/*
* Blackfin CPLB exception handling.
* Copyright 2004-2007 Analog Devices Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <asm/blackfin.h>
#include <asm/cplbinit.h>
#include <asm/mmu_context.h>
#define FAULT_RW (1 << 16)
#define FAULT_USERSUPV (1 << 17)
int page_mask_nelts;
int page_mask_order;
unsigned long *current_rwx_mask;
int nr_dcplb_miss, nr_icplb_miss, nr_icplb_supv_miss, nr_dcplb_prot;
int nr_cplb_flush;
static inline void disable_dcplb(void)
{
unsigned long ctrl;
SSYNC();
ctrl = bfin_read_DMEM_CONTROL();
ctrl &= ~ENDCPLB;
bfin_write_DMEM_CONTROL(ctrl);
SSYNC();
}
static inline void enable_dcplb(void)
{
unsigned long ctrl;
SSYNC();
ctrl = bfin_read_DMEM_CONTROL();
ctrl |= ENDCPLB;
bfin_write_DMEM_CONTROL(ctrl);
SSYNC();
}
static inline void disable_icplb(void)
{
unsigned long ctrl;
SSYNC();
ctrl = bfin_read_IMEM_CONTROL();
ctrl &= ~ENICPLB;
bfin_write_IMEM_CONTROL(ctrl);
SSYNC();
}
static inline void enable_icplb(void)
{
unsigned long ctrl;
SSYNC();
ctrl = bfin_read_IMEM_CONTROL();
ctrl |= ENICPLB;
bfin_write_IMEM_CONTROL(ctrl);
SSYNC();
}
/*
* Given the contents of the status register, return the index of the
* CPLB that caused the fault.
*/
static inline int faulting_cplb_index(int status)
{
int signbits = __builtin_bfin_norm_fr1x32(status & 0xFFFF);
return 30 - signbits;
}
/*
* Given the contents of the status register and the DCPLB_DATA contents,
* return true if a write access should be permitted.
*/
static inline int write_permitted(int status, unsigned long data)
{
if (status & FAULT_USERSUPV)
return !!(data & CPLB_SUPV_WR);
else
return !!(data & CPLB_USER_WR);
}
/* Counters to implement round-robin replacement. */
static int icplb_rr_index, dcplb_rr_index;
/*
* Find an ICPLB entry to be evicted and return its index.
*/
static int evict_one_icplb(void)
{
int i;
for (i = first_switched_icplb; i < MAX_CPLBS; i++)
if ((icplb_tbl[i].data & CPLB_VALID) == 0)
return i;
i = first_switched_icplb + icplb_rr_index;
if (i >= MAX_CPLBS) {
i -= MAX_CPLBS - first_switched_icplb;
icplb_rr_index -= MAX_CPLBS - first_switched_icplb;
}
icplb_rr_index++;
return i;
}
static int evict_one_dcplb(void)
{
int i;
for (i = first_switched_dcplb; i < MAX_CPLBS; i++)
if ((dcplb_tbl[i].data & CPLB_VALID) == 0)
return i;
i = first_switched_dcplb + dcplb_rr_index;
if (i >= MAX_CPLBS) {
i -= MAX_CPLBS - first_switched_dcplb;
dcplb_rr_index -= MAX_CPLBS - first_switched_dcplb;
}
dcplb_rr_index++;
return i;
}
static noinline int dcplb_miss(void)
{
unsigned long addr = bfin_read_DCPLB_FAULT_ADDR();
int status = bfin_read_DCPLB_STATUS();
unsigned long *mask;
int idx;
unsigned long d_data;
nr_dcplb_miss++;
d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
#ifdef CONFIG_BFIN_DCACHE
if (addr < _ramend - DMA_UNCACHED_REGION ||
(reserved_mem_dcache_on && addr >= _ramend &&
addr < physical_mem_end)) {
d_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
#ifdef CONFIG_BFIN_WT
d_data |= CPLB_L1_AOW | CPLB_WT;
#endif
}
#endif
if (addr >= physical_mem_end) {
if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE
&& (status & FAULT_USERSUPV)) {
addr &= ~0x3fffff;
d_data &= ~PAGE_SIZE_4KB;
d_data |= PAGE_SIZE_4MB;
} else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
&& (status & (FAULT_RW | FAULT_USERSUPV)) == FAULT_USERSUPV) {
addr &= ~(1 * 1024 * 1024 - 1);
d_data &= ~PAGE_SIZE_4KB;
d_data |= PAGE_SIZE_1MB;
} else
return CPLB_PROT_VIOL;
} else if (addr >= _ramend) {
d_data |= CPLB_USER_RD | CPLB_USER_WR;
} else {
mask = current_rwx_mask;
if (mask) {
int page = addr >> PAGE_SHIFT;
int offs = page >> 5;
int bit = 1 << (page & 31);
if (mask[offs] & bit)
d_data |= CPLB_USER_RD;
mask += page_mask_nelts;
if (mask[offs] & bit)
d_data |= CPLB_USER_WR;
}
}
idx = evict_one_dcplb();
addr &= PAGE_MASK;
dcplb_tbl[idx].addr = addr;
dcplb_tbl[idx].data = d_data;
disable_dcplb();
bfin_write32(DCPLB_DATA0 + idx * 4, d_data);
bfin_write32(DCPLB_ADDR0 + idx * 4, addr);
enable_dcplb();
return 0;
}
static noinline int icplb_miss(void)
{
unsigned long addr = bfin_read_ICPLB_FAULT_ADDR();
int status = bfin_read_ICPLB_STATUS();
int idx;
unsigned long i_data;
nr_icplb_miss++;
/* If inside the uncached DMA region, fault. */
if (addr >= _ramend - DMA_UNCACHED_REGION && addr < _ramend)
return CPLB_PROT_VIOL;
if (status & FAULT_USERSUPV)
nr_icplb_supv_miss++;
/*
* First, try to find a CPLB that matches this address. If we
* find one, then the fact that we're in the miss handler means
* that the instruction crosses a page boundary.
