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* Switched default PCI speed for 8540 ADS back to 33MHz
* Added comments and a printf to warn that PCI-X won't
work at 33MHz
Patch by Andy Fleming 17-Mar-2006

Signed-off-by: Andy Fleming <afleming@freescale.com>

Matthew McClintock 18 years ago
parent
commit
38433ccc58
3 changed files with 11 additions and 1 deletions
  1. 3 0
      cpu/mpc85xx/pci.c
  2. 3 0
      doc/README.mpc85xxads
  3. 5 1
      include/configs/MPC8540ADS.h

+ 3 - 0
cpu/mpc85xx/pci.c

@@ -72,6 +72,9 @@ pci_mpc85xx_init(struct pci_controller *board_hose)
 
 	if (!(gur->pordevsr & PORDEVSR_PCI)) {
 		/* PCI-X init */
+		if (CONFIG_SYS_CLK_FREQ < 66000000)
+			printf("PCI-X will only work at 66 MHz\n");
+
 		reg16 = PCI_X_CMD_MAX_SPLIT | PCI_X_CMD_MAX_READ
 			| PCI_X_CMD_ERO | PCI_X_CMD_DPERR_E;
 		pci_hose_write_config_word(hose, dev, PCIX_COMMAND, reg16);

+ 3 - 0
doc/README.mpc85xxads

@@ -100,6 +100,9 @@ Updated 13-July-2004 Jon Loeliger
 	SW7[1:4]  =    0101 =  5    => 5 x 66	 = 330	CCB Sysclk
 	SW7[5:6]  =	 01	    => 5:2 x 330 = 825	Core clock
 
+    In order to use PCI-X (only in the first PCI slot.  The one with
+    the RIO connector), you need to set SW1[4] (config) to 1 (off).
+    Also, configure the board to run PCI at 66 MHz.
 
 2. MEMORY MAP TO WORK WITH LINUX KERNEL
 

+ 5 - 1
include/configs/MPC8540ADS.h

@@ -68,10 +68,14 @@
  * The board, however, can run at 66MHz.  In any event, this value
  * must match the settings of some switches.  Details can be found
  * in the README.mpc85xxads.
+ *
+ * XXX -- Can't we run at 66 MHz, anyway?  PCI should drop to
+ * 33MHz to accommodate, based on a PCI pin.
+ * Note that PCI-X won't work at 33MHz.
  */
 
 #ifndef CONFIG_SYS_CLK_FREQ
-#define CONFIG_SYS_CLK_FREQ	66000000
+#define CONFIG_SYS_CLK_FREQ	33000000
 #endif