/* If there are too many pages then just blow the cache */
if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
__raw_writel(__raw_readl(CCR) | CCR_ICACHE_INVALIDATE, CCR);
} else {
for (v = start; v < end; v += L1_CACHE_BYTES)
sh2a_invalidate_line(CACHE_IC_ADDRESS_ARRAY, v);
}

back_to_cached();
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