From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Tue, 20 Oct 2015 15:41:28 -0400 Subject: [U-Boot] [PATCH v2 07/14] fastboot: Implement flashing session counter In-Reply-To: <1444912462-3949-8-git-send-email-maxime.ripard@free-electrons.com> References: <1444912462-3949-1-git-send-email-maxime.ripard@free-electrons.com> <1444912462-3949-8-git-send-email-maxime.ripard@free-electrons.com> Message-ID: <20151020194128.GC23893@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Thu, Oct 15, 2015 at 02:34:15PM +0200, Maxime Ripard wrote: > 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 Reviewed-by: Tom Rini -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: