stm32/storage: Make pyb.Flash configurable, and support ext block proto.

The pyb.Flash() class can now be used to construct objects which reference
sections of the flash storage, starting at a certain offset and going for a
certain length.  Such objects also support the extended block protocol.
The signature for the constructor is: pyb.Flash(start=-1, len=-1).

ports/stm32/flashbdev.c

@@ -292,4 +292,44 @@ bool flash_bdev_writeblock(const uint8_t *src, uint32_t block) {
     return true;
 }
 
+int flash_bdev_readblocks_ext(uint8_t *dest, uint32_t block, uint32_t offset, uint32_t len) {
+    // Get data from flash memory, possibly via cache
+    while (len) {
+        uint32_t l = MIN(len, FLASH_BLOCK_SIZE - offset);
+        uint32_t flash_addr = convert_block_to_flash_addr(block);
+        if (flash_addr == -1) {
+            // bad block number
+            return -1;
+        }
+        uint8_t *src = flash_cache_get_addr_for_read(flash_addr + offset);
+        memcpy(dest, src, l);
+        dest += l;
+        block += 1;
+        offset = 0;
+        len -= l;
+    }
+    return 0;
+}
+
+int flash_bdev_writeblocks_ext(const uint8_t *src, uint32_t block, uint32_t offset, uint32_t len) {
+    // Copy to cache
+    while (len) {
+        uint32_t l = MIN(len, FLASH_BLOCK_SIZE - offset);
+        uint32_t flash_addr = convert_block_to_flash_addr(block);
+        if (flash_addr == -1) {
+            // bad block number
+            return -1;
+        }
+        uint32_t basepri = raise_irq_pri(IRQ_PRI_FLASH); // prevent cache flushing and USB access
+        uint8_t *dest = flash_cache_get_addr_for_write(flash_addr + offset);
+        memcpy(dest, src, l);
+        restore_irq_pri(basepri);
+        src += l;
+        block += 1;
+        offset = 0;
+        len -= l;
+    }
+    return 0;
+}
+
 #endif // MICROPY_HW_ENABLE_INTERNAL_FLASH_STORAGE

ports/stm32/spibdev.c

@@ -55,6 +55,13 @@ int32_t spi_bdev_ioctl(spi_bdev_t *bdev, uint32_t op, uint32_t arg) {
                 restore_irq_pri(basepri);
             }
             return 0;
+
+        case BDEV_IOCTL_BLOCK_ERASE: {
+            uint32_t basepri = raise_irq_pri(IRQ_PRI_FLASH); // prevent cache flushing and USB access
+            mp_spiflash_erase_block(&bdev->spiflash, arg * MP_SPIFLASH_ERASE_BLOCK_SIZE);
+            restore_irq_pri(basepri);
+            return 0;
+        }
     }
     return -MP_EINVAL;
 }
@@ -79,4 +86,20 @@ int spi_bdev_writeblocks(spi_bdev_t *bdev, const uint8_t *src, uint32_t block_nu
     return ret;
 }
 
+int spi_bdev_readblocks_raw(spi_bdev_t *bdev, uint8_t *dest, uint32_t block_num, uint32_t block_offset, uint32_t num_bytes) {
+    uint32_t basepri = raise_irq_pri(IRQ_PRI_FLASH); // prevent cache flushing and USB access
+    mp_spiflash_read(&bdev->spiflash, block_num * MP_SPIFLASH_ERASE_BLOCK_SIZE + block_offset, num_bytes, dest);
+    restore_irq_pri(basepri);
+
+    return 0;
+}
+
+int spi_bdev_writeblocks_raw(spi_bdev_t *bdev, const uint8_t *src, uint32_t block_num, uint32_t block_offset, uint32_t num_bytes) {
+    uint32_t basepri = raise_irq_pri(IRQ_PRI_FLASH); // prevent cache flushing and USB access
+    int ret = mp_spiflash_write(&bdev->spiflash, block_num * MP_SPIFLASH_ERASE_BLOCK_SIZE + block_offset, num_bytes, src);
+    restore_irq_pri(basepri);
+
+    return ret;
+}
+
 #endif

ports/stm32/storage.c

@@ -28,6 +28,7 @@
 #include <string.h>
 
 #include "py/runtime.h"
+#include "py/mperrno.h"
 #include "extmod/vfs_fat.h"
 
 #include "systick.h"
@@ -233,41 +234,197 @@ mp_uint_t storage_write_blocks(const uint8_t *src, uint32_t block_num, uint32_t
 //
 // Expose the flash as an object with the block protocol.
 
