/*
* arch/arm/mm/cache-feroceon-l2.c - Feroceon L2 cache controller support
*
* Copyright (C) 2008 Marvell Semiconductor
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* References:
* - Unified Layer 2 Cache for Feroceon CPU Cores,
* Document ID MV-S104858-00, Rev. A, October 23 2007.
*/
#include <linux/init.h>
#include <asm/cacheflush.h>
#include <plat/cache-feroceon-l2.h>
/*
* Low-level cache maintenance operations.
*
* As well as the regular 'clean/invalidate/flush L2 cache line by
* MVA' instructions, the Feroceon L2 cache controller also features
* 'clean/invalidate L2 range by MVA' operations.
*
* Cache range operations are initiated by writing the start and
* end addresses to successive cp15 registers, and process every
* cache line whose first byte address lies in the inclusive range
* [start:end].
*
* The cache range operations stall the CPU pipeline until completion.
*
* The range operations require two successive cp15 writes, in
* between which we don't want to be preempted.
*/
static inline void l2_clean_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c15, c9, 3" : : "r" (addr));
}
static inline void l2_clean_mva_range(unsigned long start, unsigned long end)
{
unsigned long flags;
/*
* Make sure 'start' and 'end' reference the same page, as
* L2 is PIPT and range operations only do a TLB lookup on
* the start address.
*/
BUG_ON((start ^ end) >> PAGE_SHIFT);
raw_local_irq_save(flags);
__asm__("mcr p15, 1, %0, c15, c9, 4\n\t"
"mcr p15, 1, %1, c15, c9, 5"
: : "r" (start), "r" (end));
raw_local_irq_restore(flags);
}
static inline void l2_clean_pa_range(unsigned long start, unsigned long end)
{
l2_clean_mva_range(__phys_to_virt(start), __phys_to_virt(end));
}
static inline void l2_clean_inv_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c15, c10, 3" : : "r" (addr));
}
static inline void l2_inv_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c15, c11, 3" : : "r" (addr));
}
static inline void l2_inv_mva_range(unsigned long start, unsigned long end)
{
unsigned long flags;
/*
* Make sure 'start' and 'end' reference the same page, as
* L2 is PIPT and range operations only do a TLB lookup on
* the start address.
*/
BUG_ON((start ^ end) >> PAGE_SHIFT);
raw_local_irq_save(flags);
__asm__("mcr p15, 1, %0, c15, c11, 4\n\t"
"mcr p15, 1, %1, c15, c11, 5"
: : "r" (start), "r" (end));
raw_local_irq_restore(flags);
}
static inline void l2_inv_pa_range(unsigned long start, unsigned long end)
{
l2_inv_mva_range(__phys_to_virt(start), __phys_to_virt(end));
}
/*
* Linux primitives.
*
* Note that the end addresses passed to Linux primitives are
* noninclusive, while the hardware cache range operations use
* inclusive start and end addresses.
*/
#define CACHE_LINE_SIZE 32
#define MAX_RANGE_SIZE 1024
static int l2_wt_override;
static unsigned long calc_range_end(unsigned long start, unsigned long end)
{
unsigned long range_end;
BUG_ON(start & (CACHE_LINE_SIZE - 1));
BUG_ON(end & (CACHE_LINE_SIZE - 1));
/*
* Try to process all cache lines between 'start' and 'end'.
*/
range_end = end;
/*
* Limit the number of cache lines processed at once,
* since cache range operations stall the CPU pipeline
* until completion.
*/
if (range_end > start + MAX_RANGE_SIZE)
range_end = start + MAX_RANGE_SIZE;
/*
* Cache range operations can't straddle a page boundary.
*/
if (range_end > (start | (PAGE_SIZE - 1)) + 1)
range_end = (start | (PAGE_SIZE - 1)) + 1;
return range_end;
}
static void feroceon_l2_inv_range(unsigned long start, unsigned long end)
{
/*
* Clean and invalidate partial first cache line.
