Parse FADT to find ACPI Timer Base Address and specs

system/acpi.c

@@ -44,6 +44,14 @@
 // Types
 //------------------------------------------------------------------------------
 
+typedef struct __attribute__ ((packed)) {
+    uint8_t     address_space;
+    uint8_t     bit_width;
+    uint8_t     bit_offset;
+    uint8_t     access_size;
+    uint64_t    address;
+} acpi_gen_addr_struct;
+
 typedef struct {
     char        signature[8];   // "RSD PTR "
     uint8_t     checksum;
@@ -81,10 +89,7 @@ static const efi_guid_t EFI_ACPI_2_RDSP_GUID = { 0x8868e871, 0xe4f1, 0x11d3, {0x
 
 const char *rsdp_source = "";
 
-uintptr_t rsdp_addr = 0;
+acpi_t acpi_config = {0, 0, 0, 0, 0, 0, 0, 0, false};
-uintptr_t madt_addr = 0;
-uintptr_t fadt_addr = 0;
-uintptr_t hpet_addr = 0;
 
 //------------------------------------------------------------------------------
 // Private Functions
@@ -197,11 +202,16 @@ static uintptr_t find_rsdp(void)
 
 static uintptr_t find_acpi_table(uint32_t table_signature)
 {
-   rsdp_t *rp = (rsdp_t *)rsdp_addr;;
+   rsdp_t *rp = (rsdp_t *)acpi_config.rsdp_addr;
 
-    // Found the RSDP, now get either the RSDT or XSDT and scan it for a pointer to the MADT.
+    // Found the RSDP, now get either the RSDT or XSDT
+    // and scan it for a pointer to the table we're looking for
     rsdt_header_t *rt;
 
+    if (acpi_config.ver_maj < rp->revision) {
+        acpi_config.ver_maj = rp->revision;
+    }
+
     if (rp->revision >= 2) {
         rt = (rsdt_header_t *)map_region(rp->xsdt_addr, sizeof(rsdt_header_t), true);
         if (rt == NULL) {
@@ -215,7 +225,7 @@ static uintptr_t find_acpi_table(uint32_t table_signature)
         if (rt == NULL || acpi_checksum(rt, rt->length) != 0) {
             return 0;
         }
-        // Scan the XSDT for a pointer to the MADT.
+        // Scan the XSDT for a pointer to the table we're looking for.
         uint64_t *tab_ptr = (uint64_t *)((uint8_t *)rt + sizeof(rsdt_header_t));
         uint64_t *tab_end = (uint64_t *)((uint8_t *)rt + rt->length);
 
@@ -240,7 +250,7 @@ static uintptr_t find_acpi_table(uint32_t table_signature)
         if (rt == NULL || acpi_checksum(rt, rt->length) != 0) {
             return 0;
         }
-        // Scan the RSDT for a pointer to the MADT.
+        // Scan the RSDT for a pointer to the table we're looking for.
         uint32_t *tab_ptr = (uint32_t *)((uint8_t *)rt + sizeof(rsdt_header_t));
         uint32_t *tab_end = (uint32_t *)((uint8_t *)rt + rt->length);
 
@@ -257,6 +267,48 @@ static uintptr_t find_acpi_table(uint32_t table_signature)
     return 0;
 }
 
