// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008-2009 ST-Ericsson AB
* TCM memory handling for ARM systems
*
* Author: Linus Walleij <linus.walleij@stericsson.com>
* Author: Rickard Andersson <rickard.andersson@stericsson.com>
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/genalloc.h>
#include <linux/string.h> /* memcpy */
#include <asm/cputype.h>
#include <asm/mach/map.h>
#include <asm/page.h>
#include <asm/system_info.h>
#include <asm/traps.h>
#include <asm/tcm.h>
#define TCMTR_FORMAT_MASK 0xe0000000U
static struct gen_pool *tcm_pool;
static bool dtcm_present;
static bool itcm_present;
/* TCM section definitions from the linker */
extern char __itcm_start, __sitcm_text, __eitcm_text;
extern char __dtcm_start, __sdtcm_data, __edtcm_data;
/* These will be increased as we run */
static u32 dtcm_end = DTCM_OFFSET;
static u32 itcm_end = ITCM_OFFSET;
/*
* TCM memory resources
*/
static struct resource dtcm_res = {
.name = "DTCM RAM",
.start = DTCM_OFFSET,
.end = DTCM_OFFSET,
.flags = IORESOURCE_MEM
};
static struct resource itcm_res = {
.name = "ITCM RAM",
.start = ITCM_OFFSET,
.end = ITCM_OFFSET,
.flags = IORESOURCE_MEM
};
static struct map_desc dtcm_iomap[] __initdata = {
{
.virtual = DTCM_OFFSET,
.pfn = __phys_to_pfn(DTCM_OFFSET),
.length = 0,
.type = MT_MEMORY_RW_DTCM
}
};
static struct map_desc itcm_iomap[] __initdata = {
{
.virtual = ITCM_OFFSET,
.pfn = __phys_to_pfn(ITCM_OFFSET),
.length = 0,
.type = MT_MEMORY_RWX_ITCM,
}
};
/*
* Allocate a chunk of TCM memory
*/
void *tcm_alloc(size_t len)
{
unsigned long vaddr;
if (!tcm_pool)
return NULL;
vaddr = gen_pool_alloc(tcm_pool, len);
if (!vaddr)
return NULL;
return (void *) vaddr;
}
EXPORT_SYMBOL(tcm_alloc);
/*
* Free a chunk of TCM memory
*/
void tcm_free(void *addr, size_t len)
{
gen_pool_free(tcm_pool, (unsigned long) addr, len);
}
EXPORT_SYMBOL(tcm_free);
bool tcm_dtcm_present(void)
{
return dtcm_present;
}
EXPORT_SYMBOL(tcm_dtcm_present);
bool tcm_itcm_present(void)
{
return itcm_present;
}
EXPORT_SYMBOL(tcm_itcm_present);
static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
u32 *offset)
{
const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
256, 512, 1024, -1, -1, -1, -1 };
u32 tcm_region;
int tcm_size;
/*
* If there are more than one TCM bank of this type,
* select the TCM bank to operate on in the TCM selection
* register.
*/
if (banks > 1)
asm("mcr p15, 0, %0, c9, c2, 0"
: /* No output operands */
: "r" (bank));
/* Read the special TCM region register c9, 0 */
if (!type)
asm("mrc p15, 0, %0, c9, c1, 0"
: "=r" (tcm_region));
else
asm("mrc p15, 0, %0, c9, c1, 1"
: "=r" (tcm_region));
tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
if (tcm_size < 0) {
pr_err("CPU: %sTCM%d of unknown size\n",
type ? "I" : "D", bank);
return -EINVAL;
} else if (tcm_size > 32) {
pr_err("CPU: %sTCM%d larger than 32k found\n",
type ? "I" : "D", bank);
return -EINVAL;
} else {
pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
type ? "I" : "D",
bank,
tcm_size,
(tcm_region & 0xfffff000U),
(tcm_region & 1) ? "" : "not ");
}
/* Not much fun you can do with a size 0 bank */
if (tcm_size == 0)
return 0;
/* Force move the TCM bank to where we want it, enable */
tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
if (!type)
asm("mcr p15, 0, %0, c9, c1, 0"
: /* No output operands */
: "r" (tcm_region));
else
asm("mcr p15, 0, %0, c9, c1, 1"
: /* No output operands */
: "r" (tcm_region));
/* Increase offset */
*offset += (tcm_size << 10);
pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
type ? "I" : "D",
bank,
tcm_size,
(tcm_region & 0xfffff000U));
return 0;
}
/*
* When we are running in the non-secure world and the secure world
* has not explicitly given us access to the TCM we will get an
* undefined error when reading the TCM region register in the
* setup_tcm_bank function (above).
