[PATCH v7 2/4] PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed
From: Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.linaro.org@kernel.org>
Date: 2024-09-11 15:26:30
Also in:
b4-sent, imx, linux-arm-msm, linux-pci, linux-renesas-soc, linux-tegra, lkml
Subsystem:
pci driver for synopsys designware, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Jingoo Han, Manivannan Sadhasivam, Lorenzo Pieralisi, Krzysztof Wilczyński, Bjorn Helgaas, Linus Torvalds
From: Manivannan Sadhasivam <redacted> Currently, dw_pcie::max_link_speed has a valid value only if the controller driver restricts the maximum link speed in the driver or if the platform does so in the devicetree using the 'max-link-speed' property. But having the maximum supported link speed of the platform would be helpful for the vendor drivers to configure any link specific settings. So in the case of non-valid value in dw_pcie::max_link_speed, just cache the hardware default value from Link Capability register. While at it, let's also remove the 'max_link_speed' argument to the dw_pcie_link_set_max_speed() function since the value can be retrieved within the function. Reviewed-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Frank Li <Frank.Li@nxp.com> Tested-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Manivannan Sadhasivam <redacted> --- drivers/pci/controller/dwc/pcie-designware.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 86c49ba097c6..7c4e316eb749 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c@@ -687,16 +687,27 @@ void dw_pcie_upconfig_setup(struct dw_pcie *pci) } EXPORT_SYMBOL_GPL(dw_pcie_upconfig_setup); -static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 max_link_speed) +static void dw_pcie_link_set_max_speed(struct dw_pcie *pci) { u32 cap, ctrl2, link_speed; u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); cap = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP); + + /* + * Even if the platform doesn't want to limit the maximum link speed, + * just cache the hardware default value so that the vendor drivers can + * use it to do any link specific configuration. + */ + if (pci->max_link_speed < 1) { + pci->max_link_speed = FIELD_GET(PCI_EXP_LNKCAP_SLS, cap); + return; + } + ctrl2 = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCTL2); ctrl2 &= ~PCI_EXP_LNKCTL2_TLS; - switch (pcie_link_speed[max_link_speed]) { + switch (pcie_link_speed[pci->max_link_speed]) { case PCIE_SPEED_2_5GT: link_speed = PCI_EXP_LNKCTL2_TLS_2_5GT; break;
@@ -1058,8 +1069,7 @@ void dw_pcie_setup(struct dw_pcie *pci) { u32 val; - if (pci->max_link_speed > 0) - dw_pcie_link_set_max_speed(pci, pci->max_link_speed); + dw_pcie_link_set_max_speed(pci); /* Configure Gen1 N_FTS */ if (pci->n_fts[0]) {
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2.25.1