-// there is a singleton Flash object
-const mp_obj_base_t pyb_flash_obj = {&pyb_flash_type};
+#ifdef MICROPY_HW_BDEV_SPIFLASH_EXTENDED
+// Board defined an external SPI flash for use with extended block protocol
+#define SPIFLASH (MICROPY_HW_BDEV_SPIFLASH_EXTENDED)
+#define PYB_FLASH_NATIVE_BLOCK_SIZE (MP_SPIFLASH_ERASE_BLOCK_SIZE)
+#define MICROPY_HW_BDEV_READBLOCKS_EXT(dest, bl, off, len) (spi_bdev_readblocks_raw(SPIFLASH, (dest), (bl), (off), (len)))
+#define MICROPY_HW_BDEV_WRITEBLOCKS_EXT(dest, bl, off, len) (spi_bdev_writeblocks_raw(SPIFLASH, (dest), (bl), (off), (len)))
+
+#elif (MICROPY_VFS_LFS1 || MICROPY_VFS_LFS2) && MICROPY_HW_ENABLE_INTERNAL_FLASH_STORAGE
+// Board uses littlefs and internal flash, so enable extended block protocol on internal flash
+#define PYB_FLASH_NATIVE_BLOCK_SIZE (FLASH_BLOCK_SIZE)
+#define MICROPY_HW_BDEV_READBLOCKS_EXT(dest, bl, off, len) (flash_bdev_readblocks_ext((dest), (bl), (off), (len)))
+#define MICROPY_HW_BDEV_WRITEBLOCKS_EXT(dest, bl, off, len) (flash_bdev_writeblocks_ext((dest), (bl), (off), (len)))
+#endif
+
+#ifndef PYB_FLASH_NATIVE_BLOCK_SIZE
+#define PYB_FLASH_NATIVE_BLOCK_SIZE (FLASH_BLOCK_SIZE)
+#endif
+
+typedef struct _pyb_flash_obj_t {
+    mp_obj_base_t base;
+    uint32_t start; // in bytes
+    uint32_t len; // in bytes
+    #if defined(SPIFLASH)
+    bool use_native_block_size;
+    #endif
+} pyb_flash_obj_t;
+
+// This Flash object represents the entire available flash, with emulated partition table at start
+const pyb_flash_obj_t pyb_flash_obj = {
+    { &pyb_flash_type },
+    -(FLASH_PART1_START_BLOCK * FLASH_BLOCK_SIZE), // to offset FLASH_PART1_START_BLOCK
+    0, // actual size handled in ioctl, MP_BLOCKDEV_IOCTL_BLOCK_COUNT case
+};
+
+STATIC void pyb_flash_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    pyb_flash_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    if (self == &pyb_flash_obj) {
+        mp_printf(print, "Flash()");
+    } else {
+        mp_printf(print, "Flash(start=%u, len=%u)", self->start, self->len);
+    }
+}
+
+STATIC mp_obj_t pyb_flash_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
+    // Parse arguments
+    enum { ARG_start, ARG_len };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_start, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_len,   MP_ARG_INT, {.u_int = -1} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    if (args[ARG_start].u_int == -1 && args[ARG_len].u_int == -1) {
+        // Default singleton object that accesses entire flash, including virtual partition table
+        return MP_OBJ_FROM_PTR(&pyb_flash_obj);
+    }
+
+    pyb_flash_obj_t *self = m_new_obj(pyb_flash_obj_t);
+    self->base.type = &pyb_flash_type;
+    #if defined(SPIFLASH)
+    self->use_native_block_size = false;
+    #endif
+
+    uint32_t bl_len = (storage_get_block_count() - FLASH_PART1_START_BLOCK) * FLASH_BLOCK_SIZE;
+
+    mp_int_t start = args[ARG_start].u_int;
+    if (start == -1) {
+        start = 0;
+    } else if (!(0 <= start && start < bl_len && start % PYB_FLASH_NATIVE_BLOCK_SIZE == 0)) {
+        mp_raise_ValueError(NULL);
+    }
+
+    mp_int_t len = args[ARG_len].u_int;
+    if (len == -1) {
+        len = bl_len - start;
+    } else if (!(0 < len && start + len <= bl_len && len % PYB_FLASH_NATIVE_BLOCK_SIZE == 0)) {
+        mp_raise_ValueError(NULL);
+    }
 
-STATIC mp_obj_t pyb_flash_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
-    // check arguments
-    mp_arg_check_num(n_args, n_kw, 0, 0, false);
+    self->start = start;
+    self->len = len;
 
-    // return singleton object
-    return MP_OBJ_FROM_PTR(&pyb_flash_obj);
+    return MP_OBJ_FROM_PTR(self);
 }
 
