[ARM] S3C: Add UART FIFO selection during arch decompression

Add a configuration option to start the UART FIFOs during the
decompressions sequence to improve boot time when the bootloader
fails to enable the UART FIFOs.

For example, the SMDK6410 UBoot 1.1.6 leaves the FIFOs off.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c/include/plat/uncompress.h b/arch/arm/plat-s3c/include/plat/uncompress.h
index 8a8a927292e..2c39a309aeb 100644
--- a/arch/arm/plat-s3c/include/plat/uncompress.h
+++ b/arch/arm/plat-s3c/include/plat/uncompress.h
@@ -139,6 +139,28 @@ static void arch_decomp_error(const char *x)
 
 static void error(char *err);
 
+#ifdef CONFIG_S3C_BOOT_UART_FORCE_FIFO
+static inline void arch_enable_uart_fifo(void)
+{
+	u32 fifocon = uart_rd(S3C2410_UFCON);
+
+	if (!(fifocon & S3C2410_UFCON_FIFOMODE)) {
+		fifocon |= S3C2410_UFCON_RESETBOTH;
+		uart_wr(S3C2410_UFCON, fifocon);
+
+		/* wait for fifo reset to complete */
+		while (1) {
+			fifocon = uart_rd(S3C2410_UFCON);
+			if (!(fifocon & S3C2410_UFCON_RESETBOTH))
+				break;
+		}
+	}
+}
+#else
+#define arch_enable_uart_fifo() do { } while(0)
+#endif
+
+
 static void
 arch_decomp_setup(void)
 {
@@ -149,6 +171,12 @@ arch_decomp_setup(void)
 
 	arch_detect_cpu();
 	arch_decomp_wdog_start();
+
+	/* Enable the UART FIFOs if they where not enabled and our
+	 * configuration says we should turn them on.
+	 */
+
+	arch_enable_uart_fifo();
 }