fastboot: Implement flashing session counter

The fastboot flash command that writes an image to a partition works in
several steps:

1 - Retrieve the maximum size the device can download through the
    "max-download-size" variable

2 - Retrieve the partition type through the "partition-type:%s" variable,
    that indicates whether or not the partition needs to be erased (even
    though the fastboot client has minimal support for that)

3a - If the image is smaller than what the device can handle, send the image
     and flash it.

3b - If the image is larger than what the device can handle, create a
     sparse image, and split it in several chunks that would fit. Send the
     chunk, flash it, repeat until we have no more data to send.

However, in the 3b case, the subsequent transfers have no particular
identifiers, the protocol just assumes that you would resume the writes
where you left it.

While doing so works well, it also means that flashing two subsequent
images on the same partition (for example because the user made a mistake)
would not work withouth flashing another partition or rebooting the board,
which is not really intuitive.

Since we have always the same pattern, we can however maintain a counter
that will be reset every time the client will retrieve max-download-size,
and incremented after each buffer will be flashed, that will allow us to
tell whether we should simply resume the flashing where we were, or start
back at the beginning of the partition.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/common/aboot.c b/common/aboot.c
index 6c35d8226903251b221ad3e0ac27ca42d1c6c856..7f412ac0ad4f6620f6e150ba5a25248b6bc408e8 100644 (file)
--- a/common/aboot.c
+++ b/common/aboot.c
@@ -264,8 +264,8 @@ static void sparse_put_data_buffer(sparse_buffer_t *buffer)
        free(buffer);
 }
 
-int store_sparse_image(sparse_storage_t *storage,
-                      void *storage_priv, void *data)
+int store_sparse_image(sparse_storage_t *storage, void *storage_priv,
+                      unsigned int session_id, void *data)
 {
        unsigned int chunk, offset;
        sparse_header_t *sparse_header;

diff --git a/common/fb_mmc.c b/common/fb_mmc.c
index c9f2ed6b58635aa7d9e73ca64770c08c392a32a5..c6989668ae5b914bdec8913654441b108ee02195 100644 (file)
--- a/common/fb_mmc.c
+++ b/common/fb_mmc.c
@@ -96,8 +96,9 @@ static void write_raw_image(block_dev_desc_t *dev_desc, disk_partition_t *info,
        fastboot_okay(response_str, "");
 }
 
-void fb_mmc_flash_write(const char *cmd, void *download_buffer,
-                       unsigned int download_bytes, char *response)
+void fb_mmc_flash_write(const char *cmd, unsigned int session_id,
+                       void *download_buffer, unsigned int download_bytes,
+                       char *response)
 {
        block_dev_desc_t *dev_desc;
        disk_partition_t info;
@@ -151,7 +152,8 @@ void fb_mmc_flash_write(const char *cmd, void *download_buffer,
                printf("Flashing sparse image at offset " LBAFU "\n",
                       info.start);
 
-               store_sparse_image(&sparse, &sparse_priv, download_buffer);
+               store_sparse_image(&sparse, &sparse_priv, session_id,
+                                  download_buffer);
        } else {
                write_raw_image(dev_desc, &info, cmd, download_buffer,
                                download_bytes);

diff --git a/drivers/usb/gadget/f_fastboot.c b/drivers/usb/gadget/f_fastboot.c
index 05fb77302b3e10b04aa06082747f32d44708369f..a70463db33987a47e3a0398139dec60cefa0c40a 100644 (file)
--- a/drivers/usb/gadget/f_fastboot.c
+++ b/drivers/usb/gadget/f_fastboot.c
@@ -51,6 +51,7 @@ static inline struct f_fastboot *func_to_fastboot(struct usb_function *f)
 }
 
 static struct f_fastboot *fastboot_func;
+static unsigned int fastboot_flash_session_id;
 static unsigned int download_size;
 static unsigned int download_bytes;
 static bool is_high_speed;
@@ -393,6 +394,15 @@ static void cb_getvar(struct usb_ep *ep, struct usb_request *req)
 
                sprintf(str_num, "0x%08x", CONFIG_FASTBOOT_BUF_SIZE);
                strncat(response, str_num, chars_left);
+
+               /*
+                * This also indicates the start of a new flashing
+                * "session", in which we could have 1-N buffers to
+                * write to a partition.
+                *
+                * Reset our session counter.
+                */
+               fastboot_flash_session_id = 0;
        } else if (!strcmp_l1("serialno", cmd)) {
                s = getenv("serial#");
                if (s)
@@ -555,9 +565,11 @@ static void cb_flash(struct usb_ep *ep, struct usb_request *req)
 
        strcpy(response, "FAILno flash device defined");
 #ifdef CONFIG_FASTBOOT_FLASH_MMC_DEV
-       fb_mmc_flash_write(cmd, (void *)CONFIG_FASTBOOT_BUF_ADDR,
+       fb_mmc_flash_write(cmd, fastboot_flash_session_id,
+                          (void *)CONFIG_FASTBOOT_BUF_ADDR,
                           download_bytes, response);
 #endif
+       fastboot_flash_session_id++;
        fastboot_tx_write_str(response);
 }
 #endif

diff --git a/include/aboot.h b/include/aboot.h
index a2b0694190d99ed8235f98c622a581e589f347e3..0382f5bd2639fecd498b7a2635ed5035381ee58d 100644 (file)
--- a/include/aboot.h
+++ b/include/aboot.h
@@ -32,4 +32,4 @@ static inline int is_sparse_image(void *buf)
 }
 
 int store_sparse_image(sparse_storage_t *storage, void *storage_priv,
-                      void *data);
+                      unsigned int session_id, void *data);

diff --git a/include/fb_mmc.h b/include/fb_mmc.h
index 402ba9b1b47079864a6d97d1863435380b84ae52..978a1395a185a31b5be5646f6d3042b8ac3d22fa 100644 (file)
--- a/include/fb_mmc.h
+++ b/include/fb_mmc.h
@@ -4,6 +4,7 @@
  * SPDX-License-Identifier:    GPL-2.0+
  */
 
-void fb_mmc_flash_write(const char *cmd, void *download_buffer,
-                       unsigned int download_bytes, char *response);
+void fb_mmc_flash_write(const char *cmd, unsigned int session_id,
+                       void *download_buffer, unsigned int download_bytes,
+                       char *response);
 void fb_mmc_erase(const char *cmd, char *response);