MPC85xxCDS: Fix missing LCRR_DBYP bits for 66-133MHz LBC
authorPaul Gortmaker <paul.gortmaker@windriver.com>
Fri, 16 Dec 2011 22:31:53 +0000 (17:31 -0500)
committerKumar Gala <galak@kernel.crashing.org>
Wed, 11 Jan 2012 19:57:56 +0000 (13:57 -0600)
These boards were meaning to deploy this value:

  #define LCRR_DBYP        0x80000000

but were missing a zero, and hence toggling a bit that
lands in an area marked as reserved in the 8548 reference
manual.

According to the documentation, LCRR_DBYP should be used as:

   PLL bypass. This bit should be set when using low bus
   clock frequencies if the PLL is unable to lock.  When in
   PLL bypass mode, incoming data is captured in the middle
   of the bus clock cycle.  It is recommended that PLL bypass
   mode be used at frequencies of 83 MHz or less.

So the impact would most likely be undefined behaviour for
LBC peripherals on boards that were running below 83MHz LBC.
Looking at the actual u-boot code, the missing DBYP bit was
meant to be deployed as follows:

      Between 66 and 133, the DLL is enabled with an
      override workaround.

In the future, we'll convert all boards to use the symbolic
DBYP constant to avoid these "count the zeros" problems, but
for now, just fix the impacted boards.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
board/freescale/mpc8541cds/mpc8541cds.c
board/freescale/mpc8555cds/mpc8555cds.c

index d127137ddb05f440d334ee6c0c6e6fda8a395683..532d32ac7cb19335960f92edd4f2ac087249c7e4 100644 (file)
@@ -275,7 +275,7 @@ local_bus_init(void)
                lbc->lcrr &= (~0x80000000);             /* DLL Enabled */
 
        } else {
-               lbc->lcrr &= (~0x8000000);      /* DLL Enabled */
+               lbc->lcrr &= (~0x80000000);     /* DLL Enabled */
                udelay(200);
 
                /*
index 48ede9840f40ca83b42726c445f6c844d8e12d77..3361614de5f7b2961514be207bab0a165cf0c170 100644 (file)
@@ -273,7 +273,7 @@ local_bus_init(void)
                lbc->lcrr &= (~0x80000000);             /* DLL Enabled */
 
        } else {
-               lbc->lcrr &= (~0x8000000);      /* DLL Enabled */
+               lbc->lcrr &= (~0x80000000);     /* DLL Enabled */
                udelay(200);
 
                /*