/*
* ARC700 VIPT Cache Management
*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* 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.
*
* vineetg: May 2011: for Non-aliasing VIPT D-cache following can be NOPs
* -flush_cache_dup_mm (fork)
* -likewise for flush_cache_mm (exit/execve)
* -likewise for flush_cache_range,flush_cache_page (munmap, exit, COW-break)
*
* vineetg: Apr 2011
* -Now that MMU can support larger pg sz (16K), the determiniation of
* aliasing shd not be based on assumption of 8k pg
*
* vineetg: Mar 2011
* -optimised version of flush_icache_range( ) for making I/D coherent
* when vaddr is available (agnostic of num of aliases)
*
* vineetg: Mar 2011
* -Added documentation about I-cache aliasing on ARC700 and the way it
* was handled up until MMU V2.
* -Spotted a three year old bug when killing the 4 aliases, which needs
* bottom 2 bits, so we need to do paddr | {0x00, 0x01, 0x02, 0x03}
* instead of paddr | {0x00, 0x01, 0x10, 0x11}
* (Rajesh you owe me one now)
*
* vineetg: Dec 2010
* -Off-by-one error when computing num_of_lines to flush
* This broke signal handling with bionic which uses synthetic sigret stub
*
* vineetg: Mar 2010
* -GCC can't generate ZOL for core cache flush loops.
* Conv them into iterations based as opposed to while (start < end) types
*
* Vineetg: July 2009
* -In I-cache flush routine we used to chk for aliasing for every line INV.
* Instead now we setup routines per cache geometry and invoke them
* via function pointers.
*
* Vineetg: Jan 2009
* -Cache Line flush routines used to flush an extra line beyond end addr
* because check was while (end >= start) instead of (end > start)
* =Some call sites had to work around by doing -1, -4 etc to end param
* =Some callers didnt care. This was spec bad in case of INV routines
* which would discard valid data (cause of the horrible ext2 bug
* in ARC IDE driver)
*
* vineetg: June 11th 2008: Fixed flush_icache_range( )
* -Since ARC700 caches are not coherent (I$ doesnt snoop D$) both need
* to be flushed, which it was not doing.
* -load_module( ) passes vmalloc addr (Kernel Virtual Addr) to the API,
* however ARC cache maintenance OPs require PHY addr. Thus need to do
* vmalloc_to_phy.
* -Also added optimisation there, that for range > PAGE SIZE we flush the
* entire cache in one shot rather than line by line. For e.g. a module
* with Code sz 600k, old code flushed 600k worth of cache (line-by-line),
* while cache is only 16 or 32k.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/cache.h>
#include <linux/mmu_context.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/cachectl.h>
#include <asm/setup.h>
char *arc_cache_mumbojumbo(int cpu_id, char *buf, int len)
{
int n = 0;
unsigned int c = smp_processor_id();
#define PR_CACHE(p, enb, str) \
{ \
if (!(p)->ver) \
n += scnprintf(buf + n, len - n, str"\t\t: N/A\n"); \
else \
n += scnprintf(buf + n, len - n, \
str"\t\t: (%uK) VIPT, %dway set-asc, %ub Line %s\n", \
TO_KB((p)->sz), (p)->assoc, (p)->line_len, \
enb ? "" : "DISABLED (kernel-build)"); \
}
PR_CACHE(&cpuinfo_arc700[c].icache, __CONFIG_ARC_HAS_ICACHE, "I-Cache");
PR_CACHE(&cpuinfo_arc700[c].dcache, __CONFIG_ARC_HAS_DCACHE, "D-Cache");
return buf;
}
/*
* Read the Cache Build Confuration Registers, Decode them and save into
* the cpuinfo structure for later use.
