diff options
| -rw-r--r-- | Documentation/arm/tcm.txt | 145 | ||||
| -rw-r--r-- | arch/arm/Kconfig | 5 | ||||
| -rw-r--r-- | arch/arm/include/asm/cputype.h | 5 | ||||
| -rw-r--r-- | arch/arm/include/asm/tcm.h | 31 | ||||
| -rw-r--r-- | arch/arm/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/kernel/setup.c | 2 | ||||
| -rw-r--r-- | arch/arm/kernel/tcm.c | 246 | ||||
| -rw-r--r-- | arch/arm/kernel/tcm.h | 17 | ||||
| -rw-r--r-- | arch/arm/kernel/vmlinux.lds.S | 57 | ||||
| -rw-r--r-- | arch/arm/mach-u300/include/mach/memory.h | 8 | ||||
| -rw-r--r-- | arch/arm/mm/init.c | 8 |
11 files changed, 525 insertions, 0 deletions
diff --git a/Documentation/arm/tcm.txt b/Documentation/arm/tcm.txt new file mode 100644 index 0000000..074f4be --- /dev/null +++ b/Documentation/arm/tcm.txt @@ -0,0 +1,145 @@ +ARM TCM (Tightly-Coupled Memory) handling in Linux +---- +Written by Linus Walleij <linus.walleij@stericsson.com> + +Some ARM SoC:s have a so-called TCM (Tightly-Coupled Memory). +This is usually just a few (4-64) KiB of RAM inside the ARM +processor. + +Due to being embedded inside the CPU The TCM has a +Harvard-architecture, so there is an ITCM (instruction TCM) +and a DTCM (data TCM). The DTCM can not contain any +instructions, but the ITCM can actually contain data. +The size of DTCM or ITCM is minimum 4KiB so the typical +minimum configuration is 4KiB ITCM and 4KiB DTCM. + +ARM CPU:s have special registers to read out status, physical +location and size of TCM memories. arch/arm/include/asm/cputype.h +defines a CPUID_TCM register that you can read out from the +system control coprocessor. Documentation from ARM can be found +at http://infocenter.arm.com, search for "TCM Status Register" +to see documents for all CPUs. Reading this register you can +determine if ITCM (bit 0) and/or DTCM (bit 16) is present in the +machine. + +There is further a TCM region register (search for "TCM Region +Registers" at the ARM site) that can report and modify the location +size of TCM memories at runtime. This is used to read out and modify +TCM location and size. Notice that this is not a MMU table: you +actually move the physical location of the TCM around. At the +place you put it, it will mask any underlying RAM from the +CPU so it is usually wise not to overlap any physical RAM with +the TCM. The TCM memory exists totally outside the MMU and will +override any MMU mappings. + +Code executing inside the ITCM does not "see" any MMU mappings +and e.g. register accesses must be made to physical addresses. + +TCM is used for a few things: + +- FIQ and other interrupt handlers that need deterministic + timing and cannot wait for cache misses. + +- Idle loops where all external RAM is set to self-refresh + retention mode, so only on-chip RAM is accessible by + the CPU and then we hang inside ITCM waiting for an + interrupt. + +- Other operations which implies shutting off or reconfiguring + the external RAM controller. + +There is an interface for using TCM on the ARM architecture +in <asm/tcm.h>. Using this interface it is possible to: + +- Define the physical address and size of ITCM and DTCM. + +- Tag functions to be compiled into ITCM. + +- Tag data and constants to be allocated to DTCM and ITCM. + +- Have the remaining TCM RAM added to a special + allocation pool with gen_pool_create() and gen_pool_add() + and provice tcm_alloc() and tcm_free() for this + memory. Such a heap is great for things like saving + device state when shutting off device power domains. + +A machine that has TCM memory shall select HAVE_TCM in +arch/arm/Kconfig for itself, and then the +rest of the functionality will depend on the physical +location and size of ITCM and DTCM to be defined in +mach/memory.h for the machine. Code that needs to use +TCM shall #include <asm/tcm.h> If the TCM is not located +at the place given in memory.h it will be moved using +the TCM Region registers. + +Functions