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spf=pass smtp.mailfrom=angelogioacchino.delregno@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1722937724; s=zohomail; d=collabora.com; i=angelogioacchino.delregno@collabora.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=fjnwescS6RYWERrcmekhT5uZ+q6kP6WerdRasypvbyk=; b=T9bc55Z+YdQ/cPd4SbKweMbmkQo6w4HjTzSrQGBF+F57IXOQ1prVYnJwa4PqDoB1 maH2M6XHPKgZ/jQ1+XNZrUUd84JKhNqZ4Akl8rCmOSHzaMSSbfvMri3pY+FYakkRwfM cvh80wxXPBT79l6wB49yatp2ZEsy1+f4KOrwD/jg= Received: by mx.zohomail.com with SMTPS id 1722937722255263.116205413227; Tue, 6 Aug 2024 02:48:42 -0700 (PDT) From: AngeloGioacchino Del Regno To: linux-pci@vger.kernel.org Cc: ryder.lee@mediatek.com, jianjun.wang@mediatek.com, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@collabora.com Subject: [PATCH 2/2] PCI: mediatek-gen3: Add support for restricting link width Date: Tue, 6 Aug 2024 11:48:16 +0200 Message-ID: <20240806094816.92137-3-angelogioacchino.delregno@collabora.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240806094816.92137-1-angelogioacchino.delregno@collabora.com> References: <20240806094816.92137-1-angelogioacchino.delregno@collabora.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ZohoMailClient: External 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). Signed-off-by: AngeloGioacchino Del Regno --- drivers/pci/controller/pcie-mediatek-gen3.c | 22 ++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 905dc635ead3..5eaa4d1376a7 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -29,6 +29,7 @@ #define PCIE_BASE_CFG_SPEED_MASK GENMASK(15, 8) #define PCIE_SETTING_REG 0x80 +#define PCIE_SETTING_LINK_WIDTH GENMASK(11, 8) #define PCIE_SETTING_GEN_SUPPORT_MASK GENMASK(14, 12) #define PCIE_PCI_IDS_1 0x9c #define PCI_CLASS(class) (class << 8) @@ -131,6 +132,7 @@ 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 @@ -151,6 +153,7 @@ 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; @@ -350,7 +353,7 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie) int err; u32 val; - /* Set as RC mode and set controller PCIe Gen speed restriction, if any */ + /* Set as RC mode and set controller PCIe Gen speed/lanes restriction, if any */ val = readl_relaxed(pcie->base + PCIE_SETTING_REG); val |= PCIE_RC_MODE; if (pcie->max_link_speed) { @@ -361,6 +364,14 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie) val |= FIELD_PREP(PCIE_SETTING_GEN_SUPPORT_MASK, 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(pcie->num_lanes >> 1, 0)); + }; writel_relaxed(val, pcie->base + PCIE_SETTING_REG); /* Set Link Control 2 (LNKCTL2) speed restriction, if any */ @@ -804,6 +815,7 @@ 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; int ret; regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); @@ -850,6 +862,14 @@ 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; }