[U-Boot] [PATCH 062/126] x86: Add a function to set variable MTRRs

[Bin Meng]

On Mon, Oct 7, 2019 at 9:53 PM Bin Meng <bmeng.cn at gmail.com> wrote:
>
> On Wed, Sep 25, 2019 at 10:58 PM Simon Glass <sjg at chromium.org> wrote:
> >
> > Normally U-Boot handles MTRRs through an add/commit process which
> > overwrites all MTRRs. But in very early boot it is not desirable to clear
> > the existing MTRRs since they may be in use and it can cause a hang.
> >
> > Add a new mtrr_set_next_var() function which sets up the next available
> > MTRR to the required region.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
> >
> >  arch/x86/cpu/mtrr.c         | 38 +++++++++++++++++++++++++++++++++++++
> >  arch/x86/include/asm/mtrr.h | 12 ++++++++++++
> >  2 files changed, 50 insertions(+)
> >
> > diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
> > index 6218d149e30..1a7c292fa8b 100644
> > --- a/arch/x86/cpu/mtrr.c
> > +++ b/arch/x86/cpu/mtrr.c
> > @@ -112,3 +112,41 @@ int mtrr_add_request(int type, uint64_t start, uint64_t size)
> >
> >         return 0;
> >  }
> > +
> > +static int get_var_mtrr_count(void)
> > +{
> > +       return msr_read(MSR_MTRR_CAP_MSR).lo & MSR_MTRR_CAP_VCNT;
> > +}
> > +
> > +static int get_free_var_mtrr(void)
> > +{
> > +       struct msr_t maskm;
> > +       int vcnt;
> > +       int i;
> > +
> > +       vcnt = get_var_mtrr_count();
> > +
> > +       /* Identify the first var mtrr which is not valid */
> > +       for (i = 0; i < vcnt; i++) {
> > +               maskm = msr_read(MTRR_PHYS_MASK_MSR(i));
> > +               if ((maskm.lo & MTRR_PHYS_MASK_VALID) == 0)
> > +                       return i;
> > +       }
> > +
> > +       /* No free var mtrr */
> > +       return -ENOSPC;
> > +}
> > +
> > +int mtrr_set_next_var(uint type, uint64_t start, uint64_t size)
> > +{
> > +       int mtrr;
> > +
> > +       mtrr = get_free_var_mtrr();
> > +       if (mtrr < 0)
> > +               return mtrr;
> > +
> > +       set_var_mtrr(mtrr, MTRR_TYPE_WRPROT, start, size);
>
> I think MTRR_TYPE_WRPROT should be parameter 'type'

Fixed this, and

>
> > +       debug("MTRR %x: start=%x, size=%x\n", mtrr, (uint)start, (uint)size);
> > +
> > +       return 0;
> > +}
> > diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
> > index 6f29e75ce65..672617256e9 100644
> > --- a/arch/x86/include/asm/mtrr.h
> > +++ b/arch/x86/include/asm/mtrr.h
> > @@ -117,6 +117,18 @@ int mtrr_add_request(int type, uint64_t start, uint64_t size);
> >   */
> >  int mtrr_commit(bool do_caches);
> >
> > +/**
> > + * mtrr_set_next_var() - set up a variable MTRR
> > + *
> > + * This finds the first free variable MTRR and sets to the given area
> > + *
> > + * @type:      Requested type (MTRR_TYPE_)
> > + * @start:     Start address
> > + * @size:      Size
> > + * @return 0 on success, -ENOSPC if there are no more MTRRs
> > + */
> > +int mtrr_set_next_var(uint type, uint64_t base, uint64_t size);
> > +
> >  #endif
> >
> >  #if ((CONFIG_XIP_ROM_SIZE & (CONFIG_XIP_ROM_SIZE - 1)) != 0)
> > --
>
> Other than above,
>
> Reviewed-by: Bin Meng <bmeng.cn at gmail.com>

applied to u-boot-x86/next, thanks!