Hi Boris, > -----Original Message----- > From: Boris Brezillon [mailto:boris.brezillon@xxxxxxxxxxx] > Sent: Monday, December 10, 2018 4:39 PM > To: Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx> > Cc: Schrempf Frieder <frieder.schrempf@xxxxxxxxxx>; linux- > mtd@xxxxxxxxxxxxxxxxxxx; marek.vasut@xxxxxxxxx; broonie@xxxxxxxxxx; linux- > spi@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; robh@xxxxxxxxxx; > mark.rutland@xxxxxxx; shawnguo@xxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; computersforpeace@xxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v5 1/5] spi: spi-mem: Add driver for NXP FlexSPI controller > > On Mon, 10 Dec 2018 10:59:54 +0000 > Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx> wrote: > > > Hi Boris, > > > > > -----Original Message----- > > > From: Boris Brezillon [mailto:boris.brezillon@xxxxxxxxxxx] > > > Sent: Monday, December 10, 2018 4:20 PM > > > To: Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx> > > > Cc: Schrempf Frieder <frieder.schrempf@xxxxxxxxxx>; linux- > > > mtd@xxxxxxxxxxxxxxxxxxx; marek.vasut@xxxxxxxxx; broonie@xxxxxxxxxx; > > > linux- spi@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > > > robh@xxxxxxxxxx; mark.rutland@xxxxxxx; shawnguo@xxxxxxxxxx; > > > linux-arm- kernel@xxxxxxxxxxxxxxxxxxx; computersforpeace@xxxxxxxxx; > > > linux- kernel@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH v5 1/5] spi: spi-mem: Add driver for NXP FlexSPI > > > controller > > > > > > On Mon, 10 Dec 2018 10:43:56 +0000 > > > Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx> wrote: > > > > > > > > > Thus, in LUT preparation we have assigned only the base address. > > > > > > Now if I have assigned ahb_buf_size to FSPI_FLSHXXCR0 register > > > > > > then for > > > > > read/write data beyond limit of ahb_buf_size offset I get data corruption. > > > > > > > > > > Why would you do that? We have the ->adjust_op_size() exactly > > > > > for this reason, so, if someone tries to do a spi_mem_op with > > > > > data.nbytes > ahb_buf_size you should return an error. > > > > > > > > > Let me explain my implementation with example. If I have to write > > > > data of size > > > 0x100 bytes at offset 0x1200 for CS1, I would program as below: > > > > In func nxp_fspi_select_mem(), would set value of controller > > > > address space > > > size, memmap_phy_size, to FSPI_FLSHA2CR0 and rest all FSPI_FLSHXXCR0 as > 0. > > > > Value of memmap_phy_size is 0x10000000 i.e. 256 MB for my > > > > LX2160ARDB > > > target. > > > > Then in nxp_fspi_prepare_lut(), I would prepare LUT ADDR with > > > > address length > > > requirement 3/4 byte for NOR or 1/2/3/4 bytes for NAND flash. > > > > Also for LUT_NXP_WRITE would program data bytes as 0. > > > > > > > > Then inside func nxp_fspi_do_op(), set register FSPI_IPCR0 as the > > > > address offset i.e. 0x1200 and in register FSPI_IPCR1 program the > > > > data size to write i.e. 0x100 > > > > > > > > If, as suggested if I tries to mark value of register > > > > FSPI_FLSHA2CR0 equal to > > > ahb_buf_size (0x800), then access for address 0x1200 gives me wrong > > > data. This is because as per the controller specification access to > > > flash connected at CS1 can be performed under range of FSPI_ FLSHA1CR0 > and FSPI_ FLSHA2CR0. > > > > > > Don't you have a way to set an offset to apply to the address > > > accessed through the AHB? And if you don't, how will it work if your > > > mapping is smaller than the flash size? > > > > Write operations are triggered using IP commands instead of AHB command. > > For Read AHB command is used and in this we are adding the offset when > performing memcpy_fromIO operation > > memcpy_fromio(op->data.buf.in, (f->ahb_addr + op->addr.val), > > len); > > > > AHB/IP operations are independent of the way how CS got selected. CS > selection depends, e.g. CS1 on the value of register FSPI_FLSHA1CR0 and > FSPI_FLSHA2CR0. > > > > Mapping can never going to be smaller than the connected flash size as per > discussion with the Board design team and if it's possible by user manually > changes the non-soldered part then flash area beyond complete mapping is not > accessible. > > On LX2160ARDB, with mapping of 256MB, for now we are having 4 flash > devices connected with size as 64 MB. If user wants he can have only one single > flash with flash size of 256MB. > > Given that the dirmap interface has now been merged and the MTD side of > things is soon to be merged, I'd recommend you to implement it in your > v6 and only use non-AHB accesses for the ->exec_op() implementation. This would going to be performance hit if I would use non-AHB accesses for ->exec_op(). In read in v5 I am using AHB mode for read if read data size is greater than rxfifo size and if its less than rxfifo then use IP mode for read. -- Regards Yogesh Gaur
