> From: Rob Herring <robh@xxxxxxxxxx> > Subject: Re: [PATCH] PCI: dwc: Add upper limit address for outbound iATU > > On Sun, Dec 20, 2020 at 6:56 PM Shradha Todi <shradha.t@xxxxxxxxxxx> > wrote: > > > > The size parameter is unsigned long type which can accept size > 4GB. > > In that case, the upper limit address must be programmed. Add support > > to program the upper limit address and set INCREASE_REGION_SIZE in > > case size > 4GB. > > Not all DWC h/w versions have the upper register and bit. Is it safe to write to > the non-existent register? Thanks for the review. Surely it exists post 4.80a version of controller but I am not sure in which version of the controller this was introduced. I can figure this out from the SNPS team and update the patch accordingly. > > > > > Signed-off-by: Shradha Todi <shradha.t@xxxxxxxxxxx> > > --- > > drivers/pci/controller/dwc/pcie-designware.c | 8 ++++++-- > > drivers/pci/controller/dwc/pcie-designware.h | 1 + > > 2 files changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c > > b/drivers/pci/controller/dwc/pcie-designware.c > > index 28c56a1..7eba3b2 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware.c > > +++ b/drivers/pci/controller/dwc/pcie-designware.c > > @@ -290,12 +290,16 @@ static void __dw_pcie_prog_outbound_atu(struct > dw_pcie *pci, u8 func_no, > > upper_32_bits(cpu_addr)); > > dw_pcie_writel_dbi(pci, PCIE_ATU_LIMIT, > > lower_32_bits(cpu_addr + size - 1)); > > + dw_pcie_writel_dbi(pci, PCIE_ATU_UPPER_LIMIT, > > + upper_32_bits(cpu_addr + size - 1)); > > If not safe, perhaps only write if non-zero. > Writing zero has no side-affect and we have tested this. > > dw_pcie_writel_dbi(pci, PCIE_ATU_LOWER_TARGET, > > lower_32_bits(pci_addr)); > > dw_pcie_writel_dbi(pci, PCIE_ATU_UPPER_TARGET, > > upper_32_bits(pci_addr)); > > - dw_pcie_writel_dbi(pci, PCIE_ATU_CR1, type | > > - PCIE_ATU_FUNC_NUM(func_no)); > > + val = type | PCIE_ATU_FUNC_NUM(func_no); > > + val = upper_32_bits(size - 1) ? > > + val | PCIE_ATU_INCREASE_REGION_SIZE : val; > > + dw_pcie_writel_dbi(pci, PCIE_ATU_CR1, val); > > dw_pcie_writel_dbi(pci, PCIE_ATU_CR2, PCIE_ATU_ENABLE); > > > > /* > > diff --git a/drivers/pci/controller/dwc/pcie-designware.h > > b/drivers/pci/controller/dwc/pcie-designware.h > > index b09329b..28b72fb 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware.h > > +++ b/drivers/pci/controller/dwc/pcie-designware.h > > @@ -106,6 +106,7 @@ > > #define PCIE_ATU_DEV(x) FIELD_PREP(GENMASK(23, 19), x) > > #define PCIE_ATU_FUNC(x) FIELD_PREP(GENMASK(18, 16), x) > > #define PCIE_ATU_UPPER_TARGET 0x91C > > +#define PCIE_ATU_UPPER_LIMIT 0x924 > > > > #define PCIE_MISC_CONTROL_1_OFF 0x8BC > > #define PCIE_DBI_RO_WR_EN BIT(0) > > -- > > 2.7.4 > >
