Hi Philip, On Fri, Nov 4, 2011 at 7:48 PM, Philip Balister <philip@xxxxxxxxxxxx> wrote: > On 11/03/2011 03:25 PM, Tony Lindgren wrote: >> * James <angweiyang@xxxxxxxxx> [111023 18:13]: >>> Dear all, >>> >>> I'm learning embedded linux development and need help on my task. >>> >>> I'm trying to communicate with a FPGA via the GPMC bus on my Overo FE >>> board and need assistance with writing a simple device driver & test >>> application that uses the GPMC bus to read & write a WORD size data >>> and also a BLOCK of WORD data to the FPGA. >>> >>> The FPGA-OMAP3530 will be use synchronous read/write over the 16-bit >>> datapath and CS 6. >>> The GPMC bus is shared with an Ethernet chip and NAND chip as per >>> Gumstix COM + TOBI/Chestnut design and these standard devices must >>> still work as per norm. >>> >>> I've been searching via GMANE for similar questions but some are >>> pointing to non-existence archives. >>> >>> I believe I have to develop a kernel device driver to register the >>> FPGA and from which will expose a device node for the test >>> application. >>> or is there a generic GPMC driver that does it? >>> >>> Can someone share with me similar layout and code so that I can base >>> my learning from a starting point? >>> >>> Many thanks in adv. >> >> Please take a look at the various arch/arm/mach-omap2/gpmc-*.c files. >> The biggest pain is to get the timings right. > > Also take a look at: > > https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2 > > Philip > I've been reading the codes from your e100-2.6.38-2 repo as suggested by your earlier replies to me in Gumstix Mailing List. (^^,) In usrp1_e_init() inside board-overo.c, GPMC_CS_CONFIG7 for both CS4 and CS6 are both written with 0x00. I couldn't understand the background/why behind this line of code as the Use-case in the TRM writes the base address of the device to it. Do you have some timing diagram or documents that explains the data flow / interactions / protocol between the FPGA and Overo as reference to the codes? Many many thanks in adv. -- Regards, James -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
