Hi Russell,
Russell King - ARM Linux admin linux@armlinux.org.uk wrote on Tue, 22 Oct 2019 10:26:19 +0100:
On Tue, Oct 22, 2019 at 11:17:07AM +0200, Miquel Raynal wrote:
Hi Russell,
Russell King - ARM Linux admin linux@armlinux.org.uk wrote on Tue, 22 Oct 2019 09:26:43 +0100:
On Fri, Oct 18, 2019 at 04:36:43PM +0200, Miquel Raynal wrote:
Any write with either dd or flashcp to a device driven by the spear_smi.c driver will pass through the spear_smi_cpy_toio() function. This function will get called for chunks of up to 256 bytes. If the amount of data is smaller, we may have a problem if the data length is not 4-byte aligned. In this situation, the kernel panics during the memcpy:
# dd if=/dev/urandom bs=1001 count=1 of=/dev/mtd6 spear_smi_cpy_toio [620] dest c9070000, src c7be8800, len 256 spear_smi_cpy_toio [620] dest c9070100, src c7be8900, len 256 spear_smi_cpy_toio [620] dest c9070200, src c7be8a00, len 256 spear_smi_cpy_toio [620] dest c9070300, src c7be8b00, len 233 Unhandled fault: external abort on non-linefetch (0x808) at 0xc90703e8 [...] PC is at memcpy+0xcc/0x330I need the full oops if you want me to comment on this.
FYI, I ran the dd command within a for loop, incrementing the block size (bs) by one byte, if failed with bs=6.
Disabling WB_MODE (burst mode) does not change anything.
Adding a wmb() right after the memcpy_toio() prevents the fault.
Thanks. Can you check what the result of the write buffer test earlier in the kernel boot is?
CPU: Testing write buffer coherency: ...
?
CPU: Testing write buffer coherency: ok