linux-kernel - [PATCH 3/3] PCI: uniphier-ep: Add EPC restart management support

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Message-Id: <1601614127-13837-4-git-send-email-hayashi.kunihiko@socionext.com>
Date:   Fri,  2 Oct 2020 13:48:47 +0900
From:   Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Kishon Vijay Abraham I <kishon@...com>
Cc:     linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Subject: [PATCH 3/3] PCI: uniphier-ep: Add EPC restart management support

Set the polling function and call the init function to enable EPC restart
management. The polling function detects that the bus-reset signal is a
rising edge.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
---
 drivers/pci/controller/dwc/Kconfig            |  1 +
 drivers/pci/controller/dwc/pcie-uniphier-ep.c | 34 +++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index bc04986..4932095 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -296,6 +296,7 @@ config PCIE_UNIPHIER_EP
 	depends on OF && HAS_IOMEM
 	depends on PCI_ENDPOINT
 	select PCIE_DW_EP
+	select PCI_ENDPOINT_RESTART
 	help
 	  Say Y here if you want PCIe endpoint controller support on
 	  UniPhier SoCs. This driver supports Pro5 SoC.
diff --git a/drivers/pci/controller/dwc/pcie-uniphier-ep.c b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
index 1483559..bd187b1 100644
--- a/drivers/pci/controller/dwc/pcie-uniphier-ep.c
+++ b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
@@ -26,6 +26,7 @@
 #define PCL_RSTCTRL_PIPE3		BIT(0)
 
 #define PCL_RSTCTRL1			0x0020
+#define PCL_RSTCTRL_PERST_MON		BIT(16)
 #define PCL_RSTCTRL_PERST		BIT(0)
 
 #define PCL_RSTCTRL2			0x0024
@@ -60,6 +61,7 @@ struct uniphier_pcie_ep_priv {
 	struct clk *clk, *clk_gio;
 	struct reset_control *rst, *rst_gio;
 	struct phy *phy;
+	bool bus_reset_status;
 	const struct pci_epc_features *features;
 };
 
@@ -218,6 +220,23 @@ static const struct dw_pcie_ep_ops uniphier_pcie_ep_ops = {
 	.get_features = uniphier_pcie_get_features,
 };
 
+static bool uniphier_pcie_ep_poll_reset(void *data)
+{
+	struct uniphier_pcie_ep_priv *priv = data;
+	bool ret, status;
+
+	if (!priv)
+		return false;
+
+	status = !(readl(priv->base + PCL_RSTCTRL1) & PCL_RSTCTRL_PERST_MON);
+
+	/* return true if the rising edge of bus reset is detected */
+	ret = !!(status == false && priv->bus_reset_status == true);
+	priv->bus_reset_status = status;
+
+	return ret;
+}
+
 static int uniphier_add_pcie_ep(struct uniphier_pcie_ep_priv *priv,
 				struct platform_device *pdev)
 {
@@ -241,10 +260,21 @@ static int uniphier_add_pcie_ep(struct uniphier_pcie_ep_priv *priv,
 	ep->addr_size = resource_size(res);
 
 	ret = dw_pcie_ep_init(ep);
-	if (ret)
+	if (ret) {
 		dev_err(dev, "Failed to initialize endpoint (%d)\n", ret);
+		return ret;
+	}
 
-	return ret;
+	/* Set up epc-restart thread */
+	pci_epc_restart_register_poll_func(ep->epc,
+					    uniphier_pcie_ep_poll_reset, priv);
+	/* With call of poll_reset() directly, initialize internal state */
+	uniphier_pcie_ep_poll_reset(priv);
+	ret = pci_epc_restart_init(ep->epc);
+	if (ret)
+		dev_err(dev, "Failed to initialize epc-restart (%d)\n", ret);
+
+	return 0;
 }
 
 static int uniphier_pcie_ep_enable(struct uniphier_pcie_ep_priv *priv)
-- 
2.7.4