* No Validation done here, simply read/convert the BCRs
*/
void __cpuinit read_decode_cache_bcr(void)
{
struct bcr_cache ibcr, dbcr;
struct cpuinfo_arc_cache *p_ic, *p_dc;
unsigned int cpu = smp_processor_id();
p_ic = &cpuinfo_arc700[cpu].icache;
READ_BCR(ARC_REG_IC_BCR, ibcr);
if (ibcr.config == 0x3)
p_ic->assoc = 2;
p_ic->line_len = 8 << ibcr.line_len;
p_ic->sz = 0x200 << ibcr.sz;
p_ic->ver = ibcr.ver;
p_dc = &cpuinfo_arc700[cpu].dcache;
READ_BCR(ARC_REG_DC_BCR, dbcr);
if (dbcr.config == 0x2)
p_dc->assoc = 4;
p_dc->line_len = 16 << dbcr.line_len;
p_dc->sz = 0x200 << dbcr.sz;
p_dc->ver = dbcr.ver;
}
/*
* 1. Validate the Cache Geomtery (compile time config matches hardware)
* 2. If I-cache suffers from aliasing, setup work arounds (difft flush rtn)
* (aliasing D-cache configurations are not supported YET)
* 3. Enable the Caches, setup default flush mode for D-Cache
* 3. Calculate the SHMLBA used by user space
*/
void __cpuinit arc_cache_init(void)
{
unsigned int temp;
unsigned int cpu = smp_processor_id();
struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache;
struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache;
int way_pg_ratio = way_pg_ratio;
char str[256];
printk(arc_cache_mumbojumbo(0, str, sizeof(str)));
if (!ic->ver)
goto chk_dc;
#ifdef CONFIG_ARC_HAS_ICACHE
/* 1. Confirm some of I-cache params which Linux assumes */
if ((ic->assoc != ARC_ICACHE_WAYS) ||
(ic->line_len != ARC_ICACHE_LINE_LEN)) {
panic("Cache H/W doesn't match kernel Config");
}
#if (CONFIG_ARC_MMU_VER > 2)
if (ic->ver != 3) {
if (running_on_hw)
panic("Cache ver doesn't match MMU ver\n");
/* For ISS - suggest the toggles to use */
pr_err("Use -prop=icache_version=3,-prop=dcache_version=3\n");
}
#endif
#endif
/* Enable/disable I-Cache */
temp = read_aux_reg(ARC_REG_IC_CTRL);
#ifdef CONFIG_ARC_HAS_ICACHE
temp &= ~IC_CTRL_CACHE_DISABLE;
#else
temp |= IC_CTRL_CACHE_DISABLE;
#endif
write_aux_reg(ARC_REG_IC_CTRL, temp);
chk_dc:
if (!dc->ver)
return;
#ifdef CONFIG_ARC_HAS_DCACHE
if ((dc->assoc != ARC_DCACHE_WAYS) ||
(dc->line_len != ARC_DCACHE_LINE_LEN)) {
panic("Cache H/W doesn't match kernel Config");
}
/* check for D-Cache aliasing */
if ((dc->sz / ARC_DCACHE_WAYS) > PAGE_SIZE)
panic("D$ aliasing not handled right now\n");
#endif
/* Set the default Invalidate Mode to "simpy discard dirty lines"
* as this is more frequent then flush before invalidate
* Ofcourse we toggle this default behviour when desired
*/
temp = read_aux_reg(ARC_REG_DC_CTRL);
temp &= ~DC_CTRL_INV_MODE_FLUSH;
#ifdef CONFIG_ARC_HAS_DCACHE
/* Enable D-Cache: Clear Bit 0 */
write_aux_reg(ARC_REG_DC_CTRL, temp & ~IC_CTRL_CACHE_DISABLE);
#else
/* Flush D cache */
write_aux_reg(ARC_REG_DC_FLSH, 0x1);
/* Disable D cache */
write_aux_reg(ARC_REG_DC_CTRL, temp | IC_CTRL_CACHE_DISABLE);
#endif
return;
}
#define OP_INV 0x1
#define OP_FLUSH 0x2
#define OP_FLUSH_N_INV 0x3
#ifdef CONFIG_ARC_HAS_DCACHE
/***************************************************************
* Machine specific helpers for Entire D-Cache or Per Line ops
*/
static inline void wait_for_flush(void)
{
while (read_aux_reg(ARC_REG_DC_CTRL) & DC_CTRL_FLUSH_STATUS)
;
}
/*
* Operation on Entire D-Cache
* @cacheop = {OP_INV, OP_FLUSH, OP_FLUSH_N_INV}
* Note that constant propagation ensures all the checks are gone
* in generated code
