diff options
Diffstat (limited to 'kernel/main/acpi.c')
| -rw-r--r-- | kernel/main/acpi.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/kernel/main/acpi.c b/kernel/main/acpi.c new file mode 100644 index 0000000..cb0f221 --- /dev/null +++ b/kernel/main/acpi.c @@ -0,0 +1,161 @@ +#include "main/acpi.h" + +#include "boot/config.h" +#include "mm/page.h" +#include "types.h" +#include "util/debug.h" +#include "util/string.h" + +#define XSDT_SIGNATURE (*(uint32_t *)"XSDT") +#define RSDT_SIGNATURE (*(uint32_t *)"RSDT") +#define FACP_SIGNATURE (*(uint32_t *)"FACP") +#define DSDT_SIGNATURE (*(uint32_t *)"DSDT") + +#define RSDP_ALIGN 16 + +#define EBDA_MIN_PADDR 0x80000 +#define EBDA_MAX_PADDR 0xa0000 +#define EBDA_PTR_LOC_PADDR 0x040e + +#define EBDA_MIN (PHYS_OFFSET + EBDA_MIN_PADDR) +#define EBDA_MAX (PHYS_OFFSET + EBDA_MAX_PADDR) +#define EBDA_PTR_LOC (PHYS_OFFSET + EBDA_PTR_LOC_PADDR) + +static const uint8_t rsdp_sig[8] = {'R', 'S', 'D', ' ', 'P', 'T', 'R', ' '}; + +typedef struct rsdp +{ + uint8_t rp_sign[8]; + uint8_t rp_checksum; + uint8_t rp_oemid[6]; + uint8_t rp_rev; + uint32_t rp_addr; +} packed rsdp_t; + +typedef struct rsdp_20 +{ + rsdp_t rsdp; + uint32_t length; + uint64_t xsdt_addr; + uint8_t ext_checksum; + uint8_t reserved[3]; +} packed rsdp_20_t; + +typedef struct rsd_table +{ + acpi_header_t rt_header; + uint64_t rt_other[]; +} packed rsd_table_t; + +static uint8_t __acpi_checksum(const uint8_t *buf, long size) +{ + uint8_t sum = 0; + for (long i = 0; i < size; i++) + sum += buf[i]; + return sum; +} + +static rsdp_20_t *__rsdp_search_range(uintptr_t start, uintptr_t end) +{ + uintptr_t rsdp_candidate = start; + while (rsdp_candidate <= end - sizeof(struct rsdp)) + { + if (memcmp((void *)rsdp_candidate, rsdp_sig, sizeof(rsdp_sig)) == 0 && + __acpi_checksum((uint8_t *)rsdp_candidate, sizeof(rsdp_20_t)) == + 0) + { + return (rsdp_20_t *)rsdp_candidate; + } + rsdp_candidate += RSDP_ALIGN; + } + return NULL; +} + +static void *__rsdp_search() +{ + // detect the location of the EBDA from the BIOS data section + uintptr_t ebda = + ((uintptr_t) * (uint16_t *)EBDA_PTR_LOC << 4) + PHYS_OFFSET; + rsdp_20_t *rsdp = 0; + if (ebda >= EBDA_MIN && ebda <= EBDA_MAX && ebda % RSDP_ALIGN == 0) + { + // check only if it's valid + rsdp = __rsdp_search_range(ebda, EBDA_MAX); + } + if (!rsdp) + { + // darmanio: unsure where these magic constants came from... + rsdp = + __rsdp_search_range(PHYS_OFFSET + 0xe0000, PHYS_OFFSET + 0x100000); + } + return rsdp; +} + +static rsdp_20_t *rsd_ptr = NULL; +static rsd_table_t *rsd_table = NULL; + +static rsd_table_t *_acpi_load_table(uintptr_t paddr) +{ + page_mark_reserved(PAGE_ALIGN_DOWN(paddr)); + return (rsd_table_t *)(PHYS_OFFSET + paddr); +} + +void acpi_init() +{ + if (rsd_ptr == NULL) + { + rsd_ptr = __rsdp_search(); + KASSERT(rsd_ptr && "Could not find the ACPI Root Descriptor Table."); + + rsd_table = _acpi_load_table(rsd_ptr->xsdt_addr); + KASSERT(XSDT_SIGNATURE == rsd_table->rt_header.ah_sign); + if (__acpi_checksum((void *)rsd_table, rsd_table->rt_header.ah_size)) + { + panic("Weenix only supports ACPI 2.0 or higher"); + } + + dbgq(DBG_CORE, "--- ACPI INIT ---\n"); + dbgq(DBG_CORE, "rsdp addr: %p\n", rsd_ptr); + dbgq(DBG_CORE, "rsdt addr: %p\n", rsd_table); + dbgq(DBG_CORE, "rev: %i\n", (int)rsd_ptr->rsdp.rp_rev); + + rsd_ptr->rsdp.rp_oemid[5] = 0; + dbgq(DBG_CORE, "oem: %s\n", (char *)rsd_ptr->rsdp.rp_oemid); + + // search for all tables listed in the RSDT and checksum them + dbgq(DBG_CORE, "ents:\t"); + size_t headers = + (rsd_table->rt_header.ah_size - sizeof(rsd_table->rt_header)) / + sizeof(rsd_table->rt_other[0]); + + for (size_t i = 0; i < headers; ++i) + { + acpi_header_t *header = + &_acpi_load_table(rsd_table->rt_other[i])->rt_header; + rsd_table->rt_other[i] = (uintptr_t)header; + + dbgq(DBG_CORE, "%.4s ", (char *)&header->ah_sign); + KASSERT(0 == __acpi_checksum((void *)header, header->ah_size)); + } + dbgq(DBG_CORE, "\n"); + } +} + +void *acpi_table(uint32_t signature, int index) +{ + KASSERT(index >= 0); + + size_t headers = + (rsd_table->rt_header.ah_size - sizeof(rsd_table->rt_header)) / + sizeof(rsd_table->rt_other[0]); + + for (size_t i = 0; i < headers; ++i) + { + acpi_header_t *header = (acpi_header_t *)rsd_table->rt_other[i]; + if (header->ah_sign == signature && 0 == index--) + { + return header; + } + } + return NULL; +} |