ppc4xx: Fix 460EX errata with CPU lockup upon high AHB traffic

This patch implements a fix provided by AMCC so that the lockup upon
simultanious traffic on AHB USB OTG, USB 2.0 and SATA doesn't occur
anymore:

Set SDR0_AHB_CFG[A2P_INCR4] (bit 24) and clear SDR0_AHB_CFG[A2P_PROT2]
(bit 25) for a new 460EX errata regarding concurrent use of AHB USB OTG,
USB 2.0 host and SATA.

This errata is not officially available yet. I'll update the comment
to add the errata number later.

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

cpu/ppc4xx/cpu_init.c

@@ -138,8 +138,8 @@ void reconfigure_pll(u32 new_cpu_freq)
 void
 cpu_init_f (void)
 {
-#if defined(CONFIG_WATCHDOG)
-	unsigned long val;
+#if defined(CONFIG_WATCHDOG) || defined(CONFIG_460EX)
+	u32 val;
 #endif
 	reconfigure_pll(CFG_PLL_RECONFIG);
 
@@ -272,6 +272,22 @@ cpu_init_f (void)
 
 	reset_4xx_watchdog();
 #endif /* CONFIG_WATCHDOG */
+
+#if defined(CONFIG_460EX)
+	/*
+	 * Set SDR0_AHB_CFG[A2P_INCR4] (bit 24) and
+	 * clear SDR0_AHB_CFG[A2P_PROT2] (bit 25) for a new 460EX errata
+	 * regarding concurrent use of AHB USB OTG, USB 2.0 host and SATA
+	 */
+	mfsdr(SDR0_AHB_CFG, val);
+	val |= 0x80;
+	val &= ~0x40;
+	mtsdr(SDR0_AHB_CFG, val);
+	mfsdr(SDR0_USB2HOST_CFG, val);
+	val &= ~0xf00;
+	val |= 0x400;
+	mtsdr(SDR0_USB2HOST_CFG, val);
+#endif /* CONFIG_460EX */
 }
 
 /*

include/ppc440.h

@@ -2471,6 +2471,8 @@
 
 #define AHB_TOP			0xA4
 #define AHB_BOT			0xA5
+#define SDR0_AHB_CFG		0x370
+#define SDR0_USB2HOST_CFG	0x371
 #endif /* CONFIG_460EX || CONFIG_460GT */
 
 #define SDR0_SDCS_SDD			(0x80000000 >> 31)