to go into itcm can be tagged like this: +int __tcmfunc foo(int bar); + +Variables to go into dtcm can be tagged like this: +int __tcmdata foo; + +Constants can be tagged like this: +int __tcmconst foo; + +To put assembler into TCM just use +.section ".tcm.text" or .section ".tcm.data" +respectively. + +Example code: + +#include <asm/tcm.h> + +/* Uninitialized data */ +static u32 __tcmdata tcmvar; +/* Initialized data */ +static u32 __tcmdata tcmassigned = 0x2BADBABEU; +/* Constant */ +static const u32 __tcmconst tcmconst = 0xCAFEBABEU; + +static void __tcmlocalfunc tcm_to_tcm(void) +{ + int i; + for (i = 0; i < 100; i++) + tcmvar ++; +} + +static void __tcmfunc hello_tcm(void) +{ + /* Some abstract code that runs in ITCM */ + int i; + for (i = 0; i < 100; i++) { + tcmvar ++; + } + tcm_to_tcm(); +} + +static void __init test_tcm(void) +{ + u32 *tcmem; + int i; + + hello_tcm(); + printk("Hello TCM executed from ITCM RAM\n"); + + printk("TCM variable from testrun: %u @ %p\n", tcmvar, &tcmvar); + tcmvar = 0xDEADBEEFU; + printk("TCM variable: 0x%x @ %p\n", tcmvar, &tcmvar); + + printk("TCM assigned variable: 0x%x @ %p\n", tcmassigned, &tcmassigned); + + printk("TCM constant: 0x%x @ %p\n", tcmconst, &tcmconst); + + /* Allocate some TCM memory from the pool */ + tcmem = tcm_alloc(20); + if (tcmem) { + printk("TCM Allocated 20 bytes of TCM @ %p\n", tcmem); + tcmem[0] = 0xDEADBEEFU; + tcmem[1] = 0x2BADBABEU; + tcmem[2] = 0xCAFEBABEU; + tcmem[3] = 0xDEADBEEFU; + tcmem[4] = 0x2BADBABEU; + for (i = 0; i < 5; i++) + printk("TCM tcmem[%d] = %08x\n", i, tcmem[i]); + tcm_free(tcmem, 20); + } +} diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d778a69..1c4119c 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -46,6 +46,10 @@ config GENERIC_CLOCKEVENTS_BROADCAST depends on GENERIC_CLOCKEVENTS default y if SMP && !LOCAL_TIMERS +config HAVE_TCM + bool + select GENERIC_ALLOCATOR + config NO_IOPORT bool @@ -649,6 +653,7 @@ config ARCH_U300 bool "ST-Ericsson U300 Series" depends on MMU select CPU_ARM926T + select HAVE_TCM select ARM_AMBA select ARM_VIC select GENERIC_TIME diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h index b3e656c..54a1f1d 100644 --- a/arch/arm/include/asm/cputype.h +++ b/arch/arm/include/asm/cputype.h @@ -63,6 +63,11 @@ static inline unsigned int __attribute_const__ read_cpuid_cachetype(void) return read_cpuid(CPUID_CACHETYPE); } +static inline unsigned int __attribute_const__ read_cpuid_tcmstatus(void) +{ + return read_cpuid(CPUID_TCM); +} + /* * Intel's XScale3 core supports some v6 features (supersections, L2) * but advertises itself as v5 as it does not support the v6 ISA. For diff --git a/arch/arm/include/asm/tcm.h b/arch/arm/include/asm/tcm.h new file mode 100644 index 0000000..5929ef5 --- /dev/null +++ b/arch/arm/include/asm/tcm.h @@ -0,0 +1,31 @@ +/* + * + * Copyright (C) 2008-2009 ST-Ericsson AB + * License terms: GNU General Public License (GPL) version 2 + * + * Author: Rickard Andersson <rickard.andersson@stericsson.com> + * Author: Linus Walleij <linus.walleij@stericsson.com> + * + */ +#ifndef __ASMARM_TCM_H +#define __ASMARM_TCM_H + +#ifndef CONFIG_HAVE_TCM +#error "You should not be including tcm.h unless you have a TCM!" +#endif + +#include <linux/compiler.h> + +/* Tag variables with this */ +#define __tcmdata __section(.tcm.data) +/* Tag constants with this */ +#define __tcmconst __section(.tcm.rodata) +/* Tag functions inside TCM called from outside TCM with this */ +#define __tcmfunc __attribute__((long_call)) __section(.tcm.text) noinline +/* Tag function inside TCM called from inside TCM with this */ +#define __tcmlocalfunc __section(.tcm.text) + +void *tcm_alloc(size_t len); +void tcm_free(void *addr, size_t len); + +#endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 3213c93..6808e01 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o obj-$(CONFIG_ARM_THUMBEE) += thumbee.