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authorWolfgang Denk <wd@denx.de>2010-06-21 22:29:59 +0200
committerWolfgang Denk <wd@denx.de>2010-06-23 02:09:20 +0200
commit460c2ce362e56890c2a029e2c3b1ff2796c7fc54 (patch)
tree625be474d895469685f41febbe93f278542076f3 /arch/powerpc/cpu/mpc5xxx
parent47ea6edfb3004fb2d2a979e19c3f6e4e32f45e51 (diff)
downloadu-boot-linaro-stable-460c2ce362e56890c2a029e2c3b1ff2796c7fc54.tar.gz
MPC5200: workaround data corruption for unaligned local bus accesses
The MPC5200 has a nasty problem that will cause silent data corruption when performing unaligned 16 or 32 byte accesses when reading from the local bus - typically this affects reading from flash. The problem can be easily shown: => md fc0c0000 10 fc0c0000: 323e4337 01626f6f 74636d64 3d72756e 2>C7.bootcmd=run fc0c0010: 206e6574 5f6e6673 00626f6f 7464656c net_nfs.bootdel fc0c0020: 61793d35 00626175 64726174 653d3131 ay=5.baudrate=11 fc0c0030: 35323030 00707265 626f6f74 3d656368 5200.preboot=ech => md fc0c0001 10 fc0c0001: 65636801 00000074 0000003d 00000020 ech....t...=... fc0c0011: 0000005f 00000000 00000074 00000061 ..._.......t...a fc0c0021: 00000000 00000064 00000065 00000035 .......d...e...5 fc0c0031: 00000000 00000062 0000003d 0000006f .......b...=...o => md.w fc0c0001 10 fc0c0001: 0000 3701 0000 6f74 0000 643d 0000 6e20 ..7...ot..d=..n fc0c0011: 0000 745f 0000 7300 0000 6f74 0000 6c61 ..t_..s...ot..la This commit implements a workaround at least for the most blatant problem: using memcpy() from NOR flash. We rename the assembler routine into __memcpy() and provide a wrapper, which will use a byte-wise copy loop for unaligned source or target addresses when reading from NOR flash, and branch to the optimized __memcpy() in all other cases, thus minimizing the performance impact. Tested on lite5200b and TQM5200S. Signed-off-by: Wolfgang Denk <wd@denx.de> Cc: Detlev Zundel <dzu@denx.de>
Diffstat (limited to 'arch/powerpc/cpu/mpc5xxx')
-rw-r--r--arch/powerpc/cpu/mpc5xxx/Makefile5
-rw-r--r--arch/powerpc/cpu/mpc5xxx/memcpy_mpc5200.c71
2 files changed, 76 insertions, 0 deletions
diff --git a/arch/powerpc/cpu/mpc5xxx/Makefile b/arch/powerpc/cpu/mpc5xxx/Makefile
index 0ee061155..4ab2b7be7 100644
--- a/arch/powerpc/cpu/mpc5xxx/Makefile
+++ b/arch/powerpc/cpu/mpc5xxx/Makefile
@@ -30,6 +30,11 @@ SOBJS = io.o firmware_sc_task_bestcomm.impl.o
COBJS = i2c.o traps.o cpu.o cpu_init.o ide.o interrupts.o \
loadtask.o pci_mpc5200.o serial.o speed.o usb_ohci.o usb.o
+# Workaround for local bus unaligned access problem on MPC5200
+#ifdef CONFIG_MPC5200
+COBJS += memcpy_mpc5200.o
+#endif
+
SRCS := $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
START := $(addprefix $(obj),$(START))
diff --git a/arch/powerpc/cpu/mpc5xxx/memcpy_mpc5200.c b/arch/powerpc/cpu/mpc5xxx/memcpy_mpc5200.c
new file mode 100644
index 000000000..09503548a
--- /dev/null
+++ b/arch/powerpc/cpu/mpc5xxx/memcpy_mpc5200.c
@@ -0,0 +1,71 @@
+/*
+ * (C) Copyright 2010
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * This is a workaround for issues on the MPC5200, where unaligned
+ * 32-bit-accesses to the local bus will deliver corrupted data. This
+ * happens for example when trying to use memcpy() from an odd NOR
+ * flash address; the behaviour can be also seen when using "md" on an
+ * odd NOR flash address (but there it is not a bug in U-Boot, which
+ * only shows the behaviour of this processor).
+ *
+ * For memcpy(), we test if either the source or the target address
+ * are not 32 bit aligned, and - if so - if the source address is in
+ * NOR flash: in this case we perform a byte-wise (slow) then; for
+ * aligned operations of non-flash areas we use the optimized (fast)
+ * real __memcpy(). This way we minimize the performance impact of
+ * this workaround.
+ *
+ */
+
+#include <common.h>
+#include <flash.h>
+#include <linux/types.h>
+
+void *memcpy(void *trg, const void *src, size_t len)
+{
+ extern void* __memcpy(void *, const void *, size_t);
+ char *s = (char *)src;
+ char *t = (char *)trg;
+ void *dest = (void *)src;
+
+ /*
+ * Check is source address is in flash:
+ * If not, we use the fast assembler code
+ */
+ if (((((unsigned long)s & 3) == 0) /* source aligned */
+ && /* AND */
+ (((unsigned long)t & 3) == 0)) /* target aligned, */
+ || /* or */
+ (addr2info((ulong)s) == NULL)) { /* source not in flash */
+ return __memcpy(trg, src, len);
+ }
+
+ /*
+ * Copying from flash, perform byte by byte copy.
+ */
+ while (len-- > 0)
+ *t++ = *s++;
+
+ return dest;
+}