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ARM: 6984/1: enhance TCM robustness 

The PB11MPCore reports "3" DTCM banks, but anything above 2 is an
"undefined" value, so push this to become 0. Further add some checks
if code is compiled to TCM even if there is no D/ITCM present in the
system, and if we can really fit the compiled code. We don't do the
BUG() since it's not helpful, it's better to deal with non-present
TCM dynamically. If there is nothing compiled to the TCM and no TCM
is detected, it will now just shut up even if TCM support is enabled.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Linus Walleij 2011-07-01 08:23:06 +01:00 committed by Russell King
parent e4b6381009
commit 9715efb8dc
1 changed files with 39 additions and 8 deletions
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47
arch/arm/kernel/tcm.c
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@ -134,6 +134,10 @@ static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
(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;
@ -165,12 +169,20 @@ void __init tcm_init(void)
u32 tcm_status = read_cpuid_tcmstatus();
u8 dtcm_banks = (tcm_status >> 16) & 0x03;
u8 itcm_banks = (tcm_status & 0x03);
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;
/* 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++) {
@ -178,6 +190,13 @@ void __init tcm_init(void)
if (ret)
return;
}
/* 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;
}
dtcm_res.end = dtcm_end - 1;
request_resource(&iomem_resource, &dtcm_res);
dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
@ -186,12 +205,15 @@ void __init tcm_init(void)
start = &__sdtcm_data;
end = &__edtcm_data;
ram = &__dtcm_start;
/* This means you compiled more code than fits into DTCM */
BUG_ON((end - start) > (dtcm_end - DTCM_OFFSET));
memcpy(start, ram, (end-start));
pr_debug("CPU DTCM: copied data from %p - %p\n", start, end);
memcpy(start, ram, dtcm_code_sz);
pr_debug("CPU DTCM: copied data from %p - %p\n",
start, end);
} 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++) {
@ -199,6 +221,13 @@ void __init tcm_init(void)
if (ret)
return;
}
/* 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));
return;
}
itcm_res.end = itcm_end - 1;
request_resource(&iomem_resource, &itcm_res);
itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
@ -207,10 +236,12 @@ void __init tcm_init(void)
start = &__sitcm_text;
end = &__eitcm_text;
ram = &__itcm_start;
/* This means you compiled more code than fits into ITCM */
BUG_ON((end - start) > (itcm_end - ITCM_OFFSET));
memcpy(start, ram, (end-start));
pr_debug("CPU ITCM: copied code from %p - %p\n", start, end);
memcpy(start, ram, itcm_code_sz);
pr_debug("CPU ITCM: copied code from %p - %p\n",
start, end);
} 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);
}
}