[OpenWrt-Devel] uboot-lantiq cgu settings for ramboot image

[Daniel Schwierzeck]

2015-01-19 15:44 GMT+01:00 Ben Mulvihill <ben.mulvihill at gmail.com>:
> On Mon, 2015-01-19 at 11:51 +0000, Conor O'Gorman wrote:
>> On 19/01/15 10:46, Ben Mulvihill wrote:
>> > Hello,
>> >
>> > I am trying to build uboot-lantiq for the BT Home Hub 3A (lantiq
>> > ar9), and am wondering where to initialise the cgu, in the case
>> > of a ramboot image for uart booting. Normally the cgu is initialised
>> > in lowlevel_init, but that code is bypassed in ramboot images. The
>> > result is that the board boots with the wrong cgu settings, which
>> > sends the console haywire. So far I have tried two solutions:
>>
>> Another option is to try and not change anything. The console is already
>> configured and running. The ram does need config.
>>
>> I was used to seeing the ramboot version running at half clock speed, at
>> least on danube, previous to ar9.
>>
>> Conor
>
> Hi Conor,
>
> Thanks for the reply. But with the latest uboot-lantiq, not changing
> anything means that I don't get a usable console. With an older
> version I do at least get a uboot console, but no linux console when
> I boot openwrt. Correcting the cgu settings solves both problems.
>

could you try this?

diff --git a/arch/mips/cpu/mips32/arx100/cgu.c
b/arch/mips/cpu/mips32/arx100/cgu.c
index 6e71ee7..e0afbda 100644
--- a/arch/mips/cpu/mips32/arx100/cgu.c
+++ b/arch/mips/cpu/mips32/arx100/cgu.c
@@ -95,15 +95,5 @@ unsigned long ltq_get_cpu_clock(void)

 unsigned long ltq_get_bus_clock(void)
 {
-       u32 fpi_sel;
-       unsigned long clk;
-
-       fpi_sel = ltq_cgu_sys_readl(1, CGU_SYS_FPI_SEL);
-
-       if (fpi_sel)
-               clk = ltq_get_io_region_clock() / 2;
-       else
-               clk = ltq_get_io_region_clock();
-
-       return clk;
+       return ltq_get_io_region_clock();
 }

the UART driver calculates the baudrate from the FPI bus clock, but
FPI_SEL is not available on AR9. FPI bus clock is always the same as
DDR clock, Obviously a copy&paste error from VR9 code ;)

-- 
- Daniel
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