*/
static inline void __dc_entire_op(const int cacheop)
{
unsigned long flags, tmp = tmp;
int aux;
local_irq_save(flags);
if (cacheop == OP_FLUSH_N_INV) {
/* Dcache provides 2 cmd: FLUSH or INV
* INV inturn has sub-modes: DISCARD or FLUSH-BEFORE
* flush-n-inv is achieved by INV cmd but with IM=1
* Default INV sub-mode is DISCARD, which needs to be toggled
*/
tmp = read_aux_reg(ARC_REG_DC_CTRL);
write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH);
}
if (cacheop & OP_INV) /* Inv or flush-n-inv use same cmd reg */
aux = ARC_REG_DC_IVDC;
else
aux = ARC_REG_DC_FLSH;
write_aux_reg(aux, 0x1);
if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */
wait_for_flush();
/* Switch back the DISCARD ONLY Invalidate mode */
if (cacheop == OP_FLUSH_N_INV)
write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH);
local_irq_restore(flags);
}
/*
* Per Line Operation on D-Cache
* Doesn't deal with type-of-op/IRQ-disabling/waiting-for-flush-to-complete
* It's sole purpose is to help gcc generate ZOL
*/
static inline void __dc_line_loop(unsigned long start, unsigned long sz,
int aux_reg)
{
int num_lines, slack;
/* Ensure we properly floor/ceil the non-line aligned/sized requests
* and have @start - aligned to cache line and integral @num_lines.
* This however can be avoided for page sized since:
* -@start will be cache-line aligned already (being page aligned)
* -@sz will be integral multiple of line size (being page sized).
*/
if (!(__builtin_constant_p(sz) && sz == PAGE_SIZE)) {
slack = start & ~DCACHE_LINE_MASK;
sz += slack;
start -= slack;
}
num_lines = DIV_ROUND_UP(sz, ARC_DCACHE_LINE_LEN);
while (num_lines-- > 0) {
#if (CONFIG_ARC_MMU_VER > 2)
/*
* Just as for I$, in MMU v3, D$ ops also require
* "tag" bits in DC_PTAG, "index" bits in FLDL,IVDL ops
* But we pass phy addr for both. This works since Linux
* doesn't support aliasing configs for D$, yet.
* Thus paddr is enough to provide both tag and index.
*/
write_aux_reg(ARC_REG_DC_PTAG, start);
#endif
write_aux_reg(aux_reg, start);
start += ARC_DCACHE_LINE_LEN;
}
}
/*
* D-Cache : Per Line INV (discard or wback+discard) or FLUSH (wback)
*/
static inline void __dc_line_op(unsigned long start, unsigned long sz,
const int cacheop)
{
unsigned long flags, tmp = tmp;
int aux;
local_irq_save(flags);
if (cacheop == OP_FLUSH_N_INV) {
/*
* Dcache provides 2 cmd: FLUSH or INV
* INV inturn has sub-modes: DISCARD or FLUSH-BEFORE
* flush-n-inv is achieved by INV cmd but with IM=1
* Default INV sub-mode is DISCARD, which needs to be toggled
*/
tmp = read_aux_reg(ARC_REG_DC_CTRL);
write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH);
}
if (cacheop & OP_INV) /* Inv / flush-n-inv use same cmd reg */
aux = ARC_REG_DC_IVDL;
else
aux = ARC_REG_DC_FLDL;
__dc_line_loop(start, sz, aux);
if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */
wait_for_flush();
/* Switch back the DISCARD ONLY Invalidate mode */
if (cacheop == OP_FLUSH_N_INV)
write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH);
local_irq_restore(flags);
}
#else
#define __dc_entire_op(cacheop)
#define __dc_line_op(start, sz, cacheop)
#endif /* CONFIG_ARC_HAS_DCACHE */
#ifdef CONFIG_ARC_HAS_ICACHE
/*
* I-Cache Aliasing in ARC700 VIPT caches
*
* ARC VIPT I-cache uses vaddr to index into cache and paddr to match the tag.
