Kevin,
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of G,
> Manjunath Kondaiah
> Sent: Tuesday, September 07, 2010 5:18 PM
> To: Kevin Hilman
> Cc: [email protected]; Cousson, Benoit; Shilimkar, Santosh
> Subject: RE: [PATCH v2 09/11] OMAP: DMA: Implement generic
> errata handling
>
>
>
> > -----Original Message-----
> > From: Kevin Hilman [mailto:[email protected]]
> > Sent: Saturday, September 04, 2010 4:12 AM
> > To: G, Manjunath Kondaiah
> > Cc: [email protected]; Cousson, Benoit; Shilimkar, Santosh
> > Subject: Re: [PATCH v2 09/11] OMAP: DMA: Implement generic errata
> > handling
> >
> > Manjunatha GK <[email protected]> writes:
> >
> > > This patch introduces generic way of handling all OMAP
> DMA errata's
> > > which are applicable for OMAP1 and OMAP2PLUS processors.
> > >
> > > Signed-off-by: Manjunatha GK <[email protected]>
> > > Cc: Benoit Cousson <[email protected]>
> > > Cc: Kevin Hilman <[email protected]>
> > > Cc: Santosh Shilimkar <[email protected]>
> > > ---
> > > arch/arm/mach-omap1/dma.c | 6 ++++
> > > arch/arm/mach-omap2/dma.c | 34
> > +++++++++++++++++++++++
> > > arch/arm/plat-omap/dma.c | 48
> > ++++++++++++++++++--------------
> > > arch/arm/plat-omap/include/plat/dma.h | 9 ++++++
> > > 4 files changed, 76 insertions(+), 21 deletions(-)
> > >
> > > diff --git a/arch/arm/mach-omap1/dma.c
> b/arch/arm/mach-omap1/dma.c
> > > index 26ab6e3..615c5f5 100644
> > > --- a/arch/arm/mach-omap1/dma.c
> > > +++ b/arch/arm/mach-omap1/dma.c
> > > @@ -170,6 +170,12 @@ static int __init omap1_system_dma_init(void)
> > > goto exit_device_put;
> > > }
> > >
> > > + /* Errata handling for all omap1 plus processors */
> > > + pdata->errata = 0;
> >
> > This isn't needed as you just kzalloc'd pdata.
> ok
> >
> > > + if (cpu_class_is_omap1() && !cpu_is_omap15xx())
> >
> > You don't need cpu_class_is_omap1() as this is OMAP1 specific code.
> Ok. Looks like copy, paste issue from plat-omap dma.c. I will fix it.
> >
> > > + pdata->errata |= OMAP3_3_ERRATUM;
> > > +
> > > d = pdata->dma_attr;
> > >
> > > /* Valid attributes for omap1 plus processors */ diff --git
> > > a/arch/arm/mach-omap2/dma.c b/arch/arm/mach-omap2/dma.c index
> > > f369bee..8832bd1 100644
> > > --- a/arch/arm/mach-omap2/dma.c
> > > +++ b/arch/arm/mach-omap2/dma.c
> > > @@ -80,6 +80,40 @@ static int __init
> > omap2_system_dma_init_dev(struct omap_hwmod *oh, void *user)
> > >
> > > pdata->dma_attr = (struct omap_dma_dev_attr
> > *)oh->dev_attr;
> > >
> > > + /* Handling Errata's for all OMAP2PLUS processors */
> > > + pdata->errata = 0;
> >
> > not needed, see above
> ok
> >
> > > + if (cpu_is_omap242x() ||
> > > + (cpu_is_omap243x() && omap_type() <=
> > OMAP2430_REV_ES1_0))
> > > + pdata->errata = DMA_CHAINING_ERRATA;
> > > +
> > > + /*
> > > + * Errata: On ES2.0 BUFFERING disable must be set.
