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/*
* Based on linux/arch/arm/mm/nommu.c
*
* ARM PMSAv7 supporting functions.
*/
#include <linux/bitops.h>
#include <linux/memblock.h>
#include <linux/string.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/cputype.h>
#include <asm/mpu.h>
#include <asm/sections.h>
#include "mm.h"
struct region {
phys_addr_t base;
phys_addr_t size;
unsigned long subreg;
};
static struct region __initdata mem[MPU_MAX_REGIONS];
#ifdef CONFIG_XIP_KERNEL
static struct region __initdata xip[MPU_MAX_REGIONS];
#endif
static unsigned int __initdata mpu_min_region_order;
static unsigned int __initdata mpu_max_regions;
static int __init __mpu_min_region_order(void);
static int __init __mpu_max_regions(void);
#ifndef CONFIG_CPU_V7M
#define DRBAR __ACCESS_CP15(c6, 0, c1, 0)
#define IRBAR __ACCESS_CP15(c6, 0, c1, 1)
#define DRSR __ACCESS_CP15(c6, 0, c1, 2)
#define IRSR __ACCESS_CP15(c6, 0, c1, 3)
#define DRACR __ACCESS_CP15(c6, 0, c1, 4)
#define IRACR __ACCESS_CP15(c6, 0, c1, 5)
#define RNGNR __ACCESS_CP15(c6, 0, c2, 0)
/* Region number */
static inline void rgnr_write(u32 v)
{
write_sysreg(v, RNGNR);
}
/* Data-side / unified region attributes */
/* Region access control register */
static inline void dracr_write(u32 v)
{
write_sysreg(v, DRACR);
}
/* Region size register */
static inline void drsr_write(u32 v)
{
write_sysreg(v, DRSR);
}
/* Region base address register */
static inline void drbar_write(u32 v)
{
write_sysreg(v, DRBAR);
}
static inline u32 drbar_read(void)
{
return read_sysreg(DRBAR);
}
/* Optional instruction-side region attributes */
/* I-side Region access control register */
static inline void iracr_write(u32 v)
{
write_sysreg(v, IRACR);
}
/* I-side Region size register */
static inline void irsr_write(u32 v)
{
write_sysreg(v, IRSR);
}
/* I-side Region base address register */
static inline void irbar_write(u32 v)
{
write_sysreg(v, IRBAR);
}
static inline u32 irbar_read(void)
{
return read_sysreg(IRBAR);
}
#else
static inline void rgnr_write(u32 v)
{
writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RNR);
}
/* Data-side / unified region attributes */
/* Region access control register */
static inline void dracr_write(u32 v)
{
u32 rsr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(15, 0);
writel_relaxed((v << 16) | rsr, BASEADDR_V7M_SCB + PMSAv7_RASR);
}
/* Region size register */
static inline void drsr_write(u32 v)
{
u32 racr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(31, 16);
writel_relaxed(v | racr, BASEADDR_V7M_SCB + PMSAv7_RASR);
}
/* Region base address register */
static inline void drbar_write(u32 v)
{
writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RBAR);
}
static inline u32 drbar_read(void)
{
return readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RBAR);
}
/* ARMv7-M only supports a unified MPU, so I-side operations are nop */
static inline void iracr_write(u32 v) {}
static inline void irsr_write(u32 v) {}
static inline void irbar_write(u32 v) {}
static inline unsigned long irbar_read(void) {return 0;}
#endif
static bool __init try_split_region(phys_addr_t base, phys_addr_t size, struct region *region)
{
unsigned long subreg, bslots, sslots;
phys_addr_t abase = base & ~(size - 1);
phys_addr_t asize = base + size - abase;
phys_addr_t p2size = 1 << __fls(asize);
phys_addr_t bdiff, sdiff;
if (p2size != asize)
p2size *= 2;
bdiff = base - abase;
sdiff = p2size - asize;
subreg = p2size / PMSAv7_NR_SUBREGS;
if ((bdiff % subreg) || (sdiff % subreg))
return false;
bslots = bdiff / subreg;
sslots = sdiff / subreg;
if (bslots || sslots) {
int i;
if (subreg < PMSAv7_MIN_SUBREG_SIZE)
return false;
if (bslots + sslots > PMSAv7_NR_SUBREGS)
return false;
for (i = 0; i < bslots; i++)
_set_bit(i, &region->subreg);
for (i = 1; i <= sslots; i++)
_set_bit(PMSAv7_NR_SUBREGS - i, &region->subreg);
}
region->base = abase;
region->size = p2size;
return true;
}
static int __init allocate_region(phys_addr_t base, phys_addr_t size,
unsigned int limit, struct region *regions)
{
int count = 0;
phys_addr_t diff = size;
int attempts = MPU_MAX_REGIONS;
while (diff) {
/* Try cover region as is (maybe with help of subregions) */
if (try_split_region(base, size, &regions[count])) {
count++;
base += size;
diff -= size;
size = diff;
} else {
/*
* Maximum aligned region might overflow phys_addr_t
* if "base" is 0. Hence we keep everything below 4G
* until we take the smaller of the aligned region
* size ("asize") and rounded region size ("p2size"),
* one of which is guaranteed to be smaller than the
* maximum physical address.
