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, 17 insertions, 22 deletions

diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c
index 13901f359a41..dd2926bbb901 100644
--- a/drivers/pci/controller/dwc/pcie-armada8k.c
+++ b/drivers/pci/controller/dwc/pcie-armada8k.c
@@ -154,10 +154,24 @@ static int armada8k_pcie_link_up(struct dw_pcie *pci)
 	return 0;
 }
 
-static void armada8k_pcie_establish_link(struct armada8k_pcie *pcie)
+static int armada8k_pcie_start_link(struct dw_pcie *pci)
+{
+	u32 reg;
+
+	/* Start LTSSM */
+	reg = dw_pcie_readl_dbi(pci, PCIE_GLOBAL_CONTROL_REG);
+	reg |= PCIE_APP_LTSSM_EN;
+	dw_pcie_writel_dbi(pci, PCIE_GLOBAL_CONTROL_REG, reg);
+
+	return 0;
+}
+
+static int armada8k_pcie_host_init(struct pcie_port *pp)
 {
-	struct dw_pcie *pci = pcie->pci;
 	u32 reg;
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+
+	dw_pcie_setup_rc(pp);
 
 	if (!dw_pcie_link_up(pci)) {
 		/* Disable LTSSM state machine to enable configuration */
@@ -193,26 +207,6 @@ static void armada8k_pcie_establish_link(struct armada8k_pcie *pcie)
 	       PCIE_INT_C_ASSERT_MASK | PCIE_INT_D_ASSERT_MASK;
 	dw_pcie_writel_dbi(pci, PCIE_GLOBAL_INT_MASK1_REG, reg);
 
-	if (!dw_pcie_link_up(pci)) {
-		/* Configuration done. Start LTSSM */
-		reg = dw_pcie_readl_dbi(pci, PCIE_GLOBAL_CONTROL_REG);
-		reg |= PCIE_APP_LTSSM_EN;
-		dw_pcie_writel_dbi(pci, PCIE_GLOBAL_CONTROL_REG, reg);
-	}
-
-	/* Wait until the link becomes active again */
-	if (dw_pcie_wait_for_link(pci))
-		dev_err(pci->dev, "Link not up after reconfiguration\n");
-}
-
-static int armada8k_pcie_host_init(struct pcie_port *pp)
-{
-	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	struct armada8k_pcie *pcie = to_armada8k_pcie(pci);
-
-	dw_pcie_setup_rc(pp);
-	armada8k_pcie_establish_link(pcie);
-
 	return 0;
 }
 
@@ -269,6 +263,7 @@ static int armada8k_add_pcie_port(struct armada8k_pcie *pcie,
 
 static const struct dw_pcie_ops dw_pcie_ops = {
 	.link_up = armada8k_pcie_link_up,
+	.start_link = armada8k_pcie_start_link,
 };
 
 static int armada8k_pcie_probe(struct platform_device *pdev)