-STATIC mp_obj_t pyb_flash_readblocks(mp_obj_t self, mp_obj_t block_num, mp_obj_t buf) {
+STATIC mp_obj_t pyb_flash_readblocks(size_t n_args, const mp_obj_t *args) {
+    pyb_flash_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    uint32_t block_num = mp_obj_get_int(args[1]);
     mp_buffer_info_t bufinfo;
-    mp_get_buffer_raise(buf, &bufinfo, MP_BUFFER_WRITE);
-    mp_uint_t ret = storage_read_blocks(bufinfo.buf, mp_obj_get_int(block_num), bufinfo.len / FLASH_BLOCK_SIZE);
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_WRITE);
+    mp_uint_t ret = -MP_EIO;
+    if (n_args == 3) {
+        // Cast self->start to signed in case it's pyb_flash_obj with negative start
+        block_num += FLASH_PART1_START_BLOCK + (int32_t)self->start / FLASH_BLOCK_SIZE;
+        ret = storage_read_blocks(bufinfo.buf, block_num, bufinfo.len / FLASH_BLOCK_SIZE);
+    }
+    #if defined(MICROPY_HW_BDEV_READBLOCKS_EXT)
+    else if (self != &pyb_flash_obj) {
+        // Extended block read on a sub-section of the flash storage
+        uint32_t offset = mp_obj_get_int(args[3]);
+        block_num += self->start / PYB_FLASH_NATIVE_BLOCK_SIZE;
+        ret = MICROPY_HW_BDEV_READBLOCKS_EXT(bufinfo.buf, block_num, offset, bufinfo.len);
+    }
+    #endif
     return MP_OBJ_NEW_SMALL_INT(ret);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(pyb_flash_readblocks_obj, pyb_flash_readblocks);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_flash_readblocks_obj, 3, 4, pyb_flash_readblocks);
 
-STATIC mp_obj_t pyb_flash_writeblocks(mp_obj_t self, mp_obj_t block_num, mp_obj_t buf) {
+STATIC mp_obj_t pyb_flash_writeblocks(size_t n_args, const mp_obj_t *args) {
+    pyb_flash_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    uint32_t block_num = mp_obj_get_int(args[1]);
     mp_buffer_info_t bufinfo;
-    mp_get_buffer_raise(buf, &bufinfo, MP_BUFFER_READ);
-    mp_uint_t ret = storage_write_blocks(bufinfo.buf, mp_obj_get_int(block_num), bufinfo.len / FLASH_BLOCK_SIZE);
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_READ);
+    mp_uint_t ret = -MP_EIO;
+    if (n_args == 3) {
+        // Cast self->start to signed in case it's pyb_flash_obj with negative start
+        block_num += FLASH_PART1_START_BLOCK + (int32_t)self->start / FLASH_BLOCK_SIZE;
+        ret = storage_write_blocks(bufinfo.buf, block_num, bufinfo.len / FLASH_BLOCK_SIZE);
+    }
+    #if defined(MICROPY_HW_BDEV_WRITEBLOCKS_EXT)
+    else if (self != &pyb_flash_obj) {
+        // Extended block write on a sub-section of the flash storage
+        uint32_t offset = mp_obj_get_int(args[3]);
+        block_num += self->start / PYB_FLASH_NATIVE_BLOCK_SIZE;
+        ret = MICROPY_HW_BDEV_WRITEBLOCKS_EXT(bufinfo.buf, block_num, offset, bufinfo.len);
+    }
+    #endif
     return MP_OBJ_NEW_SMALL_INT(ret);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(pyb_flash_writeblocks_obj, pyb_flash_writeblocks);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_flash_writeblocks_obj, 3, 4, pyb_flash_writeblocks);
 