*
* There are two variants of this register read that we need to trap,
* the read for the data TCM and the read for the instruction TCM:
* c0370628: ee196f11 mrc 15, 0, r6, cr9, cr1, {0}
* c0370674: ee196f31 mrc 15, 0, r6, cr9, cr1, {1}
*
* Our undef hook mask explicitly matches all fields of the encoded
* instruction other than the destination register. The mask also
* only allows operand 2 to have the values 0 or 1.
*
* The undefined hook is defined as __init and __initdata, and therefore
* must be removed before tcm_init returns.
*
* In this particular case (MRC with ARM condition code ALways) the
* Thumb-2 and ARM instruction encoding are identical, so this hook
* will work on a Thumb-2 kernel.
*
* See A8.8.107, DDI0406C_C ARM Architecture Reference Manual, Encoding
* T1/A1 for the bit-by-bit details.
*
* mrc p15, 0, XX, c9, c1, 0
* mrc p15, 0, XX, c9, c1, 1
* | | | | | | | +---- opc2 0|1 = 000|001
* | | | | | | +------- CRm 0 = 0001
* | | | | | +----------- CRn 0 = 1001
* | | | | +--------------- Rt ? = ????
* | | | +------------------- opc1 0 = 000
* | | +----------------------- coproc 15 = 1111
* | +-------------------------- condition ALways = 1110
* +----------------------------- instruction MRC = 1110
*
* Encoding this as per A8.8.107 of DDI0406C, Encoding T1/A1, yields:
* 1111 1111 1111 1111 0000 1111 1101 1111 Required Mask
* 1110 1110 0001 1001 ???? 1111 0001 0001 mrc p15, 0, XX, c9, c1, 0
* 1110 1110 0001 1001 ???? 1111 0011 0001 mrc p15, 0, XX, c9, c1, 1
* [ ] [ ] [ ]| [ ] [ ] [ ] [ ]| +--- CRm
* | | | | | | | | +----- SBO
* | | | | | | | +------- opc2
* | | | | | | +----------- coproc
* | | | | | +---------------- Rt
* | | | | +--------------------- CRn
* | | | +------------------------- SBO
* | | +--------------------------- opc1
* | +------------------------------- instruction
* +------------------------------------ condition
*/
#define TCM_REGION_READ_MASK 0xffff0fdf
#define TCM_REGION_READ_INSTR 0xee190f11
#define DEST_REG_SHIFT 12
#define DEST_REG_MASK 0xf
static int __init tcm_handler(struct pt_regs *regs, unsigned int instr)
{
regs->uregs[(instr >> DEST_REG_SHIFT) & DEST_REG_MASK] = 0;
regs->ARM_pc += 4;
return 0;
}
static struct undef_hook tcm_hook __initdata = {
.instr_mask = TCM_REGION_READ_MASK,
.instr_val = TCM_REGION_READ_INSTR,
.cpsr_mask = MODE_MASK,
.cpsr_val = SVC_MODE,
.fn = tcm_handler
};
/*
* This initializes the TCM memory
*/
void __init tcm_init(void)
{
u32 tcm_status;
u8 dtcm_banks;
u8 itcm_banks;
size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
char *start;
char *end;
char *ram;
int ret;
int i;
/*
* Prior to ARMv5 there is no TCM, and trying to read the status
* register will hang the processor.
*/
if (cpu_architecture() < CPU_ARCH_ARMv5) {
if (dtcm_code_sz || itcm_code_sz)
pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
"ITCM code compiled in, but no TCM present "
"in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
return;
}
tcm_status = read_cpuid_tcmstatus();
/*
* This code only supports v6-compatible TCMTR implementations.
