[PATCH v23 02/16] PCI: dwc: Add dw_pcie_link_set_max_link_width()

Yoshihiro Shimoda
2023-09-26T12:24:41Z

This is a preparation before adding the Max-Link-width capability
setup which would in its turn complete the max-link-width setup
procedure defined by Synopsys in the HW-manual.

Seeing there is a max-link-speed setup method defined in the DW PCIe
core driver it would be good to have a similar function for the link
width setup.

That's why we need to define a dedicated function first from already
implemented but incomplete link-width setting up code.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20230825093219.2685912-7-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
---
drivers/pci/controller/dwc/pcie-designware.c | 86 ++++++++++----------
1 file changed, 41 insertions(+), 45 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 1c1c7348972b..da4aba4aee62 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -732,6 +732,46 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen)

}

+static void dw_pcie_link_set_max_link_width(struct dw_pcie *pci, u32 num_lanes)
+{
+ u32 lwsc, plc;
+
+ if (!num_lanes)
+ return;
+
+ /* Set the number of lanes */
+ plc = dw_pcie_readl_dbi(pci, PCIE_PORT_LINK_CONTROL);
+ plc &= ~PORT_LINK_FAST_LINK_MODE;
+ plc &= ~PORT_LINK_MODE_MASK;
+
+ /* Set link width speed control register */
+ lwsc = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
+ lwsc &= ~PORT_LOGIC_LINK_WIDTH_MASK;
+ switch (num_lanes) {
+ case 1:
+ plc |= PORT_LINK_MODE_1_LANES;
+ lwsc |= PORT_LOGIC_LINK_WIDTH_1_LANES;
+ break;
+ case 2:
+ plc |= PORT_LINK_MODE_2_LANES;
+ lwsc |= PORT_LOGIC_LINK_WIDTH_2_LANES;
+ break;
+ case 4:
+ plc |= PORT_LINK_MODE_4_LANES;
+ lwsc |= PORT_LOGIC_LINK_WIDTH_4_LANES;
+ break;
+ case 8:
+ plc |= PORT_LINK_MODE_8_LANES;
+ lwsc |= PORT_LOGIC_LINK_WIDTH_8_LANES;
+ break;
+ default:
+ dev_err(pci->dev, "num-lanes %u: invalid value\n", num_lanes);
+ return;
+ }
+ dw_pcie_writel_dbi(pci, PCIE_PORT_LINK_CONTROL, plc);
+ dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, lwsc);
+}
+
void dw_pcie_iatu_detect(struct dw_pcie *pci)
{
int max_region, ob, ib;
@@ -1013,49 +1053,5 @@ void dw_pcie_setup(struct dw_pcie *pci)
val |= PORT_LINK_DLL_LINK_EN;
dw_pcie_writel_dbi(pci, PCIE_PORT_LINK_CONTROL, val);

- if (!pci->num_lanes) {
- dev_dbg(pci->dev, "Using h/w default number of lanes\n");
- return;
- }
-
- /* Set the number of lanes */
- val &= ~PORT_LINK_FAST_LINK_MODE;
- val &= ~PORT_LINK_MODE_MASK;
- switch (pci->num_lanes) {
- case 1:
- val |= PORT_LINK_MODE_1_LANES;
- break;
- case 2:
- val |= PORT_LINK_MODE_2_LANES;
- break;
- case 4:
- val |= PORT_LINK_MODE_4_LANES;
- break;
- case 8:
- val |= PORT_LINK_MODE_8_LANES;
- break;
- default:
- dev_err(pci->dev, "num-lanes %u: invalid value\n", pci->num_lanes);
- return;
- }
- dw_pcie_writel_dbi(pci, PCIE_PORT_LINK_CONTROL, val);
-
- /* Set link width speed control register */
- val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
- val &= ~PORT_LOGIC_LINK_WIDTH_MASK;
- switch (pci->num_lanes) {
- case 1:
- val |= PORT_LOGIC_LINK_WIDTH_1_LANES;
- break;
- case 2:
- val |= PORT_LOGIC_LINK_WIDTH_2_LANES;
- break;
- case 4:
- val |= PORT_LOGIC_LINK_WIDTH_4_LANES;
- break;
- case 8:
- val |= PORT_LOGIC_LINK_WIDTH_8_LANES;
- break;
- }
- dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
+ dw_pcie_link_set_max_link_width(pci, pci->num_lanes);
}
--
2.25.1