From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: Query: spi-nor: dummy buswidth calculation Date: Tue, 4 Sep 2018 14:30:28 +0200 Message-ID: <20180904143028.4629fe10@bbrezillon> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "juliensu@mxic.com.tw" , "zhengxunli@mxic.com.tw" , "linux-mtd@lists.infradead.org" , "masonccyang@mxic.com.tw" , "linux-spi@vger.kernel.org" To: Yogesh Narayan Gaur Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+gldm-linux-mtd-36=gmane.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org +Macronix team On Tue, 4 Sep 2018 09:28:11 +0000 Yogesh Narayan Gaur wrote: > Hi Boris, > > I have query regarding dummy bus width calculation for the read commands, added in the patch series [1] > > In func m25p80_read(), dummy.buswidth is being assigned as > + op.dummy.buswidth = op.addr.buswidth; > > Above, buswidth for dummy commands are being assigned and are marked equal to the buswidth of the address command. > This is true for case when we are doing operation in 1-4-4 or 1-2-2 protocol where data as well as address are running on same data lines and having same buswidth. > > I am adding support of octal commands in framework and for this needs to add support for 1-1-8 protocol for Micron flash MT35XU512ABA1G12. > For octal command, 7Ch, flash is sending data and the dummy on the 8 data lines and address on 1 data line. Interesting. Macronix is also working on octo-mode support. I think we should sync instead of duplicating the work. > > If I do below code change, then I am getting correct data else there is data corruption only in the first byte read. > - op.dummy.buswidth = op.addr.buswidth; > + op.dummy.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto); Regarding this particular aspect, I just followed what was done before the conversion to spi_mem_exec_op(). Maybe it was not correct though. Regards, Boris ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/