Re: [PATCH RESEND v4 03/15] PCI: dwc: Convert to using native IP-core versions representation

Bjorn Helgaas
2022-07-28T16:34:38Z

On Thu, Jul 28, 2022 at 04:31:17PM +0100, Ben Dooks wrote:
> On 28/07/2022 16:24, Bjorn Helgaas wrote:
> > On Fri, Jun 24, 2022 at 05:39:35PM +0300, Serge Semin wrote:
> > > Since DWC PCIe v4.70a the controller version can be read from the
> > > PORT_LOGIC.PCIE_VERSION_OFF register. Version is represented in the FourCC
> > > format [1]. It's standard versioning approach for the Synopsys DWC
> > > IP-cores. Moreover some of the DWC kernel drivers already make use of it
> > > to fixup version-dependent functionality (See DWC USB3, Stmicro STMMAC or
> > > recent DW SPI driver).
> >
> > These references to other drivers might be useful, but without a
> > function name or file name, I can't easily find them.
> >
> > > In order to preserve the standard version
> > > representation and prevent the data conversion back and forth, we suggest
> > > to preserve the native version representation in the DWC PCIe driver too
> > > in the same way as it has already been done in the rest of the DWC
> > > drivers. IP-core version reading from the CSR will be introduced in the
> > > next commit together with a simple macro-based API to use it.
> > >
> > > [1] https://en.wikipedia.org/wiki/FourCC
>
> I'm currently looking at a OF based dw-apb-timers-pwm driver, so also
> would like to follow this.

FWIW, the breadcrumbs I found are:

dwc3_core_is_valid()
stmmac_hwif_init()
dw_spi_hw_init()