diff options
Diffstat (limited to 'arch/arm/kernel/tcm.c')
| -rw-r--r-- | arch/arm/kernel/tcm.c | 246 |
1 files changed, 246 insertions, 0 deletions
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); |