* The orig Cache Management Module "CDU" only required paddr to invalidate a
* certain line since it sufficed as index in Non-Aliasing VIPT cache-geometry.
* Infact for distinct V1,V2,P: all of {V1-P},{V2-P},{P-P} would end up fetching
* the exact same line.
*
* However for larger Caches (way-size > page-size) - i.e. in Aliasing config,
* paddr alone could not be used to correctly index the cache.
*
* ------------------
* MMU v1/v2 (Fixed Page Size 8k)
* ------------------
* The solution was to provide CDU with these additonal vaddr bits. These
* would be bits [x:13], x would depend on cache-geometry, 13 comes from
* standard page size of 8k.
* H/w folks chose [17:13] to be a future safe range, and moreso these 5 bits
* of vaddr could easily be "stuffed" in the paddr as bits [4:0] since the
* orig 5 bits of paddr were anyways ignored by CDU line ops, as they
* represent the offset within cache-line. The adv of using this "clumsy"
* interface for additional info was no new reg was needed in CDU programming
* model.
*
* 17:13 represented the max num of bits passable, actual bits needed were
* fewer, based on the num-of-aliases possible.
* -for 2 alias possibility, only bit 13 needed (32K cache)
* -for 4 alias possibility, bits 14:13 needed (64K cache)
*
* ------------------
* MMU v3
* ------------------
* This ver of MMU supports variable page sizes (1k-16k): although Linux will
* only support 8k (default), 16k and 4k.
* However from hardware perspective, smaller page sizes aggrevate aliasing
* meaning more vaddr bits needed to disambiguate the cache-line-op ;
* the existing scheme of piggybacking won't work for certain configurations.
* Two new registers IC_PTAG and DC_PTAG inttoduced.
* "tag" bits are provided in PTAG, index bits in existing IVIL/IVDL/FLDL regs
*/
/***********************************************************
* Machine specific helper for per line I-Cache invalidate.
*/
static void __ic_line_inv_vaddr(unsigned long phy_start, unsigned long vaddr,
unsigned long sz)
{
unsigned long flags;
int num_lines, slack;
unsigned int addr;
slack = phy_start & ~ICACHE_LINE_MASK;
sz += slack;
phy_start -= slack;
num_lines = DIV_ROUND_UP(sz, ARC_ICACHE_LINE_LEN);
#if (CONFIG_ARC_MMU_VER > 2)
vaddr &= ~ICACHE_LINE_MASK;
addr = phy_start;
#else
/* bits 17:13 of vaddr go as bits 4:0 of paddr */
addr = phy_start | ((vaddr >> 13) & 0x1F);
#endif
local_irq_save(flags);
while (num_lines-- > 0) {
#if (CONFIG_ARC_MMU_VER > 2)
/* tag comes from phy addr */
write_aux_reg(ARC_REG_IC_PTAG, addr);
/* index bits come from vaddr */
write_aux_reg(ARC_REG_IC_IVIL, vaddr);
vaddr += ARC_ICACHE_LINE_LEN;
#else
/* paddr contains stuffed vaddrs bits */
write_aux_reg(ARC_REG_IC_IVIL, addr);
#endif
addr += ARC_ICACHE_LINE_LEN;
}
local_irq_restore(flags);
}
#else
#define __ic_line_inv_vaddr(pstart, vstart, sz)
#endif /* CONFIG_ARC_HAS_ICACHE */
/***********************************************************
* Exported APIs
*/
/* TBD: use pg_arch_1 to optimize this */
void flush_dcache_page(struct page *page)
{
__dc_line_op((unsigned long)page_address(page), PAGE_SIZE, OP_FLUSH);
}
EXPORT_SYMBOL(flush_dcache_page);
void dma_cache_wback_inv(unsigned long start, unsigned long sz)
{
__dc_line_op(start, sz, OP_FLUSH_N_INV);
}
EXPORT_SYMBOL(dma_cache_wback_inv);
void dma_cache_inv(unsigned long start, unsigned long sz)
{
__dc_line_op(start, sz, OP_INV);
}
EXPORT_SYMBOL(dma_cache_inv);
void dma_cache_wback(unsigned long start, unsigned long sz)
{
__dc_line_op(start, sz, OP_FLUSH);
}
EXPORT_SYMBOL(dma_cache_wback);
/*
* This is API for making I/D Caches consistent when modifying
* kernel code (loadable modules, kprobes, kgdb...)
