This commit adds spi_flash_mmap_pages(), a function to map a set of unordered 64K pages in flash into a contiguous region in memory space.

components/spi_flash/flash_mmap.c

@@ -99,13 +99,41 @@ esp_err_t IRAM_ATTR spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_
                          const void** out_ptr, spi_flash_mmap_handle_t* out_handle)
 {
     esp_err_t ret;
-    bool did_flush, need_flush = false;
     if (src_addr & 0xffff) {
         return ESP_ERR_INVALID_ARG;
     }
     if (src_addr + size > g_rom_flashchip.chip_size) {
         return ESP_ERR_INVALID_ARG;
     }
+    // region which should be mapped
+    int phys_page = src_addr / SPI_FLASH_MMU_PAGE_SIZE;
+    int page_count = (size + SPI_FLASH_MMU_PAGE_SIZE - 1) / SPI_FLASH_MMU_PAGE_SIZE;
+    //prepare a linear pages array to feed into spi_flash_mmap_pages
+    int *pages=malloc(sizeof(int)*page_count);
+    if (pages==NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+    for (int i = 0; i < page_count; i++) {
+        pages[i] = phys_page+i;
+    }
+    ret=spi_flash_mmap_pages(pages, page_count, memory, out_ptr, out_handle);
+    free(pages);
+    return ret;
+}
+
+esp_err_t IRAM_ATTR spi_flash_mmap_pages(int *pages, size_t page_count, spi_flash_mmap_memory_t memory,
+                         const void** out_ptr, spi_flash_mmap_handle_t* out_handle)
+{
+    esp_err_t ret;
+    bool did_flush, need_flush = false;
+    if (!page_count) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    for (int i = 0; i < page_count; i++) {
+        if (pages[i] < 0 || pages[i]*SPI_FLASH_MMU_PAGE_SIZE >= g_rom_flashchip.chip_size) {
+            return ESP_ERR_INVALID_ARG;
+        }
+    }
     mmap_entry_t* new_entry = (mmap_entry_t*) malloc(sizeof(mmap_entry_t));
     if (new_entry == 0) {
         return ESP_ERR_NO_MEM;
@@ -113,8 +141,12 @@ esp_err_t IRAM_ATTR spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_
 
     spi_flash_disable_interrupts_caches_and_other_cpu();
 
-    did_flush = spi_flash_ensure_unmodified_region(src_addr, size);
-
+    did_flush = 0;
+    for (int i = 0; i < page_count; i++) {
+        if (spi_flash_ensure_unmodified_region(pages[i]*SPI_FLASH_MMU_PAGE_SIZE, SPI_FLASH_MMU_PAGE_SIZE)) {
+            did_flush = 1;
+        }
+    }
     spi_flash_mmap_init();
     // figure out the memory region where we should look for pages
     int region_begin;   // first page to check
@@ -131,21 +163,21 @@ esp_err_t IRAM_ATTR spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_
         region_size = 3 * 64 - region_begin;
         region_addr = VADDR1_FIRST_USABLE_ADDR;
     }
-    // region which should be mapped
-    int phys_page = src_addr / SPI_FLASH_MMU_PAGE_SIZE;
-    int page_count = (size + SPI_FLASH_MMU_PAGE_SIZE - 1) / SPI_FLASH_MMU_PAGE_SIZE;
+    if (region_size < page_count) {
+        return ESP_ERR_NO_MEM;
+    }
     // The following part searches for a range of MMU entries which can be used.
     // Algorithm is essentially naïve strstr algorithm, except that unused MMU
     // entries are treated as wildcards.
     int start;
     int end = region_begin + region_size - page_count;
     for (start = region_begin; start < end; ++start) {
-        int page = phys_page;
+        int pageno = 0;
         int pos;
-        for (pos = start; pos < start + page_count; ++pos, ++page) {
+        for (pos = start; pos < start + page_count; ++pos, ++pageno) {
             int table_val = (int) DPORT_PRO_FLASH_MMU_TABLE[pos];
             uint8_t refcnt = s_mmap_page_refcnt[pos]; 
-            if (refcnt != 0 && table_val != page) {
+            if (refcnt != 0 && table_val != pages[pageno]) {
                 break;
             }
         }
@@ -160,17 +192,17 @@ esp_err_t IRAM_ATTR spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_
         *out_ptr = NULL;
         ret = ESP_ERR_NO_MEM;
     } else {
-        // set up mapping using pages [start, start + page_count)
-        uint32_t entry_val = (uint32_t) phys_page;
-        for (int i = start; i != start + page_count; ++i, ++entry_val) {
+        // set up mapping using pages
+        uint32_t pageno = 0;
+        for (int i = start; i != start + page_count; ++i, ++pageno) {
             // sanity check: we won't reconfigure entries with non-zero reference count
             assert(s_mmap_page_refcnt[i] == 0 ||
-                    (DPORT_PRO_FLASH_MMU_TABLE[i] == entry_val &&
-                     DPORT_APP_FLASH_MMU_TABLE[i] == entry_val));
+                    (DPORT_PRO_FLASH_MMU_TABLE[i] == pages[pageno] &&
+                     DPORT_APP_FLASH_MMU_TABLE[i] == pages[pageno]));
             if (s_mmap_page_refcnt[i] == 0) {
-                if (DPORT_PRO_FLASH_MMU_TABLE[i] != entry_val || DPORT_APP_FLASH_MMU_TABLE[i] != entry_val) {
-                    DPORT_PRO_FLASH_MMU_TABLE[i] = entry_val;
-                    DPORT_APP_FLASH_MMU_TABLE[i] = entry_val;
+                if (DPORT_PRO_FLASH_MMU_TABLE[i] != pages[pageno] || DPORT_APP_FLASH_MMU_TABLE[i] != pages[pageno]) {
+                    DPORT_PRO_FLASH_MMU_TABLE[i] = pages[pageno];
+                    DPORT_APP_FLASH_MMU_TABLE[i] = pages[pageno];
                     need_flush = true;
                 }
             }

