Re: [PATCH]PM: Initialization of SDRC params for DVFS on Zoom2

[Kevin Hilman <khilman@deeprootsystems.com>]

"Reddy, Teerth" <teerth@ti.com> writes:

> Kevin,Jean
>
> Sorry for the late reply.
> I have tested DVFS on Zoom2 with 256Mb with this patch and it works fine.
> In Zoom2 SDRC module uses 2 chip selects. Since u-boot is configuring the SDRC module to use 2 chip selects do we need to configure it in the kernel as well? 
> If you think so then this change is needed. 

Yes, otherwise the settings for the 2nd CS will not be modified during
DVFS and DVFS will not work properly when using both CSes.

Kevin



>
> Regards
> Teerth
>
>
>
> -----Original Message-----
> From: Kevin Hilman [mailto:khilman@deeprootsystems.com] 
> Sent: Wednesday, September 30, 2009 11:36 PM
> To: Reddy, Teerth
> Cc: linux-omap@vger.kernel.org; Jean Pihet
> Subject: Re: [PATCH]PM: Initialization of SDRC params for DVFS on Zoom2
>
> Teerth,  ping.
>
> On Wed, Sep 9, 2009 at 5:12 AM, Jean Pihet <jpihet@mvista.com> wrote:
>> On Wednesday 09 September 2009 00:17:42 Kevin Hilman wrote:
>>> "Reddy, Teerth" <teerth@ti.com> writes:
>>> > This patch initializes the SDRC params for DVFS on Zoom2.
>>> >
>>> > Signed-off-by: Teerth Reddy <teerth@ti.com>
>>> > ---
>>> >  arch/arm/mach-omap2/board-zoom2.c |    6 ++++--
>>> >  1 files changed, 4 insertions(+), 2 deletions(-)
>>> >
>>> > Index: linux-omap-pm/arch/arm/mach-omap2/board-zoom2.c
>>> > ===================================================================
>>> > --- linux-omap-pm.orig/arch/arm/mach-omap2/board-zoom2.c
>>> > +++ linux-omap-pm/arch/arm/mach-omap2/board-zoom2.c
>>> > @@ -23,6 +23,7 @@
>>> >
>>> >  #include "mmc-twl4030.h"
>>> >  #include "omap3-opp.h"
>>> > +#include "sdram-micron-mt46h32m32lf-6.h"
>>> >
>>> >  static struct omap_uart_config zoom2_uart_config __initdata = {
>>> >     .enabled_uarts  = ((1 << 0) | (1 << 1) | (1 << 2)),
>>> > @@ -36,8 +37,9 @@ static void __init omap_zoom2_init_irq(v
>>> >  {
>>> >     omap_board_config = zoom2_config;
>>> >     omap_board_config_size = ARRAY_SIZE(zoom2_config);
>>> > -   omap2_init_common_hw(NULL, NULL, omap3_mpu_rate_table,
>>> > -                        omap3_dsp_rate_table, omap3_l3_rate_table);
>>> > +   omap2_init_common_hw(mt46h32m32lf6_sdrc_params, NULL,
>>> > +           omap3_mpu_rate_table, omap3_dsp_rate_table,
>>> > +                                   omap3_l3_rate_table);
>>>
>>> Not having looked at the Zoom2 schematics, are you sure this is only
>>> using a single chip select?  The other boards using the same part
>>> (beagle, overo) are interfacing to this part using both CSes.
>>>
>>> Have you tested DVFS on Zoom2 using the full 256Mb?
>> Good point!
>>
>> DVFS works fine using the two chip selects:
>>        omap2_init_common_hw(mt46h32m32lf6_sdrc_params,
>>                             mt46h32m32lf6_sdrc_params,
>>                             omap3_mpu_rate_table,
>>                             omap3_dsp_rate_table,
>>                             omap3_l3_rate_table);
>>
>> One remark though: since the memory chips are popped on top of the OMAP chip
>> the schematics are not showing the chip selects connections. In any case
>> U-Boot is configuring the SDRC module to use the 2 chip selects, so I think
>> this change is needed.
>>
>> We need confirmation. Anyone from TI knows?
>>
>> Regards,
>> Jean
>>
>>>
>>> Kevin
>>>
>>> >     omap_init_irq();
>>> >     omap_gpio_init();
>>> >  }
>>>
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>>
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