From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Mon, 17 Aug 2015 19:56:13 +0200 Subject: [U-Boot] spi-nor: Choices of choosing bank or 4-byte addressing In-Reply-To: References: Message-ID: <201508171956.13254.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Monday, August 17, 2015 at 03:54:50 PM, Jagan Teki wrote: > For accessing SPI-NOR flash's with > 16MiB we have two choices like > Bank/Extended and 4-byte addressing register support. > > Status in u-boot: > 1) BAR (Bank/Extended) > - Added support in u-boot already, tested > > 2) 4-byte addressing > - No support yet > - Hou Zhiqiang sent patches, those are review. Patchwork or gmane link would really help. > Ideally we may support any one of them, but there is some situation > where (q)spi controller can only support 3-byte addressing (not > supporting 4-byte addressing) but the connected flash could be > > 16MiB, example: Xilinx Zynq QSPI > > In this case as controller not supporting 4-byte commands we must use > BAR for accessing > 16MiB flash's. So the controller in QSPI controller in Zynq is explicitly broken ? > Siva, suggested like from controller driver (spi_slave {} ) we need to > inform the flash about addressing width, so-that flash can configure > accordingly. Absolutelly not, you're mixing together SPI driver and a SPI NOR driver. > I indeed agree with this, and if we have both supported then the flash > will configure accordingly with controller check. > > Pls- share for any other thoughts. > > thanks! Best regards, Marek Vasut