[PATCH 2/6 v4] tpm2: Add a TPMv2 MMIO TIS driver

[Simon Glass]

Hi Ilias,

On Fri, 5 Nov 2021 at 02:23, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> On Fri, Nov 05, 2021 at 10:17:21AM +0200, Ilias Apalodimas wrote:
> > Hi Simon,
> >
> > [...]
> >
> > > > +                          u8 *result)
> > > > +{
> > > > +       struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> > > > +
> > > > +       while (len--)
> > > > +               *result++ = ioread8(drv_data->iobase + addr);
> > > > +       return 0;
> > > > +}
> > > > +
> > > > +static int mmio_write_bytes(struct udevice *udev, u32 addr, u16 len,
> > > > +                           const u8 *value)
> > > > +{
> > > > +       struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> > > > +
> > > > +       while (len--)
> > > > +               iowrite8(*value++, drv_data->iobase + addr);
> > >
> > > So should this use regmap?
> > >
> >
> > Isn't the point of regmap abstracting the bus access itself? Something
> > along the lines of

It is for MMIO at present, but I suppose it could handle the bus. It
would need to know about register numbers though, and we've never
really figured out if it is a win or not.

> >
> > ********                      **********       ***********
> > * SPI **  -->                 *        * -->   * SPI DM ** --> Device
> > ********                      *        *       ***********
> >                                       * REGMAP *
> > ********                      *        *
> > * MMIO *  -->         *        * -->   **************
> > ********                      **********               * MMIO access*  --> Device
> >                                                                        **************
> >
>
> Hopefully I'll get the ASCII right this time...
>
> ********          **********       ***********
> * SPI **  -->     *        * -->   * SPI DM ** --> Device
> ********          *        *       ***********
>                   * REGMAP *
> ********          *        *
> * MMIO *  -->     *        * -->   **************
> ********          **********       * MMIO access*  --> Device
>                                    **************
> > Right now we have discrete drivers for the SPI and MMIO TPMs.
> > However using it makes sense if we want to merge parts of the SPI, MMIO and I2C
> > drivers in the future. That though is not what this patchset deals with.
> > Let's first clean up the crud of the TIS APIs duplication  we've been
> > carrying over various TPM drivers and worry about consolidating the bus
> > accesses later.

That's OK with me.

Regards,
Simon