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| author | AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> | 2024-11-04 12:49:35 +0100 |
|---|---|---|
| committer | Krzysztof Wilczyński <kwilczynski@kernel.org> | 2024-11-06 19:57:26 +0000 |
| commit | b609a15e7969d6a50d65067ee783b5d9365b04dd (patch) | |
| tree | 6df49c9216e2d00f192315d69761faa3a876a59e /drivers/pci/controller | |
| parent | ade7da14954a5d1003ceb316a230189c445ba357 (diff) | |
| download | linux-b609a15e7969d6a50d65067ee783b5d9365b04dd.tar.gz linux-b609a15e7969d6a50d65067ee783b5d9365b04dd.tar.bz2 linux-b609a15e7969d6a50d65067ee783b5d9365b04dd.zip | |
PCI: mediatek-gen3: Add support for restricting link width
Add support for restricting the port's link width by specifying
the num-lanes devicetree property in the PCIe node.
The setting is done in the GEN_SETTINGS register (in the driver
named as PCIE_SETTING_REG), where each set bit in [11:8] activates
a set of lanes (from bits 11 to 8 respectively, x16/x8/x4/x2).
Link: https://lore.kernel.org/r/20241104114935.172908-3-angelogioacchino.delregno@collabora.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Fei Shao <fshao@chromium.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Diffstat (limited to 'drivers/pci/controller')
| -rw-r--r-- | drivers/pci/controller/pcie-mediatek-gen3.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 1d208d58e94a..bbfbfe5752e6 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -32,6 +32,7 @@ #define PCIE_BASE_CFG_SPEED GENMASK(15, 8) #define PCIE_SETTING_REG 0x80 +#define PCIE_SETTING_LINK_WIDTH GENMASK(11, 8) #define PCIE_SETTING_GEN_SUPPORT GENMASK(14, 12) #define PCIE_PCI_IDS_1 0x9c #define PCI_CLASS(class) (class << 8) @@ -168,6 +169,7 @@ struct mtk_msi_set { * @clks: PCIe clocks * @num_clks: PCIe clocks count for this port * @max_link_speed: Maximum link speed (PCIe Gen) for this port + * @num_lanes: Number of PCIe lanes for this port * @irq: PCIe controller interrupt number * @saved_irq_state: IRQ enable state saved at suspend time * @irq_lock: lock protecting IRQ register access @@ -189,6 +191,7 @@ struct mtk_gen3_pcie { struct clk_bulk_data *clks; int num_clks; u8 max_link_speed; + u8 num_lanes; int irq; u32 saved_irq_state; @@ -401,6 +404,14 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie) val |= FIELD_PREP(PCIE_SETTING_GEN_SUPPORT, GENMASK(pcie->max_link_speed - 2, 0)); } + if (pcie->num_lanes) { + val &= ~PCIE_SETTING_LINK_WIDTH; + + /* Zero means one lane, each bit activates x2/x4/x8/x16 */ + if (pcie->num_lanes > 1) + val |= FIELD_PREP(PCIE_SETTING_LINK_WIDTH, + GENMASK(fls(pcie->num_lanes >> 2), 0)); + }; writel_relaxed(val, pcie->base + PCIE_SETTING_REG); /* Set Link Control 2 (LNKCTL2) speed restriction, if any */ @@ -838,6 +849,7 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie) struct device *dev = pcie->dev; struct platform_device *pdev = to_platform_device(dev); struct resource *regs; + u32 num_lanes; regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); if (!regs) @@ -883,6 +895,14 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie) return pcie->num_clks; } + ret = of_property_read_u32(dev->of_node, "num-lanes", &num_lanes); + if (ret == 0) { + if (num_lanes == 0 || num_lanes > 16 || (num_lanes != 1 && num_lanes % 2)) + dev_warn(dev, "invalid num-lanes, using controller defaults\n"); + else + pcie->num_lanes = num_lanes; + } + return 0; } |