[ARM] S3C: Add UART FIFO selection during arch decompression
authorBen Dooks <ben-linux@fluff.org>
Tue, 2 Dec 2008 19:34:52 +0000 (19:34 +0000)
committerBen Dooks <ben-linux@fluff.org>
Tue, 2 Dec 2008 19:34:52 +0000 (19:34 +0000)
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>

arch/arm/plat-s3c/Kconfig
arch/arm/plat-s3c/include/plat/uncompress.h

index e80a328..def0bb4 100644 (file)
@@ -57,6 +57,14 @@ config S3C_BOOT_ERROR_RESET
          Say y here to use the watchdog to reset the system if the
          kernel decompressor detects an error during decompression.
 
+config S3C_BOOT_UART_FORCE_FIFO
+       bool "Force UART FIFO on during boot process"
+       depends on PLAT_S3C
+       default y
+       help
+         Say Y here to force the UART FIFOs on during the kernel
+        uncompressor
+
 comment "Power management"
 
 config S3C2410_PM_DEBUG
index eeef32c..6061de8 100644 (file)
@@ -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();
 }