| Message ID | 1611223156-8787-1-git-send-email-bharat.kumar.gogada@xilinx.com |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: xilinx-nwl: Enable coherenct PCIe traffic using CCI | expand |
[+cc Rob] s/coherenct/coherent/ in subject s/traffic/DMA/ (this applies specifically to DMA, not to MMIO) On Thu, Jan 21, 2021 at 03:29:16PM +0530, Bharat Kumar Gogada wrote: > - Add support for routing PCIe traffic coherently when > Cache Coherent Interconnect(CCI) is enabled in the system. s/- Add/Add/ s/Interconnect(CCI)/Interconnect (CCI)/ Can you include a URL to a CCI spec? I'm not familiar with it. I guess this is something upstream from the host bridge, i.e., between the CPU and the host bridge, so it's outside the PCI domain? I'd like to mention the DT "dma-coherent" property in the commit log to help connect this with the knob that controls it. The "dma-coherent" property is mentioned several places in Documentation/devicetree/bindings/pci/ (but not anything obviously related to xilinx-nwl). Should it be moved to something like Documentation/devicetree/bindings/pci/pci.txt to make it more generic? > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com> > --- > drivers/pci/controller/pcie-xilinx-nwl.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c > index 07e3666..08e06057 100644 > --- a/drivers/pci/controller/pcie-xilinx-nwl.c > +++ b/drivers/pci/controller/pcie-xilinx-nwl.c > @@ -26,6 +26,7 @@ > > /* Bridge core config registers */ > #define BRCFG_PCIE_RX0 0x00000000 > +#define BRCFG_PCIE_RX1 0x00000004 > #define BRCFG_INTERRUPT 0x00000010 > #define BRCFG_PCIE_RX_MSG_FILTER 0x00000020 > > @@ -128,6 +129,7 @@ > #define NWL_ECAM_VALUE_DEFAULT 12 > > #define CFG_DMA_REG_BAR GENMASK(2, 0) > +#define CFG_PCIE_CACHE GENMASK(7, 0) > > #define INT_PCI_MSI_NR (2 * 32) > > @@ -675,6 +677,12 @@ static int nwl_pcie_bridge_init(struct nwl_pcie *pcie) > nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK, > BRCFG_PCIE_RX_MSG_FILTER); > > + /* This routes the PCIe DMA traffic to go through CCI path */ > + if (of_dma_is_coherent(dev->of_node)) { > + nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, BRCFG_PCIE_RX1) | > + CFG_PCIE_CACHE, BRCFG_PCIE_RX1); > + } > + > err = nwl_wait_for_link(pcie); > if (err) > return err; > -- > 2.7.4 >
> [+cc Rob] > > s/coherenct/coherent/ in subject > s/traffic/DMA/ (this applies specifically to DMA, not to MMIO) > > On Thu, Jan 21, 2021 at 03:29:16PM +0530, Bharat Kumar Gogada wrote: > > - Add support for routing PCIe traffic coherently when Cache Coherent > > Interconnect(CCI) is enabled in the system. > > s/- Add/Add/ > s/Interconnect(CCI)/Interconnect (CCI)/ > Thanks Bjorn for corrections. Here is the CCI spec https://developer.arm.com/documentation/ddi0470/k/preface > Can you include a URL to a CCI spec? I'm not familiar with it. I guess this is > something upstream from the host bridge, i.e., between the CPU and the > host bridge, so it's outside the PCI domain? > > I'd like to mention the DT "dma-coherent" property in the commit log to > help connect this with the knob that controls it. Yes will add it. > > The "dma-coherent" property is mentioned several places in > Documentation/devicetree/bindings/pci/ (but not anything obviously related > to xilinx-nwl). Should it be moved to something like > Documentation/devicetree/bindings/pci/pci.txt to make it more generic? > I will update this property in documentation as optional property. Rob can confirm if this can be moved to generic. > > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com> > > --- > > drivers/pci/controller/pcie-xilinx-nwl.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c > > b/drivers/pci/controller/pcie-xilinx-nwl.c > > index 07e3666..08e06057 100644 > > --- a/drivers/pci/controller/pcie-xilinx-nwl.c > > +++ b/drivers/pci/controller/pcie-xilinx-nwl.c > > @@ -26,6 +26,7 @@ > > > > /* Bridge core config registers */ > > #define BRCFG_PCIE_RX0 0x00000000 > > +#define BRCFG_PCIE_RX1 0x00000004 > > #define BRCFG_INTERRUPT 0x00000010 > > #define BRCFG_PCIE_RX_MSG_FILTER 0x00000020 > > > > @@ -128,6 +129,7 @@ > > #define NWL_ECAM_VALUE_DEFAULT 12 > > > > #define CFG_DMA_REG_BAR GENMASK(2, 0) > > +#define CFG_PCIE_CACHE GENMASK(7, 0) > > > > #define INT_PCI_MSI_NR (2 * 32) > > > > @@ -675,6 +677,12 @@ static int nwl_pcie_bridge_init(struct nwl_pcie > *pcie) > > nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK, > > BRCFG_PCIE_RX_MSG_FILTER); > > > > + /* This routes the PCIe DMA traffic to go through CCI path */ > > + if (of_dma_is_coherent(dev->of_node)) { > > + nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, > BRCFG_PCIE_RX1) | > > + CFG_PCIE_CACHE, BRCFG_PCIE_RX1); > > + } > > + > > err = nwl_wait_for_link(pcie); > > if (err) > > return err; > > -- > > 2.7.4 > >
On Wed, Jan 27, 2021 at 05:03:12AM +0000, Bharat Kumar Gogada wrote: > > On Thu, Jan 21, 2021 at 03:29:16PM +0530, Bharat Kumar Gogada wrote: > Here is the CCI spec > https://developer.arm.com/documentation/ddi0470/k/preface I'm sure it was obvious, but please include this in the commit log as well. > > Can you include a URL to a CCI spec? I'm not familiar with it. I > > guess this is something upstream from the host bridge, i.e., > > between the CPU and the host bridge, so it's outside the PCI > > domain?