+static bool parse_fadt(uintptr_t fadt_addr)
+{
+    // FADT is a very big & complex table and we only need a few data.
+    // We use byte offset instead of a complete struct.
+
+    // FADT Header is identical to RSDP Header
+    rsdt_header_t *fadt = (rsdt_header_t *)fadt_addr;
+
+    // Validate FADT
+    if (fadt == NULL || acpi_checksum(fadt, fadt->length) != 0) {
+        return false;
+    }
+
+    // Get ACPI Version
+    acpi_config.ver_maj = fadt->revision;
+
+    if (fadt->length > FADT_MINOR_REV_OFFSET) {
+        acpi_config.ver_min = *(uint8_t *)(fadt_addr+FADT_MINOR_REV_OFFSET) & 0xF;
+    }
+
+    // Get Old PM Base Address (32bit IO)
+    acpi_config.pm_addr  = *(uint32_t *)(fadt_addr+FADT_PM_TMR_BLK_OFFSET);
+    acpi_config.pm_is_io = true;
+
+#ifdef __x86_64__
+    acpi_gen_addr_struct *rt;
+
+    // Get APIC Timer Address
+    if (fadt->length > FADT_X_PM_TMR_BLK_OFFSET) {
+        rt = (acpi_gen_addr_struct *)map_region(fadt_addr+FADT_X_PM_TMR_BLK_OFFSET, sizeof(acpi_gen_addr_struct), true);
+
+        acpi_config.pm_is_io = (rt->address_space == 1) ? true : false;
+
+        if (rt->address != 0) {
+            acpi_config.pm_addr = rt->address;
+        }
+    }
+#endif
+
+    return true;
+}
+
 //------------------------------------------------------------------------------
 // Public Functions
 //------------------------------------------------------------------------------
@@ -275,14 +327,19 @@ int acpi_checksum(const void *data, int length)
 void acpi_init(void)
 {
     // Find ACPI RDST Table Address
-    rsdp_addr = find_rsdp();
+    acpi_config.rsdp_addr = find_rsdp();
 
     // Find ACPI MADT Table Address
-    madt_addr = find_acpi_table(MADTSignature);
+    acpi_config.madt_addr = find_acpi_table(MADTSignature);
 
     // Find ACPI FADT Table Address
-    fadt_addr = find_acpi_table(FADTSignature);
+    acpi_config.fadt_addr = find_acpi_table(FADTSignature);
+
+    // Parse FADT
+    if (acpi_config.fadt_addr) {
+        parse_fadt(acpi_config.fadt_addr);
+    }
 
     // Find ACPI HPET Table Address
-    hpet_addr = find_acpi_table(HPETSignature);
+    acpi_config.hpet_addr = find_acpi_table(HPETSignature);
 }

system/acpi.h

@@ -14,30 +14,35 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#define FADT_PM_TMR_BLK_OFFSET      76
+#define FADT_MINOR_REV_OFFSET       131
+#define FADT_X_PM_TMR_BLK_OFFSET    208
+
+/**
+ * A struct containing various ACPI-related infos for later uses.
+ */
+
+typedef struct {
+    uint8_t     ver_maj;
+    uint8_t     ver_min;
+    uint64_t    test;
+    uintptr_t   rsdp_addr;
+    uintptr_t   madt_addr;
+    uintptr_t   fadt_addr;
+    uintptr_t   hpet_addr;
+    uintptr_t   pm_addr;
+    bool        pm_is_io;
+} acpi_t;
+
 /**
  * The search step that located the ACPI RSDP (for debug).
  */
 extern const char *rsdp_source;
 
 /**
- * The address of the ACPI RSDP
+ * Global ACPI config struct
  */
-extern uintptr_t rsdp_addr;
+extern acpi_t acpi_config;
-
-/**
- * The address of the ACPI MADT
- */
-extern uintptr_t madt_addr;
-
-/**
- * The address of the ACPI FADT
- */
-extern uintptr_t fadt_addr;
-
-/**
- * The address of the ACPI HPET
- */
-extern uintptr_t hpet_addr;
 
 /**
  * ACPI Table Checksum Function

system/smp.c

@@ -376,12 +376,12 @@ static bool find_cpus_in_floating_mp_struct(void)
 
 static bool find_cpus_in_madt(void)
 {
-    if(madt_addr == 0) return false;
+    if(acpi_config.madt_addr == 0) return false;
 
-    madt_table_header_t *mpc = (madt_table_header_t *)map_region(madt_addr, sizeof(madt_table_header_t), true);
+    madt_table_header_t *mpc = (madt_table_header_t *)map_region(acpi_config.madt_addr, sizeof(madt_table_header_t), true);
     if (mpc == NULL) return false;
 
-    mpc = (madt_table_header_t *)map_region(madt_addr, mpc->length, true);
+    mpc = (madt_table_header_t *)map_region(acpi_config.madt_addr, mpc->length, true);
     if (mpc == NULL) return false;
 
     if (acpi_checksum(mpc, mpc->length) != 0) {