1*4882a593SmuzhiyunU-Boot for Freescale i.MX5x 2*4882a593Smuzhiyun 3*4882a593SmuzhiyunThis file contains information for the port of U-Boot to the Freescale 4*4882a593Smuzhiyuni.MX5x SoCs. 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun1. CONFIGURATION OPTIONS/SETTINGS 7*4882a593Smuzhiyun--------------------------------- 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun1.1 CONFIG_MX51_PLL_ERRATA: Workaround for i.MX51 PLL errata. 10*4882a593Smuzhiyun This option should be enabled by all boards using the i.MX51 silicon 11*4882a593Smuzhiyun version up until (including) 3.0 running at 800MHz. 12*4882a593Smuzhiyun The PLL's in the i.MX51 processor can go out of lock due to a metastable 13*4882a593Smuzhiyun condition in an analog flip-flop when used at high frequencies. 14*4882a593Smuzhiyun This workaround implements an undocumented feature in the PLL (dither 15*4882a593Smuzhiyun mode), which causes the effect of this failure to be much lower (in terms 16*4882a593Smuzhiyun of frequency deviation), avoiding system failure, or at least decreasing 17*4882a593Smuzhiyun the likelihood of system failure. 18*4882a593Smuzhiyun 19*4882a593Smuzhiyun1.2 CONFIG_SYS_MAIN_PWR_ON: Trigger MAIN_PWR_ON upon startup. 20*4882a593Smuzhiyun This option should be enabled for boards having a SYS_ON_OFF_CTL signal 21*4882a593Smuzhiyun connected to GPIO1[23] and triggering the MAIN_PWR_ON signal like in the 22*4882a593Smuzhiyun reference designs. 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun2. CONVENTIONS FOR FUSE ASSIGNMENTS 25*4882a593Smuzhiyun----------------------------------- 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun2.1 MAC Address: It is stored in the words 9 to 14 of fuse bank 1, using the 28*4882a593Smuzhiyun natural MAC byte order (i.e. MSB first). 29*4882a593Smuzhiyun 30*4882a593Smuzhiyun This is an example how to program an example MAC address 01:23:45:67:89:ab 31*4882a593Smuzhiyun into the eFuses. Assure that the programming voltage is available and then 32*4882a593Smuzhiyun execute: 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun => fuse prog -y 1 9 01 23 45 67 89 ab 35*4882a593Smuzhiyun 36*4882a593Smuzhiyun After programming a MAC address, consider locking the MAC fuses. This is 37*4882a593Smuzhiyun done by programming the MAC_ADDR_LOCK fuse, which is bit 4 of word 0 in 38*4882a593Smuzhiyun bank 1: 39*4882a593Smuzhiyun 40*4882a593Smuzhiyun => fuse prog -y 1 0 10 41