*/
for (idx = first_switched_icplb; idx < MAX_CPLBS; idx++) {
if (icplb_tbl[idx].data & CPLB_VALID) {
unsigned long this_addr = icplb_tbl[idx].addr;
if (this_addr <= addr && this_addr + PAGE_SIZE > addr) {
addr += PAGE_SIZE;
break;
}
}
}
i_data = CPLB_VALID | CPLB_PORTPRIO | PAGE_SIZE_4KB;
#ifdef CONFIG_BFIN_ICACHE
/*
* Normal RAM, and possibly the reserved memory area, are
* cacheable.
*/
if (addr < _ramend ||
(addr < physical_mem_end && reserved_mem_icache_on))
i_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
#endif
if (addr >= physical_mem_end) {
if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
&& (status & FAULT_USERSUPV)) {
addr &= ~(1 * 1024 * 1024 - 1);
i_data &= ~PAGE_SIZE_4KB;
i_data |= PAGE_SIZE_1MB;
} else
return CPLB_PROT_VIOL;
} else if (addr >= _ramend) {
i_data |= CPLB_USER_RD;
} else {
/*
* Two cases to distinguish - a supervisor access must
* necessarily be for a module page; we grant it
* unconditionally (could do better here in the future).
* Otherwise, check the x bitmap of the current process.
*/
if (!(status & FAULT_USERSUPV)) {
unsigned long *mask = current_rwx_mask;
if (mask) {
int page = addr >> PAGE_SHIFT;
int offs = page >> 5;
int bit = 1 << (page & 31);
mask += 2 * page_mask_nelts;
if (mask[offs] & bit)
i_data |= CPLB_USER_RD;
}
}
}
idx = evict_one_icplb();
addr &= PAGE_MASK;
icplb_tbl[idx].addr = addr;
icplb_tbl[idx].data = i_data;
disable_icplb();
bfin_write32(ICPLB_DATA0 + idx * 4, i_data);
bfin_write32(ICPLB_ADDR0 + idx * 4, addr);
enable_icplb();
return 0;
}
static noinline int dcplb_protection_fault(void)
{
int status = bfin_read_DCPLB_STATUS();
nr_dcplb_prot++;
if (status & FAULT_RW) {
int idx = faulting_cplb_index(status);
unsigned long data = dcplb_tbl[idx].data;
if (!(data & CPLB_WT) && !(data & CPLB_DIRTY) &&
write_permitted(status, data)) {
data |= CPLB_DIRTY;
dcplb_tbl[idx].data = data;
bfin_write32(DCPLB_DATA0 + idx * 4, data);
return 0;
}
}
return CPLB_PROT_VIOL;
}
int cplb_hdr(int seqstat, struct pt_regs *regs)
{
int cause = seqstat & 0x3f;
switch (cause) {
case 0x23:
return dcplb_protection_fault();
case 0x2C:
return icplb_miss();
case 0x26:
return dcplb_miss();
default:
return 1;
}
}
void flush_switched_cplbs(void)
{
int i;
nr_cplb_flush++;
disable_icplb();
for (i = first_switched_icplb; i < MAX_CPLBS; i++) {
icplb_tbl[i].data = 0;
bfin_write32(ICPLB_DATA0 + i * 4, 0);
}
enable_icplb();
disable_dcplb();
for (i = first_switched_dcplb; i < MAX_CPLBS; i++) {
dcplb_tbl[i].data = 0;
bfin_write32(DCPLB_DATA0 + i * 4, 0);
}
enable_dcplb();
}
void set_mask_dcplbs(unsigned long *masks)
{
int i;
unsigned long addr = (unsigned long)masks;
unsigned long d_data;
current_rwx_mask = masks;
if (!masks)
return;
d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
#ifdef CONFIG_BFIN_DCACHE
d_data |= CPLB_L1_CHBL;
#ifdef CONFIG_BFIN_WT
d_data |= CPLB_L1_AOW | CPLB_WT;
#endif
#endif
disable_dcplb();
for (i = first_mask_dcplb; i < first_switched_dcplb; i++) {
dcplb_tbl[i].addr = addr;
dcplb_tbl[i].data = d_data;
bfin_write32(DCPLB_DATA0 + i * 4, d_data);
bfin_write32(DCPLB_ADDR0 + i * 4, addr);
addr += PAGE_SIZE;
}
enable_dcplb();
}
