| Message ID | 20230426045557.3613826-12-yoshihiro.shimoda.uh@renesas.com |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: rcar-gen4: Add R-Car Gen4 PCIe support | expand |
On Wed, Apr 26, 2023 at 01:55:47PM +0900, Yoshihiro Shimoda wrote: > Add dw_pcie_link_set_max_cap_width() to set PCI_EXP_LNKCAP_MLW. > In accordance with the DW PCIe RC/EP HW manuals [1,2,3,...] aside with > the PORT_LINK_CTRL_OFF.LINK_CAPABLE and GEN2_CTRL_OFF.NUM_OF_LANES[8:0] > field there is another one which needs to be updated. It's > LINK_CAPABILITIES_REG.PCIE_CAP_MAX_LINK_WIDTH. If it isn't done at > the very least the maximum link-width capability CSR won't expose > the actual maximum capability. > > [1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, > Version 4.60a, March 2015, p.1032 > [2] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, > Version 4.70a, March 2016, p.1065 > [3] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, > Version 4.90a, March 2016, p.1057 > ... > [X] DesignWare Cores PCI Express Controller Databook - DWC PCIe Endpoint, > Version 5.40a, March 2019, p.1396 > [X+1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, > Version 5.40a, March 2019, p.1266 > > The commit description is suggested by Serge Semin. > > Suggested-by: Serge Semin <fancer.lancer@gmail.com> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> > --- > drivers/pci/controller/dwc/pcie-designware.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > index f8926d5ec422..bdc5ebd7cd5f 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.c > +++ b/drivers/pci/controller/dwc/pcie-designware.c > @@ -737,6 +737,21 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen) > dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, cap | link_speed); > } > > +static void dw_pcie_link_set_max_cap_width(struct dw_pcie *pci, int num_lanes) > +{ > + u32 val; > + u8 cap; > + > + if (!num_lanes) > + return; > + > + cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); > + val = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP); > + val &= ~PCI_EXP_LNKCAP_MLW; > + val |= num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT; > + dw_pcie_writel_dbi(pci, cap + PCI_EXP_LNKCAP, val); > +} Just move the function body to dw_pcie_link_set_max_link_width() thus the later method will be as coherent as possible. Also note the duplicated code can be dropped from the pcie-tegra194.c driver. Please submit an additional cleanup patch so the Tegra driver author would have it reviewed. -Serge(y) > + > static void dw_pcie_link_set_max_width(struct dw_pcie *pci, u32 num_lanes) > { > u32 val; > @@ -1074,6 +1089,7 @@ void dw_pcie_setup(struct dw_pcie *pci) > dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, val); > } > > + dw_pcie_link_set_max_cap_width(pci, pci->num_lanes); > dw_pcie_link_set_max_width(pci, pci->num_lanes); > dw_pcie_link_set_max_link_width(pci, pci->num_lanes); > } > -- > 2.25.1 >
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index f8926d5ec422..bdc5ebd7cd5f 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -737,6 +737,21 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen) dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, cap | link_speed); } +static void dw_pcie_link_set_max_cap_width(struct dw_pcie *pci, int num_lanes) +{ + u32 val; + u8 cap; + + if (!num_lanes) + return; + + cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + val = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP); + val &= ~PCI_EXP_LNKCAP_MLW; + val |= num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT; + dw_pcie_writel_dbi(pci, cap + PCI_EXP_LNKCAP, val); +} + static void dw_pcie_link_set_max_width(struct dw_pcie *pci, u32 num_lanes) { u32 val; @@ -1074,6 +1089,7 @@ void dw_pcie_setup(struct dw_pcie *pci) dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, val); } + dw_pcie_link_set_max_cap_width(pci, pci->num_lanes); dw_pcie_link_set_max_width(pci, pci->num_lanes); dw_pcie_link_set_max_link_width(pci, pci->num_lanes); }
Add dw_pcie_link_set_max_cap_width() to set PCI_EXP_LNKCAP_MLW. In accordance with the DW PCIe RC/EP HW manuals [1,2,3,...] aside with the PORT_LINK_CTRL_OFF.LINK_CAPABLE and GEN2_CTRL_OFF.NUM_OF_LANES[8:0] field there is another one which needs to be updated. It's LINK_CAPABILITIES_REG.PCIE_CAP_MAX_LINK_WIDTH. If it isn't done at the very least the maximum link-width capability CSR won't expose the actual maximum capability. [1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.60a, March 2015, p.1032 [2] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.70a, March 2016, p.1065 [3] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.90a, March 2016, p.1057 ... [X] DesignWare Cores PCI Express Controller Databook - DWC PCIe Endpoint, Version 5.40a, March 2019, p.1396 [X+1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 5.40a, March 2019, p.1266 The commit description is suggested by Serge Semin. Suggested-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> --- drivers/pci/controller/dwc/pcie-designware.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)