components/spi_flash/include/esp_spi_flash.h

@@ -176,6 +176,29 @@ typedef uint32_t spi_flash_mmap_handle_t;
 esp_err_t spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_memory_t memory,
                          const void** out_ptr, spi_flash_mmap_handle_t* out_handle);
 
+/**
+ * @brief Map sequences of pages of flash memory into data or instruction address space
+ *
+ * This function allocates sufficient number of 64k MMU pages and configures
+ * them to map the indicated pages of flash memory contiguously into data address 
+ * space or into instruction address space. In this respect, it works in a similar
+ * way as spi_flash_mmap but it allows mapping a (maybe non-contiguous) set of pages
+ * into a contiguous region of memory.
+ *
+ * @param pages An array of numbers indicating the 64K pages in flash to be mapped
+ *              contiguously into memory. These indicate the indexes of the 64K pages,
+ *              not the byte-size addresses as used in other functions.
+ * @param pagecount  Size of the pages array
+ * @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_pages(int *pages, size_t pagecount, 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
  *

components/spi_flash/test/test_mmap.c

@@ -184,6 +184,49 @@ TEST_CASE("Can mmap into instruction address space", "[mmap]")
 
 }
 
+TEST_CASE("Can mmap unordered pages into contiguous memory", "[spi_flash]")
+{
+    int nopages;
+    int *pages;
+    int startpage;
+
+    setup_mmap_tests();
+    nopages=(end-start)/SPI_FLASH_MMU_PAGE_SIZE;
+    pages=alloca(sizeof(int)*nopages);
+
+    startpage=start/SPI_FLASH_MMU_PAGE_SIZE;
+
+    //make inverse mapping: virt 0 -> page (nopages-1), virt 1 -> page (nopages-2), ...
+    for (int i=0; i<nopages; i++) {
+        pages[i]=startpage+(nopages-1)-i;
+        printf("Offset %x page %d\n", i*0x10000, pages[i]);
+    }
+    
+    printf("Attempting mapping of unordered pages to contiguous memory area\n");
+
+    spi_flash_mmap_handle_t handle1;
+    const void *ptr1;
+    ESP_ERROR_CHECK( spi_flash_mmap_pages(pages, nopages, SPI_FLASH_MMAP_DATA, &ptr1, &handle1) );
+    printf("mmap_res: handle=%d ptr=%p\n", handle1, ptr1);
+
+    spi_flash_mmap_dump();
+
+    srand(0);
+    const uint32_t *data = (const uint32_t *) ptr1;
+    for (int block = 0; block < nopages; ++block) {
+        for (int sector = 0; sector < 16; ++sector) {
+            for (uint32_t word = 0; word < 1024; ++word) {
+                TEST_ASSERT_EQUAL_UINT32(rand(), data[(((nopages-1)-block) * 16 + sector) * 1024 + word]);
+            }
+        }
+    }
+
+    printf("Unmapping handle1\n");
+    spi_flash_munmap(handle1);
+    spi_flash_mmap_dump();
+}
+
+
 TEST_CASE("flash_mmap invalidates just-written data", "[spi_flash]")
 {
     const void *ptr1;