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_ARM_UNWIND) += unwind.o +obj-$(CONFIG_HAVE_TCM) += tcm.o obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index d4d4f77..c6c57b6 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -45,6 +45,7 @@ #include "compat.h" #include "atags.h" +#include "tcm.h" #ifndef MEM_SIZE #define MEM_SIZE (16*1024*1024) @@ -749,6 +750,7 @@ void __init setup_arch(char **cmdline_p) #endif cpu_init(); + tcm_init(); /* * Set up various architecture-specific pointers diff --git a/arch/arm/kernel/tcm.c b/arch/arm/kernel/tcm.c new file mode 100644 index 0000000..e503038 --- /dev/null +++ b/arch/arm/kernel/tcm.c @@ -0,0 +1,246 @@ +/* + * Copyright (C) 2008-2009 ST-Ericsson AB + * License terms: GNU General Public License (GPL) version 2 + * 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/page.h> /* PAGE_SHIFT */ +#include <asm/cputype.h> +#include <asm/mach/map.h> +#include <mach/memory.h> +#include "tcm.h" + +/* Scream and warn about misuse */ +#if !defined(ITCM_OFFSET) || !defined(ITCM_END) || \ + !defined(DTCM_OFFSET) || !defined(DTCM_END) +#error "TCM support selected but offsets not defined!" +#endif + +static struct gen_pool *tcm_pool; + +/* TCM section definitions from the linker */ +extern char __itcm_start, __sitcm_text, __eitcm_text; +extern char __dtcm_start, __sdtcm_data, __edtcm_data; + +/* + * TCM memory resources + */ +static struct resource dtcm_res = { + .name = "DTCM RAM", + .start = DTCM_OFFSET, + .end = DTCM_END, + .flags = IORESOURCE_MEM +}; + +static struct resource itcm_res = { + .name = "ITCM RAM", + .start = ITCM_OFFSET, + .end = ITCM_END, + .flags = IORESOURCE_MEM +}; + +static struct map_desc dtcm_iomap[] __initdata = { + { + .virtual = DTCM_OFFSET, + .pfn = __phys_to_pfn(DTCM_OFFSET), + .length = (DTCM_END - DTCM_OFFSET + 1), + .type = MT_UNCACHED + } +}; + +static struct map_desc itcm_iomap[] __initdata = { + { + .virtual = ITCM_OFFSET, + .pfn = __phys_to_pfn(ITCM_OFFSET), + .length = (ITCM_END - ITCM_OFFSET + 1), + .type = MT_UNCACHED + } +}; + +/* + * 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); + + +static void __init setup_tcm_bank(u8 type, u32 offset, u32 expected_size) +{ + 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; + + /* 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 of unknown size!\n", + type ? "I" : "D"); + } else { + pr_info("CPU: found %sTCM %dk @ %08x, %senabled\n", + type ? "I" : "D", + tcm_size, + (tcm_region & 0xfffff000U), + (tcm_region & 1) ? "" : "not "); + } + + if (tcm_size != expected_size) { + pr_crit("CPU: %sTCM was detected %dk but expected %dk!\n", + type ? "I" : "D", + tcm_size, + expected_size); + /* Adjust to the expected size? what can we do... */ + } + + /* 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)); + + pr_debug("CPU: moved %sTCM %dk to %08x, enabled\n", + type ? "I" : "D", + tcm_size, + (tcm_region & 0xfffff000U)); +} + +/* + * This initializes the TCM memory + */ +void __init tcm_init(void) +{ + u32 tcm_status = read_cpuid_tcmstatus(); + char *start; + char *end; + char *ram; + + /* Setup DTCM if present */ + if (tcm_status & (1 << 16)) { + setup_tcm_bank(0, DTCM_OFFSET, + (DTCM_END - DTCM_OFFSET + 1) >> 10); + request_resource(&iomem_resource, &dtcm_res); + iotable_init(dtcm_iomap, 1); + /* Copy data from RAM to DTCM */ + start = &__sdtcm_data; + end = &__edtcm_data; + ram = &__dtcm_start; + memcpy(start, ram, (end-start)); + pr_debug("CPU DTCM: copied data from %p - %p\n", start, end); + } + + /* Setup ITCM if present */ + if (tcm_status & 1) { + setup_tcm_bank(1, ITCM_OFFSET, + (ITCM_END - ITCM_OFFSET + 1) >> 10); + request_resource(&iomem_resource, &itcm_res); + iotable_init(itcm_iomap, 1); + /* Copy code from RAM to ITCM */ + start = &__sitcm_text; + end = &__eitcm_text; + ram = &__itcm_start; + memcpy(start, ram, (end-start)); + pr_debug("CPU ITCM: copied code from %p - %p\n", start, end); + } +} + +/* + * 