> > > + * This will always fail on ES1.0
> > > + */
> > > + if (cpu_is_omap24xx())
> > > + pdata->errata |= DMA_BUFF_DISABLE_ERRATA;
> > > +
> > > + /*
> > > + * Errata: OMAP2: sDMA Channel is not disabled
> > > + * after a transaction error. So we explicitely
> > > + * disable the channel
> > > + */
> > > + if (cpu_class_is_omap2())
> > > + pdata->errata |= DMA_CH_DISABLE_ERRATA;
> > > +
> > > + /* Errata: OMAP3 :
> >
> > fix multi-line comment style
> Ok.
>
> >
> > > + * A bug in ROM code leaves IRQ status for channels 0
> > and 1 uncleared
> > > + * after secure sram context save and restore. Hence we need to
> > > + * manually clear those IRQs to avoid spurious interrupts. This
> > > + * affects only secure devices.
> > > + */
> > > + if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
> > > + pdata->errata |= DMA_IRQ_STATUS_ERRATA;
> > > +
> > > + /* Errata3.3: Applicable for all omap2 plus */
> > > + pdata->errata |= OMAP3_3_ERRATUM;
> > > +
> > > od = omap_device_build(name, 0, oh, pdata, sizeof(*pdata),
> > > omap2_dma_latency,
> > ARRAY_SIZE(omap2_dma_latency), 0);
> > >
> > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> > > index 36c3dde..409586a 100644
> > > --- a/arch/arm/plat-omap/dma.c
> > > +++ b/arch/arm/plat-omap/dma.c
> > > @@ -187,6 +187,25 @@ static inline void set_gdma_dev(int
> > req, int dev)
> > > #define set_gdma_dev(req, dev) do {} while (0)
> > > #endif
> > >
> > > +static void dma_ocpsysconfig_errata(u32 *sys_cf, bool flag)
> >
> > Please use (or extend) hwmod layer for modifying device SYSCONFIG.
>
> I will check this.
I propose following options for addressing this errata:
Option 1:
Creating 2 new API's with 1 static function in omap_hwmod.c for handling
midle mode errata issues.
static int _get_master_standbymode(oh, u32 *idlemode, u32 v);
int omap_hwmod_set_master_idlemode(struct omap_hwmod *oh, u8 idlemode);
int omap_hwmod_get_master_idlemode(struct omap_hwmod *oh, u32 *idlemode);
In dma driver, the api's will be used as:
omap_hwmod_get_master_idlemode(oh, midle_mode);
omap_hwmod_set_master_idlemode(oh, 1);
/* disable channels which completed data transfer */
...
/* Restore original standby mode values */
omap_hwmod_set_master_idlemode(oh, *midle_mode)
Option 2:
Create 1 new exported API for modifying sysconfig standby mode bits.
In this case, restoring original standby mode value is through accessing
sysc flags and _sysc_cache values through oh in DMA driver.
I feel option #1 seems to be cleaner approach since it avoids accessing
oh contents in driver. Let me know if you have objections for the same.
/Code snippet for option 1 */
static int _get_master_standbymode(oh, u32 *idlemode)
{
u32 mstandby_mask;
u8 mstandby_shift;
...
mstandby_shift = oh->class->sysc->sysc_fields->midle_shift;
mstandby_mask = (0x3 << mstandby_shift);
*idle_mode = ((oh->_sysc_cache) & mstandby_mask) >> mstandby_shift;
return 0;
}
int omap_hwmod_set_master_idlemode(struct omap_hwmod *oh, u8 idlemode)
{
u32 v;
int retval = 0;
...
v = oh->_sysc_cache;
retval = _set_master_standbymode(oh, idlemode, &v);
if (!retval)
_write_sysconfig(v, oh);
return retval;
}
int omap_hwmod_get_master_idlemode(struct omap_hwmod *oh, u32 *idlemode)
{
u32 v;
int retval = 0;
...
retval = _get_master_standbymode(oh, idlemode);
return retval;
}
-Manjunath
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