AM335X GPMC 地址数据总线复用问题

zhongchen zhao

Other Parts Discussed in Thread: AM3354

使用AM3354的GPMC总线异步方式与FPGA进行通信，用的是linux 4.4代码。

在设备树中已配置了相关引脚的复用方式。（部分引脚与NAND FLASH复用，未在此列出）

            0x20 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad8.gpmc_ad8 */
           0x24 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad9.gpmc_ad9 */
           0x28 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad10.gpmc_ad10 */
           0x2c (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad11.gpmc_ad11 */
           0x30 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad12.gpmc_ad12 */
           0x34 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad13.gpmc_ad13 */
           0x38 (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad14.gpmc_ad14 */
           0x3c (PIN_INPUT_PULLUP | MUX_MODE0)   /* gpmc_ad15.gpmc_ad15 */
           0x84 (PIN_OUTPUT | MUX_MODE0)       /* gpmc_csn2.gpmc_csn2 */

在设备树中已设置异步方式，16位数据，address-data复用及相关的时序：

fpga@2,2 {
       reg = <2 0 0x400>;
       compatible = "fpga-dpram";
       bank-width = <2>; /* 16 bit mode */

       gpmc,mux-add-data = <2>; /* address-data multiplexing */
       gpmc,cs-on-ns = <0>;
       gpmc,cs-rd-off-ns = <60>;
       gpmc,cs-wr-off-ns = <60>;
       gpmc,adv-on-ns = <0>;
       gpmc,adv-rd-off-ns = <20>;
       gpmc,adv-wr-off-ns = <20>;
       gpmc,we-on-ns = <20>;
       gpmc,we-off-ns = <50>;
       gpmc,oe-on-ns = <20>;
       gpmc,oe-off-ns = <50>;
       gpmc,rd-cycle-ns = <60>;
       gpmc,wr-cycle-ns = <60>;
   };