When building u-boot with the latest Linaro toolchain, such as gcc-linaro-4.9, u-boot will hang at PCIE init on LS1021A platform. The issue is reported on http://comments.gmane.org/gmane.linux.linaro.toolchain/5163.
As volatile is missing when reading SCTLR register and SCTLR is set according to the value read from SCTLR, it causes CR_M bit is not set. Then MMU is not enabled, the access to VA for PCIE fails.
This patch will add the missing volatile for reading SCTLR register.
Signed-off-by: Alison Wang alison.wang@freescale.com --- arch/arm/include/asm/system.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 89f2294..f5096dc 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -155,7 +155,7 @@ void flush_l3_cache(void); static inline unsigned int get_cr(void) { unsigned int val; - asm("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc"); + asm volatile("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc"); return val; }