From 83feee4d454ac253191fb65bfca93e65d546ce40 Mon Sep 17 00:00:00 2001
From: Raphael Coeffic <raphaelcoeffic@users.noreply.github.com>
Date: Thu, 8 May 2025 12:44:33 +0200
Subject: [PATCH] feat(radio): static disk cache (#6170)

---
 .../linker/stm32h750_sdram/extra_sections.ld              | 7 +++++++
 .../linker/stm32h7rs_sdram/extra_sections.ld              | 7 +++++++
 radio/src/disk_cache.cpp                                  | 8 +++++++-
 radio/src/disk_cache.h                                    | 5 +++++
 radio/src/targets/common/arm/stm32/h7/memory_sections.h   | 3 +--
 5 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/radio/src/boards/generic_stm32/linker/stm32h750_sdram/extra_sections.ld b/radio/src/boards/generic_stm32/linker/stm32h750_sdram/extra_sections.ld
index a6da2e2f1..e0cc41760 100644
--- a/radio/src/boards/generic_stm32/linker/stm32h750_sdram/extra_sections.ld
+++ b/radio/src/boards/generic_stm32/linker/stm32h750_sdram/extra_sections.ld
@@ -29,6 +29,13 @@
 
 _stext_iram = LOADADDR(.iram);
 
+/* Disk cache buffers */
+.disk_cache (NOLOAD) :
+{
+  . = ALIGN(4);
+  *(.disk_cache)
+} > RAM_D1
+
 /* Extra DMA section */
 .dram (NOLOAD) :
 {
diff --git a/radio/src/boards/generic_stm32/linker/stm32h7rs_sdram/extra_sections.ld b/radio/src/boards/generic_stm32/linker/stm32h7rs_sdram/extra_sections.ld
index 82785b1e7..f9382cd3a 100644
--- a/radio/src/boards/generic_stm32/linker/stm32h7rs_sdram/extra_sections.ld
+++ b/radio/src/boards/generic_stm32/linker/stm32h7rs_sdram/extra_sections.ld
@@ -29,6 +29,13 @@
 
 _stext_iram = LOADADDR(.iram);
 
+/* Disk cache buffers */
+.disk_cache (NOLOAD) :
+{
+  . = ALIGN(4);
+  *(.disk_cache)
+} > PSRAM
+
 /* Extra DMA section */
 .dram (NOLOAD) :
 {
diff --git a/radio/src/disk_cache.cpp b/radio/src/disk_cache.cpp
index 4280b075b..9bd48776a 100644
--- a/radio/src/disk_cache.cpp
+++ b/radio/src/disk_cache.cpp
@@ -38,6 +38,10 @@
 #define BLOCK_SIZE FF_MAX_SS
 #define DISK_CACHE_BLOCK_SIZE (DISK_CACHE_BLOCK_SECTORS * BLOCK_SIZE)
 
+#if !defined(__DISK_CACHE)
+#define __DISK_CACHE __SDRAM
+#endif
+
 DiskCache diskCache;
 
 class DiskCacheBlock
@@ -112,9 +116,11 @@ DiskCache::DiskCache() : lastBlock(0), blocks(nullptr), diskDrv(nullptr)
   stats.noWrites = 0;
 }
 
+static DiskCacheBlock _cache_blocks[DISK_CACHE_BLOCKS_NUM] __DISK_CACHE;
+
 void DiskCache::initialize(const diskio_driver_t* drv)
 {
-  blocks = new DiskCacheBlock[DISK_CACHE_BLOCKS_NUM];
+  blocks = _cache_blocks;
   diskDrv = drv;
 }
 
diff --git a/radio/src/disk_cache.h b/radio/src/disk_cache.h
index b8869107f..83f1abbc5 100644
--- a/radio/src/disk_cache.h
+++ b/radio/src/disk_cache.h
@@ -24,8 +24,13 @@
 #include "hal/fatfs_diskio.h"
 
 // tunable parameters
+#if !defined(DISK_CACHE_BLOCKS_NUM)
 #define DISK_CACHE_BLOCKS_NUM      32   // no cache blocks
+#endif
+
+#if !defined(DISK_CACHE_BLOCK_SECTORS)
 #define DISK_CACHE_BLOCK_SECTORS   16   // no sectors
+#endif
 
 struct DiskCacheStats
 {
diff --git a/radio/src/targets/common/arm/stm32/h7/memory_sections.h b/radio/src/targets/common/arm/stm32/h7/memory_sections.h
index 29fd715bb..51fa6eb9e 100644
--- a/radio/src/targets/common/arm/stm32/h7/memory_sections.h
+++ b/radio/src/targets/common/arm/stm32/h7/memory_sections.h
@@ -27,5 +27,4 @@
 #define __IRAM         __attribute__((section(".iram")))
 #define __SDRAM        __attribute__((section(".sdram"), aligned(4)))
 #define __SDRAMFONTS   __attribute__((section(".sdram_fonts"), aligned(4)))
-
-
+#define __DISK_CACHE   __attribute__((section(".disk_cache"), aligned(4)))