The reference implementation of the PCI initialization code almost
everywhere contain this fragile loop of "a few usecs", and its
use of volatile variables to delay a number of bus cycles is indeed
uncertain.
Reading the manual "Integrator/AP Users Guide", page 5-15 it is
clearly stated:
"Wait until 230ms after the end of the reset period before
accessing V360EPC internal registers. The V360EPC supports the
use of a serial configuration PROM and the software must wait for
the device to detect the absence of this PROM before accessing any
registers. The required delay is a function of the PCI Clock, but
at the lower frequency (25MHz) is 230ms".
So let's simply wait 230ms per the spec.
This solves the compilation error that looked like this:
pci.c: In function ‘pci_init_board’:
pci.c:286:18: warning: variable ‘j’ set but not used
Reported-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The PCI support for the Integrator AP has apparently never
been finished and I strongly suspect that it has never worked,
so let's fix it. This is a list of the more or less
un-splittable changes done in this driver rewrite:
- Replace the register definitions stashed into the config
file (!) with a copy if the register file from the Linux
kernels arch/arm/include/asm/hardware/pci_v3.h
- Delete the unreadable gigantic macros that perform the
config accesses and replace them with copyedited code from
Linux arch/arm/mach-integrator/pci_v3.c
- Rewrite the rest of the setup code to use the
v3_[read|write][lwb]() accessors.
- Enable PCI by default in the AP board configuration.
- Fix checkpatch warnings and make code more conformant.
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Wolfgang Denk
Linus Walleij
Jean-Christophe PLAGNIOL-VILLARD