spi_flash: implement mmap/munmap

components/spi_flash/include/esp_spi_flash.h

@@ -70,6 +70,63 @@ esp_err_t spi_flash_write(uint32_t des_addr, const uint32_t *src_addr, uint32_t
 esp_err_t spi_flash_read(uint32_t src_addr, uint32_t *des_addr, uint32_t size);
 
 
+/**
+ * @brief Enumeration which specifies memory space requested in an mmap call
+ */
+typedef enum {
+    SPI_FLASH_MMAP_DATA,    /**< map to data memory (Vaddr0), allows byte-aligned access, 4 MB total */
+    SPI_FLASH_MMAP_INST,    /**< map to instruction memory (Vaddr1-3), allows only 4-byte-aligned access, 11 MB total */
+} spi_flash_mmap_memory_t;
+
+/**
+ * @brief Opaque handle for memory region obtained from spi_flash_mmap.
+ */
+typedef uint32_t spi_flash_mmap_handle_t;
+
+/**
+ * @brief Map region of flash memory into data or instruction address space
+ *
+ * This function allocates sufficient number of 64k MMU pages and configures
+ * them to map request region of flash memory into data address space or into
+ * instruction address space. It may reuse MMU pages which already provide
+ * required mapping. As with any allocator, there is possibility of fragmentation
+ * of address space if mmap/munmap are heavily used. To troubleshoot issues with
+ * page allocation, use spi_flash_mmap_dump function.
+ *
+ * @param src_addr  Physical address in flash where requested region starts.
+ *                  This address *must* be aligned to 64kB boundary.
+ * @param size  Size of region which has to be mapped. This size will be rounded
+ *              up to a 64k boundary.
+ * @param memory  Memory space where the region should be mapped
+ * @param out_ptr  Output, pointer to the mapped memory region
+ * @param out_handle  Output, handle which should be used for spi_flash_munmap call
+ *
+ * @return  ESP_OK on success, ESP_ERR_NO_MEM if pages can not be allocated
+ */
+esp_err_t spi_flash_mmap(uint32_t src_addr, size_t size, spi_flash_mmap_memory_t memory,
+                         const void** out_ptr, spi_flash_mmap_handle_t* out_handle);
+
+/**
+ * @brief Release region previously obtained using spi_flash_mmap
+ *
+ * @note Calling this function will not necessarily unmap memory region.
+ *       Region will only be unmapped when there are no other handles which
+ *       reference this region. In case of partially overlapping regions
+ *       it is possible that memory will be unmapped partially.
+ *
+ * @param handle  Handle obtained from spi_flash_mmap
+ */
+void spi_flash_munmap(spi_flash_mmap_handle_t handle);
+
+/**
+ * @brief Display information about mapped regions
+ *
+ * This function lists handles obtained using spi_flash_mmap, along with range
+ * of pages allocated to each handle. It also lists all non-zero entries of
+ * MMU table and corresponding reference counts.
+ */
+void spi_flash_mmap_dump();
+
 #if CONFIG_SPI_FLASH_ENABLE_COUNTERS
 
 /**