*/
if (start & (CACHE_LINE_SIZE - 1)) {
l2_clean_inv_pa(start & ~(CACHE_LINE_SIZE - 1));
start = (start | (CACHE_LINE_SIZE - 1)) + 1;
}
/*
* Clean and invalidate partial last cache line.
*/
if (end & (CACHE_LINE_SIZE - 1)) {
l2_clean_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
end &= ~(CACHE_LINE_SIZE - 1);
}
/*
* Invalidate all full cache lines between 'start' and 'end'.
*/
while (start != end) {
unsigned long range_end = calc_range_end(start, end);
l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
start = range_end;
}
dsb();
}
static void feroceon_l2_clean_range(unsigned long start, unsigned long end)
{
/*
* If L2 is forced to WT, the L2 will always be clean and we
* don't need to do anything here.
*/
if (!l2_wt_override) {
start &= ~(CACHE_LINE_SIZE - 1);
end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
while (start != end) {
unsigned long range_end = calc_range_end(start, end);
l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
start = range_end;
}
}
dsb();
}
static void feroceon_l2_flush_range(unsigned long start, unsigned long end)
{
start &= ~(CACHE_LINE_SIZE - 1);
end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
while (start != end) {
unsigned long range_end = calc_range_end(start, end);
if (!l2_wt_override)
l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
start = range_end;
}
dsb();
}
/*
* Routines to disable and re-enable the D-cache and I-cache at run
* time. These are necessary because the L2 cache can only be enabled
* or disabled while the L1 Dcache and Icache are both disabled.
*/
static int __init flush_and_disable_dcache(void)
{
u32 cr;
cr = get_cr();
if (cr & CR_C) {
unsigned long flags;
raw_local_irq_save(flags);
flush_cache_all();
set_cr(cr & ~CR_C);
raw_local_irq_restore(flags);
return 1;
}
return 0;
}
static void __init enable_dcache(void)
{
u32 cr;
cr = get_cr();
set_cr(cr | CR_C);
}
static void __init __invalidate_icache(void)
{
int dummy;
__asm__ __volatile__("mcr p15, 0, %0, c7, c5, 0" : "=r" (dummy));
}
static int __init invalidate_and_disable_icache(void)
{
u32 cr;
cr = get_cr();
if (cr & CR_I) {
set_cr(cr & ~CR_I);
__invalidate_icache();
return 1;
}
return 0;
}
static void __init enable_icache(void)
{
u32 cr;
cr = get_cr();
set_cr(cr | CR_I);
}
static inline u32 read_extra_features(void)
{
u32 u;
__asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));
return u;
}
static inline void write_extra_features(u32 u)
{
__asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u));
}
static void __init disable_l2_prefetch(void)
{
u32 u;
/*
* Read the CPU Extra Features register and verify that the
* Disable L2 Prefetch bit is set.
*/
u = read_extra_features();
if (!(u & 0x01000000)) {
printk(KERN_INFO "Feroceon L2: Disabling L2 prefetch.\n");
write_extra_features(u | 0x01000000);
}
}
static void __init enable_l2(void)
{
u32 u;
u = read_extra_features();
if (!(u & 0x00400000)) {
int i, d;
printk(KERN_INFO "Feroceon L2: Enabling L2\n");
d = flush_and_disable_dcache();
i = invalidate_and_disable_icache();
write_extra_features(u | 0x00400000);
if (i)
enable_icache();
if (d)
enable_dcache();
}
}
void __init feroceon_l2_init(int __l2_wt_override)
{
l2_wt_override = __l2_wt_override;
disable_l2_prefetch();
outer_cache.inv_range = feroceon_l2_inv_range;
outer_cache.clean_range = feroceon_l2_clean_range;
outer_cache.flush_range = feroceon_l2_flush_range;
enable_l2();
printk(KERN_INFO "Feroceon L2: Cache support initialised%s.\n",
l2_wt_override ? ", in WT override mode" : "");
}