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 tcm_status = read_cpuid_tcmstatus(); + 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 (tcm_status & (1 << 16)) { + if (dtcm_pool_start < DTCM_END) { + ret = gen_pool_add(tcm_pool, dtcm_pool_start, + DTCM_END - dtcm_pool_start + 1, -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 + 1, + dtcm_pool_start); + } + } + + /* Add the rest of ITCM to the TCM pool */ + if (tcm_status & 1) { + if (itcm_pool_start < ITCM_END) { + ret = gen_pool_add(tcm_pool, itcm_pool_start, + ITCM_END - itcm_pool_start + 1, -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 + 1, + itcm_pool_start); + } + } + return 0; +} + +core_initcall(setup_tcm_pool); diff --git a/arch/arm/kernel/tcm.h b/arch/arm/kernel/tcm.h new file mode 100644 index 0000000..8015ad4 --- /dev/null +++ b/arch/arm/kernel/tcm.h @@ -0,0 +1,17 @@ +/* + * Copyright (C) 2008-2009 ST-Ericsson AB + * License terms: GNU General Public License (GPL) version 2 + * TCM memory handling for ARM systems + * + * Author: Linus Walleij <linus.walleij@stericsson.com> + * Author: Rickard Andersson <rickard.andersson@stericsson.com> + */ + +#ifdef CONFIG_HAVE_TCM +void __init tcm_init(void); +#else +/* No TCM support, just blank inlines to be optimized out */ +inline void tcm_init(void) +{ +} +#endif diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index 6937102..39d3ffb 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -198,6 +198,63 @@ SECTIONS } _edata_loc = __data_loc + SIZEOF(.data); +#ifdef CONFIG_HAVE_TCM + /* + * We align everything to a page boundary so we can + * free it after init has commenced and TCM contents have + * been copied to its destination. + */ + .tcm_start : { + . = ALIGN(PAGE_SIZE); + __tcm_start = .; + __itcm_start = .; + } + + /* + * Link these to the ITCM RAM + * Put VMA to the TCM address and LMA to the common RAM + * and we'll upload the contents from RAM to TCM and free + * the used RAM after that. + */ + .text_itcm ITCM_OFFSET : AT(__itcm_start) + { + __sitcm_text = .; + *(.tcm.text) + *(.tcm.rodata) + . = ALIGN(4); + __eitcm_text = .; + } + + /* + * Reset the dot pointer, this is needed to create the + * relative __dtcm_start below (to be used as extern in code). + */ + . = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_itcm); + + .dtcm_start : { + __dtcm_start = .; + } + + /* TODO: add remainder of ITCM as well, that can be used for data! */ + .data_dtcm DTCM_OFFSET : AT(__dtcm_start) + { + . = ALIGN(4); + __sdtcm_data = .; + *(.tcm.data) + . = ALIGN(4); + __edtcm_data = .; + } + + /* Reset the dot pointer or the linker gets confused */ + . = ADDR(.dtcm_start) + SIZEOF(.data_dtcm); + + /* End marker for freeing TCM copy in linked object */ + .tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_dtcm)){ + . = ALIGN(PAGE_SIZE); + __tcm_end = .; + } +#endif + .bss : { __bss_start = .; /* BSS */ *(.bss) diff --git a/arch/arm/mach-u300/include/mach/memory.h b/arch/arm/mach-u300/include/mach/memory.h index bf134bc..ab000df 100644 --- a/arch/arm/mach-u300/include/mach/memory.h +++ b/arch/arm/mach-u300/include/mach/memory.h @@ -35,6 +35,14 @@ #endif /* + * TCM memory whereabouts + */ +#define ITCM_OFFSET 0xffff2000 +#define ITCM_END 0xffff3fff +#define DTCM_OFFSET 0xffff4000 +#define DTCM_END 0xffff5fff + +/* * We enable a real big DMA buffer if need be. */ #define CONSISTENT_DMA_SIZE SZ_4M diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index ea36186..764d5dc 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -613,6 +613,14 @@ void __init mem_init(void) void free_initmem(void) { +#ifdef CONFIG_HAVE_TCM + extern char *__tcm_start, *__tcm_end; + + totalram_pages += free_area(__phys_to_pfn(__pa(__tcm_start)), + __phys_to_pfn(__pa(__tcm_end)), + "TCM link"); +#endif + if (!machine_is_integrator() && !machine_is_cintegrator()) totalram_pages += free_area(__phys_to_pfn(__pa(__init_begin)), __phys_to_pfn(__pa(__init_end)), |