Force UARTBAUD on before uncompressing.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>

Index: linux-2.6.22/include/asm-arm/arch-ep93xx/uncompress.h
===================================================================
--- linux-2.6.22.orig/include/asm-arm/arch-ep93xx/uncompress.h
+++ linux-2.6.22/include/asm-arm/arch-ep93xx/uncompress.h
@@ -77,9 +77,56 @@ static void ethernet_reset(void)
 }
 
 
+/*
+ * Some bootloaders don't turn on the UARTBAUD bit, which means that
+ * the UARTs will be running off a divided 7.3728 MHz clock instead of
+ * the 14.7456 MHz peripheral clock when linux boots.
+ *
+ * We detect that condition here and fix it by turning on UARTBAUD, and
+ * then reprogramming the divisors on all enabled UARTs to twice what
+ * they were before we turned UARTBAUD on, to preserve the programmed
+ * baud rate.
+ */
+#define PHYS_SYSCON_CLOCK_CONTROL	0x80930004
+#define SYSCON_CLOCK_UARTBAUD		0x20000000
+#define PHYS_UART1_BASE			0x808c0000
+#define PHYS_UART2_BASE			0x808d0000
+#define PHYS_UART3_BASE			0x808e0000
+
+static void uart_divisor_times_two(unsigned int base)
+{
+	u16 divisor;
+
+	divisor = __raw_readb(base + 0x0c) << 8;
+	divisor |= __raw_readb(base + 0x10);
+	if (divisor) {
+		divisor = (2 * (divisor + 1)) - 1;
+		__raw_writeb(divisor >> 8, base + 0x0c);
+		__raw_writeb(divisor & 0xff, base + 0x10);
+		__raw_writeb(__raw_readb(base + 0x08), base + 0x08);
+	}
+}
+
+static void fix_uart_base(void)
+{
+	unsigned int v;
+
+	v = __raw_readl(PHYS_SYSCON_CLOCK_CONTROL);
+	if ((v & SYSCON_CLOCK_UARTBAUD) == 0) {
+		v |= SYSCON_CLOCK_UARTBAUD;
+		__raw_writel(v, PHYS_SYSCON_CLOCK_CONTROL);
+
+		uart_divisor_times_two(PHYS_UART1_BASE);
+		uart_divisor_times_two(PHYS_UART2_BASE);
+		uart_divisor_times_two(PHYS_UART3_BASE);
+	}
+}
+
+
 static void arch_decomp_setup(void)
 {
 	ethernet_reset();
+	fix_uart_base();
 }
 
 #define arch_decomp_wdog()