On Thu, Jan 21, 2021 at 10:28 AM Bjorn Helgaas <helgaas@kernel.org> wrote: > > [+cc Rob] > > s/coherenct/coherent/ in subject > s/traffic/DMA/ (this applies specifically to DMA, not to MMIO) > > On Thu, Jan 21, 2021 at 03:29:16PM +0530, Bharat Kumar Gogada wrote: > > - Add support for routing PCIe traffic coherently when > > Cache Coherent Interconnect(CCI) is enabled in the system. > > s/- Add/Add/ > s/Interconnect(CCI)/Interconnect (CCI)/ > > Can you include a URL to a CCI spec? I'm not familiar with it. I > guess this is something upstream from the host bridge, i.e., between > the CPU and the host bridge, so it's outside the PCI domain? > > I'd like to mention the DT "dma-coherent" property in the commit log > to help connect this with the knob that controls it. > > The "dma-coherent" property is mentioned several places in > Documentation/devicetree/bindings/pci/ (but not anything obviously > related to xilinx-nwl). Should it be moved to something like > Documentation/devicetree/bindings/pci/pci.txt to make it more generic? It is generic (beyond PCI), but needs to be documented as used in each PCI host binding. Don't need any more than 'dma-coherent: true'. > > > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com> > > --- > > drivers/pci/controller/pcie-xilinx-nwl.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c > > index 07e3666..08e06057 100644 > > --- a/drivers/pci/controller/pcie-xilinx-nwl.c > > +++ b/drivers/pci/controller/pcie-xilinx-nwl.c > > @@ -26,6 +26,7 @@ > > > > /* Bridge core config registers */ > > #define BRCFG_PCIE_RX0 0x00000000 > > +#define BRCFG_PCIE_RX1 0x00000004 > > #define BRCFG_INTERRUPT 0x00000010 > > #define BRCFG_PCIE_RX_MSG_FILTER 0x00000020 > > > > @@ -128,6 +129,7 @@ > > #define NWL_ECAM_VALUE_DEFAULT 12 > > > > #define CFG_DMA_REG_BAR GENMASK(2, 0) > > +#define CFG_PCIE_CACHE GENMASK(7, 0) > > > > #define INT_PCI_MSI_NR (2 * 32) > > > > @@ -675,6 +677,12 @@ static int nwl_pcie_bridge_init(struct nwl_pcie *pcie) > > nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK, > > BRCFG_PCIE_RX_MSG_FILTER); > > > > + /* This routes the PCIe DMA traffic to go through CCI path */ > > + if (of_dma_is_coherent(dev->of_node)) { > > + nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, BRCFG_PCIE_RX1) | > > + CFG_PCIE_CACHE, BRCFG_PCIE_RX1); > > + } > > + > > err = nwl_wait_for_link(pcie); > > if (err) > > return err; > > -- > > 2.7.4 > >
diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c index 07e3666..08e06057 100644 --- a/drivers/pci/controller/pcie-xilinx-nwl.c +++ b/drivers/pci/controller/pcie-xilinx-nwl.c @@ -26,6 +26,7 @@ /* Bridge core config registers */ #define BRCFG_PCIE_RX0 0x00000000 +#define BRCFG_PCIE_RX1 0x00000004 #define BRCFG_INTERRUPT 0x00000010 #define BRCFG_PCIE_RX_MSG_FILTER 0x00000020 @@ -128,6 +129,7 @@ #define NWL_ECAM_VALUE_DEFAULT 12 #define CFG_DMA_REG_BAR GENMASK(2, 0) +#define CFG_PCIE_CACHE GENMASK(7, 0) #define INT_PCI_MSI_NR (2 * 32) @@ -675,6 +677,12 @@ static int nwl_pcie_bridge_init(struct nwl_pcie *pcie) nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK, BRCFG_PCIE_RX_MSG_FILTER); + /* This routes the PCIe DMA traffic to go through CCI path */ + if (of_dma_is_coherent(dev->of_node)) { + nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, BRCFG_PCIE_RX1) | + CFG_PCIE_CACHE, BRCFG_PCIE_RX1); + } + err = nwl_wait_for_link(pcie); if (err) return err;
- Add support for routing PCIe traffic coherently when Cache Coherent Interconnect(CCI) is enabled in the system. Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com> --- drivers/pci/controller/pcie-xilinx-nwl.c | 8 ++++++++ 1 file changed, 8 insertions(+)