[U-Boot] [PATCH 13/14] tegra: Add EMC settings for Seaboard, Harmony

[Simon Glass]

Hi Stephen,

On Tue, Jan 10, 2012 at 10:46 AM, Stephen Warren <swarren at nvidia.com> wrote:
> On 12/26/2011 12:33 PM, Simon Glass wrote:
>> From: Jimmy Zhang <jimmzhang at nvidia.com>
>>
>> Set Seaboard and Harmony to optimal memory settings based on the SOC
>> in use (T20 or T25).
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>
>> diff --git a/board/nvidia/common/emc.c b/board/nvidia/common/emc.c
> ...
>> +static const struct tegra_emc_table seaboard_emc_tables_hynix_333Mhz[] = {
> ...
>> +static const struct tegra_emc_table seaboard_emc_tables_hynix_380Mhz[] = {
> ...
>> +void seaboard_emc_init(void)
> ...
>> +static struct emc_init board_table[] = {
>> +       {
>> +               .id     = MACH_TYPE_HARMONY,
>> +               .init   = NULL,
>> +       },
>> +       {
>> +               .id     = MACH_TYPE_SEABOARD,
>> +               .init   = seaboard_emc_init,
>> +       },
>> +};
>
> Why not just put the Seaboard-specific code into Seaboard's board
> directory instead of a common location? Then you wouldn't need this
> table at all, and boards other than Seaboard wouldn't be required to
> carry the Seaboard EMC tables.

I have moved this into the device tree.

> There don't appear to be any tables for Harmony, which is inconsistent
> with the commit description.

Updated the commit description :-)

>
>> +int board_emc_init(void)
>> +{
>> +       int     i;
>> +       DECLARE_GLOBAL_DATA_PTR;
>> +
>> +#ifdef CONFIG_TEGRA_PMU
>> +       /* if voltage has not been set properly, return */
>> +       if (!pmu_is_voltage_nominal())
>> +               return -1;
>> +#endif
>
> Why/when would the PMU voltage not be nominal?

On boot, it starts up lower and we raise it to nominal so we can run
at full speed.

>
> Can't we error out the compile if the options that cause the PMU voltage
> to be initialized to nominal are not set, instead of detecting this at
> runtime?

I don't think so, since we can't know in U-Boot what the start-up voltages are.

> Finally, I don't think there are EMC tables here for all the EMC
> frequencies that we have BCTs for. Perhaps that's not an issue, and
> perhaps I should ignore the other BCTs (e.g. 400MHZ EMC) since nobody
> actually uses them?

Yes I think maximum speed is all anyone is probably interested in now.

Regards,
Simon

>
> --
> nvpublic