/*
* arch/arm/mm/cache-tauros2.c - Tauros2 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:
* - PJ1 CPU Core Datasheet,
* Document ID MV-S104837-01, Rev 0.7, January 24 2008.
* - PJ4 CPU Core Datasheet,
* Document ID MV-S105190-00, Rev 0.7, March 14 2008.
*/
#include <linux/init.h>
#include <asm/cacheflush.h>
#include <asm/hardware/cache-tauros2.h>
/*
* When Tauros2 is used on a CPU that supports the v7 hierarchical
* cache operations, the cache handling code in proc-v7.S takes care
* of everything, including handling DMA coherency.
*
* So, we only need to register outer cache operations here if we're
* being used on a pre-v7 CPU, and we only need to build support for
* outer cache operations into the kernel image if the kernel has been
* configured to support a pre-v7 CPU.
*/
#if __LINUX_ARM_ARCH__ < 7
/*
* Low-level cache maintenance operations.
*/
static inline void tauros2_clean_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c7, c11, 3" : : "r" (addr));
}
static inline void tauros2_clean_inv_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c7, c15, 3" : : "r" (addr));
}
static inline void tauros2_inv_pa(unsigned long addr)
{
__asm__("mcr p15, 1, %0, c7, c7, 3" : : "r" (addr));
}
/*
* Linux primitives.
*
* Note that the end addresses passed to Linux primitives are
* noninclusive.
*/
#define CACHE_LINE_SIZE 32
static void tauros2_inv_range(unsigned long start, unsigned long end)
{
/*
* Clean and invalidate partial first cache line.
*/
if (start & (CACHE_LINE_SIZE - 1)) {
tauros2_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)) {
tauros2_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) {
tauros2_inv_pa(start);
start += CACHE_LINE_SIZE;
}
dsb();
}
static void tauros2_clean_range(unsigned long start, unsigned long end)
{
start &= ~(CACHE_LINE_SIZE - 1);
while (start < end) {
tauros2_clean_pa(start);
start += CACHE_LINE_SIZE;
}
dsb();
}
static void tauros2_flush_range(unsigned long start, unsigned long end)
{
start &= ~(CACHE_LINE_SIZE - 1);
while (start < end) {
tauros2_clean_inv_pa(start);
start += CACHE_LINE_SIZE;
}
dsb();
}
#endif
static inline u32 __init read_extra_features(void)
{
u32 u;
__asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));
return u;
}
static inline void __init 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 "Tauros2: Disabling L2 prefetch.\n");
write_extra_features(u | 0x01000000);
}
}
static inline int __init cpuid_scheme(void)
{
extern int processor_id;
return !!((processor_id & 0x000f0000) == 0x000f0000);
}
static inline u32 __init read_mmfr3(void)
{
u32 mmfr3;
__asm__("mrc p15, 0, %0, c0, c1, 7\n" : "=r" (mmfr3));
return mmfr3;
}
static inline u32 __init read_actlr(void)
{
u32 actlr;
__asm__("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));
return actlr;
}
static inline void __init write_actlr(u32 actlr)
{
__asm__("mcr p15, 0, %0, c1, c0, 1\n" : : "r" (actlr));
}
void __init tauros2_init(void)
{
extern int processor_id;
char *mode;
disable_l2_prefetch();
#ifdef CONFIG_CPU_32v5
if ((processor_id & 0xff0f0000) == 0x56050000) {
u32 feat;
/*
* v5 CPUs with Tauros2 have the L2 cache enable bit
* located in the CPU Extra Features register.
*/
feat = read_extra_features();
if (!(feat & 0x00400000)) {
printk(KERN_INFO "Tauros2: Enabling L2 cache.\n");
write_extra_features(feat | 0x00400000);
}
mode = "ARMv5";
outer_cache.inv_range = tauros2_inv_range;
outer_cache.clean_range = tauros2_clean_range;
outer_cache.flush_range = tauros2_flush_range;
}
#endif
#ifdef CONFIG_CPU_32v6
/*
* Check whether this CPU lacks support for the v7 hierarchical
* cache ops. (PJ4 is in its v6 personality mode if the MMFR3
* register indicates no support for the v7 hierarchical cache
* ops.)
*/
if (cpuid_scheme() && (read_mmfr3() & 0xf) == 0) {
/*
* When Tauros2 is used in an ARMv6 system, the L2
* enable bit is in the ARMv6 ARM-mandated position
* (bit [26] of the System Control Register).
*/
if (!(get_cr() & 0x04000000)) {
printk(KERN_INFO "Tauros2: Enabling L2 cache.\n");
adjust_cr(0x04000000, 0x04000000);
}
mode = "ARMv6";
outer_cache.inv_range = tauros2_inv_range;
outer_cache.clean_range = tauros2_clean_range;
outer_cache.flush_range = tauros2_flush_range;
}
#endif
#ifdef CONFIG_CPU_32v7
/*
* Check whether this CPU has support for the v7 hierarchical
* cache ops. (PJ4 is in its v7 personality mode if the MMFR3
* register indicates support for the v7 hierarchical cache
* ops.)
*
* (Although strictly speaking there may exist CPUs that
* implement the v7 cache ops but are only ARMv6 CPUs (due to
* not complying with all of the other ARMv7 requirements),
* there are no real-life examples of Tauros2 being used on
* such CPUs as of yet.)
*/
if (cpuid_scheme() && (read_mmfr3() & 0xf) == 1) {
u32 actlr;
/*
* When Tauros2 is used in an ARMv7 system, the L2
* enable bit is located in the Auxiliary System Control
* Register (which is the only register allowed by the
* ARMv7 spec to contain fine-grained cache control bits).
*/
actlr = read_actlr();
if (!(actlr & 0x00000002)) {
printk(KERN_INFO "Tauros2: Enabling L2 cache.\n");
write_actlr(actlr | 0x00000002);
}
mode = "ARMv7";
}
#endif
if (mode == NULL) {
printk(KERN_CRIT "Tauros2: Unable to detect CPU mode.\n");
return;
}
printk(KERN_INFO "Tauros2: L2 cache support initialised "
"in %s mode.\n", mode);
}