sp1: bpt: Add helper to obtain memory map entry

Signed-off-by: Ian Moffett <ian@mirocom.org>

usr/src/sp1/common/bpt/bpt.c

@@ -36,6 +36,20 @@ bpt_get_protovar(struct bpt_protovar *res)
     return ops.get_protovar(res);
 }
 
+status_t
+bpt_mem_entry_i(size_t index, struct mem_entry *res)
+{
+    if (res == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    if (ops.mem_entry_i == NULL) {
+        return STATUS_IO_ERROR;
+    }
+
+    return ops.mem_entry_i(index, res);
+}
+
 status_t
 bpt_init(void)
 {

usr/src/sp1/common/bpt/bpt_limine.c

@@ -13,6 +13,13 @@
 #include <lib/limine.h>
 #include <lib/printf.h>
 
+/* Memory map request */
+static struct limine_memmap_response *memmap_resp = NULL;
+static volatile struct limine_memmap_request memmap_req = {
+    .id = LIMINE_MEMMAP_REQUEST,
+    .revision = 0
+};
+
 /* HHDM request */
 static struct limine_hhdm_response *hhdm_resp = NULL;
 static volatile struct limine_hhdm_request hhdm_req = {
@@ -36,6 +43,34 @@ limine_get_protovar(struct bpt_protovar *res)
     return STATUS_SUCCESS;
 }
 
+/*
+ * Obtain a memory map entry by index
+ *
+ * @index: Index of memory map entry to obtain
+ * @res:   Result is written here
+ */
+static status_t
+limine_mem_entry_i(size_t index, struct mem_entry *res)
+{
+    struct limine_memmap_entry *entry;
+
+    if (res == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    /* Don't overflow */
+    if (index >= memmap_resp->entry_count) {
+        return STATUS_NOT_FOUND;
+    }
+
+    /* 1:1 */
+    entry = memmap_resp->entries[index];
+    res->base = entry->base;
+    res->length = entry->length;
+    res->type = entry->type;
+    return STATUS_SUCCESS;
+}
+
 status_t
 bpt_init_limine(struct bpt_ops *ops)
 {
@@ -44,6 +79,9 @@ bpt_init_limine(struct bpt_ops *ops)
     }
 
     hhdm_resp = hhdm_req.response;
+    memmap_resp = memmap_req.response;
+
     ops->get_protovar = limine_get_protovar;
+    ops->mem_entry_i = limine_mem_entry_i;
     return STATUS_SUCCESS;
 }

usr/src/sp1/head/os/bpt.h

@@ -15,6 +15,34 @@
 #include <sys/types.h>
 #include <sys/status.h>
 
+/*
+ * Memory map entry types
+ */
+typedef enum {
+    MEMORY_USABLE,
+    MEMORY_RESERVED,
+    MEMORY_ACPI_RECLAIM,
+    MEMORY_ACPI_NVS,
+    MEMORY_BAD,
+    MEMORY_BOOTLOADER,
+    MEMORY_KERNEL,
+    MEMORY_FRAMEBUFFER,
+    MEMORY_ACPI_TABLES
+} mem_type_t;
+
+/*
+ * Represents a memory map entry
+ *
+ * @base:   Entry base address
+ * @length: Entry length
+ * @type:   Entry type
+ */
+struct mem_entry {
+    uintptr_t base;
+    size_t length;
+    mem_type_t type;
+};
+
 /*
  * The protovar stores a list of information passed
  * by the bootloader.
@@ -30,6 +58,7 @@ struct bpt_protovar {
  */
 struct bpt_ops {
     status_t(*get_protovar)(struct bpt_protovar *res);
+    status_t(*mem_entry_i)(size_t index, struct mem_entry *res);
 };
 
 /*
@@ -39,6 +68,13 @@ struct bpt_ops {
  */
 status_t bpt_get_protovar(struct bpt_protovar *res);
 
+/*
+ * Obtain a memory map entry by index
+ *
+ * Returns STATUS_NOT_FOUND on failure
+ */
+status_t bpt_mem_entry_i(size_t index, struct mem_entry *res);
+
 /*
  * Initialize the boot protocol translation layer
  */