On Thu, Mar 01, 2018 at 03:23:33PM +0100, Giorgio Dal Molin wrote: > Hi, > > working with the TI AM335x Evaluation Module I noticed that the function > am335x_sdram_size() always returns 0 instead of the computed sdram size. > > I could trace back the problem to the fact that the function does its > computation based on the value of the register CM_EMIF_SDRAM_CONFIG > (addr. 0x44e10110), but this register is not written to by the function > am33xx_config_sdram() and just returns its initial value (0). > The datasheet says CM_EMIF_SDRAM_CONFIG should have the same value as > AM33XX_EMIF4_0_REG(SDRAM_CONFIG) (addr. 0x4c000008) CM_EMIF_SDRAM_CONFIG is written when regs->zq_config is set and if it's set then indeed the same value is written there as also written to AM33XX_EMIF4_0_REG(SDRAM_CONFIG). > > To conclude, to fix the problem with am335x_sdram_size() you can either > use AM33XX_EMIF4_0_REG(SDRAM_CONFIG) instead of CM_EMIF_SDRAM_CONFIG > in am335x_sdram_size(). > > or > > initialize CM_EMIF_SDRAM_CONFIG in am33xx_config_sdram() with the same value > as AM33XX_EMIF4_0_REG(SDRAM_CONFIG) (regs->sdram_config) I'm fine with either way. Maybe the datasheet gives us a hint which way to choose? Why is CM_EMIF_SDRAM_CONFIG only written when regs->zq_config is set? Is this correct? Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
