Add psram_or_malloc and psram_or_free

These will either statically allocate in psram, or malloc if the static allocation is not in available psram. Sections are sorted, so the group can be used to set priority.

Not sure how useful these are, so could be removed if not wanted.

Author: will-v-pi

src/rp2_common/hardware_psram/include/hardware/psram.h

@@ -220,6 +220,22 @@ int psram_reinitialise(void);
  */
 size_t psram_eid_to_size(uint8_t kgd, uint8_t eid);
 
+/*! \brief Provide a static PSRAM allocation, or malloc if PSRAM is not available
+ *  \ingroup hardware_psram
+ *
+ * This will allocate a static buffer in PSRAM and if available use that, otherwise it will use the heap.
+ * 
+ * This will fail to compile if PICO_PSRAM_SIZE_BYTES is not set
+ */
+#define psram_or_malloc(group, type, var, size) static type __psram_uninitialised(group) var##_psram[size]; type* var; if (psram_check_address(var##_psram + size)) { var = (type*)var##_psram; } else { var = (type*)malloc(size * sizeof(type)); }
+
+/*! \brief Free a buffer if it is not in PSRAM
+ *  \ingroup hardware_psram
+ *
+ * This will free the buffer from \ref psram_or_malloc if it was created by malloc
+ */
+#define psram_or_free(var) if (!psram_check_address(var##_psram)) { free(var); }
+
 #ifdef __cplusplus
 }
 #endif

test/kitchen_sink/CMakeLists.txt

@@ -178,6 +178,16 @@ if (NOT PICO_RP2040)
     set_target_properties(kitchen_sink_psram_tiny PROPERTIES PICO_TEST_SUCCESS_STRING "psram tiny size binary")
     set_target_properties(kitchen_sink_psram_tiny PROPERTIES PICO_TEST_FAILURE_STRING "PASSED")
 
+    add_executable(kitchen_sink_psram_small ${CMAKE_CURRENT_LIST_DIR}/kitchen_sink.c)
+    target_link_libraries(kitchen_sink_psram_small kitchen_sink_libs kitchen_sink_options)
+    target_compile_definitions(kitchen_sink_psram_small PRIVATE FIXED_PSRAM_SIZE=1 SMALL_PSRAM=1)
+    # Override the PSRAM size to allow variables in PSRAM
+    target_compile_definitions(kitchen_sink_psram_small PRIVATE PICO_AUTO_DETECT_PSRAM=1)
+    pico_override_psram_size(kitchen_sink_psram_small "(1 * 1024 * 1024)")
+    pico_add_extra_outputs(kitchen_sink_psram_small)
+    target_compile_definitions(kitchen_sink_psram_small PRIVATE KITCHEN_SINK_ID="psram small size binary")
+    set_target_properties(kitchen_sink_psram_small PROPERTIES PICO_TEST_FAILURE_STRING "ERROR:")
+
     add_executable(kitchen_sink_psram_detect ${CMAKE_CURRENT_LIST_DIR}/kitchen_sink.c)
     target_link_libraries(kitchen_sink_psram_detect kitchen_sink_libs kitchen_sink_options)
     target_compile_definitions(kitchen_sink_psram_detect PRIVATE PICO_AUTO_DETECT_PSRAM=1)

test/kitchen_sink/kitchen_sink.c

@@ -51,10 +51,15 @@ uint32_t dma_from = 0xaaaa5555;
 #ifdef FIXED_PSRAM_SIZE
 int __psram("foo") foo_psram = 23;
 char __psram_uninitialised("bar") bar_psram[0x8000];
-#ifdef TINY_PSRAM
+#if defined(TINY_PSRAM) || defined(SMALL_PSRAM)
 void make_tiny_psram(void) {
+#if defined(TINY_PSRAM)
     // Override flash_devinfo cs size to be tiny, so bar_psram doesn't fit in it
     flash_devinfo_set_cs_size(1, FLASH_DEVINFO_SIZE_8K);
+#elif defined(SMALL_PSRAM)
+    // Override flash_devinfo cs size to be small, so bar_psram fits but int_buffer doesn't
+    flash_devinfo_set_cs_size(1, FLASH_DEVINFO_SIZE_128K);
+#endif
     // Still auto-detect CS pin, as we don't know that
     uint8_t cs_gpios[] = PICO_AVAILABLE_CS1_GPIOS;
     psram_detect_cs_and_size(cs_gpios, sizeof(cs_gpios));
@@ -152,6 +157,17 @@ int main(void) {
 #endif
 #endif
 
+#if PICO_PSRAM_SIZE_BYTES
+    psram_or_malloc("z0000", char, char_buffer, 0x8000);
+    memset(char_buffer, 0x55, 0x8000);
+    printf("char_buffer in %s at %p\n", char_buffer < (char*)SRAM_BASE ? "PSRAM" : "Normal SRAM", char_buffer);
+    psram_or_free(char_buffer);
+    psram_or_malloc("z0001", int, int_buffer, 0x8000);
+    memset(int_buffer, 0x55, 0x8000 * sizeof(int));
+    printf("int_buffer in %s at %p\n", int_buffer < (int*)SRAM_BASE ? "PSRAM" : "Normal SRAM", int_buffer);
+    psram_or_free(int_buffer);
+#endif
+
 #ifdef FIXED_PSRAM_SIZE
     if (psram_is_available()) {
         printf("PSRAM is available\n");