ppc4xx: Move 405EP pci code from cpu_init_f() to __pci_pre_init()

This patch moves some basic PCI initialisation from the 4xx cpu_init_f()
to cpu/ppc4xx/4xx_pci.c.

The original cpu_init_f() function enabled the 405EP's internal arbiter
in all situations. Also the HCE bit in cpc0_pci is always set.
The first is not really wanted for PCI adapter designs and the latter
is a general bug for PCI adapter U-Boots. Because it enables
PCI configuration by the system CPU even when the PCI configuration has
not been setup by the 405EP. The one and only correct place is
in pci_405gp_init() (see "Set HCE bit" comment).

So for compatibility reasons the arbiter is still enabled in any case,
but from weak pci_pre_init() so that it can be replaced by board specific
code.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Signed-off-by: Stefan Roese <sr@denx.de>

cpu/ppc4xx/4xx_pci.c

@@ -87,6 +87,20 @@ DECLARE_GLOBAL_DATA_PTR;
  */
 int __pci_pre_init(struct pci_controller *hose)
 {
+#if defined (CONFIG_405EP)
+	/*
+	 * Enable the internal PCI arbiter by default.
+	 *
+	 * On 405EP CPUs the internal arbiter can be controlled
+	 * by the I2C strapping EEPROM. If you want to do so
+	 * or if you want to disable the arbiter pci_pre_init()
+	 * must be reimplemented without enabling the arbiter.
+	 * The arbiter is enabled in this place because of
+	 * compatibility reasons.
+	 */
+	mtdcr(cpc0_pci, mfdcr(cpc0_pci) | CPC0_PCI_ARBIT_EN);
+#endif /* CONFIG_405EP */
+
 	return 1;
 }
 int pci_pre_init(struct pci_controller *hose) __attribute__((weak, alias("__pci_pre_init")));

cpu/ppc4xx/cpu_init.c

@@ -174,11 +174,6 @@ cpu_init_f (void)
 	 * Set EMAC noise filter bits
 	 */
 	mtdcr(cpc0_epctl, CPC0_EPRCSR_E0NFE | CPC0_EPRCSR_E1NFE);
-
-	/*
-	 * Enable the internal PCI arbiter
-	 */
-	mtdcr(cpc0_pci, mfdcr(cpc0_pci) | CPC0_PCI_HOST_CFG_EN | CPC0_PCI_ARBIT_EN);
 #endif /* CONFIG_405EP */
 
 #if defined(CONFIG_SYS_4xx_GPIO_TABLE)