*/
phys_addr_t asize = (base - 1) ^ base;
phys_addr_t p2size = (1 << __fls(diff)) - 1;
size = asize < p2size ? asize + 1 : p2size + 1;
}
if (count > limit)
break;
if (!attempts)
break;
attempts--;
}
return count;
}
/* MPU initialisation functions */
void __init pmsav7_adjust_lowmem_bounds(void)
{
phys_addr_t specified_mem_size = 0, total_mem_size = 0;
struct memblock_region *reg;
bool first = true;
phys_addr_t mem_start;
phys_addr_t mem_end;
unsigned int mem_max_regions;
int num, i;
/* Free-up PMSAv7_PROBE_REGION */
mpu_min_region_order = __mpu_min_region_order();
/* How many regions are supported */
mpu_max_regions = __mpu_max_regions();
mem_max_regions = min((unsigned int)MPU_MAX_REGIONS, mpu_max_regions);
/* We need to keep one slot for background region */
mem_max_regions--;
#ifndef CONFIG_CPU_V7M
/* ... and one for vectors */
mem_max_regions--;
#endif
#ifdef CONFIG_XIP_KERNEL
/* plus some regions to cover XIP ROM */
num = allocate_region(CONFIG_XIP_PHYS_ADDR, __pa(_exiprom) - CONFIG_XIP_PHYS_ADDR,
mem_max_regions, xip);
mem_max_regions -= num;
#endif
for_each_memblock(memory, reg) {
if (first) {
phys_addr_t phys_offset = PHYS_OFFSET;
/*
* Initially only use memory continuous from
* PHYS_OFFSET */
if (reg->base != phys_offset)
panic("First memory bank must be contiguous from PHYS_OFFSET");
mem_start = reg->base;
mem_end = reg->base + reg->size;
specified_mem_size = reg->size;
first = false;
} else {
/*
* memblock auto merges contiguous blocks, remove
* all blocks afterwards in one go (we can't remove
* blocks separately while iterating)
*/
pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
&mem_end, &reg->base);
memblock_remove(reg->base, 0 - reg->base);
break;
}
}
memset(mem, 0, sizeof(mem));
num = allocate_region(mem_start, specified_mem_size, mem_max_regions, mem);
for (i = 0; i < num; i++) {
unsigned long subreg = mem[i].size / PMSAv7_NR_SUBREGS;
total_mem_size += mem[i].size - subreg * hweight_long(mem[i].subreg);
pr_debug("MPU: base %pa size %pa disable subregions: %*pbl\n",
&mem[i].base, &mem[i].size, PMSAv7_NR_SUBREGS, &mem[i].subreg);
}
if (total_mem_size != specified_mem_size) {
pr_warn("Truncating memory from %pa to %pa (MPU region constraints)",
&specified_mem_size, &total_mem_size);
memblock_remove(mem_start + total_mem_size,
specified_mem_size - total_mem_size);
}
}
static int __init __mpu_max_regions(void)
{
/*
* We don't support a different number of I/D side regions so if we
* have separate instruction and data memory maps then return
* whichever side has a smaller number of supported regions.
