ppc4xx: (Re-)Enable CONFIG_PCI_PNP on AMCC 440EPx Sequoia

The 440EPx has a problem when the PCI_CACHE_LINE_SIZE register is
set to non-zero, because it doesn't support MRM (memory-read-
multiple) correctly. We now added the possibility to configure
this register in the board config file, so that the default value
of 8 can be overridden.

Here the details of this patch:

o drivers_pci_auto.c: introduce CFG_PCI_CACHE_LINE_SIZE to allow
  board-specific settings. As an example the sequoia board requires 0.
  Idea from Stefan Roese <sr@denx.de>.
o board/amcc/sequoia/init.S: add a TLB mapping at 0xE8000000 for the
  PCI IO-space. Obtained from Stefan Roese <sr@denx.de>.
o include/configs/sequoia.h: turn CONFIG_PCI_PNP back on and set
  CFG_PCI_CACHE_LINE_SIZE to 0.

Signed-off-by: Gary Jennejohn <garyj@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>

board/amcc/sequoia/init.S

@@ -126,6 +126,9 @@ tlbtab:
 	/* TLB-entry for peripherals */
 	tlbentry( 0xEF000000, SZ_16M, 0xEF000000, 1, AC_R|AC_W|AC_X|SA_G|SA_I)
 
+	/* TLB-entry PCI IO Space - from sr@denx.de */
+	tlbentry(0xE8000000, SZ_64K, 0xE8000000, 1, AC_R|AC_W|AC_X|SA_G|SA_I)
+
 	tlbtab_end
 
 #if defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)

drivers/pci_auto.c

@@ -28,6 +28,11 @@
 
 #define	PCIAUTO_IDE_MODE_MASK		0x05
 
+/* the user can define CFG_PCI_CACHE_LINE_SIZE to avoid problems */
+#ifndef CFG_PCI_CACHE_LINE_SIZE
+#define CFG_PCI_CACHE_LINE_SIZE	8
+#endif
+
 /*
  *
  */
@@ -150,7 +155,8 @@ void pciauto_setup_device(struct pci_controller *hose,
 	}
 
 	pci_hose_write_config_dword(hose, dev, PCI_COMMAND, cmdstat);
-	pci_hose_write_config_byte(hose, dev, PCI_CACHE_LINE_SIZE, 0x08);
+	pci_hose_write_config_byte(hose, dev, PCI_CACHE_LINE_SIZE,
+		CFG_PCI_CACHE_LINE_SIZE);
 	pci_hose_write_config_byte(hose, dev, PCI_LATENCY_TIMER, 0x80);
 }
 

include/configs/sequoia.h

@@ -400,7 +400,8 @@
  *----------------------------------------------------------------------*/
 /* General PCI */
 #define CONFIG_PCI			/* include pci support	        */
-#undef CONFIG_PCI_PNP			/* do (not) pci plug-and-play   */
+#define CONFIG_PCI_PNP			/* do pci plug-and-play   */
+#define CFG_PCI_CACHE_LINE_SIZE	0 /* to avoid problems with PNP */
 #define CONFIG_PCI_SCAN_SHOW		/* show pci devices on startup  */
 #define CFG_PCI_TARGBASE        0x80000000 /* PCIaddr mapped to CFG_PCI_MEMBASE*/