PCI: dwc: Move link handling into common code

All the DWC drivers do link setup and checks at roughly the same time.
Let's use the existing .start_link() hook (currently only used in EP
mode) and move the link handling to the core code.

The behavior for a link down was inconsistent as some drivers would fail
probe in that case while others succeed. Let's standardize this to
succeed as there are usecases where devices (and the link) appear later
even without hotplug. For example, a reconfigured FPGA device.

Link: https://lore.kernel.org/r/20201105211159.1814485-11-robh@kernel.org
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Yue Wang <yue.wang@Amlogic.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Xiaowei Song <songxiaowei@hisilicon.com>
Cc: Binghui Wang <wangbinghui@hisilicon.com>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: Pratyush Anand <pratyush.anand@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-omap@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-kernel@axis.com
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-tegra@vger.kernel.org

1 files changed, 16 insertions, 18 deletions

diff --git a/drivers/pci/controller/dwc/pcie-histb.c b/drivers/pci/controller/dwc/pcie-histb.c
index 777e24902afb..ece544165059 100644
--- a/drivers/pci/controller/dwc/pcie-histb.c
+++ b/drivers/pci/controller/dwc/pcie-histb.c
@@ -169,39 +169,36 @@ static int histb_pcie_link_up(struct dw_pcie *pci)
 	return 0;
 }
 
-static int histb_pcie_establish_link(struct pcie_port *pp)
+static int histb_pcie_start_link(struct dw_pcie *pci)
 {
-	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct histb_pcie *hipcie = to_histb_pcie(pci);
 	u32 regval;
 
-	if (dw_pcie_link_up(pci)) {
-		dev_info(pci->dev, "Link already up\n");
-		return 0;
-	}
-
-	/* PCIe RC work mode */
-	regval = histb_pcie_readl(hipcie, PCIE_SYS_CTRL0);
-	regval &= ~PCIE_DEVICE_TYPE_MASK;
-	regval |= PCIE_WM_RC;
-	histb_pcie_writel(hipcie, PCIE_SYS_CTRL0, regval);
-
-	/* setup root complex */
-	dw_pcie_setup_rc(pp);
-
 	/* assert LTSSM enable */
 	regval = histb_pcie_readl(hipcie, PCIE_SYS_CTRL7);
 	regval |= PCIE_APP_LTSSM_ENABLE;
 	histb_pcie_writel(hipcie, PCIE_SYS_CTRL7, regval);
 
-	return dw_pcie_wait_for_link(pci);
+	return 0;
 }
 
 static int histb_pcie_host_init(struct pcie_port *pp)
 {
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct histb_pcie *hipcie = to_histb_pcie(pci);
+	u32 regval;
+
 	pp->bridge->ops = &histb_pci_ops;
 
-	histb_pcie_establish_link(pp);
+	/* PCIe RC work mode */
+	regval = histb_pcie_readl(hipcie, PCIE_SYS_CTRL0);
+	regval &= ~PCIE_DEVICE_TYPE_MASK;
+	regval |= PCIE_WM_RC;
+	histb_pcie_writel(hipcie, PCIE_SYS_CTRL0, regval);
+
+	/* setup root complex */
+	dw_pcie_setup_rc(pp);
+
 	dw_pcie_msi_init(pp);
 
 	return 0;
@@ -300,6 +297,7 @@ static const struct dw_pcie_ops dw_pcie_ops = {
 	.read_dbi = histb_pcie_read_dbi,
 	.write_dbi = histb_pcie_write_dbi,
 	.link_up = histb_pcie_link_up,
+	.start_link = histb_pcie_start_link,
 };
 
 static int histb_pcie_probe(struct platform_device *pdev)