Hi,
I am in the process of creating a U-Boot port for Cogent CSB272 board (PPC405)
Working from U-Boot 1.0.0 tarball sources, I got CSB272 running. I still have some work done for it so I am not submitting CSB272 board support yet. Maybe next week or so after I complete work on it and make sure Linux boots OK.
Anyway, CSB272 board has Intel LXT971A PHY. I could not get this PHY working initially. After investigation I have found:
1) LXT971A requires some recovery time (~300usec) before any register access after reset. This is documented in the datasheet on page 70, table 40.
2) LXT971A requires some time after command is issued before polling EMAC_STACR_OC is valid. I am not sure why this is needed but it is needed for this particular PHY or otherwise it does not work. I have found this to be minimum 32usec. I used 40usec for some safety margin.
Thus, to get it working I had to patch two shared files:
cpu/ppc4xx/miiphy.c common/miiphyutil.c
The code added are conditional for each change and without those macro definitions it compiles exactly as it is right now. The macros are as follows (from my include/configs/csb272.h):
#define CONFIG_PHY_CMD_DELAY 40 /* PHY COMMAND delay */ /* 32usec min. for LXT971A */ #define CONFIG_PHY_RESET_DELAY 300 /* PHY RESET recovery delay */
Here is the patch (I can resend it as an attachment if format is broken)
--- u-boot-1.0.0/cpu/ppc4xx/miiphy.c 2003-09-02 18:08:13.000000000 -0500 +++ u-boot/cpu/ppc4xx/miiphy.c 2004-01-11 02:56:16.000000000 -0600 @@ -110,7 +110,9 @@ int miiphy_read (unsigned char addr, uns #if 0 /* test-only */ printf ("a2: write: EMAC_STACR=0x%0x\n", sta_reg); /* test-only */ #endif - +#if defined(CONFIG_PHY_CMD_DELAY) + udelay(CONFIG_PHY_CMD_DELAY); /* Intel LXT971A needs this */ +#endif sta_reg = in32 (EMAC_STACR); i = 0; while ((sta_reg & EMAC_STACR_OC) == 0) { @@ -166,6 +168,9 @@ int miiphy_write (unsigned char addr, un memcpy (&sta_reg, &value, 2); /* put in data */
out32 (EMAC_STACR, sta_reg); +#if defined(CONFIG_PHY_CMD_DELAY) + udelay(CONFIG_PHY_CMD_DELAY); /* Intel LXT971A needs this */ +#endif
/* wait for completion */ i = 0; --- u-boot-1.0.0/common/miiphyutil.c 2003-10-08 17:33:00.000000000 -0500 +++ u-boot/common/miiphyutil.c 2004-01-11 22:42:42.249886108 -0600 @@ -103,6 +103,9 @@ int miiphy_reset (unsigned char addr) return (-1); }
+#if defined(CONFIG_PHY_RESET_DELAY) + udelay(CONFIG_PHY_RESET_DELAY); /* Intel LXT971A needs this */ +#endif /* * Poll the control register for the reset bit to go to 0 (it is * auto-clearing). This should happen within 0.5 seconds per the