RE: [PATCH v16 13/22] PCI: dwc: Add EDMA_UNROLL capability flag

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Hello Serge,

> From: Serge Semin, Sent: Monday, June 5, 2023 8:16 PM
> 
> On Wed, May 10, 2023 at 03:22:25PM +0900, Yoshihiro Shimoda wrote:
> > Renesas R-Car Gen4 PCIe controllers have an unexpected register value on
> > the dbi+0x97b register. So, add a new capability flag "EDMA_UNROLL"
> > which would force the unrolled eDMA mapping for the problematic
> > device,
> 
> > as suggested by Serge Semin.
> 
> Drop this. Suggested-by tag already means that.

I got it.

> >
> > Suggested-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pcie-designware.c | 8 +++++++-
> >  drivers/pci/controller/dwc/pcie-designware.h | 5 +++--
> >  2 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> > index 8b2978c6eb23..e405bfae0191 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware.c
> > @@ -881,8 +881,14 @@ static int dw_pcie_edma_find_chip(struct dw_pcie *pci)
> >  	 * Indirect eDMA CSRs access has been completely removed since v5.40a
> >  	 * thus no space is now reserved for the eDMA channels viewport and
> >  	 * former DMA CTRL register is no longer fixed to FFs.
> > +	 *
> > +	 * Note that Renesas R-Car S4-8's PCIe controllers for unknown reason
> 
> > +	 * may have zeros in the eDMA CTRL register even though the HW-manual
> 
> s/may have/have

I'll fix it.

> (your comment is about a particular device which for sure has the
> denoted problem.)

I understood it.

> Other than that the change looks good. Thanks!
> Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>

Thank you very much for your review!

Best regards,
Yoshihiro Shimoda

> -Serge(y)
> 
> > +	 * explicitly states there must FFs if the unrolled mapping is enabled.
> > +	 * For such cases the low-level drivers are supposed to manually
> > +	 * activate the unrolled mapping to bypass the auto-detection procedure.
> >  	 */
> > -	if (dw_pcie_ver_is_ge(pci, 540A))
> > +	if (dw_pcie_ver_is_ge(pci, 540A) || dw_pcie_cap_is(pci, EDMA_UNROLL))
> >  		val = 0xFFFFFFFF;
> >  	else
> >  		val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL);
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> > index 06e044e2163a..2639206b4c18 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -54,8 +54,9 @@
> >
> >  /* DWC PCIe controller capabilities */
> >  #define DW_PCIE_CAP_REQ_RES		0
> > -#define DW_PCIE_CAP_IATU_UNROLL		1
> > -#define DW_PCIE_CAP_CDM_CHECK		2
> > +#define DW_PCIE_CAP_EDMA_UNROLL		1
> > +#define DW_PCIE_CAP_IATU_UNROLL		2
> > +#define DW_PCIE_CAP_CDM_CHECK		3
> >
> >  #define dw_pcie_cap_is(_pci, _cap) \
> >  	test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps)
> > --
> > 2.25.1
> >




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