*/
if (tcm_status & TCMTR_FORMAT_MASK)
return;
dtcm_banks = (tcm_status >> 16) & 0x03;
itcm_banks = (tcm_status & 0x03);
register_undef_hook(&tcm_hook);
/* Values greater than 2 for D/ITCM banks are "reserved" */
if (dtcm_banks > 2)
dtcm_banks = 0;
if (itcm_banks > 2)
itcm_banks = 0;
/* Setup DTCM if present */
if (dtcm_banks > 0) {
for (i = 0; i < dtcm_banks; i++) {
ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
if (ret)
goto unregister;
}
/* This means you compiled more code than fits into DTCM */
if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
pr_info("CPU DTCM: %u bytes of code compiled to "
"DTCM but only %lu bytes of DTCM present\n",
dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
goto no_dtcm;
}
/*
* This means that the DTCM sizes were 0 or the DTCM banks
* were inaccessible due to TrustZone configuration.
*/
if (!(dtcm_end - DTCM_OFFSET))
goto no_dtcm;
dtcm_res.end = dtcm_end - 1;
request_resource(&iomem_resource, &dtcm_res);
dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
iotable_init(dtcm_iomap, 1);
/* Copy data from RAM to DTCM */
start = &__sdtcm_data;
end = &__edtcm_data;
ram = &__dtcm_start;
memcpy(start, ram, dtcm_code_sz);
pr_debug("CPU DTCM: copied data from %p - %p\n",
start, end);
dtcm_present = true;
} else if (dtcm_code_sz) {
pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
"DTCM banks present in CPU\n", dtcm_code_sz);
}
no_dtcm:
/* Setup ITCM if present */
if (itcm_banks > 0) {
for (i = 0; i < itcm_banks; i++) {
ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
if (ret)
goto unregister;
}
/* This means you compiled more code than fits into ITCM */
if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
pr_info("CPU ITCM: %u bytes of code compiled to "
"ITCM but only %lu bytes of ITCM present\n",
itcm_code_sz, (itcm_end - ITCM_OFFSET));
goto unregister;
}
/*
* This means that the ITCM sizes were 0 or the ITCM banks
* were inaccessible due to TrustZone configuration.
*/
if (!(itcm_end - ITCM_OFFSET))
goto unregister;
itcm_res.end = itcm_end - 1;
request_resource(&iomem_resource, &itcm_res);
itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
iotable_init(itcm_iomap, 1);
/* Copy code from RAM to ITCM */
start = &__sitcm_text;
end = &__eitcm_text;
ram = &__itcm_start;
memcpy(start, ram, itcm_code_sz);
pr_debug("CPU ITCM: copied code from %p - %p\n",
start, end);
itcm_present = true;
} else if (itcm_code_sz) {
pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
"ITCM banks present in CPU\n", itcm_code_sz);
}
unregister:
unregister_undef_hook(&tcm_hook);
}
/*
* This creates the TCM memory pool and has to be done later,
* during the core_initicalls, since the allocator is not yet
* up and running when the first initialization runs.
*/
static int __init setup_tcm_pool(void)
{
u32 dtcm_pool_start = (u32) &__edtcm_data;
u32 itcm_pool_start = (u32) &__eitcm_text;
int ret;
/*
* Set up malloc pool, 2^2 = 4 bytes granularity since
* the TCM is sometimes just 4 KiB. NB: pages and cache
* line alignments does not matter in TCM!
*/
tcm_pool = gen_pool_create(2, -1);
pr_debug("Setting up TCM memory pool\n");
/* Add the rest of DTCM to the TCM pool */
if (dtcm_present) {
if (dtcm_pool_start < dtcm_end) {
ret = gen_pool_add(tcm_pool, dtcm_pool_start,
dtcm_end - dtcm_pool_start, -1);
if (ret) {
pr_err("CPU DTCM: could not add DTCM " \
"remainder to pool!\n");
return ret;
}
pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
"the TCM memory pool\n",
dtcm_end - dtcm_pool_start,
dtcm_pool_start);
}
}
/* Add the rest of ITCM to the TCM pool */
if (itcm_present) {
if (itcm_pool_start < itcm_end) {
ret = gen_pool_add(tcm_pool, itcm_pool_start,
itcm_end - itcm_pool_start, -1);
if (ret) {
pr_err("CPU ITCM: could not add ITCM " \
"remainder to pool!\n");
return ret;
}
pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
"the TCM memory pool\n",
itcm_end - itcm_pool_start,
itcm_pool_start);
}
}
return 0;
}
core_initcall(setup_tcm_pool);