Blackfin: catch hardware errors earlier during booting

Allow hardware errors to be caught during early portions of booting, and
leave something in the shadow console that people can use to debug their
system with (to be printed out by the bootloader on next reset).

This enables the hardare error interrupts in head.S, allowing us to find
hardware errors when they happen (well, as much as you can with a hardware
error) and prints out the trace if it is enabled.  This will catch errors
(like booting the wrong image on a 533) which previously resulted in a
infinite loop/hang, as well as random hardware errors before before
setup_arch().

To disable this debug only feature - turn off EARLY_PRINTK.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/bfin_dma_5xx.c b/arch/blackfin/kernel/bfin_dma_5xx.c
index 9f9b828..14dea1a 100644
--- a/arch/blackfin/kernel/bfin_dma_5xx.c
+++ b/arch/blackfin/kernel/bfin_dma_5xx.c
@@ -19,6 +19,7 @@
 #include <asm/cacheflush.h>
 #include <asm/dma.h>
 #include <asm/uaccess.h>
+#include <asm/early_printk.h>
 
 /*
  * To make sure we work around 05000119 - we always check DMA_DONE bit,
@@ -236,6 +237,7 @@ void blackfin_dma_resume(void)
  */
 void __init blackfin_dma_early_init(void)
 {
+	early_shadow_stamp();
 	bfin_write_MDMA_S0_CONFIG(0);
 	bfin_write_MDMA_S1_CONFIG(0);
 }
@@ -246,6 +248,8 @@ void __init early_dma_memcpy(void *pdst, const void *psrc, size_t size)
 	unsigned long src = (unsigned long)psrc;
 	struct dma_register *dst_ch, *src_ch;
 
+	early_shadow_stamp();
+
 	/* We assume that everything is 4 byte aligned, so include
 	 * a basic sanity check
 	 */
@@ -300,6 +304,8 @@ void __init early_dma_memcpy(void *pdst, const void *psrc, size_t size)
 
 void __init early_dma_memcpy_done(void)
 {
+	early_shadow_stamp();
+
 	while ((bfin_read_MDMA_S0_CONFIG() && !(bfin_read_MDMA_D0_IRQ_STATUS() & DMA_DONE)) ||
 	       (bfin_read_MDMA_S1_CONFIG() && !(bfin_read_MDMA_D1_IRQ_STATUS() & DMA_DONE)))
 		continue;