[U-Boot] [PATCH v2 06/10] powerpc/ppc4xx: Use generic FPGA accessors on all gdsys 405ep/ex boards
Dirk Eibach
dirk.eibach at gdsys.cc
Mon May 6 17:55:22 CEST 2013
Hi Wolfgang,
Am 06.05.2013 17:22, schrieb Wolfgang Denk:
> Dear Dirk Eibach,
>
> In message <e8fccb4d422d619744521268691e5a9b at gdsys.cc> you wrote:
>>
>>> You had the this, and now attempt to throw it away. This makes no
>>> sense.
>>
>> In fact it does.
>> We have FPGAs that are memory mapped and others that are not. They
>> must
>> be accessed by the same drivers. So the alternative would be to
>> create
>> FPGA instances at address NULL and getting the register offesets by
>> casting pointers to u16. Not very nice either.
>
> Your new code still boils down to using the same standard I/O
> accessors.
>
> So your FPGA registers must be mapped somehow to I/O memory.
>
> When you can do something like
>
> +u16 fpga_get_reg(unsigned int fpga, u16 reg)
> +{
> + return in_le16((u16 *)CONFIG_SYS_FPGA_BASE(fpga) + reg /
> sizeof(u16));
> +}
>
> why would you not be able to continue using in_le16() directly?
>
> Sorry, I don't get it.
Read the source, Luke :)
On our iocon platform you find:
+void fpga_set_reg(unsigned int fpga, u16 reg, u16 data)
+{
+ int res;
+ struct ihs_fpga *fpga_0 = (struct ihs_fpga *)CONFIG_SYS_FPGA_BASE(0);
+
+ switch (fpga) {
+ case 0:
+ out_le16((u16 *)fpga_0 + reg / sizeof(u16), data);
+ break;
+ default:
+ res = mclink_send(fpga - 1, reg, data);
+ if (res < 0)
+ printf("mclink_send reg %02x data %04x returned %d\n",
+ reg, data, res);
+ break;
+ }
+}
So no memory mapping here. That's the reason for all this fuzz.
And sorry for the messed up series. Sometimes rebase can make things
worse :)
Cheers
Dirk
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