diff options
| author | Dave Liu <daveliu@freescale.com> | 2008-10-23 21:18:53 +0800 |
|---|---|---|
| committer | Andrew Fleming-AFLEMING <afleming@freescale.com> | 2008-10-24 17:29:37 -0500 |
| commit | ae5f943ba8ede448a4b1a145fd8911856701ecc5 (patch) | |
| tree | ebf3d075628bb6dd14b8f6dc1ab0b01fd6515d5a /cpu/mpc85xx | |
| parent | d5b693090ed08d24c18491df9d8fc7387b2906f3 (diff) | |
85xx: Fix the incorrect register used for DDR erratum1
The 8572 DDR erratum1:
DDR controller may enter an illegal state when operating
in 32-bit bus mode with 4-beat bursts.
Description:
When operating with a 32-bit bus, it is recommended that
DDR_SDRAM_CFG[8_BE] is cleared when DDR2 memories are used.
This forces the DDR controller to use 4-beat bursts when
communicating to the DRAMs. However, an issue exists that
could lead to data corruption when the DDR controller is
in 32-bit bus mode while using 4-beat bursts.
Projected Impact:
If the DDR controller is operating in 32-bit bus mode with
4-beat bursts, then the controller may enter into a bad state.
All subsequent reads from memory is corrupted.
Four-beat bursts with a 32-bit bus only is used with DDR2 memories.
Therefore, this erratum does not affect DDR3 mode.
Work Arounds:
To work around this issue, software must set DEBUG_1[31] in
DDR memory mapped space (CCSRBAR offset + 0x2f00 for DDR_1
and CCSRBAR offset + 0x6f00 for DDR_2).
Currenlty, the code is using incorrect register DDR_SDRAM_CFG_2
as condition, but it should be DDR_SDRAM_CFG register.
Signed-off-by: Dave Liu <daveliu@freescale.com>
Diffstat (limited to 'cpu/mpc85xx')
| -rw-r--r-- | cpu/mpc85xx/ddr-gen3.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/cpu/mpc85xx/ddr-gen3.c b/cpu/mpc85xx/ddr-gen3.c index e0654bb3f..a2b45c571 100644 --- a/cpu/mpc85xx/ddr-gen3.c +++ b/cpu/mpc85xx/ddr-gen3.c @@ -79,15 +79,18 @@ void fsl_ddr_set_memctl_regs(const fsl_ddr_cfg_regs_t *regs, out_be32(&ddr->ddr_sdram_rcw_2, regs->ddr_sdram_rcw_2); /* - * 32-bit workaround for DDR2 - * 32_BE + * For 8572 DDR1 erratum - DDR controller may enter illegal state + * when operatiing in 32-bit bus mode with 4-beat bursts, + * This erratum does not affect DDR3 mode, only for DDR2 mode. */ +#ifdef CONFIG_MPC8572 if ((((in_be32(&ddr->sdram_cfg) >> 24) & 0x7) == SDRAM_TYPE_DDR2) - && in_be32(&ddr->sdram_cfg_2) & 0x80000) { + && in_be32(&ddr->sdram_cfg) & 0x80000) { /* set DEBUG_1[31] */ u32 temp = in_be32(&ddr->debug_1); out_be32(&ddr->debug_1, temp | 1); } +#endif /* * 200 painful micro-seconds must elapse between |