This patch fixes a potentially serious issue related to USB which was discouvered by Martin Krause martin.krause@tqs.de and fixed for ARM920T. Martin wrote:
Turn off USB to prevent the host controller from writing to the SDRAM while Linux is booting. This could happen, because the HCCA (Host Controller Communication Area) lies within the SDRAM and the host controller writes continously to this area (as busmaster!), for example to increase the HccaFrameNumber variable, which happens every 1 ms.
This is a slightly modified version of the patch in order to shutdown USB when booting on all architectures.
Signed-off-by: Markus Klotzbuecher mk@denx.de --- common/cmd_bootm.c | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c index 959689e..f914815 100644 --- a/common/cmd_bootm.c +++ b/common/cmd_bootm.c @@ -36,6 +36,10 @@ #include <lmb.h> #include <asm/byteorder.h>
+#if (CONFIG_COMMANDS & CFG_CMD_USB) +#include <usb.h> +#endif + #ifdef CFG_HUSH_PARSER #include <hush.h> #endif @@ -213,6 +217,20 @@ int do_bootm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) */ iflag = disable_interrupts();
+#if (CONFIG_COMMANDS & CFG_CMD_USB) + /* + * turn off USB to prevent the host controller from writing to the + * SDRAM while Linux is booting. This could happen (at least for OHCI + * controller), because the HCCA (Host Controller Communication Area) + * lies within the SDRAM and the host controller writes continously to + * this area (as busmaster!). The HccaFrameNumber is for example + * updated every 1 ms within the HCCA structure in SDRAM! For more + * details see the OpenHCI specification. + */ + usb_stop(); +#endif + + #ifdef CONFIG_AMIGAONEG3SE /* * We've possible left the caches enabled during