* This is called on insmod, with kernel virtual address for CODE of
* the module. ARC cache maintenance ops require PHY address thus we
* need to convert vmalloc addr to PHY addr
*/
void flush_icache_range(unsigned long kstart, unsigned long kend)
{
unsigned int tot_sz, off, sz;
unsigned long phy, pfn;
/* printk("Kernel Cache Cohenercy: %lx to %lx\n",kstart, kend); */
/* This is not the right API for user virtual address */
if (kstart < TASK_SIZE) {
BUG_ON("Flush icache range for user virtual addr space");
return;
}
/* Shortcut for bigger flush ranges.
* Here we don't care if this was kernel virtual or phy addr
*/
tot_sz = kend - kstart;
if (tot_sz > PAGE_SIZE) {
flush_cache_all();
return;
}
/* Case: Kernel Phy addr (0x8000_0000 onwards) */
if (likely(kstart > PAGE_OFFSET)) {
/*
* The 2nd arg despite being paddr will be used to index icache
* This is OK since no alternate virtual mappings will exist
* given the callers for this case: kprobe/kgdb in built-in
* kernel code only.
*/
__sync_icache_dcache(kstart, kstart, kend - kstart);
return;
}
/*
* Case: Kernel Vaddr (0x7000_0000 to 0x7fff_ffff)
* (1) ARC Cache Maintenance ops only take Phy addr, hence special
* handling of kernel vaddr.
*
* (2) Despite @tot_sz being < PAGE_SIZE (bigger cases handled already),
* it still needs to handle a 2 page scenario, where the range
* straddles across 2 virtual pages and hence need for loop
*/
while (tot_sz > 0) {
off = kstart % PAGE_SIZE;
pfn = vmalloc_to_pfn((void *)kstart);
phy = (pfn << PAGE_SHIFT) + off;
sz = min_t(unsigned int, tot_sz, PAGE_SIZE - off);
__sync_icache_dcache(phy, kstart, sz);
kstart += sz;
tot_sz -= sz;
}
}
/*
* General purpose helper to make I and D cache lines consistent.
* @paddr is phy addr of region
* @vaddr is typically user or kernel vaddr (vmalloc)
* Howver in one instance, flush_icache_range() by kprobe (for a breakpt in
* builtin kernel code) @vaddr will be paddr only, meaning CDU operation will
* use a paddr to index the cache (despite VIPT). This is fine since since a
* built-in kernel page will not have any virtual mappings (not even kernel)
* kprobe on loadable module is different as it will have kvaddr.
*/
void __sync_icache_dcache(unsigned long paddr, unsigned long vaddr, int len)
{
unsigned long flags;
local_irq_save(flags);
__ic_line_inv_vaddr(paddr, vaddr, len);
__dc_line_op(paddr, len, OP_FLUSH);
local_irq_restore(flags);
}
/* wrapper to compile time eliminate alignment checks in flush loop */
void __inv_icache_page(unsigned long paddr, unsigned long vaddr)
{
__ic_line_inv_vaddr(paddr, vaddr, PAGE_SIZE);
}
void flush_icache_all(void)
{
unsigned long flags;
local_irq_save(flags);
write_aux_reg(ARC_REG_IC_IVIC, 1);
/* lr will not complete till the icache inv operation is not over */
read_aux_reg(ARC_REG_IC_CTRL);
local_irq_restore(flags);
}
noinline void flush_cache_all(void)
{
unsigned long flags;
local_irq_save(flags);
flush_icache_all();
__dc_entire_op(OP_FLUSH_N_INV);
local_irq_restore(flags);
}
/**********************************************************************
* Explicit Cache flush request from user space via syscall
* Needed for JITs which generate code on the fly
*/
SYSCALL_DEFINE3(cacheflush, uint32_t, start, uint32_t, sz, uint32_t, flags)
{
/* TBD: optimize this */
flush_cache_all();
return 0;
}
