[PATCH v3 06/13] OMAP3: DMA: hwmod: add system DMA

[G, Manjunath Kondaiah]

Hi Benoit, 

> -----Original Message-----
> From: Cousson, Benoit 
> Sent: Thursday, November 04, 2010 9:59 AM
> To: G, Manjunath Kondaiah
> Cc: Kevin Hilman; linux-arm-kernel at lists.infradead.org; 
> Shilimkar, Santosh; linux-omap at vger.kernel.org
> Subject: Re: [PATCH v3 06/13] OMAP3: DMA: hwmod: add system DMA
> 
> Hi Manjunath,
> 
> On 11/3/2010 8:59 AM, G, Manjunath Kondaiah wrote:
> > Kevin/Benoit,
> >
> >> [mailto:linux-omap-owner at vger.kernel.org] On Behalf Of G,
> >> Manjunath Kondaiah
> >> Sent: Tuesday, October 26, 2010 6:55 PM
> >>
> >> Add OMAP3 DMA hwmod structures.
> >>
> >> Signed-off-by: G, Manjunath Kondaiah<manjugk at ti.com>
> >> Cc: Benoit Cousson<b-cousson at ti.com>
> >> Cc: Kevin Hilman<khilman at deeprootsystems.com>
> >> Cc: Santosh Shilimkar<santosh.shilimkar at ti.com>
> >> ---
> >>   arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   93
> >> ++++++++++++++++++++++++++++
> >>   1 files changed, 93 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
> >> b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
> >> index ed6bf4a..4a5231c 100644
> > [...]
> >> +	.prcm = {
> >> +		.omap2 = {
> >> +			.prcm_reg_id		= 1,
> >> +			.module_bit		=
> >> OMAP3430_ST_SDMA_SHIFT,
> >> +			.idlest_reg_id		= 1,
> >> +			.idlest_idle_bit	=
> >> OMAP3430_ST_SDMA_SHIFT,
> >
> > Looks like the .module_offs field is missing here. Since
> > ST_SDMA bit belongs to CM_IDLEST1_CORE register, .module_offs should
> > be CORE_MOD.
> >
> > But, it is observed that, using .module_offs results in warning dump
> > during bootup. This is due to, ST_SDMA bit in standby mode. Since
> > there is no fclk for DMA, this bit will never change till 
> DMA channel
> > is requested for data transfer.
> >
> > We might have to bypass calling "omap2_cm_wait_module_ready" in
> > "_wait_target_ready" in omap_hwmod.c
> >
> > With exising flags, we can use "HWMOD_NO_IDLEST" flag, but this
> > flag has different meaning. How about using new flag like
> > "HWMOD_NO_FCLK_OPCLK" and if it is set, return without calling
> > "omap2_cm_wait_module_ready"
> >
> > Any better suggestion to handle this issue?
> 
> Well, yes, use HWMOD_NO_IDLEST and remove idlest_reg_id & 
> idlest_idle_bit entries in the omap2 structure.
> 
> ST_SDMA is the standby status of the SDMA, but there is no 
> idle status 
> on that IP, so you cannot do anything.
> The standby will just reflect the activity of the master port of the 
> DMA, but it will give you no information about the slave port 
> and thus 
> we do not have any module ready information.

Thanks for the feedback.

This change is introduced as per kevin's review comment at:
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg34278.html

I am ok to use "HWMOD_NO_IDLEST" if kevin also agrees 

-Manjunath