From 9715efb8dc9ffa629bf5a1215b11bf2f2f29908b Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Fri, 1 Jul 2011 08:23:06 +0100 Subject: 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 Signed-off-by: Russell King --- arch/arm/kernel/tcm.c | 47 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 39 insertions(+), 8 deletions(-) (limited to 'arch/arm/kernel/tcm.c') diff --git a/arch/arm/kernel/tcm.c b/arch/arm/kernel/tcm.c index f5cf660eefcc..d402d4829524 100644 --- a/arch/arm/kernel/tcm.c +++ b/arch/arm/kernel/tcm.c @@ -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); } } -- cgit