*/
u32 dregions, iregions, mpuir;
mpuir = read_cpuid_mputype();
dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;
/* Check for separate d-side and i-side memory maps */
if (mpuir & MPUIR_nU)
iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION;
/* Use the smallest of the two maxima */
return min(dregions, iregions);
}
static int __init mpu_iside_independent(void)
{
/* MPUIR.nU specifies whether there is *not* a unified memory map */
return read_cpuid_mputype() & MPUIR_nU;
}
static int __init __mpu_min_region_order(void)
{
u32 drbar_result, irbar_result;
/* We've kept a region free for this probing */
rgnr_write(PMSAv7_PROBE_REGION);
isb();
/*
* As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum
* region order
*/
drbar_write(0xFFFFFFFC);
drbar_result = irbar_result = drbar_read();
drbar_write(0x0);
/* If the MPU is non-unified, we use the larger of the two minima*/
if (mpu_iside_independent()) {
irbar_write(0xFFFFFFFC);
irbar_result = irbar_read();
irbar_write(0x0);
}
isb(); /* Ensure that MPU region operations have completed */
/* Return whichever result is larger */
return __ffs(max(drbar_result, irbar_result));
}
static int __init mpu_setup_region(unsigned int number, phys_addr_t start,
unsigned int size_order, unsigned int properties,
unsigned int subregions, bool need_flush)
{
u32 size_data;
/* We kept a region free for probing resolution of MPU regions*/
if (number > mpu_max_regions
|| number >= MPU_MAX_REGIONS)
return -ENOENT;
if (size_order > 32)
return -ENOMEM;
if (size_order < mpu_min_region_order)
return -ENOMEM;
/* Writing N to bits 5:1 (RSR_SZ) specifies region size 2^N+1 */
size_data = ((size_order - 1) << PMSAv7_RSR_SZ) | 1 << PMSAv7_RSR_EN;
size_data |= subregions << PMSAv7_RSR_SD;
if (need_flush)
flush_cache_all();
dsb(); /* Ensure all previous data accesses occur with old mappings */
rgnr_write(number);
isb();
drbar_write(start);
dracr_write(properties);
isb(); /* Propagate properties before enabling region */
drsr_write(size_data);
/* Check for independent I-side registers */
if (mpu_iside_independent()) {
irbar_write(start);
iracr_write(properties);
isb();
irsr_write(size_data);
}
isb();
/* Store region info (we treat i/d side the same, so only store d) */
mpu_rgn_info.rgns[number].dracr = properties;
mpu_rgn_info.rgns[number].drbar = start;
mpu_rgn_info.rgns[number].drsr = size_data;
mpu_rgn_info.used++;
return 0;
}
/*
* Set up default MPU regions, doing nothing if there is no MPU
*/
void __init pmsav7_setup(void)
{
int i, region = 0, err = 0;
/* Setup MPU (order is important) */
/* Background */
err |= mpu_setup_region(region++, 0, 32,
PMSAv7_ACR_XN | PMSAv7_RGN_STRONGLY_ORDERED | PMSAv7_AP_PL1RW_PL0RW,
0, false);
#ifdef CONFIG_XIP_KERNEL
/* ROM */
for (i = 0; i < ARRAY_SIZE(xip); i++) {
/*
* In case we overwrite RAM region we set earlier in
* head-nommu.S (which is cachable) all subsequent
* data access till we setup RAM bellow would be done
* with BG region (which is uncachable), thus we need
* to clean and invalidate cache.
*/
bool need_flush = region == PMSAv7_RAM_REGION;
if (!xip[i].size)
continue;
err |= mpu_setup_region(region++, xip[i].base, ilog2(xip[i].size),
PMSAv7_AP_PL1RO_PL0NA | PMSAv7_RGN_NORMAL,
xip[i].subreg, need_flush);
}
#endif
/* RAM */
for (i = 0; i < ARRAY_SIZE(mem); i++) {
if (!mem[i].size)
continue;
err |= mpu_setup_region(region++, mem[i].base, ilog2(mem[i].size),
PMSAv7_AP_PL1RW_PL0RW | PMSAv7_RGN_NORMAL,
mem[i].subreg, false);
}
/* Vectors */
#ifndef CONFIG_CPU_V7M
err |= mpu_setup_region(region++, vectors_base, ilog2(2 * PAGE_SIZE),
PMSAv7_AP_PL1RW_PL0NA | PMSAv7_RGN_NORMAL,
0, false);
#endif
if (err) {
panic("MPU region initialization failure! %d", err);
} else {
pr_info("Using ARMv7 PMSA Compliant MPU. "
"Region independence: %s, Used %d of %d regions\n",
mpu_iside_independent() ? "Yes" : "No",
mpu_rgn_info.used, mpu_max_regions);
}
}