Hi For A13-OLinuxino till now we conservatively used the Linux-Sunxi uboot, but we recently got new lot of Samsung memories and we decided to tweak some parameters for this DDR in Linux-Sunxi uboot and found problems. As this uboot is with status not maintained anymore I will not discuss the problems, as probably no one will spend time on it, so we wisely decided to move to mainline uboot :) but it seems there are other issues to address.
The PLL5 and PLL6 values are changed and this cause problems, this is what we found so far: 1. mainline u-boot ================= 1.1 pll5 address 0x01c20020, value 0xb1049091 - P=1, N=16, K=2, M=2. The PLL5 output for DDR = (24MHz*N*K)/M. DDR=24*16*2/2 = 384MHz The PLL5 output for other module = (24MHz*N*K)/P. DDR=24*16*2/1 = 768MHz - This high frequency cause LCDs connected to the board to flicker 1.2 pll6 address 0x01c20028, value 0xA1009900 - N=25, K=1, M=1 The PLL6 output is (24MHz*N*K)/M/2 = 24*25*1/1/2 = 300MHz 1.3 MBUS clock address 0x01c2015c, value 0x81000001 - MBUS clock source is PLL6/2 = 300/2 = 150MHz - This is connected to PLL6 setup, at this 150 Mhz the board cant play video smoothly and sometimes drop video packets when the video is playing 2. sunxi u-boot ================= 1.1 pll5 address 0x01c20020, value 0xb1049091 - P=2, N=17, K=2, M=2. The PLL5 output for DDR = (24MHz*N*K)/M. DDR=24*17*2/2 = 408MHz The PLL5 output for other module = (24MHz*N*K)/P. DDR=24*16*2/2 = 408MHz - this frequency was OK, There is no problem with LCD flickering, why the frequency increase was necessary? 1.2 pll6 address 0x01c20028, value 0xA1009900 - N=25, K=1, M=1 The PLL6 output is (24MHz*N*K)/M/2 = 24*25*1/1/2 = 300MHz 1.3 about MBUS clock address 0x01c2015c, value 0x82000001 - MBUS clock source is PLL5/2 = 408/2 = 204MHz - at this frequency No packet drop when the video is playing Can you tell me the reasons for the PLL5 and PLL6 frequency changes to mainline uboot? Best regards Tsvetan -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
