kernel-fxtec-pro1x/arch/arm/mm/cache-l2x0.c
Russell King 3d1074349b ARM: cache-l2x0: make better use of background cache handling
There's no point having the hardware support background operations
if we issue a cache operation, and then wait for it to complete
before calculating the address of the next operation.  We gain no
advantage in the cache controller stalling the bus until completion.

What we should be doing is using the 'wait' time productively by
calculating the address of the next operation, and only then waiting
for the previous operation to complete.  This means that cache
operations can occur in parallel with the CPU calculating the next
address.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
2009-12-14 13:35:13 +00:00

171 lines
4.3 KiB
C

/*
* arch/arm/mm/cache-l2x0.c - L210/L220 cache controller support
*
* Copyright (C) 2007 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/hardware/cache-l2x0.h>
#define CACHE_LINE_SIZE 32
static void __iomem *l2x0_base;
static DEFINE_SPINLOCK(l2x0_lock);
static inline void cache_wait(void __iomem *reg, unsigned long mask)
{
/* wait for the operation to complete */
while (readl(reg) & mask)
;
}
static inline void cache_sync(void)
{
void __iomem *base = l2x0_base;
writel(0, base + L2X0_CACHE_SYNC);
cache_wait(base + L2X0_CACHE_SYNC, 1);
}
static inline void l2x0_inv_all(void)
{
unsigned long flags;
/* invalidate all ways */
spin_lock_irqsave(&l2x0_lock, flags);
writel(0xff, l2x0_base + L2X0_INV_WAY);
cache_wait(l2x0_base + L2X0_INV_WAY, 0xff);
cache_sync();
spin_unlock_irqrestore(&l2x0_lock, flags);
}
static void l2x0_inv_range(unsigned long start, unsigned long end)
{
void __iomem *base = l2x0_base;
unsigned long flags;
spin_lock_irqsave(&l2x0_lock, flags);
if (start & (CACHE_LINE_SIZE - 1)) {
start &= ~(CACHE_LINE_SIZE - 1);
cache_wait(base + L2X0_CLEAN_INV_LINE_PA, 1);
writel(start, base + L2X0_CLEAN_INV_LINE_PA);
start += CACHE_LINE_SIZE;
}
if (end & (CACHE_LINE_SIZE - 1)) {
end &= ~(CACHE_LINE_SIZE - 1);
cache_wait(base + L2X0_CLEAN_INV_LINE_PA, 1);
writel(end, base + L2X0_CLEAN_INV_LINE_PA);
}
while (start < end) {
unsigned long blk_end = start + min(end - start, 4096UL);
while (start < blk_end) {
cache_wait(base + L2X0_INV_LINE_PA, 1);
writel(start, base + L2X0_INV_LINE_PA);
start += CACHE_LINE_SIZE;
}
if (blk_end < end) {
spin_unlock_irqrestore(&l2x0_lock, flags);
spin_lock_irqsave(&l2x0_lock, flags);
}
}
cache_wait(base + L2X0_INV_LINE_PA, 1);
cache_sync();
spin_unlock_irqrestore(&l2x0_lock, flags);
}
static void l2x0_clean_range(unsigned long start, unsigned long end)
{
void __iomem *base = l2x0_base;
unsigned long flags;
spin_lock_irqsave(&l2x0_lock, flags);
start &= ~(CACHE_LINE_SIZE - 1);
while (start < end) {
unsigned long blk_end = start + min(end - start, 4096UL);
while (start < blk_end) {
cache_wait(base + L2X0_CLEAN_LINE_PA, 1);
writel(start, base + L2X0_CLEAN_LINE_PA);
start += CACHE_LINE_SIZE;
}
if (blk_end < end) {
spin_unlock_irqrestore(&l2x0_lock, flags);
spin_lock_irqsave(&l2x0_lock, flags);
}
}
cache_wait(base + L2X0_CLEAN_LINE_PA, 1);
cache_sync();
spin_unlock_irqrestore(&l2x0_lock, flags);
}
static void l2x0_flush_range(unsigned long start, unsigned long end)
{
void __iomem *base = l2x0_base;
unsigned long flags;
spin_lock_irqsave(&l2x0_lock, flags);
start &= ~(CACHE_LINE_SIZE - 1);
while (start < end) {
unsigned long blk_end = start + min(end - start, 4096UL);
while (start < blk_end) {
cache_wait(base + L2X0_CLEAN_INV_LINE_PA, 1);
writel(start, base + L2X0_CLEAN_INV_LINE_PA);
start += CACHE_LINE_SIZE;
}
if (blk_end < end) {
spin_unlock_irqrestore(&l2x0_lock, flags);
spin_lock_irqsave(&l2x0_lock, flags);
}
}
cache_wait(base + L2X0_CLEAN_INV_LINE_PA, 1);
cache_sync();
spin_unlock_irqrestore(&l2x0_lock, flags);
}
void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask)
{
__u32 aux;
l2x0_base = base;
/* disable L2X0 */
writel(0, l2x0_base + L2X0_CTRL);
aux = readl(l2x0_base + L2X0_AUX_CTRL);
aux &= aux_mask;
aux |= aux_val;
writel(aux, l2x0_base + L2X0_AUX_CTRL);
l2x0_inv_all();
/* enable L2X0 */
writel(1, l2x0_base + L2X0_CTRL);
outer_cache.inv_range = l2x0_inv_range;
outer_cache.clean_range = l2x0_clean_range;
outer_cache.flush_range = l2x0_flush_range;
printk(KERN_INFO "L2X0 cache controller enabled\n");
}