Re: [PATCH v6 03/15] soc/tegra: Add ram code reader helper

[Mikko Perttunen]

On 03/02/2015 10:46 AM, Alexandre Courbot wrote:
> On Thu, Feb 12, 2015 at 11:06 PM, Tomeu Vizoso
> <tomeu.vizoso@xxxxxxxxxxxxx> wrote:
> > From: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> >
> > Needed for the EMC and MC drivers to know what timings from the DT to use.
> >
> > Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> >
> > ---
> >
> > v4: Replace magic number with PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT
> > ---
> >   drivers/soc/tegra/fuse/tegra-apbmisc.c | 19 +++++++++++++++++++
> >   include/soc/tegra/fuse.h               |  1 +
> >   2 files changed, 20 insertions(+)
> >
> > diff --git a/drivers/soc/tegra/fuse/tegra-apbmisc.c b/drivers/soc/tegra/fuse/tegra-apbmisc.c
> > index 3bf5aba..dc96a62 100644
> > --- a/drivers/soc/tegra/fuse/tegra-apbmisc.c
> > +++ b/drivers/soc/tegra/fuse/tegra-apbmisc.c
> > @@ -28,8 +28,13 @@
> >   #define APBMISC_SIZE   0x64
> >   #define FUSE_SKU_INFO  0x10
> >
> > +#define PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT     4
> > +#define PMC_STRAPPING_OPT_A_RAM_CODE_MASK_LONG (0xf << PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT)
> > +#define PMC_STRAPPING_OPT_A_RAM_CODE_MASK_SHORT        (0x3 << PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT)
>
> I think you are slightly over 80 chars here.
>
> > +
> >   static void __iomem *apbmisc_base;
> >   static void __iomem *strapping_base;
> > +static bool          long_ram_code;
> >
> >   u32 tegra_read_chipid(void)
> >   {
> > @@ -54,6 +59,18 @@ u32 tegra_read_straps(void)
> >                  return 0;
> >   }
> >
> > +u32 tegra_read_ram_code(void)
> > +{
> > +       u32 straps = tegra_read_straps();
> > +
> > +       if (long_ram_code)
> > +               straps &= PMC_STRAPPING_OPT_A_RAM_CODE_MASK_LONG;
> > +       else
> > +               straps &= PMC_STRAPPING_OPT_A_RAM_CODE_MASK_SHORT;
> > +
> > +       return straps >> PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT;
> > +}
> > +
> >   static const struct of_device_id apbmisc_match[] __initconst = {
> >          { .compatible = "nvidia,tegra20-apbmisc", },
> >          {},
> > @@ -112,4 +129,6 @@ void __init tegra_init_apbmisc(void)
> >          strapping_base = of_iomap(np, 1);
> >          if (!strapping_base)
> >                  pr_err("ioremap tegra strapping_base failed\n");
> > +
> > +       long_ram_code = of_property_read_bool(np, "nvidia,long-ram-code");
>
> Is this long-ram property chip-dependent? If so, couldn't we just use
> the chip ID or matched compatible string to decide whether the RAM
> code length, instead of having a dedicated property for it?

I am under the impression that it is board-specific.

Mikko

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