On Wed, 2014-12-03 at 14:20 -0800, Simon Glass wrote:
> Hi Peter,
>
> On 3 December 2014 at 13:53, Peter Howard <p...@northern-ridge.com.au> wrote:
> > On Wed, 2014-12-03 at 06:38 -0700, Simon Glass wrote:
> >> Hi Peter,
> >>
> >> On 2 December 2014 at 14:59, Peter Howard <p...@northern-ridge.com.au>
> >> wrote:
> >> >
> >> > I'm trying to make two changes to building u-boot for the da850evm.
> >> > * Use the generic board code to get rid of the warning, and
> >> > * Enable libfdt to allow booting of linux with a standalone dtb
> >> > image.
> >> >
> >> > The first part appears to be simple. Just adding
> >> >
> >> > #define CONFIG_SYS_GENERIC_BOARD
> >> >
> >> > in include/configs/da850evm.h works with no obvious side-effects.
> >> >
> >> > However, adding
> >> >
> >> > #define CONFIG_OF_LIBFDT
> >> >
> >> > is a different story. It appears to introduce memory corruption when
> >> > loading the environment. On first boot it gives the "bad CRC!" warning
> >> > and uses the default environment. If you *don't* save the environment
> >> > you can boot fine (including manual editing of the environment). However
> >> > if you save the environment via saveenv bad things happen on the next
> >> > boot. An example log:
> >> >
> >> > U-Boot SPL 2015.01-rc1 (Nov 27 2014 - 14:30:26)
> >> >
> >> >
> >> > U-Boot 2015.01-rc1 (Nov 27 2014 - 14:30:26)
> >> >
> >> > I2C: ready
> >> > DRAM: 64 MiB
> >> > WARNING: Caches not enabled
> >> > MMC: davinci: 0
> >> > SF: Detected M25P64 with page size 256 Bytes, erase size 64 KiB, total 8
> >> > MiB
> >> > In: serial
> >> > Out: serial
> >> > Err: serial
> >> > SF: Detected M25P64 with page size 256 Bytes, erase size 64 KiB, total 8
> >> > MiB
> >> > Warning: Invalid MAC address read from SPI flash
> >> > Net: DaVinci-EMAC
> >> > Error: DaVinci-EMAC address not set.
> >> >
> >> > U-Boot > help
> >> > data abort
> >> > pc : [<c108ffd8>] lr : [<c10900b4>]
> >> > sp : c3e5f838 ip : 00000000 fp : c3e5fda4
> >> > r10: c10b1f28 r9 : c3e5ff08 r8 : 0000000e
> >> > r7 : c10b22c4 r6 : c10aa2a0 r5 : 00000000 r4 : 0000001b
> >> > r3 : c10b8f70 r2 : 00000001 r1 : c3e5f840 r0 : ffffffff
> >> > Flags: Nzcv IRQs off FIQs off Mode SVC_32
> >> > Resetting CPU ...
> >> >
> >> > If I rebuild with CONFIG_OF_LIBFDT removed again from da850evm.h the
> >> > problem disappears. And you can see that the saveenv worked (i.e. the
> >> > environment is what was saved before the reboot and data abort).
> >> >
> >> > I've traced the problem as far as the inline version of console_puts()
> >> > in common/console.c. The table dispatch there and the fact that the
> >> > problem appears only when you load the environment makes me think it's
> >> > memory corruption.
> >> >
> >> > Note: if you do *not* specify CONFIG_SYS_GENERIC_BOARD you still get the
> >> > data abort, however it takes a bit more effort to trigger (like actually
> >> > looking at the environment :-) )
> >> >
> >> > (Note: This is building against the u-boot-2015.01-rc1 tree)
> >> >
> >> > Suggestions?
> >>
> >> In case it helps, I got the same symptom (help crashes) and it was due
> >> to BSS not being cleared. Stefan (on cc) found this problem - he said
> >> something to do with GDT calculation or handling. However it is just a
> >> guess and probably has nothing to do with your issue.
> >
> > I may be missing something, but the GDT appears to be x86-specific
> > whereas I'm building for ARMv5.
>
> OK for some reason I thought this was PPC!
>
> Maybe you can find your pc in System.map and work out where it is
> going wrong? Are you hitting some image size limit?
>
> pc : [<c108ffd8>]
Sorry, been distracted on other stuff for a few days.
First, I now understand the global descriptor a bit better. For ARMv5
It's stored in r9 and still looks sane. The relevant info:
(gdb) print/x *((gd_t *)$r9)
$1 = {bd = 0xc3e5ffb0, flags = 0x183, baudrate = 0x1c200, cpu_clk = 0x0,
bus_clk = 0x0, pci_clk = 0x0, mem_clk = 0x0, have_console = 0x1,
env_addr = 0xc10a8fcc, env_valid = 0x1, ram_top = 0xc4000000,
relocaddr = 0xc3f80000, ram_size = 0x4000000, mon_len = 0x6ffb0,
irq_sp = 0xc3e5fef0, start_addr_sp = 0xc3e5fee0, reloc_off = 0x2f00000,
new_gd = 0xc3e5ff08, fdt_blob = 0x0, new_fdt = 0x0, fdt_size = 0x0,
jt = 0xc3e601c0, env_buf = {0x31, 0x31, 0x35, 0x32, 0x30, 0x30,
0x0 <repeats 26 times>}, cur_i2c_bus = 0x0, timebase_h = 0x0,
timebase_l = 0x0, arch = {timer_rate_hz = 0x16e360, tbu = 0x0,
tbl = 0x4cc62, lastinc = 0x0, timer_reset_value = 0x0,
tlb_addr = 0xc3ff0000, tlb_size = 0x4000}}
The pc is definitely bogus. The reloc address is 0xc3f80000 whereas
that would be a pre-reloc address (starting at 0xc1080000). And it's
definitely relocated by the time of failure. The only other bit of
information I have right now is that adding CONFIG_OF_LIBFDT drops the
reloc address from 0xc3f85000 to 0xc3f80000.
Don't know if any of that gives additional insight. Meanwhile I
continue tracing.
--
Peter Howard <p...@northern-ridge.com.au>
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