powerpc/mpc85xx: Add workaround for erratum A007212
Erratum A007212 for DDR is about a runaway condition for DDR PLL
oscilliator. Please refer to erratum document for detail.
For this workaround to work, DDR PLL needs to be disabled in RCW.
However, u-boot needs to know the expected PLL ratio. We put the
ratio in a reserved field RCW[18:23]. U-boot will skip this workaround
if DDR PLL ratio is set, or the reserved field is not set.
Workaround for erratum A007212 applies to selected versions of
B4/T4 SoCs. It is safe to apply the workaround to all versions. It
is helpful for upgrading SoC without changing u-boot. In case DDR
PLL is disabled by RCW (part of the erratum workaround), we need this
u-boot workround to bring up DDR clock.
Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/arch/powerpc/include/asm/immap_85xx.h b/arch/powerpc/include/asm/immap_85xx.h
index 4bda0f1..1ec3033 100644
--- a/arch/powerpc/include/asm/immap_85xx.h
+++ b/arch/powerpc/include/asm/immap_85xx.h
@@ -1739,6 +1739,8 @@
#ifdef CONFIG_SYS_FSL_QORIQ_CHASSIS2
#define FSL_CORENET_RCWSR0_MEM_PLL_RAT_SHIFT 16
+/* use reserved bits 18~23 as scratch space to host DDR PLL ratio */
+#define FSL_CORENET_RCWSR0_MEM_PLL_RAT_RESV_SHIFT 8
#define FSL_CORENET_RCWSR0_MEM_PLL_RAT_MASK 0x3f
#if defined(CONFIG_PPC_T4240) || defined(CONFIG_PPC_T4160)
#define FSL_CORENET2_RCWSR4_SRDS1_PRTCL 0xfc000000