-STATIC mp_obj_t pyb_flash_ioctl(mp_obj_t self, mp_obj_t cmd_in, mp_obj_t arg_in) {
+STATIC mp_obj_t pyb_flash_ioctl(mp_obj_t self_in, mp_obj_t cmd_in, mp_obj_t arg_in) {
+    pyb_flash_obj_t *self = self_in;
     mp_int_t cmd = mp_obj_get_int(cmd_in);
     switch (cmd) {
-        case MP_BLOCKDEV_IOCTL_INIT: storage_init(); return MP_OBJ_NEW_SMALL_INT(0);
+        case MP_BLOCKDEV_IOCTL_INIT: {
+            mp_int_t ret = 0;
+            storage_init();
+            if (mp_obj_get_int(arg_in) == 1) {
+                // Will be using extended block protocol
+                if (self == &pyb_flash_obj) {
+                    ret = -1;
+                #if defined(SPIFLASH)
+                } else {
+                    // Switch to use native block size of SPI flash
+                    self->use_native_block_size = true;
+                #endif
+                }
+            }
+            return MP_OBJ_NEW_SMALL_INT(ret);
+        }
         case MP_BLOCKDEV_IOCTL_DEINIT: storage_flush(); return MP_OBJ_NEW_SMALL_INT(0); // TODO properly
         case MP_BLOCKDEV_IOCTL_SYNC: storage_flush(); return MP_OBJ_NEW_SMALL_INT(0);
-        case MP_BLOCKDEV_IOCTL_BLOCK_COUNT: return MP_OBJ_NEW_SMALL_INT(storage_get_block_count());
-        case MP_BLOCKDEV_IOCTL_BLOCK_SIZE: return MP_OBJ_NEW_SMALL_INT(storage_get_block_size());
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_COUNT: {
+            mp_int_t n;
+            if (self == &pyb_flash_obj) {
+                // Get true size
+                n = storage_get_block_count();
+            #if defined(SPIFLASH)
+            } else if (self->use_native_block_size) {
+                n = self->len / PYB_FLASH_NATIVE_BLOCK_SIZE;
+            #endif
+            } else {
+                n = self->len / FLASH_BLOCK_SIZE;
+            }
+            return MP_OBJ_NEW_SMALL_INT(n);
+        }
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_SIZE: {
+            mp_int_t n = FLASH_BLOCK_SIZE;
+            #if defined(SPIFLASH)
+            if (self->use_native_block_size) {
+                n = PYB_FLASH_NATIVE_BLOCK_SIZE;
+            }
+            #endif
+            return MP_OBJ_NEW_SMALL_INT(n);
+        }
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_ERASE: {
+            int ret = 0;
+            #if defined(SPIFLASH)
+            if (self->use_native_block_size) {
+                mp_int_t block_num = self->start / PYB_FLASH_NATIVE_BLOCK_SIZE + mp_obj_get_int(arg_in);
+                ret = spi_bdev_ioctl(SPIFLASH, BDEV_IOCTL_BLOCK_ERASE, block_num);
+            }
+            #endif
+            return MP_OBJ_NEW_SMALL_INT(ret);
+        }
+
         default: return mp_const_none;
     }
 }
@@ -284,6 +441,7 @@ STATIC MP_DEFINE_CONST_DICT(pyb_flash_locals_dict, pyb_flash_locals_dict_table);
 const mp_obj_type_t pyb_flash_type = {
     { &mp_type_type },
     .name = MP_QSTR_Flash,
+    .print = pyb_flash_print,
     .make_new = pyb_flash_make_new,
     .locals_dict = (mp_obj_dict_t*)&pyb_flash_locals_dict,
 };

ports/stm32/storage.h

@@ -35,7 +35,8 @@ enum {
     BDEV_IOCTL_INIT = 1,
     BDEV_IOCTL_SYNC = 3,
     BDEV_IOCTL_NUM_BLOCKS = 4,
-    BDEV_IOCTL_IRQ_HANDLER = 6,
+    BDEV_IOCTL_BLOCK_ERASE = 6,
+    BDEV_IOCTL_IRQ_HANDLER = 7,
 };
 
 void storage_init(void);
@@ -52,6 +53,8 @@ mp_uint_t storage_write_blocks(const uint8_t *src, uint32_t block_num, uint32_t
 int32_t flash_bdev_ioctl(uint32_t op, uint32_t arg);
 bool flash_bdev_readblock(uint8_t *dest, uint32_t block);
 bool flash_bdev_writeblock(const uint8_t *src, uint32_t block);
+int flash_bdev_readblocks_ext(uint8_t *dest, uint32_t block, uint32_t offset, uint32_t len);
+int flash_bdev_writeblocks_ext(const uint8_t *src, uint32_t block, uint32_t offset, uint32_t len);
 
 typedef struct _spi_bdev_t {
     mp_spiflash_t spiflash;
@@ -62,8 +65,12 @@ int32_t spi_bdev_ioctl(spi_bdev_t *bdev, uint32_t op, uint32_t arg);
 int spi_bdev_readblocks(spi_bdev_t *bdev, uint8_t *dest, uint32_t block_num, uint32_t num_blocks);
 int spi_bdev_writeblocks(spi_bdev_t *bdev, const uint8_t *src, uint32_t block_num, uint32_t num_blocks);
 
+// These raw functions bypass the cache and go directly to SPI flash
+int spi_bdev_readblocks_raw(spi_bdev_t *bdev, uint8_t *dest, uint32_t block_num, uint32_t block_offset, uint32_t num_bytes);
+int spi_bdev_writeblocks_raw(spi_bdev_t *bdev, const uint8_t *src, uint32_t block_num, uint32_t block_offset, uint32_t num_bytes);
+
 extern const struct _mp_obj_type_t pyb_flash_type;
-extern const struct _mp_obj_base_t pyb_flash_obj;
+extern const struct _pyb_flash_obj_t pyb_flash_obj;
 
 struct _fs_user_mount_t;
 void pyb_flash_init_vfs(struct _fs_user_mount_t *vfs);