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![]() dsp_box is used to keep DSP initiated messages. The value of dsp_offset
is set by the DSP with the first message, so we need a way to bootstrap
it in order to get the first message.
We do this by setting the correct default dsp_box offset which on i.MX8
is not zero.
Very interesting is why it has worked until now.
On i.MX8, DSP communicates with ARM core using a shared SDRAM memory
area. Actually, there are two shared areas:
* SDRAM0 - starting at 0x92400000, size 0x800000
* SDRAM1 - starting at 0x92C00000, size 0x800000
SDRAM0 keeps the data sections, starting with .rodata. By chance
fw_ready structure was placed at the beginning of .rodata.
dsp_box_base is defined as SDRAM0 + dsp_box_offset and it is placed
at the beginning of SDRAM1 (dsp_box_offset should be 0x800000). But
because it is zero initialized by default it points to SDRAM0 where
by chance the fw_ready was placed in the SOF firmware.
Anyhow, SOF commit 7466bee378dd811b ("clk: make freq arrays constant")
fw_ready is no longer at the beginning of SDRAM0 and everything shows
how lucky we were until now.
Fix this by properly setting the default dsp_box offset.
Fixes:
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.. | ||
ac97 | ||
aoa | ||
arm | ||
atmel | ||
core | ||
drivers | ||
firewire | ||
hda | ||
i2c | ||
isa | ||
mips | ||
oss | ||
parisc | ||
pci | ||
pcmcia | ||
ppc | ||
sh | ||
soc | ||
sparc | ||
spi | ||
synth | ||
usb | ||
x86 | ||
xen | ||
ac97_bus.c | ||
Kconfig | ||
last.c | ||
Makefile | ||
sound_core.c |