arch: aarch64: move cache helpers to a new file

fdt.rs has helper functions to query host cache details (topology, size
etc.). Extract these helpers to a new file cache.rs so that they can be
used for PPTT construction as well.

No functional change.

Signed-off-by: Anirudh Rayabharam <anrayabh@microsoft.com>

arch/src/aarch64/cache.rs

@@ -0,0 +1,125 @@
+// Copyright 2020 Arm Limited (or its affiliates). All rights reserved.
+// Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Portions Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the THIRD-PARTY file.
+
+use std::fs;
+use std::path::Path;
+
+#[derive(Copy, Clone)]
+pub enum CacheLevel {
+    /// L1 data cache
+    L1D = 0,
+    /// L1 instruction cache
+    L1I = 1,
+    /// L2 cache
+    L2 = 2,
+    /// L3 cache
+    L3 = 3,
+}
+
+/// NOTE: cache size file directory example,
+/// "/sys/devices/system/cpu/cpu0/cache/index0/size".
+pub fn get_cache_size(cache_level: CacheLevel) -> u32 {
+    let mut file_directory: String = "/sys/devices/system/cpu/cpu0/cache".to_string();
+    match cache_level {
+        CacheLevel::L1D => file_directory += "/index0/size",
+        CacheLevel::L1I => file_directory += "/index1/size",
+        CacheLevel::L2 => file_directory += "/index2/size",
+        CacheLevel::L3 => file_directory += "/index3/size",
+    }
+
+    let file_path = Path::new(&file_directory);
+    if file_path.exists() {
+        let src = fs::read_to_string(file_directory).expect("File not exists or file corrupted.");
+        // The content of the file is as simple as a size, like: "32K"
+        let src = src.trim();
+        let src_digits: u32 = src[0..src.len() - 1].parse().unwrap();
+        let src_unit = &src[src.len() - 1..];
+
+        src_digits
+            * match src_unit {
+                "K" => 1024,
+                "M" => 1024u32.pow(2),
+                "G" => 1024u32.pow(3),
+                _ => 1,
+            }
+    } else {
+        0
+    }
+}
+
+/// NOTE: coherency_line_size file directory example,
+/// "/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size".
+pub fn get_cache_coherency_line_size(cache_level: CacheLevel) -> u32 {
+    let mut file_directory: String = "/sys/devices/system/cpu/cpu0/cache".to_string();
+    match cache_level {
+        CacheLevel::L1D => file_directory += "/index0/coherency_line_size",
+        CacheLevel::L1I => file_directory += "/index1/coherency_line_size",
+        CacheLevel::L2 => file_directory += "/index2/coherency_line_size",
+        CacheLevel::L3 => file_directory += "/index3/coherency_line_size",
+    }
+
+    let file_path = Path::new(&file_directory);
+    if file_path.exists() {
+        let src = fs::read_to_string(file_directory).expect("File not exists or file corrupted.");
+        src.trim().parse::<u32>().unwrap()
+    } else {
+        0
+    }
+}
+
+/// NOTE: number_of_sets file directory example,
+/// "/sys/devices/system/cpu/cpu0/cache/index0/number_of_sets".
+pub fn get_cache_number_of_sets(cache_level: CacheLevel) -> u32 {
+    let mut file_directory: String = "/sys/devices/system/cpu/cpu0/cache".to_string();
+    match cache_level {
+        CacheLevel::L1D => file_directory += "/index0/number_of_sets",
+        CacheLevel::L1I => file_directory += "/index1/number_of_sets",
+        CacheLevel::L2 => file_directory += "/index2/number_of_sets",
+        CacheLevel::L3 => file_directory += "/index3/number_of_sets",
+    }
+
+    let file_path = Path::new(&file_directory);
+    if file_path.exists() {
+        let src = fs::read_to_string(file_directory).expect("File not exists or file corrupted.");
+        src.trim().parse::<u32>().unwrap()
+    } else {
+        0
+    }
+}
+
+/// NOTE: shared_cpu_list file directory example,
+/// "/sys/devices/system/cpu/cpu0/cache/index0/shared_cpu_list".
+pub fn get_cache_shared(cache_level: CacheLevel) -> bool {
+    let mut file_directory: String = "/sys/devices/system/cpu/cpu0/cache".to_string();
+    let mut result = true;
+
+    match cache_level {
+        CacheLevel::L1D | CacheLevel::L1I => result = false,
+        CacheLevel::L2 => file_directory += "/index2/shared_cpu_list",
+        CacheLevel::L3 => file_directory += "/index3/shared_cpu_list",
+    }
+
+    if !result {
+        return false;
+    }
+
+    let file_path = Path::new(&file_directory);
+    if file_path.exists() {
+        let src = fs::read_to_string(file_directory).expect("File not exists or file corrupted.");
+        let src = src.trim();
+        if src.is_empty() {
+            result = false;
+        } else {
+            result = src.contains('-') || src.contains(',');
+        }
+    } else {
+        result = false;
+    }
+
+    result
+}